Univerzitet u Zenici

University of Zenica Bosnia and Herzegovina

FAKULTET ZA METALURGIJU I MATERIJALE FACULTY OF METALLURGY AND MATERIALS SCIENCE

FACHHOCHSCHULE GELSENKIRCHEN Gelsenkirchen

Germany

VII Naučno/stručni simpozijum sa međunarodnim učešćem

7th Scientific/Research Symposium

with International Participation

METALNI I NEMETALNI MATERIJALI proizvodnja – osobine – primjena

METALLIC AND NONMETALLIC MATERIALS

production – properties – application

KNJIGA ABSTRAKTA sa elektronskim izdanjem Zbornika radova BOOK OF ABSTRACTS with electronic edition of Proceedings

Zenica, Maj 2008.

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UREDNIK/EDITOR Dr Fuad Begovac IZDAVAČ/PUBLISHER Univerzitet u Zenici Organizaciona jedinica Fakultet za metalurgiju i materijale Travnička cesta 1, 72000 Zenica Tel: ++ 387 401 831, 402 832, Fax: ++ 387 406 903 KOMPJUTERSKA OBRADA TEKSTA TECHNICAL ASSISTANCE AND DTP Mr Hasan Avdušinović Mr Adnan Mujkanović Mr Almaida Gigović-Gekić Dr Diana Ćubela ŠTAMPA/PRINTED BY TIRAŽ/ISSUE: 200 primjeraka/copies

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ZAHVALNICA Organizacioni odbor VII Naučno/stručnog simpozijuma sa

međunarodnim učešćem pod nazivom „METALNI I

NEMETALNI MATERIJALI“ zahvaljuje se:

Ministarstvu energije, rudarstva i industrije FBiH

Ministarstvu razvoja, poduzetništva i obrta FBiH

Ministarstvu obrazovanja i nauke FBiH

Ministarstvu privredeZE-DO kantona,

BH Telecomu,

MAN+HUMMELU BA, D.D. Tešanj

RENACONU, autorizirani zastupnik tvrtke

PANalytical, Zagreb

Fabrici glinice „Birač“ AD Zvornik

Meisteru d.o.o Tuzla

Scholzu d.o.o Zenica

Sarajevo Osiguranju, podružnica Zenica

na ukazanom povjerenju i finansijskoj pomoći. Zahvaljajući vama uspjeli smo da organizujemo Simpozijum koji je od izuzetne važnosti za nas. Hvala!

Zenica, maj 2008.

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VII Naučno/stručni simpozijum sa međunarodnim učešćem „Metalni i nemetalni materijali“, Zenica, BiH, 22. – 23. maj 2008.

ORGANIZACIONI ODBOR / ORGANIZING COMMITTEE

Dr Fuad Begovac, President (BiH)

Dr Sybille Planitz-Penno, Co-president (Germany) M. Sc Hasan Avdušinović, secretary (BiH)

M.Sc. Almaida Gigović-Gekić, technical secretary (BiH) M.Sc. Adnan Mujkanović, technical secretary (BiH)

Dr Sulejman Muhamedagić (BiH) Dr Mediha Šestić (BiH)

Dr Darko Petković (BiH) Dr Aida Mahmutović (BiH) Dr Jusuf Duraković (BiH)

Dr Diana Ćubela (BiH) Dr Waltraut Brandl (Germany)

Dr Holger Frenz (Germany)

NAUČNI ODBOR INTERNATIONAL SCIENTIFIC/RESEARCH COMMITTEE

Dr Izet Kubat, President (BiH)

Dr Abdulah Ahmić (BiH) Dr Ivan Anžel (Slovenia) Dr Fuad Begovac (BiH) Dr Ana Beroš (BiH) Dr Suada Bikić (BiH) DrWaltraut Brandl (Germany) Dr Safet Brdarević (BiH) Dr Zijah Burzić (Serbia) Dr Scott Chumbley (USA) Dr Emilio Chirone (Italy) Dr Ranko Cvijić (BiH) Dr Diana Ćubela (BiH) Dr Kemal Delijić (CG) Dr Slavko Dolinžek (Slovenia) Dr Sulejman Drljević (BiH) Dr Jusuf Duraković (BiH) Dr Mehmed Durman (Turkey) Dr Nusreta Džonlagić (BiH) Dr Sabahudin Ekinović (BiH) Dr Mladen Franko (Slovenia) Dr Isabel Fernandez (Spain) DrHolger Frenz (Germany) Dr David dela Fuente (Spain) Dr Ahmet Hadžipašić (BiH) Dr Jiri Havrda (Bohemia) Dr Antonio Herrero (Spain) Dr Goetz Hessling (Germany)

Dr Janko Hodolič (Serbia) Dr Salim Ibrahimefendić (BiH) Dr Damir Kakaš (Serbia) Dr Dušan Kičević (Serbia) Dr Mirko Komatina (Serbia) Dr Borut Kosec (Slovenia) Dr Azra Kurtović (BiH) Dr Jakob Lamut (Slovenia) Dr Urška Lavrenčić Štangrar (Slovenia) Dr Dragica Lazić (BiH) Dr Aida Mahmutović (BiH) Dr Ilija Mamuzić (Croatia) Dr Mitar Mišović (CG) Dr Jožef Medved (Slovenia) Dr Aziz Mujezinović (BiH) Dr Sulejman Muhamedagić (BiH) Dr Mustafa Omanović (BiH) Dr Mirsada Oruč (BiH) Dr Milinko Ostojić (BiH) Dr Jose Parreno (Spain) Dr Zakir Pašalić (BiH) Dr Sead Pašić (BiH) Dr Zijad Pašić (BiH) Dr Dimitrios Panias (Greece) Dr Blagoje Pavlovski (Macedonia)

Dr Sibylle Planitz-Penno (Germany) Dr Petar Petrovski (BiH) Dr Alan Russell (USA) Dr Asim Sadibašić (Serbia)) Dr Senaid Salihović (BiH) Dr Dieter Senk (Germany) Dr Cayetano Sierra (Spain) Dr Jovan Sredojević (BiH) Dr Sead Spužić (Australia ) Dr Srećko Stopić (Germany) Dr Kemal Subašić (BiH) Dr Mediha Šestić (BiH) Dr Sreto Tomašević (BiH) Dr Milan Tomljanović (BiH) Dr Stefano Tornincasa (Italy) Dr Polonca Trebše (Slovenia) Dr Radomir Turk (Slovenia) Dr Faik Uzunović (BiH) Dr Joran Velikonja (Canada) Dr Ivan Vitez (Croatia) Dr Tatjana Volkov-Husović (Serbia) Dr Dušan Vukojević (BiH) Dr Miodrag Zlokolica (Serbia) Dr Izet Žigić (BiH) Dr Senay Yalcin (Turkey)

VII Naučno stručni simpozijum sa međunarodnim učešćem „Metalni i nemetalni materijali“, Zenica, BiH, 22. – 23. maj 2008.

SADRŽAJ/CONTENTS

stranica/page

UVODNA PREDAVANJA/KEYNOTES PAPERS 1. Materials and Sustainable Development

Jakob Lamut (Slovenia).....................................................................................3

2. Polymer Composites Reinforced with Plasma Functionalized VGCNFS Valentin Chirila (Germany).............................................................................13

3. The Use of Proficiency Test Results in the Development Process of International Standards Holger Frenz, Stefan Wieler (Germany).........................................................23

4. Production and Properties of Non-Veneered Wood Based Panels Sergej Medved (Slovenia) ................................................................................31

SEKCIJA METALNI MATERIJALI/SESSION METALLIC MATERIALS 1. Hemizam i kinetika hlorovanja bakar(I)-sulfida u sistemu Cu2S-CaCl2-O2

Chemism and Kinetic of the Chlorination of Copper(I) Sulphide in the Cu2S-CaCl2-O2 Branislav Marković, Miroslav Sokić, Vladislav Matković .............................47

2. Luženje halkopirita iz kompleksnog sulfidnog koncentrata sumpornom kiselinom i natrijum-nitratom Leaching of Copyrite from Complex Sulphide Concentrate Using Sulphuric Acid and Sodium Nitrate Miroslav Sokić, Branislav Marković, Vladislav Matković .............................48

3. Oksidaciono luženje Pb-Zn-Cu-Fe sulfidnog koncentrata na povišenom pritisku Pressure Oxidative Leaching of Pb-Zn-Cu-Fe Sulphide Concentrate Vladislav Matković, Miroslav Sokić, Branislav Marković .............................49

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4. Rezultati izučavanja primene vazduha obogaćenog kiseonikom u procesu prženja bakarnih koncentrata u fluosolid reaktoru Test Results of Use the Oxygen Reached Air in the Copper Concentrate Roasting Process in Fluosolid Reactor Milorad Ćirković, Vlastimir Trujić, Milanče Mitovski ...................................50

5. Određivanje sadržaja alumogetita u boksitu različitim metodama Determination of Alumogoethite Content in Bauxite with Different Methods D. Lazić, J. Penavin-Škundrić, Z. Popović, Lj. Vasiljević, G. Ostojić ...........51

6. Uticaj kaustičnog odnosa autoklavne pulpe na stabilnost autoklavnog mulja Influence of Caustic Ratio of Autoclave Pulp on Stability of Autoclave Mud D. Lazić, B. Škundrić, J. Penavin-Škundrić, Lj. Vasiljević, S. Sladojević, Z. Popović .........................................................................................................52

7. Proizvodnja bakra i cinkoksida u procesu prerade bakarnog otpada Production of Copper and Zinc Oxide in the process of Brass Scrap Recycling Aleksandra Ivanović, Ana Kostov, Milorad Ćirković, Mile Bugarin .............53

8. Uticaj načina dovoda kisika na izdvajanje mangana procesom oksidacije iz tečnog metala The Influence of Way of Oxygen Introduction on Separation of Manganese by Oxydation Process from Hot Metal Pihura Derviš, Oruč Mirsada, Lamut Jakob ..................................................54

9. Povećanje sadržaja dušika direktnim nitriranjem austenitnog nehrđajućeg čelika The Increase of Nitrogen Content by Direct Nitriding of Austenitising Stainless Steel Derviš Pihura, Mirsada Oruč, Arif Salkić, Milan Rimac...............................55

10. Primena procesa „Direct Metal Laser Sintering, (DMLS) u preciznom livenju The Application of Direct Metal Laser Sintering (DMLS) in Investment Casting Aleksandar Rajić, Slobodan Stojadinović .......................................................56

11. Direktno legiranje čelika postupkom injektiranja Mn ruda Direct Alloying of Steel by Mn Ore Injection Mensur Arifaj, Aida Mahmutović ...................................................................57

12. Poboljšanje energetske efikasnosti korišćenjem sekundarne toplotne energije u metalurgiji bakra Improvement of Energetic Efficiency Using the Secondary Heat Energy in Copper Metallurgy Milanče Mitovski, Aleksandra Mitovski, Milorad Ćirković ...........................58

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13. Europski trendovi u upotrebi prerađenih čeličanskih troski European Trends in Utilisation of Treated Steel Slags Aida Mahmutović, Sulejman Muhamedagić, Anida Mešić, Edina Horoz, Nermin Mujezinović, Nermin Gluhić, Vedad Karić .......................................59

14. Utjecaj alkalija na redukciju primarnih troski The Influence of the Alkalis on the Course of the Reduction of Primary Slag Mihael Tolar, Jakob Lamut, Matjaž Knap......................................................60

15. Termodinamičko ispitivanje sistema Ti-Al-Fe upotrebom FACTSAGE programa Thermodynamic Investigation of the Ti-Al-Fe System using FACTSAGE Software Ana Kostov, Bernd Friedrich, Dragana Živković ...........................................61

16. Ispitivanje termodinamičkih, strukturnih i nekih fizičkih karakteristika Bi-Ga-Sn legura Investigation of Thermodynamic, Structural and Some Physical Charasteristics of Bi-Ga-Sn Alloys D. Živković, I. Katayama, D. Manasijević, R. Novaković, L. Gomidželović ..62

17. Eksperimentalna ispitivanja i termodinamički proračun Pb-In-Sb ternernog sistema Experimental Study and Thermodinamic Calculation of Pb-In-Sb Ternery System D. Minić, A. Aljilji, I. Dervišević, D. Manasijević, D. Živković......................63

18. Eksperimentalna ispitivanja i termodinamički proračun Bi-Sb-Zn ravnotežnog faznog sistema Experimental Study and Thermodynamic Calculation Bi-Sb-Zn Phase Equilibrium System Aljiljia, I. Derviševića, J. Đokić, D. Minića, dr D. Manasijević ....................64

19. Istraživanje stabilnosti amorfnosti binarnog sistema Zr62Ni38 posmatranjem ovisnosti magnetske susceptibilnosti o temperaturi Research of the Stability States Amorphous of the Binary Zr62Ni38 System Trough the magnetic Susceptibility as a Function of Temperature Suada Bikić, Diana Ćubela, Almaida Gigović-Gekić, Suada Sulejmanović, Nusret Bajrović, Tatjana Mihać..............................................65

20. Termalna stabilnost i kristalizacija amorfnog Ni36,5Zr63,5 Thermal Stability and Chrystallization of Amorphous Ni36,5Zr63,5 Suada Sulejmanović, Suada Bikić, Tatjana Mihać, Izet Gazdić ....................66

21. Ductile Rare Earth Intermetallic Compounds Alan M. Russell ................................................................................................67

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22. Legura CuNiAlSiCr-uspešna zamena za berilijumske bronze u području elektrotehnike i proizvodnje alata CuNiAlSiCr Alloy-Succesful Substitution for Berillium Bronzes in the Field of Electrical Engineering and Production Tools Todorović Radiša, Todorović Ljubinka...........................................................68

23. Processing Analysis and Control of Galvanized Sheets Vehbi Ramaj, Bajrush Bytyqi, Hysni Osmani, Gazmend Gashi, Jorgaq Kacani, Klodian Dhoska..................................................................................69

24. Microstructural Characterisation of Metastabile Metalic Materials Ivan Anžel.........................................................................................................70

25. Mogućnost dobijanja kompozitnih materijala sa osnovom od legure ZnAl25Cu3 uz dodatak čestica ojačivača ZrO2 i grafita primenom kompokasting postupka Possibility of Obtaining Composite Based of ZnAl25Cu3 Alloy, Containing ZrO2 and Graphite Reinforcement particles by Compcasting Method Sandra Kastelec-Macura, Zagorka S. Aćimović-Pavlović, Ilija Bobić, Ljubiša D. Andrić.............................................................................................71

26. Development of Cu-C Composite Microstructure Rebeka Rudolf, Ivan Anžel, Borut Kosec........................................................72

27. Kompozitni čelik-SiC kao materijal otporan na habanje Steel-SiC Cast in Carbide Composites as Wear Resistance Material Dejan Čikara, Marko Rakin, Deana Čikara-Anić, Milan Simić....................73

28. Optimizacija hemijskog sastava austenitnog nehrđajućeg čelika Nitronic 60 u cilju sprečavanja nastanka δ ferita Optimisation of Chemical Composition Austenitic Stainless Steel Nitronic 60 with Aim of Prevention δ Ferrite Formation Omer Beganović, Branka Muminović.............................................................74

29. Istraživanje uticaja tehnologije izrade i legirajućih elemenata na osobine superlegure na bazi željeza-A286 Research of Influence of making Technology and Alloying Elements on Characteristics of Superalloy Based on Iron-A286 Belma Fakić, Emina Kratina...........................................................................75

30. Razvoj novih metalnih materijala za potrebe savremenih tehnologija Metallic Materials Development for Advanced Technologies Mirsada Oruč, Milenko Rimac........................................................................76

31. Characterisation of Cu-Al-Ni Shape Memory Alloys M. Gojić, P. Matković, T. Matković, I. Anžel, A.C. Kneissl, M. Bizjak, B. Kosec.................................................................................................................77

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32. Phase Field Simulation of Grain Growth in Two-Dimensional System According to MICRESS Software Siniša Ćatović, Aida Mahmutović ...................................................................78

33. Proces degradacije mikrostrukture materijala i uticaj na osobine u termoenergetskim postrojenjima u toku dugotrajne eksploatacije na povišenim temperaturama The Process of the Materials Microstructure Degradation and Its Influence on Properties in the Power Plant Components in Long Time Exposure to Elevated Temperature in Expolatation (POSTER) Emina Kratina, Belma Fakić, Armin Husika .................................................79

34. Influence of Deformation on the Phase Transformations of DP Steels Đogić Melisa, Aida Mahmutović .....................................................................80

35. Cementacija metanolom i acetonom u dubinskoj peći preduzeća TRD Vareš Cementation with Methanol and Acetone in Pit Furnace of Company TRD Vareš Jusuf Duraković, Fuad Begovac, Diana Ćubela ............................................81

36. Uticaj sastava i parametara obrade na mehanička svojstva polufabrikata niskolegiranih AlMgSi legura The Effect of Composition and Treatment Parameters on the Mechanical Properties of the Semiproducts of Lowalloyed AlMgSi Alloys Slobodan Stojadinović, Nikola Bajić...............................................................82

37. Heat Treatment of Cold Formed Steel Forgings Borut Kosec, Milan Bizjak, Matjaž Breziger, Grozdan Kosec........................83

38. Tehnologije indukcionog zagrijavanja metalnih materijala Metal Materils Induction heating Technologies Branko Petrič ...................................................................................................84

39. Predviđanje prokaljivosti različitih čelika na osnovu kemijskog sastava The Prediction of Vareous Steel Grades Hardenability on the Basis of Their Chemical Composition Matjaž Knap, Jakob Lamut, Jan Falkus, Alojz Rozman, Martin Debelak....85

40. Effect of Fe/Si Ratio and Thermo-Mechanical Processing of Twin Roll Cast Strips on the Mechanical and Corrosion Properties of Some Al-Fe-Si Sheets Kemal Delijić ....................................................................................................86

41. Razvoj uređaja za kalibraciju čelične trake i izradu punjene žice za MAG postupak zavarivanja Development of a Device for Calibration of Steel Strip and Manufacturing Cored Wire for the MAG Welding Process Nikola Bajić, Milan Čekerevac, Slobodan Stojadinović, Marko Rakin.........87

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42. Navarivanje u širokom sloju pod praškom sa punjenom žicom cilindričnih delova Surfacing with Broad Coating using Powder with Cored Wire of Cylindrical Parts Nikola Bajić, Marko Rakin, Predrag Karić, Dragan Anastasijević ...............88

43. Svojstva austenitnog čelika AISI321 nakon zavarivanja TIG postupkom Properties of Austenitic Steel ASI321 After Welding with TIG Procedure Mirko Gojić, Stjepan Kožuh, Ladislav Kosec, Damir Pinotić ........................89

44. Uticaj sastava obloge elektroda na sadržaj nemetalnih uključaka u šavu niskolegiranih čelika Effects of Electrode Coating Structure on Content of Non-Metallic Inclusions in Low-Alloy Steel Weld Ž. Blečić, D. Blečić, D. Čabarkapa, D. Martinović.........................................90

45. Navarivanje brodskog propelernog vratila On the Welding of Propeller Ship Crankshaft Fuad Begovac, Derviš Pihura, Saud Beganović.............................................91

46. Welding Repair of Bearing Housing of Gear Box Main Wheel SRS 470 (power 400kw) Gazmend Gashi, Bajrush Bytyqi, Hysni Osmani............................................92

47. Određivanje preostalog zamornog vijeka Fatigue life prediction Nedeljko Vukojević, Dušan Vukojević, Ahmet Hadžipašić, Mujo Šutković ..93

48. Radna dinamička čvrstoća čelika Č4732 za definisan oblik spektra radnih napona Working Dynamic Strength of Steel Č4732 for Defined Form of Workload Spectrum Mustafa Imamović, Abas Manđuka ................................................................94

49. Characterization of Iron Oxide Layers on Electromagnetic Sheets Using Auger Electron Spectroscopy Milan Bizjak, Ladislav Kosec, Janez Kovač, Petar Panjan............................95

50. Comparison of Mechanical Properties of the 32CrMoV12-28 Hot Work Tool Steel Alloyed with WC, VC and TAC Powder Using HPDL Laser l.A. Dobrzanski, K. Labisz, A. Klimpel ............................................................96

51. Ispitivanje nehrđajućih čelika na piting koroziju Estimating oh Non-Corrosion Steels Against to Pitting Corrosion Sead Ćatić, Amra Odobašić, Husejin Keran...................................................97

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52. Istraživanje utjecaja dodatka fosforne kiseline pri pripremi paste na karakteristike pozitivne elektrode olovnih elektroda A Researching of Phosporic Acid Supplement Influence While Paste Preparing on Positive Electrode Feature of the Lead Batteries Nurudin Avdić ..................................................................................................98

53. Utjecaj oblika repromaterijala na izdržljivost i vijek trajanja proizvoda Impact of the Shape of Semi Manufactured Material in Durability and Sustainability of the Product Bajrush Bytyqi, Hysni Osmani, Gazmend Gashi, Vehbi Ramaj ....................99

54. Metal-Forming Production of Innovative Components from Metal Powders Bernd-Arno Behrens, Edin Gaštan, Fabian Lange......................................100

55. Research of Application Iron Powder AHC 100.29 for Metal Foams Production by SRFS Process Diana Ćubela, Almaida Gigović-Gekić .........................................................101

SEKCIJA NEMETALNI MATERIJALI/SESSION NONMETALLIC MATERIALS 1. Thermal Shock Testing of Silicon Carbide / Cordierite Composite Material

Using Nondestructive Methods Milica Posarac, Tatjana Volkov–Husović, Marija Dimitrijević, Branko Matović, Jelena Majstorović, Karlo Raić ......................................................105

2. High-Temperature Concretes, Effect of Porosity and Phase-Content on Its Mechanical Properties Anja Terzić, Ljubica Pavlović, Tatjana Volkov-Husović, Zagorka Radojević ........................................................................................................106

3. Promjene optičkih osobina u nemetalnim nano-filmovima Changes of the Optical Properties in Non-Metalic Nanostructured Films Siniša Vučenović, Dragoljub Mirjanić, Blanka Škipina, Jovan Šetrajčić, Svetlana Pelemiš ............................................................................................107

4. Apsorpcione karakteristike ultratankih nemetalnih film-struktura Apsorption Characteristics of Ultrathin Nonmetallic Film-Structures Siniša Vučenović, Svetlana Pelemiš, Dragoljub Lj. Mirjanić, Blanka Škipina, Jovan P. Šetrajčić ............................................................................108

5. Kinetika i mehanizam procesa oksidacije prirodnog minerala galenita Kinetics and Mechanism of Oxidation Process of Natural Mineral Galena Dragana Živković, Nada Štrbac, Ivan Mihajlović, Živan Živković, Velibor Andrić .............................................................................................................109

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6. Keramička polimineralna glina “Sočkovac” korektivna i alternativna sirovina u proizvodnji portland-cementa Ceramic Semi-Mineral Clay “Sočkovac” Corrective and Alternative Raw Material In Production Process of Portland-Cement Amir Baraković, Petar C. Katanić, Džemal Mandžić, Damir Baraković.....110

7. Kalcijum sulfat kao premazni pigment Calcium Sulphat Used As A Pigment Coat S. Ibrahimefendić, M. Stanić, A. Budimlić, S. Hotić....................................111

8. Termalna obrada La0.7Ca0.3FeO3+∆ perovskita mikrovalnom iradijacijom Thermal Processing of La0.7Ca0.3FeO3+∆ Perovskite by Microwave Irradiation Saša Zeljković, Jelena Penavin – Škundrić, Slavica Sladojević, Toni Ivas.112

9. Uticaj sastava i strukture Zeolita na njegove adsorpcione karakteristike Effect of Composition and Structure of Zeolite on Its Adsorption Characteristics S. Sladojević, J. Penavin-Škundrić, B. Škundrić, D. Lazić, S. Krnetić, S. Vujasinović, S. Zeljković................................................................................113

10. Karakterizacija glina lokaliteta Čavka za proizvodnju crijepa Clay Characterization of Deposit Čavka for Roofing Tile Production Marina Jovanović .........................................................................................114

11. Destruktivne i nedestruktivne metode ispitivanja materijala kod zidanih konstrukcija Destructive and Non-Destructive Investigations Methods of Materials in Masonry Structures Amir Čaušević, Nerman Rustempašić, Milorad Skoko ................................115

12. Praćenje karbonatizacije portlandita u betonu metodom rentgenske difrakcije Investigation of Portlandite Carbonation in Concrete by X-Ray Diffraction Farzet Bikić, Petar Petrovski, Mirsada Rizvanović, Merzuk Cacan, Dina Pozderović ......................................................................................................116

13. Influence of Air Entraining Agent on Bond Improvement in Cementitious Mortars Reinforced with Continuous Carbon Filaments Andrej Ivanič, Samo Lubej, Ivan Anžel ........................................................117

14. Preparation of Raw Mixture for Clinker Production with Alternative Materials Zehrudin Osmanović, Dina Pozderović, Amira Cipurković, Sead Ćatić .....118

15. The Properties of Mortars Modified by Polymers and Reinforced by Polypropylene Fibres Samo Lubej, Andrej Ivanič, Ivan Anžel ........................................................119

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16. Dobijanje i svojstva keramičkih premaza na bazi kordijerita, mogućnosti i efekti primene u livarstvu Obtaining and Properties of the Ceramic Coatings Based on Cordierite, Possibility and Effects on the Application in Foundry Zagorka S. Aćimović-Pavlović, Ljubiša D. Andrić .......................................120

17. Uloga materijala za toplotnu zaštitu u zgradama The Role of Materials in Building Warmth Protection Neal Bijedić, Amira Salihbegović..................................................................121

18. Vakumirani izolacioni paneli Vacuum Insulation Panels Amira Salihbegović, Neal Bijedić..................................................................122

19. Sirovinski potencijali Tuzlanske regije za proizvodnju ambalažnog stakla Raw Materials Potentials of Tuzla Region for Production Of Container Glass Zijad Pašić, Adnan Ibrahimović....................................................................123

20. Proizvodnja magnezitnih kupela i glinenih lonaca za kupelacionu analizu zlata Hard Magnesite Cupels and Burned Clay Crucibles Production for Fire Assaying Analyses Ljubiša Mišić ..................................................................................................124

21. Mogućnost proizvodnje alkalno oplemenjenog bentonita Ljubiša Andrić, Vladimir Živanović, Asim Gradinčić, Miroslav Glušac, Mladen Grahovac...........................................................................................125

22. Mineraloško-petrografski sastav gline ležišta „Obrijež“ kod Bijeljine Mineralogical-Petrographic Composition of Clay Deposit „Obrijež“ near Bijeljina Amra Hamzabegović, Milan Stević, Jasmina Hadžić...................................126

23. Pillars Rezistance at ,,Trepca” Mine Ismet M. Ibishi ...............................................................................................127

24. Uticaj masenog udjela čeličnih vlakana na žilavost betona The Influence of Steel Fibres Dosage on Concrete Toughness Adnan Mujkanović, Muhamed Pašić, Zijad Pašić .......................................128

25. Mogućnost proizvodnje cementa sa dodatkom krečnjaka tipa CEM II/A – Ll 42,5 u Tvornici cementa Kakanj Possibility of Production of Portland Limestone Cement Type CEM II/A - Ll 42,5 in Cementplant Kakanj Nevzet Merdić, Nedžad Haračić, Mirsada Rizvanović,Petar Petrovski, Ilhan Bušatlić.................................................................................................129

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26. Polymers -Modified Grades Offer Greatly Improved Toughness Nedžad Repčić ................................................................................................130

27. Raspored napona u drvenim adhezivnim spojevima Stress Distribution In Wooden Adhesive Joints Seid Hajdarević ..............................................................................................131

28. Ispitivanje adsorpcione efikasnosti domaćih adsorbenata u procesu rafinaciju hidrokrekovanih baznih ulja Investigation of Adsorption Effectiveness of Domestic Adsorbents in the Process of Refining Hydrocracked Basic Oils Zoran Petrović, Tatjana Botić, Pero Dugić, Mirko Petković .......................132

29. Korištenje drvnih otpadaka u proizvodnji celuloze i papira Usage of Wood Waste in Cellulose and Paper Production S. Ibrahimefendić, M. Stanić, A. Budimlić ...................................................133

30. Dynamical Analysis of Ligno-Cellulose Plates with Numerical and Analytical Methods Mariana D. Stanciu, Ioan Curtu ...................................................................134

SEKCIJA EKOLOGIJA I ODRŽIVI RAZVOJI/SESSION ECOLOGY AND SUSTAINABLE DEVELOPMENTS

1. Uzroci kontaminacije vode u cjevovodnim sistemima Causes of Water Contamination at Pipelines Systems Ifet Šišić, Damir Hrnjica ...............................................................................137

2. Zaštita okoliša pri odlaganju čvrstog otpada na sanitarne deponije Environmental Protection Related to Solid Waste Disposal on the Sanitary Landfills Amra Serdarević ............................................................................................138

3. Napušteni kopovi i ekološka problematika općine Vareš Abandoned Excavation Sites and Ecological Problem of Vares Municipality Ramo Kurtanović, Nermina Omerhodžić, Sabit Begić .................................139

4. Dimenzioniranje taložnika putem eksperimentalnih ispitivanja sedimentacije Dimensioning of Dib Hole through Experimental Sedimentation Testing Ifet Šišić, Samira Hotić ..................................................................................140

5. Jonska izmjena – efikasan postupak izdvajanja hroma iz štavnih otpadnih voda Ion Exchange – Efficient Method of Chromium Recovery from Tanning Wastewater Ljiljana Vukić, Milorad Maksimović, Petar Gvero.......................................141

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6. Reinženjering i inovacije u funkciji čiste proizvodnje Reengineering and Inovation in Function of Cleaner Production Krsto Mijanović, Zoran Petrović ...................................................................142

7. Voltametrijsko određivanje teških metala u tlu Voltammetric Determination of Heavy Metals in Soil Sead Ćatić, Amra Odobašić, Husejin Keran ................................................143

8. Planiranje i zaštita od voda jezera Modrac Planning and Protection from Modrac Lake Water Dinka Pašić-Škripić, Izet Žigić, Jakub Pištoljević ........................................144

9. Ekološki problemi održivog razvoja ruralnih područja Ecological Problems of Sustainable Development of Rural Areas Edin Ramić.....................................................................................................145

10. Ugroženost podzemnih voda kod izgradnje i eksploatacije saobraćajnica Endangering Underground Water during Construction and Exploitations of Roads Dinka Pašić-Škripić, Izet Žigić ......................................................................146

11. Inženjering, poslovanje i zaštita životne sredine Engineering, Management and Environmental Protection Veljko N. Đukić ..............................................................................................147

12. Hemijska koagulacija i DAF flotacija industrijskih otpadnih voda Chemical Treatment and Dissolved Air Flotation of Industrial Wastewaters Veljko N. Đukić ..............................................................................................148

13. Značaj reciklaže starih automobila i aparata bijele tehnike za zaštitu okoliša iz procesa proizvodnje čelika u elektrolučnoj peći Importance of Recycling Old Cars and Hausehold Activities for Environment Protection from Steel Production in Electric Arc Furnace Jovan Sredojević, Huseinspahić Majda i Ibrić Sanel...................................149

14. Sistemi i tehnologije za selekciju, sortiranje i recikliranje plastike Systems and Technologies for Plastic Selection, Separation and Recycling Tijana Đurić, Igor Budak, Janko Hodolič, Aco Antić..................................150

15. Zaštita okoliša kod pokretanja integralne proizvodnje u Arcelor Mittal Zenica Environment Protection by Starting the Integral Production in Arcelor Mittal Zenica Šefket Goletić .................................................................................................151

16. Indikatori održivosti razvoja sa akcentom na energijske indikatore Sustainable Development Indicators with Review of Energy Indicators Nafija Šehić- Mušić, Ajla Mušić ..................................................................152

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17. Energijski audit i okolinski upravljački sistemi Energy Audit and Environmental Management Systems Nafija Šehić- Mušić, Lejla Sadiković ............................................................153

SEKCIJA ZAKONSKA REGULATIVA I STANDARDIZACIJAI/SESSION LEGISLATIVE AND STANDARDIZATION 1. Europska tehnička regulativa relevantna za drvoprerađivačku industriju

European Technical Regulation Related to Wood Processing Industry Ismar Alagić ...................................................................................................157

2. Obavezni zahtjevi kvaliteta za OEM dobavljače u automobilskoj industriji The Mandatory Quality Requirements for OEM’s Suppliers in Automotive Industry Ismar Alagić ...................................................................................................158

3. Expression the Uncertainty of Measurement Results in the Process of Tests and Measurements Klodian Dhoska, Jorgaq Kacani, Vehbi Ramaj............................................159

4. Osvrt na evropski predstandard PRENV 13381-3: Metode ispitivanja za određivanje doprinosa vatrootpornosti konstruktivnih elemenata: Dio 3: Primjenjena zaštita betonskih elemenata Comments on European Prestandard 13381-3: Test Methods for Determining the Contribution to the Fire Resistance of Structural Members Part 3: Applied Protection to Concrete Members Sanin Džidić ...................................................................................................160

5. Vrste i oznake konstrukcijskih čelika prema novoj europskoj normi Grades and Designations of Structural Steels by New European Standard Ivan Vitez, Dragomir Krumes, Vladimir Pecić, Mirsada Oruč, Božo Madunić .........................................................................................................161

6. Some Aspects of Terminology in Materials Related Knowledge Sharing Sead Spuzic, Ke Xing, Kazem Abhary...........................................................162

7. Uvođenje europskih normi u građevinskom konstrukterstvu. Primjer Euro code 8 Application of European Standards in Structural Engineering. Example Euro code 8 Mustafa Hrasnica ..........................................................................................163

8. Zahtjevi za vrstom i kvalitetom materijala koji se primjenjuju u zidanim konstrukcijama prema Euro codu 6 Demands on Types and Quality of Materials for Masonry Structure According to Euro code 6 Amir Čaušević ................................................................................................164

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9. Evropski propisi za opremu pod pritiskom European Pressure Equipment Directive – PED Nedeljko Vukojević, Dušan Vukojević, Mujo Šutković, Zlatan Ištvanić .....165

10. Process Optimization Based on Fully Automated CMM Valerian Septimiu Stanciu, Mariana Domnica Stanciu, Stefan Dan, Ioan Curtu...............................................................................................................166

11. Sistem kvaliteta u rukovanju laserima u okviru bezbednosti i zdravlja na radu Quality System in Using Lasers in Health Safety Dragan Danelišen, Rade Biočanin................................................................167

12. Poboljšanje tačnosti mjerenja temperature korištenjem Pt 100 otpornih termometara Accurate Temperature Measurements Using Pt 100 Resistance Thermometers Edin Terzić .....................................................................................................168

13. XRF spektrometrija – metode pripreme i kalibracija uzoraka XRF Spectrometry – Methods of Sample Preparation and Calibration Nedžad Haračić, Ilhan Bušatlić, Nevzet Merdić, Hakim Haračić ...............169

14. Upravljanje rizikom i odlučivanje Risk-Management and Decision-Making Veljko N. Đukić ..............................................................................................170

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VII Naučno/stručni simpozij sa međunarodnim učešćem „METALNI I NEMETALNI MATERIJALI“ Zenica, BiH, 22. - 23. maj 2008

MATERIJALI I ODRŽIVI RAZVOJ

MATERIALS AND SUSTAINABLE DEVELOPMENT

Jakob Lamut

University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Materials and Metallurgy

Ljubljana, Slovenia

Keywords: steel, light materials, ceramics ABSTRACT Man or mankind, respectively, are closely associated with materials since ancient times. Economic development is still based on those metallic and ceramic materials that are the most abundant in the Earth crust. But also other elements are important and must be taken into consideration. Ključne riječi: čelik, laki metali, keramika REZIME Čovjek i čovječanstvo su sve od davnih vremena blisko povezani sa materijalima. Ekonomski razvoj i u modernom svijetu temelji se na metalnim i keramičkim materijalima koji su najčešći u zemaljskoj kori. Pri tome se ne smiju zaboraviti i drugih materijali koji su isto tako značajni. 1. INTRODUCTION Man or mankind, respectively, are closely associated with materials since ancient times. Based on experiences and observations during the process of their winning, working and use man has developed and improved their usable properties through millenia, though he was not acknowledged with their internal structure. Use of various research methods enabled him to learn later also the structure and microstructure of materials and their influence on usable properties. Materials had great influence on the development of engineering and technologies, and consequently this had influence also on the development of the societies. Development of various materials was associated with the wish that they served people and made their lives easier. Fig. 1 presents appoximate periods of the development of single materials in the last millenia. The oldest materials are stone and wood. They were essential in the first millenia of the settled mankind, and they are indispensable still today. The oldest synthetically manufactured material is the ceramics. The upper mentioned materials were followed by noble metals, bronze, glass, iron etc. Development and use of single material is not independant from the development of other materials. The development period is much wider and dependant on many parameters. Materials had always great importance in the development of mankind

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what was illustrated by the fact that various historic ages were named by materials, like Stone Age, Bronze Age, Iron Age.

Figure 1: Periods of development of single materials Development of various synthetically made materials also shows their importance, since they are in use many millenia, like stone and wood. Development of materials means changes of their usable properties and new manufacturing technologies. Burning the clay, i.e. sintering the aluminosilicates, means the beginning of pottery as the simplest ceramic technology. Forming of clayey materials enabled manufacturing various products as pots and other vessels, to use them as building material and to create artistic objects. Strength of dried clay was increased by added straw or tree branches and thus the first synthetic composites were made. When speaking about the sustainable development, Empodocles1 must be mentioned. He claimed that world was composed of four elements: air, water, fire, and Earth. Today all want to breathe clean air and drink good water. Essence of Earth was newly recognized with the exploitation of mineral resources and environmental impact problems due to emissions, and further as needed to assure sufficient amounts of healthy food. Fire reminds us on energy in wider sense. Modern development with industrial revolution started with invention of steam engine by J. Watt. S. Carnot described the essential fundaments of the cycle process and use of steam energy as driving force for machines. Table 1 gives the first ten elements of the Earth crust composition. Sum of the first ten elements that are the most abundant in the 16 km thick outer Earth crust represents 99.5 % of Earth crust composition. The rest of elements, like copper, nickel, zinc, tungsten, chromium, lead, manganese, etc represents the rest 0.5 % of the composition.

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Table 1: Distribution of elements in the Earth crust in mass %2

Oxygen 45.5 Magnesium 2.8 Silicon 27.2 Sodium 2.3 Aluminium 8.3 Potassium 1.8 Iron 6.2 Titanium 0.6 Calcium 4.7 Hydrogen 0.14

Elements of which the greatest part of the Earth crust is composed can be placed to various positions in the Period System. Since they are not in native state they must be extracted by various pyrometallurgical and other processes. Metals like Al, Si (semimetal), Cu, Mg, Na and Ti are in the group of light metals, since their density is below 5 kg/dm3. Amomg the solid elements in the Table 1 only iron represents heavy metals (7.87 kg/dm3). Metals and alloys, next to metallic oxides and other compounds, have important role in engineering and technological development of new materials. So we speak about important industrial production of metallic and non-metallic materials. 2. LIGHT METALS AND THEIR ALLOYS Silicon is used in metallurgy as ferrosilicon, FeSi, or elementary silicon (purity 98 to 99 %), as alloying element and deoxidizer for electrical steel, spring steel, and it is also an alloying element in the non-ferrous metallurgy, etc. Silicon is an important element in the development of semiconductors and for solar or photovoltaic cells. SiO2 is the most abundant inorganic compound in nature. Quarz is used as raw material for production of silicon or ferrosilicon, carborundum (SiC), and for making glass. Glass is the material that was known already in ancient times. SiO2 forms with alkalis low-melting point compounds and eutectics with glassy structure. As name itself indicates, light metals are applied as structural materials for structures with low mass. They are used as casting alloys, and as rolled and forged products.

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3. METALLURGICAL CERAMICS AND REFRACTORY MATERIALS Oxides as SiO2, Al2O3, CaO, MgO and their compounds are industrially important ceramic materials for manufacturing refractory materials and metallurgical ceramics. Refining slag in steelmaking are mainly composed of those oxides, as well as the blast-furnace slag.

Figure 2: Opened tetrahedron of the CaO-MgO-SiO2-Al2O3 Fig. 2 shows the opened tetrahedron of the CaO-MgO-SiO2-Al2O3 quaternary system. It is composed of four ternary systems. CaO-MgO-SiO2 forms the tetrahedron base, while CaO-SiO2-Al2O3, CaO-MgO-Al2O3, and MgO-SiO2-Al2O3 systems form side faces. Refining steel slag have compositions around the composition of gehlenite, 2CaO·Al2O3·SiO2, blast-furnace slag contain monticellite, CaO·MgO·SiO2, melilithe, 2CaO·Al2O3 – 2CaO·MgO·2SiO2, merwinite, 3CaO·MgO·2SiO2, and dicalciumsilicate, 2CaO·SiO2. Cement contains 2CaO·SiO2, 3CaO·SiO2, 3CaO·Al2O3, and 4CaO·Al2O3·Fe2O3. Basic refractory material is composed of CaO, MgO (calcium and magnesium oxide), and MgO (magnesium oxide). Silica and alumina refractory materials are: Al2O3 – corundum, 3Al2O3.2SiO2 – mullite, MgO.Al2O3 – spinell. Cordierite, 2MgO·2Al2O3·5SiO2, has very low expansion and it is resistant to temperature shocks. Properties of ceramic materials can be changed by additions of Cr2O3, ZrO2 or carbon. Single constituents are made by melting in electric arc furnaces or by sintering process. Sol-gel procedures are used for special purposes.

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4. IRON AND STEEL Iron is in the Earth crust the 4th most frequent element. Increased demand and production today can mean »steel age«. Increase of present production is similar to that when H. Bessemer introduced converter process of making liquid steel. After production explosion in the beginning of the second half of 20th century the production stabilized at 700 to 800 mio tons. The beginning of this century gave an impression that steel was newly discovered and production started to increase all over the world. Fig. 3 shows the production and consumption of steel in various parts of the world.

Figure 3: Production and consumption of steel4

Parallelly to the increased production of steel also the production of pig iron was increased. In the organizing aspect, the prognosis of L. Mittal in 1998 proved to be valid - the development is in the globalization of steel production. Majority in that period supposed that regional relations among producers will be prevailing. Consolidation of steel production enabled to increase means for development and new investments. In technological field, steelmaking is constantly reducing the energy comsumption per unit product. Figure 4 presents the reduction of coke consumption and thus indirectly also the emissions of CO2 (Fig. 5).

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Figure 4: Consumption of reducing agents and fuel in making pig iron5

Figure 5: Reduced emissions of CO26

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Various technological measures helped to reduce consumption of electrical energy and of electrodes and to increase the productivity in making steel in EAF (electric arc furnace) (Fig. 6).

Figure 6: Measures to increase the productivity in EAF5

Selection of suitable technological process has influence also on the emissions of CO2 (Fig. 7). For the EAF process it is also important how electric energy is generated.

Figure 7: Influence of technological process on the amount of generated CO26

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The three-component system on figure 8 indicates various possibilities for the iron- and steelmaking by using various reducing agents or processes, respectively. The aim of all these processes is to reduce the environmental load.

Figure 8: Standard and alternative processes in ironmaking7

Figure 9: Supposed future processes in steelmaking8

In spite of numerous examinations of alternative processes in steelmaking, blast furnace is supposed to play an important role in steelmaking (Fig. 9).

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Fig. 10 presents how the use of blast-furnace slag can help to reduce CO2 emissions in manufacturing cement. Blast-furnace slag has hydraulic properties therefore it is used in cement production.

Figure 10: CO2 emissions in making cement when blast-furnace slag is used9

Some countries are already experiencing lack of engineers since there was too small interest for studies of engineering and natural sciences in the past. Lack of engineers is felt in various industrial fields. The last data show that this deficiency increased in March to about 70 000 vacancies.

Figure 11: Number of vacancies for engineers4

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5. CONCLUSIONS Economic development is still based on those metallic and ceramic materials that are the most abundant in the Earth crust. Though these materials represent old economies, these economies are still solid ones. Other elements in small or very low quantities can essentially influence the development of structures and microstructures of materials and thus their usable properties. In steelmaking, the development program is directed towards ULCOS (ultra low CO2 steelmaking). Light metals are used when weight of structure must be low. High-strength steel for automotive industry means reduced fuel consumption of vehicles, and thus it indirectly influences the reduced environmental impact. Development of steel and of other metallic and non-metallic materials is important for the development of equipment for exploitation of renewable energy sources, e.g. wind. Yield of fossile fuels in thermal power stations is increased if temperature is increased to 700 oC. Steel and other metallic and non-metallic materials are also a part of modern nanomaterials. Competent professionals on all the levels are needed to achieve various development aims. References

1. A. Sovre: Predsokratiki, Slovenska matica, Ljubljana, 1988 2. H. Briehl: Chemie der Werkstoffe, B. G. Teubner, Stuttgart 1995 3. M. Merkel, K.-H. Thomas: Taschenbuch der Werkstoffe, Carl Hanser Verlag

München Wien, 2003 4. Stahl und Eisen, 127 (2007) No. 12, p. 7 5. Stahl und Eisen, 127 (2007) No. 11, p. 72 6. Stahl und Eisen, 123 (2003) No. 9, p. 70 7. Stahl und Eisen, 123 (2003) No. 9, p. 71 8. Stahl und Eisen, 123 (2003) No. 9, p. 71 9. Stahl und Eisen, 123 (2003) No. 8, p. 62

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VII Naučno/stručni simpozij sa međunarodnim učešćem „METALNI I NEMETALNI MATERIJALI“ Zenica, BiH, 22-23. maj 2008.

POLYMER COMPOSITES REINFORCED WITH PLASMA FUNCTIONALIZED VGCNFS

Valentin Chirila University of Applied Sciences Gelsenkirchen

Neidenburgerstr. 10, 45877, Gelsenkirchen Germany

Keywords: polymer composite, vapor grown carbon nanofibers, plasma functionalization ABSTRACT Polymer composites reinforced with different quantities of vapor grown carbon fibers (unfunctionalized and oxygen plasma functionalized) were prepared using extrusion – injection molding techniques and manual labor. The morphology and structure of the carbon nanofibers as well as the fiber–matrix interface were analyzed by scanning electron microscopy and transmitting electron microscopy. Tensile tests show that the composite containing functionalized fibers has a higher tensile strength than the composite containing unfunctionalized fibers while the thermal and electrical properties remain constant. 1. INTRODUCTION Vapor grown carbon nanofibers (VGCFs) are a relatively new type of reinforcement with significant commercial potential. This type of fibers is produced from the pyrolysis of a hydrocarbon gas, such as benzene and methane, in the presence of hydrogen at temperatures around 950 – 1200° C [1-6]. The fiber growth is initiated by ultra-fine transition metal catalyst particles, usually Fe, Co, Ni, deposited on a substrate (seeded catalyst method) or directly injected into the gas (floating catalyst method) [1]. Depending on the preparation conditions, the obtained VGCFs can have diameters between several tens of nanometers up to tens of microns and length from several microns up to many centimeters [4-6] The fibers – matrix interface in vapor grown carbon nanofibers reinforced composites plays an important role in controlling the mechanical properties and overall performance of composites [7]. Effective fillers require good bonding (chemical, mechanical and physical) between the fibers and the matrix [8-12]. The chemical bonds are the most important one. Chemical or physical treatments are applied to the carbon fibers or the polymer matrix in order to improve the fiber/matrix adhesion. Among the many available treatments applicable to the reinforcement materials, the plasma treatment (functionalization) has the advantage of being a modern technique capable to improve the functionalization degree of nanofibers in a short time [13-15]. In the present work the effect of the oxygen plasma parameters onto the wettability of vapor grown carbon nanofibers as well as the mechanical, electrical and thermal properties of the composites were determined.

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2. EXPERIMENTAL 2.1. Materials The vapor grown carbon nanofibers used in these experiments are GANF®1 from Grupo Antolin Ingineria S.A, Spain, with diameters 50-150 µm and length less than 80 µm. The polypropylene (PP) matrix used is P 9400 powder with diameters of 0.2-1 mm from Sabic Polyolefine GmbH. 2.2. Vapor grown carbon nanofibers characterisation The morphology and the structure of the fibers were studied by scanning electron microscopy (SEM – Philips, model XL 30 ESEM) and transmitting electron microscopy (TEM – Philips, model CM 200). 2.3. Oxygen plasma functionanlization The oxygen plasma functionalization was carried out in a plasma reactor from Plasma Finish model V 15-G, equipped with a rotary quartz barrel (rotational speed is 4 min-1) in order to ensure a homogenous functionalization. The fibers were exposed to a RF – generated oxygen plasma functionalization. The oxygen plasma parameters are optimized using statistical software based on the mathematical approach (Statgraphic). The main important considered parameters are: plasma power, treatment time, chamber pressure and oxygen flow rate. The plasma parameter limits are shown in Table 1.

Table 1 Plasma parameters and theirs limit Plasma Parameter Notation Minimum Maximum Units

Plasma Power A 50 220 W Treatment Time B 60 1200 sec

Oxygen Flow Rate C 60 200 ml/min Chamber pressure D 70 110 Pa

The most important aim of the oxygen plasma functionalization is to introduce functional groups (carboxylic, carbonylic and hydroxylic) on the outer fiber surface. These groups are able to produce strong chemical bonds at the interface VGCNFs/PP. The different degrees of surface functionalization (surface wettability) before and after oxygen plasma functionalization was determined by water contact angle measurements using an electronic balance from DataPhysics Instruments. The surface energy of the VGCFs was calculated according to Wendt-Ovens method. The increase of the fibers surface energy (especially the polar component), is a direct result of introducing polar functional groups onto fiber surface during the oxygen plasma functionalization. The surface energy has two important components: the dispersive component and the polar component. The latter component respectively the polar component is correlated with the amount of functional groups on the fiber surface [16]. 2.4. VGCNFs/Polymer composites and their properties The composites with different weight percent nanofibers (unfunctionalized and plasma functionalized) were manufactured in a co-rotating twin screw extruder from firma Berstorff, ZE 25. The samples necessary for the measurement of the mechanical, electrical and thermal properties were manufactured by injection molding machine from Klöckner Ferromatik Desma. Besides these composites, manual labor composites were manufactured (containing 5-, 10- and 20 wt.% unfuctionalized fibers). The tensile tests were performed using a tensile

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strength machine from Instron, model 5584 and Zwick, model 1120. The measurements for tensile strength were conducted according to EN ISO 527 – 1:1996, the shape of the samples was type 1A [17]. The thermal conductivity measurements were performed using a heat conductivity apparatus from NETZSCH, model TCT 416. The necessary samples for thermal conductivity measurement were cut in prismatic shape (4 × 5 × 20 mm) from dog bone samples (tensile samples). The samples were cut in two directions in respect of “dog bone” samples, see Figure 1.

b a

Figure 1 Dimensions and shape of the sample for thermal conductivity measurements (a) and cutting direction of the sample in respect injection moulding direction (b) The thermal stability of the composites was determined by thermogravimetrical measurements, TGA from PerkinElmer. The samples were heated in an oxidative atmosphere up to 800°C with a heating rate of 5°C/min and oxygen flow rate of 25ml/min. The electrical resistivity was measured at constant temperature in order to avoid the resistivity dependence of the temperature. Electrical resistivity measurements at room temperature (20°C ±1) were performed using a standard DC electrical resistance method. The method used for measurements of specific electrical resistivity is the constant voltage method. 3. RESULTS AND DISCUTION 3.1. Morphology and structure of the VGCNFs Figure 2 shows scanning electron and transmission electron micrographs of the vapour grown carbon nanofibers. The VGCNFs are characterised by a homogeneous diameter, Figure 2a. The carbon nanofibers have a herringbone structure around a void core region, Figure 2b, c. Also, it can be observed that the thickness of the fibers wall is small in comparison with the inner diameter. 3.2. Optimization of the oxygen plasma parameters The estimated effect of the plasma parameters (plasma power, treatment time, oxygen flow rate, chamber pressure) are shown in the Pareto chart, Figure 3. The Pareto chart is a specialized version of a histogram that ranks the categories in the chart from most important to least important parameter. This chart helps us to recognize which parameter or which combination of the parameters should be focused on, in order to obtain a high functionalization degree of the vapor grown carbon nanofibers. It can be seen that, the plasma power, treatment time and their square multiplication (plasma power – plasma power and treatment time – treatment time) have the higher influence in the optimization of VGCNFs functionalization. The chamber pressure in combination with plasma power and treatment time is the third important plasma parameters.

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a

b c

Figure 2 scanning electron (a), transmission electron micrographs (b) and schematic image(c) of the VGCNFs

Figure 3 Pareto Chart

The estimated response of the water contact angle depending on the main important plasma parameters (plasma power and treatment time) is plotted in Figure 4. A lower water contact angle can be obtained if a high plasma power is applied (higher than 120W), correlated with a

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long functionalization time. If the fibers are functionalized with an extremely higher plasma power (more than 160W) for a long time (longer than 10 minutes) the lowest contact angle can be reached (≈62°). But in this case the outer graphene layers of the fibers or more than these layers, respectively the complete fibers can be burned during the functionalization. This means, a high functionalization degree of the fibers can not be achieved without destruction of the fibers surface. In order to obtain a good functionalization degree without supplementary etching effect of the fibers, it is important to accord a full attention to the correlation between the plasma power and the treatment time.

Figure 4 Estimate response of the VGCNFs water contact angle depending on the plasma power and

treatment time 3.3. Analyses of the polypropylene composites containing VGCNFs 3.3.1. Morphology of composites The morphology in the cross section (fracture of the dog-bone samples under liquid nitrogen, -196°C) of the extrudated and injection-moulded PP composites with 5 wt.% unfunctionalized and plasma fuctionalized carbon nanofibers was studied by SEM, Figure 5. The presence of pulled out fibers proves a weak adhesion between PP and unfunctionalized fibers, Figure 5a. A better adhesion was observed in the cross section SEM-micrograph of the polypropylene composite containing 5 wt.% plasma functionalized fibers, Figure 5b. It can be observed how the polymer matrix covers the fibers (see arrows). Comparing the composite containing 5 wt.% unfunctionalized fibers (Figure 5a) with the composite containing 5 wt.% plasma functionalized fibers (Figure 5b), it can easily be observed how the pull out effect of the fibers was strongly reduced in the case of composite containing functionalized fibers.

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b a Figure 5: SEM – micrographs of the PP/VGCNF composites containing 5 wt.% unfunctionalized (a),

and oxygen plasma functionalized (b) fibers 3.3.2. Mechanical properties of the VGCNFs/PP composites In order to reduce the errors from the measurements of tensile properties, at least 7 samples for each series of composite were tested. The highest and the lowest value of the tensile properties were also eliminated and than the average value was calculated. Figure 6 shows the stress-strain curve for PP and PP composites containing 5wt.% unfunctionalized and plasma functionalized fibers. It can be observed that the plastic domain of the composites increased with approximate 22-25% compared with PP.

Figure 6 Stress-strain curves for PP and PP/VGCFs composites The results of the PP and composites containing 5 wt.% unfunctionalized and oxygen plasma functionalized fibers are presented in Table 2. The weak adhesion between fibers and matrix in the case of composites containing unfunctionalized fibers was proved from the values of tensile strength and can be correlated with the SEM micrographs in cross section of the composite. It can be observed that, a slight increase of the tensile strength of around 2% for the composite containing 5wt.% unfunctionalized fibers compared with the polypropylene

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occurred. The composite containing 5 wt.% plasma functionalized fibers present an increase of tensile strength up to 14% in comparison with PP and also an increase up to 11% compared with composite containing 5 unfunctionalized fibers. Table 2 Tensile strength of the PP and VGCNFs/PP composites

PP PP+5wt.% unfunctionalized PP+5wt.% plasma

functionalized Tensile Strength [MPa] 28.6 29.3 32.6

3.3.3. Thermal properties of the VGCNFs/PP composites The results of thermal conductivity of the PP and composites containing 5-, 10wt.% unfunctionalized and 5wt.% plasma functionalized VGCNFs are shown in Table 3. The thermal conductivity measured in injection molding direction increased with the increase of VGCNFs contents in composite. The thermal conductivity measured in cross injection molding direction of the composites remain constant regardless of the quantity of fibers, that means the fibers in cross injection molding direction do not make a conductive network. Between the composites containing 5 wt.% unfunctionalized and plasma functionalized were no significant differences. Table3 Thermal conductivity of the PP and VGCNFs/PP composites

Thermal conductivity PP

PP+5wt.% unfunctionalized

PP+10wt.% unfunctionalized

PP+5wt.% plasma functionalized

in injection molding direction 26.0 28.1 31.2 28.0

in cross injection molding direction 25.2 25.3 25.4 25.3

A comparison between polypropylene, polypropylene containing 5-, 10- and 20wt.% unfunctionalized fibers (manual labor manufactured) and vapor grown carbon nanofibers is presented in Figure 7. The thermal stability of the composite increased with the increase of the fibers contents in composites. The thermal stability of the composites containing unfunctionalized and plasma functionalized fibers shows no significant differences, see Figure 8. 3.3.4. Electrical properties of the VGCNFs/PP composites The electrical resistivity of the manual labor manufactured composites containing unfunctionalized fibers is presented in Figure 9. The volume electrical resistivity of the PP was taken from literature (ρ ≈ 1 × 1012 – 1014 Ωm). The composites containing 5 wt.% unfunctionalized fibers have already the volume electrical resistivity of 2.9 × 103 Ωm which is a decrease of ten orders of magnitude larger than that of the pure PP matrix. Increasing further the amount of VGCNFs in PP composite at 10 wt.% the volume electrical resistivity was decreased up to 6.4 Ωm. This may be ascribed primarily to the large aspect ratio of the conductive nanofibers. Percolation theory predicts that there is a critical concentration or percolation threshold at which a conductive path is formed in the composite, causing the material to convert from an insulator to a conductor. As the weight percentage is increased, the number of internanofiber connections increases and many conductive paths become available. The percolation threshold is reached when a conductive path of interconnected nanofibers is formed across the volume of the composite.

19

0

20

40

60

80

100

120

0 100 200 300 400 500 600 700 800 900

temperature, T [°C]

wei

ght l

oss,

[wt.%

]

PP PP+5wt.% GANF PP+10wt.% GANF PP+20wt.% GANF GANF

Figure 7 Thermal stability of the PP composite as a function of fibers contents

0

20

40

60

80

100

120

0 100 200 300 400 500 600 700 800 900

temperature, T [°C]

wei

ght l

oss,

[wt.%

]

untreated GANF fibres plasma treated GANF fibres

Figure 8 Thermal stability of the PP composite containing unfunctionalized and plasma

functionalized fibers The composites containing plasma functionalized fibers have almost the same electrical resistivity like the composite containing unfunctionalized fibers, see Table 4. A small difference in the electrical resistivity values is due the oxidation of fibers after plasma functionalization (the oxide interrupts the electrical flow). The injection molded composites containing 5 wt.% and even 10 wt.% unfunctionalized fibers were insulators. The fibers are very well dispersed and oriented in PP matrix after injection molding. This thing perhaps leads to the isolating of fibers in matrix and the fibers do not establish a conductive network.

20

PP

VGCNFs

PP + 10wt.% VGCNFs

PP + 5wt.% VGCNFs

Figure 9 Volume electrical resistivity of the PP composites containing VGCNFs

Table 4 Volume electrical resistivity of the PP composites containing unfunctionalized and oxygen plasma functionalized VGCNFs

PP + 5wt.% unfunctionalized VGCNFs PP + 5wt.%

functionalized VGCNFs Volume electrical resistivity

[�m] 3.2 X 103 8.1 X 103

4. CONCLUSION The adequacy of oxygen plasma functionalization to improve the wettability and the functionalization degree of the vapor grown carbon nanofibers has been demonstrated in the present researches. The importance of the plasma treatment parameters (plasma power, treatment time, oxygen flow rate, and chamber pressure) on the functionalization degree of the nanofibers was

21

determined using mathematical approach. The PARETO chart showed that the plasma power and the treatment time are the most important parameters. The mechanical properties of the composites containing plasma functionalized fibers were improved while the electrical and thermal properties remain constant in comparison with the composite containing unfunctionalized fibers. The thermal conductivity, thermal stability and electrical conductivity of the composites increase with the increase of the amount of fibres. 5. ACKNOWLEDGMENTS The authors thank to Mr. C. Merino from Grupo Antolin Ingenieria, Spain for providing the vapour grown carbon nanofibers and to W. Warschewski from Sabic Polyolefine GmbH, Germany for providing the polypropylene powder. 6. REFERENCES [1] Paredes JI, Matinez-Alonso A, Tascon JMD. Surface characterizstion of submicron vapor grown

carbon fibers by scanning tunneling microscopy. Carbon 2001; 39 (10): 1575-1587. [2] Endo M et al. Vapor-grown carbon fibers (VGCFs) Basic properties and their battery applications.

Carbon 2001; 39 (9): 1287-1297. [3] Chung DDL. Comparison of submicron-diameter carbon filaments and conventional carbon fibers

as fillers in composite materials. Carbon 2001; 39 (8): 1119-1125. [4] Cheol Jim Lee, Jeunghee Park. Growth and structure of carbon nanotubes produced by thermal

chemical vapor deposition. Carbon 2001; 39 (12): 1891-1896. [5] Maragoni R, Serp P, Feuer R, Kihn Y, Kalck P, Vahlas C. Carbon nanotubes produced by

substrate free metalorganic chemical vapor deposition of iron catalysts and ethylene. Carbon 2001; 39 (3): 443-449.

[6] Ci L, Wie J, Wie B, Liang J, Xu C, Wu D. Carbon nanofibers and single-walled carbon nanotubes prepared by the folating catalyst method. Carbon 2001; 39 (3): 329-335.

[7] Chung, D.D.L. (2003). Composite Materials: Science and Applications, Springer-Verlag, ISBN 1-85233-665-X, London

[8] Ajayan, P.M., Schadler, L.S., Braun, P.V. (2003). Nanocomposite Science and Technology, Willey-VCH Verlag, ISBN 3-527-30359-6

[9] Young, R.J., Bannister, D.J., Cervenka, A.J., Ahmad, I. (2000). Effect of surface treatment upon the pull-outbehaviour of aramid fibres from epoxy resins, Journal of Materials Science 35, pp. 1939 – 1947, ISSN: 0022-2461

[10] Frankland, S.J.V., Harik, V.M. (2002). Analysis of Carbon Nanotube Pull-out from a Polymer Matrix, NASA/CR-211743

[11] Montes-Moran, M.A., Martınez-Alonso, A., Tascon, J.M.D., Young, R.J. (2001). Effects of plasma oxidation on the surface and interfacial properties of ultra-high modulus carbon fibres, Composites: Part A 32, 361–371

[12] van den Heuvel, P.W.J., Peijs, T., Young, R.J. (2000). Failure phenomena in two-dimensional multi-fibre microcomposites. Part 4: a Raman spectroscopic study on the influence of the matrix yield stress on stress concentrations, Composites: Part A 31, pp. 165–171

[13] Chawla, K.K. (1998). Material Science Engineering, Springer, ISBN 0-387-98409-7 [14] Shelestova, V.A., Serafimovich, V.V. Grakovich, P.N., Hong, J.X., Jin, Y.S. (2003). Change in

the Surface Properties of Carbon Fibers as a Result of Plasmochemical Modification, Mechanics of Composite Materials, Vol. 39, No. 5,

[15] Tibbetts, G.G., Finegan, J.C., Glasgow, D.G., Ting, J.M., Lake, M.L. (1999) Surface Treatments for Improving the Properties of Vapor-Grown Carbon Fiber/Polypropylene Composites Conference on Carbon , Charleston, SC

[16] D. K. Owens, R. C. Wendt (1969). Estimation of the surface free energy of polymers, Journal of Applied Polymer Science, 13(8): 1741-1747

[17] International Standard EN ISO 527-1 (-2 and -3):1996 (1996). Plastics – Determination of Tensile Properties, Beuth Verlag GmbH, Berlin.

22

VII Naučno/stručni simpozij sa međunarodnim učešćem „METALNI I NEMETALNI MATERIJALI“ Zenica, BiH, 22-23. maj 2008.

THE USE OF PROFICIENCY TEST RESULTS IN THE DEVELOPMENT PROCESS OF INTERNATIONAL STANDARDS

Prof. Dr.-Ing. Holger Frenz Fachhochschule Gelsenkirchen, Abteilung Recklinghausen

August-Schmidt-Ring 10, 45665 Recklinghausen Germany

Dipl.-Ing. Stefan Wieler Institut für Eignungsprüfung – IfEP GmbH

Am Erlenkamp 16-18, 45657 Recklinghausen Germany

Keywords: Proficiency Tests, Mechanical Testing, Hardness Testing Brinell, Tensile

Testing, Reference Materials, Measurement Uncertainty ABSTRACT The Institut für Eignungsprüfung, IfEP, is an independent and accredited German service institute providing proficiency tests in the field of mechanical testing, metallography and related areas. In 2007 IfEP provided more than 800 single proficiency tests on the field of mechanical testing and related areas to about 250 laboratories coming from over 40 countries worldwide. Two proficiency tests areas presented in this article to show the process from organisation to performance and finally to evaluation. Therefore the proficiency tests “HBW 10/3000” and “Tensile Test Flat Test Specimens” are presented as Hardness and Tensile testing are classical examples for the field of mechanical testing. Exemplary results from these proficiency tests are shown and graphically displayed.

1. INTRODUCTION The Institut für Eignungsprüfung, IfEP, is an independent German service institute providing proficiency tests in the field of mechanical testing, non-destructive testing, metallography and related areas. According to its DIN EN ISO/IEC 17020 accreditation, the institute feels constrained to increase its quality management system and professional competence continuously. IfEP offers a premium program of proficiency tests to customers from all over the world. The participation in the proficiency tests is open to accredited and not accredited laboratories. All data delivered by the participants is kept and evaluated in confidence by the organiser. In the last years the determination of measurement uncertainty became an important topic in laboratory work. IfEP pays attention on this problem and presents a general survey of the currently valid models for estimation of the measurement uncertainty in line with the proficiency tests. These up-to-date calculation models base on actual testing standards, updated pre-standards and related guidelines or literature. In 2007 IfEP provided more than 800 single proficiency tests on the field of mechanical testing to laboratories coming from over 40 countries worldwide. These proficiency tests had been carried out for the following testing methods:

23

• HBW 2007: Brinell Hardness Test - HBW 2,5/187,5 and HBW 10/3000 • TTSF 2007: Tensile Test Steel – Flat Test Specimen, Automotive sheets • TTSRR 2007: Tensile Test Steel – Round Bars • TTAQ 2007: Tensile Test – Nickel-based alloy (Elevated Temperatures) • TTAl 2007: Tensile Test – Aluminium • EMS-Fe 2007: Emission Spectrometry – Low-alloyed and/or unalloyed steel • EMS-Al 2007: Emission Spectrometry – Aluminium • UT 2007: Non-destructive Testing – Ultra Sonic Testing • WI 2007: Non-destructive Testing – Welding Inspection (Radiographic) • CIT 2007: Charpy Impact Testing – 20, 50 and 100 Joule • SH 2007: Shore Hardness A/D • MH 2007: Salt Spray Test

Additionally, fourteen proficiency tests were offered on the field of testing and analysis of plastics (e.g. mechanical testing, DSC, FTIR). Based on the data from proficiency tests and a long-time experience in the organisation and evaluation of proficiency tests, IfEP presents results and discusses actual models of estimation of measurement uncertainty and the applicability of reference materials for intermediate checks of testing equipment. Two proficiency tests are presented to show the process from organisation to performance and finally to evaluation. At first the proficiency test “HBW 10/3000” is presented. Hardness testing is a classical example for the field of mechanical testing with established models for the determination of measurement uncertainty. Additionally the proficiency test “TTSF 2007” is reported, as it is a good example for the applicability of reference materials from proficiency tests. 2. PROFICIENCY TEST – BRINELL HARDNESS TEST (HBW 10/3000) This proficiency test was based on the test standard EN ISO 6506-1 [1] and designed according to ISO/IEC Guide 43-1 [2] and ISO 13528 [3]. The test procedures were:

• Task A: Hardness measurement HBW 10/3000 according to EN ISO 6506-1 [1]. • Task B: Preparation of standard material and hardness testing acc. to

EN ISO 6506-1 [1], HBW 10/3000 including the estimation of the measurement uncertainty. The determination of the measurement uncertainty followed the current ISO standard.

2.1 Participants and test specimens 28 laboratories located in 10 countries participated in this proficiency test. 22 participants declared to have an accreditation according to EN ISO/IEC 17025 [4]. Five reference hardness blocks certified by the MPA NRW Dortmund (∼ 300 HBW 10/3000) were used for task A. The standard material used for task B was a cold work steel on a similar hardness level.

2.2 Evaluation of proficiency test HBW 10/3000 Task A was evaluated according to EN ISO 6506-2 [5], table 2 (“permissible repeatability” and “error of the testing machine Erel ”). Task B was performed for the calculation of measurement uncertainty. In the following only the evaluation and results for the error of testing machine Erel is presented. The full report of the proficiency test [6] (including results for every parameter evaluated in this proficiency test) can be offered by the PT provider.

The error of the testing machine Erel is calculated acc. to equation (1):

24

%100⋅−=C

Crel H

HHE (1)

The permissible error of the testing machine (2) is stated in EN ISO 6506-2, table 5 [5]:

HV 10/3000: 2% 2%relE− ≤ ≤ (2)

The criteria for result assessment was either „satisfactory“ or „unsatisfactory“. 2.3 Quantification of the laboratory performance with displaying the maximum

deviation of the hardness testing machine including the uncertainty acc. to EN ISO 6506-6

The model stated in EN ISO 6506-2 [5] determines the maximum bias of the testing machine including the measurement uncertainty maxHTMH∆ (equation 3). The bias from the testing of certified reference materials (offered by PT provider) b is combined with the measurement uncertainty of the hardness tester, UHTM [7].

maxHTM HTMH U b∆ = + (3)

The formula for UHTM is:

2ms

2H

2DCRM

2CRMHTM uuuu*2 U +++= −

(4)

%100*X

UU~CRM

HTM = (5)

with

UHTM Expanded measurement uncertainty of the hardness tester HTMU

~ Relative expanded measurement uncertainty CRMu Calibration uncertainty of the hardness reference block

Hu Standard uncertainty of hardness testing machine when measuring CRM

DCRMu − Hardness change of the hardness reference block since its last calibration due to drift (neglect able for use of the hardness reference block complying with the standard)

msu Standard uncertainty due to the resolution of the hardness testing machine in mm

CRM X Certified reference Value of the certified reference block Due to the fixed values of uCRM and ums, UHTM has a lower limitation of 0,6 %. was calculated for every participating laboratory under the condition, that it stated their smallest measurement step.

maxHTMH∆

25

2.4 Results 23 laboratories submitted results including a statement to their smallest measurement step, which is essentially needed for evaluation purposes. 30 % of these participants presented results, which do not fulfil requirements for the parameter Erel (equation 2). The results are presented graphically in figure 1. The difference between MWLab and the certified reference value is displayed. Additionally the individual measurement uncertainty (eq. 3) is indicated for every laboratory value.

maxHTMH∆

-7,0%

-5,0%

-3,0%

-1,0%

1,0%

3,0%

5,0%

7,0%

7

239

240 6

21a

176 37 86 224

150

136 46 31 124 56 21b 50 90 248

116

117 62 225

Labor- Nr. / Laboratory Code

Abw

eich

ung

der P

rüfm

asch

ine

/ Err

or o

f tes

ting

mac

hine

in %

zulässige Grenzabweichung / permissible error: +2 %

zulässige Grenzabweichung / permissible error: -2 %

Figure 1: HBW 10/3000: Max. deviation of the hardness testing machine and measurement uncertainty acc. to EN ISO 6506-2 [6]

3. PROFICIENCY TEST – TENSILE TEST, FLAT TEST SPECIMEN

HIGH-STRENGTH AUTOMOTIVE SHEETS (TTSF 2007) As tensile testing is one of the most important methods in materials testing and is daily practice in testing laboratories, intermediate checks of the equipment become an important tool of quality assurance. Therefore materials with well known properties, e.g. (certified) reference materials are used. In the following, the results from testing a potential reference material within a proficiency test are displayed. The full report of the proficiency test [8] (including results for every parameter tested in this proficiency test) can be offered by the PT provider. The proficiency test was designed acc. to ISO/IEC Guide 43-1 [2] and ILAC-G13 [9]. The participants were asked to perform the test acc. to EN 10002-1 [10]. 3.1 Participants and test specimens 32 laboratories located in 12 different countries participated in this proficiency test, 31 stated results. 21 participants indicated to be accredited according to EN ISO/IEC 17025 [4]. Within this proficiency test, high-strength automotive steel sheets were offered to the participants. The selection of this material followed up the requirements for possible reference material. Therefore intensive homogeneity testing was carried out within a diploma thesis, concluded by Institut für Eignungsprüfung and an accredited testing laboratory. The respective standard deviation of the parameters Rp0,2 and Rm are less than 1%. Therefore the material is appropriate.

26

3.2 Determination of assigned values and calculation of performance statistics The statistical design was based on ISO 13528 [3] and ISO/IEC Guide 43-1 [2]. The deviation of laboratory’s mean MWLAB value from the assigned value X was evaluated. A consensus value was used as assigned value X, determined from the results of all participating laboratories. It was calculated as the median of all laboratories results MWLAB. The normalised interquartile range (nIQR) is used as standard deviation for the proficiency assessment . The results of this proficiency tests are assessed with the help of a Z-score that is calculated for each laboratory and each test parameter according to equation (6):

σ̂

σ−

=ˆ

XMWZ LAB (6)

According to ISO Guide 43, part 1 [3] the following judgements are made:

• |Z| ≤ 2 satisfactory, • |Z| ≥ 3 unsatisfactory • 2 < |Z| < 3 result questionable.

3.3 Results The proficiency test was evaluated for the parameters proof strength Rp0,2 tensile strength Rm and Elongation after fracture A. Table 4 gives an overview of the respective assigned values X and the standard deviations for proficiency assessment σ̂ , that were used in equation (6).

Table 4: Assigned values and standard deviations of proficiency test and results Test parameter Rp0,2 in MPa Rm in MPa A in %

X 586,4 819,5 16,4 σ̂ 6,4 7,1 0,9

The results of the proficiency test underline the homogeneity of the material regarding the evaluated parameters. The standard deviation of the proficiency test σ̂ is near 1% for the parameters Rp0,2 and Rm. In the following table the total results of the proficiency test are summarised. It is obviously, that a good laboratory practice can be drawn as a conclusion from the positive scoring.

Table 5: Final score of proficiency test TTSF 2007 No. of participants Results │Z│< 3 Determination of proof strength Rp0,2 31 94 % Determination of tensile strength Rm 31 100 % Determination of percentage elongation after fracture A 31 100%

Figure 2 displays the results for parameter Rp0,2. Overall, a positive scoring is obvious, but two laboratories stated results that are significantly deviating from the median and the majority of results. An influence by the testing equipment used can often by the reason for this problem. Therefore reference materials should be used to check the equipment and to assure testing quality, as required by international standards, e.g. ISO/IEC 17025 [4].

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550,0

560,0

570,0

580,0

590,0

600,0

610,0

620,0

199

176 36 204

124

136

238 78 49 227 74 198

211 57 202 31 200 8 11 50 7 1 28 138 75 265

239

149

556

191

212

Labor-Nr. / Laboratory Code

Deh

ngre

nze

R p0,

2 / P

roof

str

engt

h R p

0,2 i

n M

Pa

Median

Z = 3

Z = 2

Z = -3

Z = -2

Lab.-Code 212: 767,1 MPaLab.-Code 191: 641,8 MPa

Figure 2: TTSF 2007 0,2%-Proof strength; mean values of all laboratories

4. CONLUSIONS Proficiency testing is a powerful tool to assist in international standardisation of testing methods. From the presented examples the following conclusions can be drawn:

• Standardised models for the determination of measurement uncertainty in hardness testing were validated within international proficiency tests. Practice has shown that these models are applicable in laboratories daily work.

• Proficiency tests can be used to establish reference values and contribute to the qualification of reference materials in the sector of mechanical testing, where it was not available for an acceptable price level until today. The use of reference materials for intermediate checks is also required by international standards regarding to quality management in testing laboratories, e.g. EN ISO/IEC 17025 [4].

4. REFERENCES [1] EN ISO 6506-1:2006, Metallic materials –hardness test according to Brinell; Part 1: Test method. Beuth Verlag, Berlin, März 2006 [2] ISO/IEC Guide 43-1:1997, Proficiency Testing by Interlaboratory Comparisons. International Organisation for Standardization, Genève, First Edition 1997. [3] ISO 13528-2005: Satistical methods for use in proficiency testing by interlaboratory comparisons. International Organisation for Standardization, Genève, September 2005. [4] EN ISO/IEC 17025:2005, General requirements for the competence of testing and calibration laboratories. Beuth Verlag, Berlin, August 2005. [5] EN ISO 6506-2:2006, Metallic material – hardness test according to Brinell; Part 2: Testing and calibration of testing machines.Beuth Verlag, Berlin, März 2006. [6] Proficiency Test: Brinell Hardness Test – HBW 10/3000 2007. Final Report, Institut für Eignungsprüfung IfEP GmbH, Recklinghausen, Februar 2008. www.ifep.eu [7] Weißmüller, C, Frenz, H.: Modelle zur Ermittlung der Messunsicherheit in der Härteprüfung; Statistische Auswertung eines Ringversuchs mit 90 Teilnehmern. In: Tagungsband Werkstoffprüfung, Neu-Ulm 25.-26.11.2004, MAT INFO, Frankfurt 2004. [8] Proficiency Test: Tensile Test Steel – Flat Test Specimen; High-strength Automotive Sheets. Final Report, Institut für Eignungsprüfung IfEP GmbH, Recklinghausen, March 2008.

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[9] ILAC-G13: 2000: Guidelines for the Requirements for the Competence of Providers of Proficiency Testing Schemes. ILAC Technical Accreditation Issues Committee, 2000. [10] EN 10002-1:2001, Metallic materials – tensile test - part 1: Method of testing at ambient temperature. Beuth Verlag, Berlin, December 2001.

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VII Naučno/stručni simpozij sa međunarodnim učešćem „METALNI I NEMETALNI MATERIJALI“ Zenica, BiH, 22. - 23. maj 2008.

PRODUCTION AND PROPERTIES OF NON–VENEERED WOOD BASED PANELS

Sergej MEDVED University of Ljubljana, Biotechnical Faculty, Department of Wood Science and Technology

Rožna dolina, Cesta VIII/34 SI–1000 Ljubljana, Slovenia

E–mail: sergej.medved@bf.uni-lj.si

1. INTRODUCTION Wood is a renewable, easily recyclable, organic construction material that requires little energy in the manufacture of building components. Wood is natures one of the most brilliant, if not the most brilliant materials. Nowadays we can’t imagine life without wood or wood based products. One can even say that wood follows us from birth until death. If one looks into history one can easily find evidences that wood was used for building houses, forth walls, bridges, transportation vehicle, etc. At the beginning wood was used only in its solid state but at the beginning of 20th century wood was used also in other form, namely in the form veneer, particles and fibres as wood based panels. The question that one my ask oneself is why did we needed those materials if we stated above that wood is the most brilliant material from nature. To understand this we must first look into some properties of wood:

∗ Properties of wood depends on the wood species (Figure 1) ∗ Properties of wood depends on the density of wood ∗ Wood is anisotropic material: the properties of wood differs on the direction ∗ Wood is hygroscopic material:

Figure 1: Microscopic structure of softwood (left) and hardwood (right)

31

mailto:sergej.medved@bf.uni-lj.si

Due to above mentioned “negative” properties of wood and the fact that logs were not used completely, we started to think how we can get more out of tree/log and how we can change those “negative” properties of wood. Now we have several wood based products that are made from wood and are known under the name wood– based composites or wood–based panels or even engineered wood. Engineered wood, also called composite wood includes a range of wood products which are manufactured by binding togethe