New Nanotechnology Developments
for Corrosion Protection
„NanoEngeneering - Hannover Messe, 21.04.2010
Dr. Thomas John-Schillings
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Content
• Tasks of metal pretreatment
• Traditional metal pretreatment: Iron- and Zincphosphating
• Question about Phosphating
• Presentation of „Nanoceramics“ – Bonderite® NT-1 & TecTalis®
• Process
• Benefits
• Corrosion protection in comparison with traditional processes
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Why metal pretreatment?
• Prior to painting substrates are often:
• Dusty
• Oily (forming oils, temporary corrosion protection)
• Corroded (rust, welding scale)
• Pretreatment provides:
• Cleaning
• Paint Adhesion
• Better Corrosion Protection
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Traditional Metal Pretreatments
• Zincphosphating
• best corrosion protection
• excellent paint adhesion
• process difficult to monitor
• very cost intensive
• Ironphosphating
• simple, flexible process
• moderate process costs
• Low corrosion protection
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Why should Phosphatings being
replaced?
• very high sludge formation
• very narrow process operation window – lot of parameter
• difficult multi metal pretreatment
• many process steps – lot of active bathes
• high amount of heavy metals (Zn, Mn, Ni)
• environmental unfriendly process (energy, phosphate, COD,
heavy metals…)
Question: “Which aspects of Zinc-/Fe-Phosphating are mostly
unsatisfying?
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Iron-
phosphating
Bonderite® NT-1
Zinc-
phosphating
TecTalis®
Eisen-
phosphatierung
„Nanoceramics“ replace phosphating
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Which benefits provide „Nanoceramics“ with respect to
„Nanoceramics“ replace phosphating
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What are “Nanoceramics”
• phosphate free metal pretreatment process
• provides excellent paint adhesion and corrosion protection
• replacement of iron- or zincphosphating
• multimetal pretreatment process (steel, zinc, aluminium)
• forming a thin “ceramic” conversionlayer (Nanoceramics)
• application in existing lines (dip or spray)
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pH = 3.8 – 5.0
T = 10 - 50 ºC
time= 30 - 180 s
ZnO
Zn
Steel
ZrOXFy
H2ZrF6 Zn+2
H2ZrF6 + M + 2H2O ZrO2 + M2+ + 4H+ + 6F- + H2
M = treated substrate; Fe, Zn, Al, Mg
Nanocearmic coatings
Chemical Reaction
10
5
250
1000
5000
10000
Zincphosphate
Ironphosphate
Chromates
““NanoceramicsNanoceramics
bigger Molecules
[nm]
100
50
AFM (Atomic Force Microscopy) AFM (Atomic Force Microscopy)
TecTalis TecTalis CoatingCoating
SEM (Scanning Electron Microscopy)SEM (Scanning Electron Microscopy)
Phosphate Phosphate CoatingCoating
Nanoceramic Coating
Dimensions
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Typical Bonderite® NT-1 process
• Alkaline cleaning – the only heated step
• DI-Rinse prior to Bonderite® NT-1
• Conversion coating with Bonderite® NT-1
(20 sec. or more)
• DI-Rinse after Bonderite® NT-1
• Optional: Dryer after Bonderite® NT-1
• Powder coat, wet paint, CED/AEDC
Cleaning RinseDI-
RinsePaintNT-1
DI-
Rinse
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TecTalis – process layout
typical typical ZincphosphateZincphosphate lineline
Cleaning Rinse Activation Phosphate. PassivationRinse DÍ-Rinse
typicaltypical TecTalis TecTalis processprocess
5555°°CC
Cleaning Rinse TecTalisTecTalis Rinse
230 m
180 m
DI-Rinse
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Corrosion protection and
paint adhesion
Corrosions tests
judgement of the area and the creep at the cut
• Constant climate test DIN EN ISO 6270-2• Neutral Salt spary DIN EN ISO 9227 AASS• Cycling climate test VDA 621 415 • Outdoor exposure VDA 621 414
Adhesion-tests
judgement before and after corrosion test
• cross hatch• stone chip -test• Erichsen-Tiefung
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Perfomance:
Bonderite® NT-1 vs FePhos
Bonderite® NT-1 Fe-Phosphate
• Customer sampes
• Creep after 500h NSS
• Bonderite® NT-1 (left)
• 2.2 mm creep
• Ironphosphate (right)
• 6,5 mm creep
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0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
E-coat 1 E-coat 2 E-coat 3 E-coat 4 E-coat 5 E-coat 6
Creep at cut [U/2 in mm] Granodine 958
TecTalis
spec
Performance: Comparison
Tectalis® vs ZnPhos
70 cycles VDA – Steel + CDP
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Comparison of process costs
example:
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Performance – comparison
ZnPhos vs TecTalis
performance, e.g.
corrosion protection
Proces-
parameter
area i.O. results ZnPhos
areaarea i.Oi.O. . resultsresults TecTalisTecTalis
TecTalisTecTalisZnPhos
Specification
ProcessProcess windowwindow TecTalisTecTalis
Process window ZnPhos
automatical processcontrole (Lineguard Supervisor) for critical parameter possible!!
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Benefits of „Nanoceramics“ vs
Phosphating
• A lot of savings, e.g.
• Maintenance and Cleaning
• Water consumption
• Heating ( ambient temperature)
• Sludge disposal
• Result in: Process costs decrease
Efficiency Process
Environment Quality
• conversion at ambient temperature
• short contact time
• simple bath monitoring (pH)
• real multimetal process
• low energy consumption
• no toxic heavy metals
• phosphate free conversion
• no contribution to COD
• less disposal (sludge)
• no hazardous substances
• enhancement of corrosion
protection vs FePhos
• replacement of Zincphosphating in
often possible
• Compatible with Al, Zn, steel and
most available paint systems
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„Nanoceramics“ - References
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Thanks for your attention!