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AFRPL; 31 May 1979
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AFRPL. 1R.66-114 COPY No............
(UNCLASSIFIED TITLE)
CHARACTERIZATIONAND
EVALUATIONOF LIGHT METAL HYDRIDES
LOCKHEED PROPULSION COMPANYREDLANDS, CAUFOR14A
TEOINICAL REPORT AFRPL.TR46.114
JUNE 1966
DOWNGrAtAED AT 3 YEAR INTERVALSDICLASOiPIED AFTER 12 YEANS
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ST2*NSSSUN Oft THE REVELATIMS OF ITS COIIENS 10 ANY A&MMTO Af
mi 0KF RCECET ROPULSIO LAMOPATM~RESEARCH: AND TECHNOLOGY DIVS'
AMR FORM SYSTEMS COMMANOWPTED STATES AIR FORCE
SbWARDS, CALIFORNIAZýI-
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I 4 4
AFRPL-T .R-66- 114 LPC Report No. 716-Q3-2
(UNCLASSIFIED TITLE)
CHARACTERIZATION AND EVALUATION OF LIGHT METAL HYDRIDES
Lockheed Propulsion CompanyP.O. Box III
Redlands, California
June 1966
4
DOWNSAD90 AT S-YEA00 INTSOVALS 9
09CLASSIFIRD AFTER it TRANS
WIV. TWOeGWSW Ofm~v IS WUJCYTO SPECIAL. 6XPOSr COW.?NOIL AND RShOW IWANOSAL TO PORRmON COVIIINANS19
". P6141016 NATIONALS WAT 09 WACO OWL? wIT06 P39.0 AS.P30*04.O. APR91"1. RPNTIWPW. 60WAM&S C*LAPOISU*
WNININL 09POWI OP TIM UMT90 STSS.M WINO "OREGOPONAAE LAWS Ifli M 0. U.S.C.. SECTlIONS 798 AND 10& M1
TSUU0 Oft TN WE VELATION OP ITS CONTENTSM 9W *5*33T16 A16M UTDNOW88OPSSOO 0S PROMOTED WVLAIL
AFRPL-TR-66-114 THIS PAGE UNCLASSIFIED 716-Q-26
FOREWORD
(U) This is the second quarterly report issued underContract No.AF04(611)-11219. This report was prepared by W.E. Baumgartner and G. Myers, ChemrisryDepartment, Lockheed Propulsion Company (LPC). Contributors to the workreported herein include W. D. Allan, W.S. Baker, G.R. Cann, G. L. Horstman,r.A. Palmer. and D.R. Szymanski. r(U) The program is monitorrd by the Air Force Rocket Propulsion Laboratory(AFRPL). Edwards, California (Lt. John Rombouts, Lt. R. Bargmeyer).
(U) This report contains information regarding the use and the performanceof light metal hydrides in solid propellants, and is ciassifed CONF DEN -1 AL.
(U) Publication of this report does not constitute Air Force approvil of thereport's findings or conclusions. It is published only for the excharne andstimulation of ideas.
John H. BoninDirector, Research BranchLockheed Propulsion Company
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LOCKKEUDr PROPULSION COMPANY A
____ ____ ____ ___
AFRPL-TR-66-114 7l6-,-Z
UNCLASSIFIED ABSTRACT
Evaluation of Beany material of recent production shows distinctimprovements in the material's particulate structure. Propellant mixesusing the newer materials gave low mix viscosity prior to ball milling.Analytical data are summarized.
A Beany double-base propellant was fired in a small motor at lowchamber pressure. A significantiy lower efficiency was obtained than wasmeasured in a control motor fired under closely similar (mass flow rate,pressure) conditions.
Experimental work was continued in obtaining basic data for LMH-lpropellant shelf-life prediction. Initial data on gas generation rates, gasdiffusion and solubility are reported.
ii
"C 2 PROPULSION COMPANYI
I
PTIM0S P= VAS &.&Ir, Y/RMM wT rFmD.
CONPIDENTIAAFRPL-TR-66- 114 716-Q-2
TABLE OF CONTENTS
Section Page
INTRODUCTION I
1. TASK I, CHARACTERIZATION AND EVALUATIONOF BERYLLIUM HYDRIDE 1
2. TASK II, METAL HYDRIDE PROPELLANT SHELFLIFE I
II. SUMMARY 2
1. TASK I, CHARACTERIZATION AND EVALUATIONOF BERYLLIUM HYDRIDE 2
2. TASK II, LIGHT METAL HYDRIDE PROPELLANTSHELFLIFE 2
a. Gas Diffusion and Solubility 2
b. Gas Generation Rate (LMH- I Stability) 3
c. LMH-I Propellant Surveillance 3
III. TECHNICAL EFFORT 4
1. TASK I, CHARACTERIZATION AND EVALUATIONOF BERYLLIUM HYDRIDE 4
a. Anaxysis by Microcombustion and InfraredSpectroscopy 4
b. Analysis by Microcombustion 4
c. Analysis by Infrared Spectroscopy 7
d. Effect of BeHa Material Purity on PropellantPerfornance 7
a. Evaluation of Leany Samples 7
f. Evaluation of Beryllium Hydride Propellants 11
(1) Ballistic Evaluation 11
(2) Propellant Shelflife Studies 11
(3) Stabilizers for BeHa Double-Base Propellants 11
IP
SOFD41LLoCK.,ED PRoPULSoN COMPANY
AFRPL-TR-66-114 CONFIDTAL 716-Q-2
TABLE OF CONTENTS (Continued)
Section Page
g. Combustion of Beryllium Hydride in SolidRocket Motors 1I
(1) Combustion Mode I 16
(2) Combustion Mode 2 16
2. TASK II, LMH-I PROPELLANT S.iELFLIFE 17
a. Gcs Diffusion and Colubility 17
(1) Experimental Procedure 17
(2) Data Analysis 20
(3) Results 21
b. Gas Generation Rate (LMH- I Stability) 25
(1) Experimental Procedure ?5
(2) Results 25
c. LMH- I Propellant Surveillance 31
(1) Experimental Procedure 31
(2) Results 32
IV. BERYLLIUM HEALTH PHYSICS PROGRAM 37
LIST OF ILLUSTRATIONS
i Amorphous Beryllium Hydride (Beany) Particles X6 9
2. Amorphous Beryllium Hydride (Beany) Particles X220 10
3. Taliani Data, DNPDN 14
4. Taliani Data, DNPDN 15
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COMIDMITIAL LOCKHEDo PROPULSION COMPANY
CONFIDENTIALAFRPL-TR-66- 114 716-Q-2
LIST OF ILLUSTRATIONS (Continued)
u Page
5. LMH-2/DNPDN and LMH-2/NIBTN Systems 18
6. Gas Diffusion Cell 19
7. H? Sorption Rate Data 2z
8. Temperature Dependence of D 24
9. Hz Generation Rate at 140CE for LMH-1 27
10. H2 Generation Rate at 100 0F for LMH-1 28
11. Total Hz Generation versus Time 29
LIST OF TABLES
Table Page
I. CARBON-HYDROGEN ANALYSES OF LMH-2 -
300°C/ARGON 5
II " MICROANALYSIS DATA, BEANY SAMPLES 6
III. THEORETICAL CALCULATIONS, LPC-1-32AXMPROPELLANT 8
IV. COMPOSIT•LON, LPC-1032 PROPELLANTS 1I
V. BALLISTIC DATA, LOW PRESSURE FIRING 13
VI. DIFFUSION AND SOLUBILITY CONSTANTS FOR Ha INPROPELLANT (LPC-1018B without LMH-1) 23
VIL PRELIMINARY SURVEIP.ANCE DATA AT 1559F FORFORMULATION A23-06ta) 33
VIII. SURVEILLANCE DATAAT 155°F AND 75OF FORFORMULATION A23-06(b) 34
IX. BERYLLIUM MONITORING IATA 38
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CONFIDENTIAL LOCKNHEO PROPULSION COMPANY
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CONFIDENTIALAFRPL-TR-66-114 716-0-2
SECTION I
INTRODUCTION
(C) The program effort conducted under Contract No. '.F05(611)-lIZ19is divided into two tasks: Task 1, the characterization and eva!uation ofberyllium hydride, and Task II. the analysis of metal hydride propellantshelflife.
(C) 1. TASK I. CHARACTERIZATION AND EVALUATION OFBERYLLIUM HYDRIDE
(C) The primary objective of Task I is to provide a meaningful evalu-ation of beryllium hydride material forms for application in solid propellarnts.
(C) The first quarterly report issued under this contract gave a summaryof ballistic data obtained in small motor tests. These tests served to definecontrolling parameters in beryllium hydride combustion in solid rocket motors.The data are now being used in establishing test conditions for a comparativeEthylane -Beany evaluation.
(C) In view of earlier difficulties in processing small grains containingthe dense beryllium hydride, and as a prerequisite for further material evala-ation. the phenomena underlying reactivity of dense BeHz in propellant mixesare being aiidlyzed further.
(U) 2. TASK II, METAL F. fDRIDE PROPELLANT SHELFLIFE
(C) The use of a sold propellant ingredient. such as aluminum hydride,which exhibits a measurable rate of gas generation within the operational tem-perature range of a propellant (motor) creates the problem of inter-lal gaspresrure build-up. If this pressure becomes excessive, the grains willdevelopcracks.
(U) More precisely, grain failure in such systems is the consequence ofan imbalance between gas generation rates and gas dissipation rates, the latterbeing highly dependent upon volumetric solid loading, grain size, and graingeometry. Because of this dependency, there are no simple means for pre-dicting motor sheliflife by extrapolation of laboratory surveillance test data.Instead. such data extrapolation has to rely on the use of a complex mathematicalmodel, and requires precise information on gas solubilities in the binder, gasdiffusion and gas generation rates, in addition to data on grain internal stressconcentrations.
(U) The previous quarterly report discussed in detail a physical modelof the gas generation-diffusion process, presented a mathematical analysis ofthat process and outlined the experimental program necessary to implementthe analysis and predict shelflives of propellant motors. The present reportdescribes the experimental procedures employed and the results obtained inthe measurements of gas generation rate, gas diffusion and solubility constantsand shelflives of laboratory specimens.
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CONFIDENTIAL LOCKHEED PROPULSION COMPANY
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CONFIDENTALAFRPL-TR-6t-l 14 716-O-2
SECTION II
SUMMAiRY
ýC) 1. TASK I, CHARACTERIZATION AND EVALUATION OFBERYLLIUM HYDRIDE
iC) Anmitical techniques for determining minor changes in samplecomposition during passivation and aging are being evaluated. These techniques2nclude micrccombustion analysis. analysis by KBr pellet technique. in combina-tion with differential thermal analysis and differential scanning calorimetry.Specific information sought includes carbonate content, and concentration ofactive hydrogen (e.g.. hydroxyl, surface moisture) not present as hydridehydrogen.
(U) Six samples of Beany material, all representiniz recent productioniots, were received for evaluation. Analytical data and re:,ults of the evalua-tion of the materials in propellant mixes are reported. The data show a distinctimprovement in particulate characteristics over samples of earlier production.
(C) Beryllium hydride was evaluated in double-base propellants contain-ing 2, 2-dinitropropanediol dinitrate (DNPDN) as an energetic plasticizer. Adistinct stabilizer effect of BeHz, comparable to the effect produced by the usualdouble-base propellant stabilizers, was observed in Taliani tests.
(C) A BeHz,'NIBTN double-base propellant (LPC-1032B) was test-fired ina l'/z-pound motor at low (270 psi) chamber pressure. A modified LPC-1005Apropellant giving comparable mass flow rates at this pressure was used as acontrol. The data show low specific impulse efficiency for the berylliumhydride system (84.4% as compared to 93.84 for the control).
(C) Cracking cylinders prepared with LPC-1032C (151 BeHz/NIBTNdouble-base propellant) were placed in elevated temperature storage. At 140°Fthe samples developed cracks between 10 and 18 days storage. All samplespassed X-ray examination after 18 days at 120 0F, and the iests are continuing.
(C) Further analysis of ballistic test data obtained during a precedingreport period leads to more detailed understanding of BeHZ combustion insolid rocket motors (Section III, subsection g).
(U) 2. TASK II. LIGHT METAL HYDRIDE PROPELLANT SHELFLIFE
(L) a. Gas Diffusion and Solubility
Measurements of gas diffvsion and solubility constants in pro-pellant are being performed by means of a sorption technique.
(U) Preliminary values of gas diffusion coefficient and solubilityhave been obtained for propellant LPC-1018B without LMH-l at several tem-peratures. Their magnitude. as well as that of a calculated energy of activa-tion for diffusion, is consistent with literature values for Ha in various polymers.
LOCKHEED PROPULSION COMPANY
AFRPL-TR-66-114 CCNMDENMAL 716-0-2THIS PAGE UNCLASSIFIED
(U) b. Gas Generation Rate (LMH-l Stability)
(U) A technique has been developed to replace the standard Talianimethod for measuring gas generation rates and is now operating satisfactorily.It uses a thermal conductivity cell for measuring the H, concentration in acarrier gas which purges sample cells after known periods of collection. AspreEently set up, six samples can be studied simultaneously. Data have beenobtained for pure Dow 1451 (blend 97-131) at 100 and 140OF over a 700-hourperiod and for the same material in propellant (formulation A23-06) at 100and 140OF over a 250-hour period. The pure Dow 1451 data agree well withthe data from Dow derived with a pressure technique. In contrast to someother reports, however, these data indicate a significantly g reater generationrate in propellant than in the pure state, particularly at 140 F. Propellantsamples employed here were chopped into I to 2-mm particles to precludeany diffusional effects upon the measurements, which if not eliminated wouldmake the observed generation rate lower than the true rate.
(U) c. LMH- I Propellant Surveillance
(U) Stainless steel surveillance containers have been fabricatedand the appropriate quantities sent to Allegheny Ballistic Laboratory (ABLIand United Technology Center (UTC) for preparation of surveillance speci-mens of their propellant formulations. Samples to be shipped to LPC includespecimens for measurements of gas generation rate, and diffusion and solu-bility constants. The surveillance containers are of such a geometry that themathematical analysis of gas generation-diffusion is applicable and the effectsof cure and thermaily-induced internal stresses can be determined.
(U) Surveillance has been initiated at 75 and I 15*F with propellantA23-06 containing blend 97-131 of LMH-l. Void formation occurs within afew days at 15*F, indicating that subsequent surveillance at this temperaturewill require the more stable LMH-l samples expected shortly from Dow.Although the combined data are not yet s,!ficiently firm to warrant detailedanalysis and correlation, preliminary calculations show the observed failuretimes to be consistent with the measured gas generation rates, diffusion con-stants and solubility.
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C'O"-PII---T'L _ LOCKNEUD PROPULSION, COMPANY
SfISmI
CONMDMALAFRPL-TR-66-l 14 716-O-2
SECTION III
TECHNICAL EFFORT
(C) 1. TASK I, CHARACTERIZATION AND EVALUATION OF
BERYLLIUM HYDRIDE
(U) a. Analysis by Microcombustion ane Infrared Spectroscopy
(C) There is reason to believe that BeHa material reactivity inpropellant mixes is caused by two independently operating phenomena. Heat-ing of the samples (especially the high density material) under vacuo affordsa distinct improvement in relative propellant density; h•wever, with thisheat-treated material, some propellant porosity generally remains. Thispartial improvement can be attributed to the thermal decomposition, desolva-tion or desorption of yet undefined species during the vacuum heat treatment.A second phenomenon involves BeH 2 particle surface reactivity with nitrateesters, and is believed to be associated with the existence of chemicallyactive beryllium species, perhaps beryllium hydroxide, on the particle surface.
(C) To arrive at a better definition of BeHa material reactivityvarious analytical techniques are being refined for measuring minor changesin material composition.
(U) b. Analysis by Microcombustioni
(C) None of the currently used methods of analysis permits accuratedistinction between hydrogen existing in the form of beryllium hydride, andhydrogen present as hydroxide (beryllium hydroxide, water). Moreover, itappears desirable to determine COz content, since passivation of amorphousBeHl is accelerated in a COA-enriched atmosphere. ro obtain the desiredinformation, various suspected impurities are being studied in the pure stateby differential thermal analysis, or differential scanning calorimetry to selectspecific operating conditions in microcombustion analysis. Additionally, infra-red analysis is being evaluated.
(C) In the microcombustion analysis method the samples are pyrol-yzed at different temperatures, either under an oxygen or argon stream, andthe pyrolysis products are passed through a CuO furnace, or absorbed (water,CO) direct.
(C) To test these various modes of operation, a variety of berylliumhydride samples were pyrolyzed under argon at 300 and 6000C, and the pyrolysisproducts were passed through the usual CuO furnace for converting the productsto water and COI. The analytical data are summarized in Tables I and II forcomparison with data reported by the Ethyl Corporation. The following commentsapply:
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CONNDITIALLOCKHEED PROPULSION COMPANWY
AFP-R6-1 CONFDENTAL 716-0-2AFRPLTR-6-I1 4 TABLE I
CARBON-HYDROGEN ANALYSES OF LMH{-2 3000C/ARGON
Materia _ L~ I1ydwosol 1%) Hydrogen(~ Carbons (%) Carbon %-P Et.vl. JZ
senny. 06d. 7 3.469 179l 0.IA149
sonny,.set. 3is$ 16 73 IT.)? 0.60 1 4?
1 6.0 0a."
14JO-i3.30 17.7 0. 04 k.47
3vs .*U 117.13 7.41 1.9 .4Inwy et -:::: 37314 3.34 3.0316.9 L19
Oftemp, soi 364.1 3 7.36 37.34 1.30 Les17.4s .3
*-90,. fed. MI3.9 37. It7.91 0.44 1.4117.34 .9
*Seamy. PaL 306.? 37.34 17.63 0.90 1.90
-- SOL.(* J96-7 11.47 37.63 3.4) 1.9037.31.3S
I3S.73 0.74
39.8 1..34CU
s9.44 1e" 36 I 77 .918a
3~p~s -81 1.46 A 1.Is39.84 .1
cals-15 L4L'~ -s
Ubyam3-20 19.40 1.65 I U1344? I03
(M r-34 19.41 . 0.81 -
1) Saw*&*e barsud is tter at pera iyis aaeed of &rpm.2) son**e pywuiysed at 4004C iaate7.L 06A.
Seamy - Pyrvolvdealy Pweds-d LWI.2.
Eabpiaa. 0 bhlhuw dmeltp. presemaue-taed L1I..8
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(C) (i) With argon as a flush gas there appears to be a significantextent of conversion of beryllium alkyls or alkoxides to beryllium carbide,with resulting low values for total carbon content. Alternatively, berylliumalkyls might be lost by vaporization and condensation in the equipment.
(C) (ii) In duplicate or triplicate analyses somewhat better repro-ducibility is obtained with the dense Ethylane than with amorohous Beany.This is due to sample nonuniformity with the Beany.
(C) (iii) Freshly received (prepared) samples give data (hydrogencontent) which are in generally good agreement with the manufacturer's data,although some samples show distinct discrepancies. There are constantlylarger differences in the data with samples which have been stored for sometime. This could be the result of autoxidation (e.g.. doped samples), a slowdegassing, or slow reaction between hydride and alkyls.
(C) Additional tests for improving the accuracy of the method willbe performed. Analyses will then be repeated without the CuO furnace (argonflush gas) in an effort to determine surface-bound moisture and CO0.
(U) c. Analysis by Infrared Spectroscopy
(C) Initial studies have shown that analysis of BeHa samples byinfrared spectroscopy (KBr pellet technique) holds promise for determiningsurface-bound moisture (including beryllium hydroxide) and beryllium oxide.Both moisture and hydroxide show a strong band centered at 3450 cm", whileberyllium oxide absorbs at 860 cm". Efforts are under way to standardizethe technique.
CC) d. Effect of BeHa Material Purity on Propellant Performance
(C) In earlier performance calculations a BeHZ material purity of94.9% was assumed, and the impurities listed in Table III were programmed inthe computer calculations. Following a review of analytical data with EthylCorporation personnel., the programs were revised to account for a somewhatdifferent average material composition. The effects of these changes uponspecific impulse and flame temperature are shown in Table III.
(U) e. Evaluation of Beany Serples
(C) Six samples of Beany material were received from the EthylCorporation for evaluation. Analytical data obtained with these materials(total hydrogen. total carbon) are shown in Table UI. Photomicrographs areshown in Figures 1 and 2. The materials are now being evaluated in smallscale propellant mAxes,. and preliminary data show a distinct reduction inmix viscosity over mix viscosities measured with previous Beany samples.
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TABLE ILLTHEORETICAL CALCULATIONSi LPCC- 103ZAXM PROPELLANT
OldValues New Values
=eanT Me a ny EthylaneT (*K) 3574 3584 3606Te (:K) Z525 Z537 2554
-o - 5825 58091peq
302.6 330.3 299.5
Density (gra/cc) 1.377 1.376 1.463(lb/ln.1) 0.050 0.050 0.053
LMH-Z puurity (v•) 94.9 92.9 89.6
LMK-Zo irmouritiem '•
Be metaL 0.7 2.0 4.0BeO
0 1.7 2.9
Aakyl.Ca
1.4 0.7 0.3C4s 1.6 1.5 0.6
Alkoxide (Et) o.Z 0.2 0.2BoCIa 0 0.5 0.5Carbon (free) 0 0.5 0.ZUH
0 0 1.7Ethyl ether 1.z 0 0
Hf% kcal/100 gm -40.1 -58.4 -67.9
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(C) f. Evaluation of Beryllium Hydride Propeliants
(U) (1) Ballistic Evaluation
(C) A beryllium hydride double-base formulation (LPC-1032B,Table IV) was test-fired in a l'/z-pound cartridge-loaded motor at a low chamberpressure. A modified LPC-1005A propellant1 was used as the control. dupli-cating mass flow rates. The ballistic data are given in Table V. The sameBeHa formulation, test-fired at 1000-psi chamber pressure, is expected togive a specific impulse efficiency only slightlr less than control motor efficiency.
(C) The data. if confirmed in later firings, imply that loweringof burn rates in BeHl propellants > 15% BeHz) cannot be accomplished by firingat lov, chamber pressure without a serious loss in efficiency unless the propel-lants are reformulated (see subsection g. below).
(U) (Z) Propellant Shelflife Studies
(C) Cracking cylinders containing LPC-i03ZC propellant(Table IV) were placed into elevated temperature storage for periodic examin-ation by X-ray. At a storage temperature of 140°F (following 48-hour cure at1400F) the samples developed cracks within a 10 to 18-day period. At a storagetemperature of 120*F all samples passed X-ray examination after 18 days andthe tests are continuing...-....-.....
(C) Under an earlier program. BeHz double-base propellantscontaining conventional binders (TMETN.,T were stored for approximately one
avea&t I120"F without the appearance of internal cracks.
(C) (3) Stabilizers for BeHa Double-Base Propellants
(C) Limited data available so far indicate that berylliumhydride (Beany) itself exerts a significantly stabilizing effect upon nitrateesters. A striking example is shown in the effect on tne thermal stability of2,2-dinitropropanediol dinitrate (Figures 3 and 4). Similar effects are ob-served in 90*C Taliani tests with NIBTN. On the other hand, the data showthat some commonly used stabilizers (e. g.. resorcinol) can adversely affectBeHa/nitrate ester mixture thermal stability. A more careful analysis of therelative merits of stabilizers in these systems is being conducted.
(C) g.. Combustion of Beryllium Hydride in Solid Rocket Motors
S(C) The conclusions regarding the controlling parameters in BeHacombustion which were derived from a small scale ballistic test program havebeen discussed in the preceding quarterly report1 . The following supplementsthe earlier discussion.
'For description of test motor, control propellant, and preceding balistictest-data, see Ist Quarterly Report. AFRPL-TR-66-48.
-1!..LOCK1NE1E PROPULSION COMPANYV
L
AFRPL- TR-66-114 CONFIDENTAL 716-0-2
TABLE IV
COMPOSITION, LPC -1032 PR OPELLANTS
LPC- 1032B LPC- 1032C
Plastisol grade nitrocellulose ()10.85 10.85J,
Nitro isobutanetr iol trinitrate (%0) 50.10 49.25
Diethyleneglycol dinitrate M% 3.90
Ethyleneglycol dinitrate M% 3.90
Ammionium perchlorate, Type 11,Size 1 (%0) 20.15 20.00
2.-Nitrodiphenylarnine (70) 0.500')
Ethyl centralite (%7) 0.5o(0)
Beany ()15.00 15.00
()Beneficial effect of stabilizers, if any, in BeHa double-base propellantsnot established.
COIIPI4TIALLOCKHEED PROPULSION COMPANY
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TABLE V
BALLISTIC DATA, LOW PRESSURE FIR-'-.
LPC-1005
LPC-1032B Mod. 454
Firing No. P-16 P-14
Grain No. ZI8B *14A
Propellant wtCast 1.335 1.714Exhaust 1.288 1.681
Residue () 3.5 2.0
Nozzle Throat Area (in.2), Average 0.711 0.737
Expansion Ratio 8.027 7.735
Burn Rate (rb) 0.452 0.378
Chamber Pressure, _Pctq Z70 278
Mass Flow Rate (rh) 1.16 1.28
c* (ft/sec) 5650 5313
Measured Isp (total time, "av) 208.3 205.6
10 Corrected (Ibi-sec) 258.38 Z51.391000
Ign Corrected, 10 Corrected (lbf-sec) 255.98 249.5910o
tsp Efficiency(• 85.19 94.51
Ign Corrected, Isp Efficiency (%o) 84.42 93.83
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(C) The existing small motor test data suggest two different modesof combustion of BeHa and, as a result, differences in the controlling phe-nomena depending upon the predominant site of BeHa pyrolysis.
(U) (1) Combustion Mode 1
(C) If beryllium hydride (or aluminum hydride) decomposes toa significant extent with-in the gaseous combustion zone rather than within thesolid region, the controlling phenomenon is a nonequilibrium flame temperaturethat canbe computed assuming no metal combustion, or only partial metal com-bustion. This temperature has to be in excess of a threshold value which isgoverned by the metal ignition point. Small scale motor tests indicate that highcombustion efficiency is obtained if theoretical calculationa, ignoring heatlosses, affort a T* value (0%o metal combustion assumed) of 2300 to 2500 0K.This temperature threshold is expected to vary with mass flow rates (heat losseffects), implying that BeHa loadings can be slightly increased without reducingefficiency if heat losses are reduced (constant "effective" T*).
(U) In these Combustion Mode I systems variations in oxidizerparticle-size distribution do not significantly affect the controlling parameter.This affords freedom in manipulating interior ballistic properties. Moreover,since T* values in Combustion Mode I systems (relatively "cool" binders)increase with increasing AP loading, improvements in efficiency are paralleledby propellant density gains.
(C) Increasing tha chamber pressure wil cause a larger degreeof metal hydride decomposition within the solid region,, and produces a com-pensating surf~ce-cooling effect. In extreme cases, this can give rise to verylow pressure exponents. It can also result in an enhanced tendency towardmetal agglomeration, complicating an analysis of chamber pressure effects onIsp efficiency because of various counteracting effects.
(C) Typical Combustion Mode I systems are LPC-10•:9/LPC-1031 (BeHa/TMETN base propellants), the UTC AIH 3 nitrato polyester system.and the Thiokol A1-109 BeHW/NF-polymer system. It can also be assumed thatsome of the systems studied by the Atlantic Research Corporation representCombustion Mode I systems, provided beryllium-metal loadings are sufficientlylow to prevent excessive agglomeration.
(U) (2) Combustion Mode Z
(C) If beryllium hydride (or aluminum hydride) decomposes pre-dominantly within the solid region, the controlling phenomenon is a nonequilib-rium flame temperature that exists in the close vicinity of the surface. Thistemperature is difficult to evaluate theoretically since it is modified by chamberpressure (heat transfer to the surfacel, and solid oxidizer particle size (diffu-sion flame structure, varying degree of solid phase interaction).- If theselatter two var-iables are held constant, a theoretical comparison of systems ispossible by calculating the flame temperature (TV) that would exist prior to
-16-
COI AL LAOCK WEE PROPULSION COMPANY
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metal ignition, and ignoring any contribution from the solid oxidizer. Judgingfrom the existing small motor data, high I31, efficiency is obtained if theseTS* values are in excess of 21000K at 1OOO-spsi chamrber pressure.
(U) Implications, supported by the limited number of testdata are:
(U) (i) Reducing solid oxidizer particle size will enhance heattransfer to the surface, thus improving 1. efficiency (higher "effective" T~)In other words, Is efficiency is likely to be affected by attempting to modifyinterior ballistic properties.
(U) (ii) Reducing chamber pressure will adversely affect the"effective" T, and low I~, efficiency can be expected at low chamberpressures nfless Tg values are increased to compensate for this decrease ineffective Ts.
(C) (iii) As* BeHW/ loadings are increased, AP loading has tobe decreased to mainta pTS. and/or more energetic binders have to be used.A comparison of T* 0TTV Tc and I 5 data for two different binder systems(NIBTS double-base binder versus MiPDN double-bate binder) is given inFigure 5.
(C)t (iv) Increasing AP loading in systems using an energeticbinder inbud odceae75 and to cause enhanced metal. agglomeration(thermal an geometry effect).. This gives rise to a large density penalty as
Bel odn sincreasedL.I(U) The existing data are still insufficient to state to what anextent bum~r rate and Iep efficiency are interrelated in Combustion Mode 2 sys-tems. There is reason to suspect that such a relationship exists, and that itwill limit the range over which interior ballistic properties can, be varied.
(U) Z.- TASK, Ir,. LMH- I PROPELLANT SHELFLIFE
(U) a-~ GLs Diffi2sion. and. Solubility
(U) (1) Experimental Procedure
(13~ - Diffusion coefficients of hydrogen in. the propellants, areIbeing determined from rates of sorption, while the solubility is obtained fromthis equilibriuz% sorption. The apparatus is a modified safety (rupture) headfitting sand is showrt in Figure 6-,.-To, reduce the effects of teanperaturer fluctua-Itions, two such. cells are employed and are connected to opposite sides of theoil manometer. One cell. contains the propellat in the form of discs 2.9-inches in. diameter and 0. 1-inch thick, separated by- glass filter paper or athin metal. screen. The second- "blank" cell contains an equal.number ofaluminum discs similarly separated. so that the. free volume in. the tocells is
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nearly identical. The lead dome below the rupture disc serves the dual purposeof supporting the gasket-rupture disc during evacuation of the cell and of re-ducing and holding constant the free volume. Difficulty was encountered initiallyin consistently obtaining a hydrogen-tight system with the aluminum gasket-rupture discs normally employed with such safety fittings. Substitution of athin lead sheet appears to have solved this problem. (Plastic or rubber wouldof course be unsuitable in this application. )
(U) After assembly, both cells are checked for vacuum tightnesswith a helium leak detector, mounted in an oven and attached to the manometerthrough 1/8 -inch insulated copper tubing by means of Swagelok couplings. Asecond, more realistic check of gas tightness is then performed by reducing theair pressure within only the sample cell by an amount greater than expectedduring an actual sorption experiment and observing constancy of that pressuredifferential overnight. If the test is satisfactory, all air is removed from cellsand propellant by pumping overnight or longer, hydrogen is let into both cellsat the same pressure (essentially one atmosphere in experiments to date), and
-the rate of pressure drop due to hydrogen sorption by the propellant is measured.
(U) (2) Data Analysis
(U) Data analysis follows the suggestions of Crank (Ref. 2) andof Michaels, et al (Ref. 3). For sorption by a plane sheet immersed n alimited volume of solute the fractional equilibration, E, is given (Ref. 2) by
-L- ='j,(I+',)q E" .t/j]= [p(t)-pf ]•,~ ~ ~ ~ ~' [ !". I++" x, D•tL Pi Pf] (f
(U) - Here, D is the diffusion coefficient in cm-/sec, t is time in
seconds, and L is the thickness of propellant sheet in cm. Y is the ratio ofinitial pressure to total pressure drop, i. e.
- (2)
(U) Th- quantity qn is a solution of the transcendental equation
ta afqC 4 (3)
and is tabulated by Crank (ReL Z.-
(U) The initial pressure. pt, cannot be directly measured. If •the diffusion rate is too great, Pi may- be obtained by an extrapolation of ob-served, pressurei back to zero time. This procedure appears to be satksfactOr-
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in our experiments to date, although the con'trary has been claimed for diffusion'coefficients of the magnitude calculated f rom our data (D > 10-6 cm Ys ec).Alternatively, p1 may be determined by an iterative procedure with a computer(Ref. 4).
(U) For l-E less than 0.3, equation (1) is given to good approxi-mation by
I an exp 41)q t/L (4)
Thus D may be obtained from the slope in the linear portionof aplot of log (1-F4 versus time.
(U) Hydrogen solubility under the above experimer~tal conditions
in given within sufficient accuracy by
wher (P d V
wher Vpand VF- are respectively propellant volume and free volume withinthe cell. (VF/Vp is approximately unity for the experiments reported herein),and Vis the volume fraction of binder in the propellant.-
(U) ts) iiesufta
(U) 11gurv, 7 represent. the semi -log plots, according to equa-.tioni 4 for the datai from two experiments. The straight lines were drawn by,visual observation through the mid-portion of the points since the points at shorttimes will not necessarily follow equation 4, while those at long times are in-accurate due to. the subtraction. of nearly equal numbers..
(U) D and S values- calculated from the initial experiments whichwere carried out with. propellant. LPC- 101 8B without LMH- I are given inTable. W.
(UV Liaraturw values for- hyrdrogen diffusion constant in variousupstcised- polymer* range between 10' and 10-1 cma/sac4. The volues re-potdherw would therefore seem to beý of the proper magnitude. though they are
perhaps somewhat larger- than, had been anticipated. The activation energy for-diffusion calwulated from these data (Figure 8) is approsimately 9 keal/mole.This is somnewhat greater- thaan. the. range of values, reported for Ha in unpiasti-cised polymer& above their glass transition, e. g. 1, 6.6 kcalfmole and 7.6 kcal/molerfoa-Ha I&neopracwand polyisobutylene, respectively (Raf. 5). Repro-
duibility of thesolubilities, is a&&yet quite poor but their magnitude is of thesame order as- reported for Ha in. palymers .e. g. .0.3 cHa(T)in poly
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AFRPL-TR-66 -114 716-Q-2
TABLE VI
DIFFUSION AND SOLUBILITY CONSTANTS FOR H2IN PROPELLANT (LPC -10 18B WITHOUT LMH- 1)
Temperature Dg RZEiperimnent ()(cmz/Sec) 1 -atm-cc binde-r
AZ3-04 86 9 x 10-6lZx 10-
A23-11 90 4.1 x 10-1 1.7 x 10-6
A23-03 iZO 1.5 x 10-1 1.71x 10-6
A23-031 120 1.5 x 10-5 1.4x 10-6AZ3-13 140 2.3 x 10- 171x 10-6
A23-15 140 2.2 x 10-11 10O6
*Average value of S ina units of C at-c binder is00
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Furtherfore, Lawson quotes an estimated solubility for nitrogen in cordite of0.05 cc Nz(STP) (Ref. 8).
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(U) It should be pointed out that in both experiments at 140cFafter the apparent cessation of pressure drop within the sample cell a veryslow additional pressure drop wa& observed to occur over the next severalhours. Whether this represents, for example. a second-stage diffusionalprocess, a very slow leak, or a volume change of the lead gasket is not asyet clear. Because of this, however, and the preliminary nature of thesefirst experiments the present values of D and _. must be considered tentativeand any detailed discussion of their significance is unwarranted at this time.
(U) b. Gas Generation Rate (LMH-1 Stability)
(U) (1) Experimental Procedure
(U) A technique has been developed wherein the samples(LMH-l by itself or in propellant) are sealed in Ha-tight metal tubes which areconnected to a thermal conductivity detector through a val'.;ing arrangement.After permitting the H? to collect in the thermnostatted sample tube for knownperiods, the proper valves are opened, thus allowing a carrier gas (argon) toflush the collected Ha into the detector. As presently set up six samples canbe studied simultaneously. A bypass loop around the valve assembly permitsa continuous flow of'carrier gas through the detector and it also contains avalve with a calibrated loop for calibration purposes. in principie, this appa-ratus is capable of being automated, although this has not yet been done. Con-siderable difficulties were encounterei initially in obtaining a leak-tightsystem and with spurious liquid peaks but these have been resolved. Eachsample tube is checked for tightness with an He leak detector before beingplaced in an oven and connected to the valve assembly. No significant pressureor flow effects are now observed unless collection times are extended to thepoint where an appreciable Ha pressure has been built up. With the presentLMH-l sample (blend 97-131, a blend of Dow pilot-plant lots) for example,collection periods must be limited to only one or two hours at 140ýF during thepeak of the gas generation rate versus time curve. Tn general, the techniqueappears to be very satisfactory, its only serious drawback being the length oftime required to p-rge the sample tubes completely of Hz (up to one hour) andthe consequent slow tailing-off of the detector curve.
(U) (2) Results
(U) Survey experiments were conducted to define the tempera-ture range over which accurate measurements could be made with LMH- I blend97-131, within the limitations of reasonable sample size. It appears that 1008Fis a practical lower limit, requiring about 5-g LMH-l or 20-g propellant. Forthe upper limit 140°F was chosen since this has been the standard temperaturefor LMH-I stability measurements, using 0.25 to 0.5-g sample, or I to 2-gpropellant.
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(U) Measurements of H, generation rate as a function of timehave been conducted upon LMH- I blend 97-131 by itself and in propellants(formulation AZ3-06) at 100 and 140 0F. Curves of gas generation rate
j I H avg LMH- -hour versus time are shown in Figures 9 and 10. Numerical inte-gration of the smooth curves drawn through the experimental points in Figures9 and 10 yields the total amount of Ha generated versus time. as shiown inFigure II. The more usual percent decomposition versus time curve canbe obtained by multiplying the ordinates of Figure I I by 103 (e. g., after 700hours the pure LMH-I at 140OF is 48% decomposed). The following pointsmay be made regarding these data.
(U) * The rather large time gap in the data for pure LMH-!at 100OF and 140OF resulted from a breakdown of thethermal detector.
(U) The solid circles in Figure 9 result from measure-ments made after relatively long collection periods(at least overnight) wherein a sufficient Ha pressure/flow surge occurred upon opening the valves. Theinstrument calibration would certainly be invalid undersuch conditions. Those points do parallel the curvedrawn through the points obtained from short (I to 5hours) collection times.
(U) The- data scatter at 100'F is believed due to ratherpoor temperature control in that particular oven.
(U) The agreement shown in Figure II between these dataand those of Dow must be considered excellent in viewof the total errors involved.
(U) * In agreement with past experience the temperaturedependence of gas generation rate is very great. At100 hours for pure LMH-I the rate is approximatelyO O Hz - at 140OF and Illsh UIH
hr - g LMH- N- g LM-at 100°F; alternatively, it requires approximately 50and 500 hours to attain 0. 1% decomposition at 140 and100oF, respectively. Calculation of true activationenergies would, of course, nece.sitate kinetic analysisof the data. This has been done only in a very pre-liminary fashion in view of the limited data.
(U) o From the present limited data it appears that the LMH- Idecomposition rate is significantly greater in propellantthan it is in the pure state. At 100l F this effect couldconceivably be the result of the prior initiation of de-composition during the propellant cure at II 50F. However,this "pre-initiation" should have little influence upon the140OF behivior, where the influence of propellant appearsthe greater.
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(U) * It has at times been reported that some lots of LMH-Iare stabilized by propellant ingredients (Ref. 9), incontrast to the present results. In such experiments, r-however, it is essential that the amount of gas which isdissolved within the total sample (propellant, liquidingredient, or whatever) at any time is small comparedto the total gas evolved up to that time. This impliesprimarily that the rate of gas diffusion to the samplesurface(s) be large compared to the rate of gas genera-tion, I. e., that the gas diffusion constant be not toosmall and the surface-to-volume ratio of sample bevery large. For the experiments discussed herein thepropellant was chopped into I to 2-mm particles, andfor 2-mm cubes it may be calculated that with D - 10-4cma/sec the observed gas generation rate reaches abuut50% of the true value some 5 hours after decompositionbegins and about 97% of the true value after 10 hours.*For a 2-cm cube the comparable times are 500 and 1000hours. It might be objected that chopping the propellantinto small particles would also cut LMH-I particles,thus exposing fresh LMH-l surfaces which might thenlead to a significantly faster decomposition rate. How-ever, chopping the propellant into 2-mm cubes at mostwould cut only about 0. 1% of the LMH-I p"ticles.
(U) It had been hoped originally that the gas generatiop. ratecould be measured during both cure and storage in order to arrive at an. ex-pression for the rate which would exactly describe the complete generation pro-cess occurring in propellant surveillance samples. Unfortunately, the abovediffusion&l effect necessitates a thin film ( I to 2 mm) of uncured propellant andit becomes impractical vo obtain sufficient sample for accurate gas generationmeasurements.
SWeight of gas lost per cc of sample in which linear diffusion occurs to only
.-... one exposed surface is given by
GwVdt- c
where Vd represents the true rate of gas generation per cc and I is theaverage gas concentration (r/cc) within the sample at time t. Further.
-1 r ti' lr Iwhere A is the maxiknum diffusion path length and D the diffusion constant.For the present case with & cube 2 mm on a side, A* may be approximatedby 0.66 m •"
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AFRPL-TR-66-114 THIS PAGE UNCLASSIFIED 716-0-2
(U) c. L.MH-l Propellant Surveillance
(U) (1) Experimental Procedure
(U) Propellant ingredients (for surveillance as well as fordiffusion and gas generation measurements) are thoroughly dried and purified.Plasticizers, for example, are passed through a combined alumina-ion ex-change bed and subsequently dried in a Rotovap at moderately elevated tem-perature. The LMH- I employed to date is a blend of six lots of Dow pilot-plant material which was acrylonitrile-treated at Dow and subsequentlyretreated at LPC. Weighout of propellant ingredients is conducted in a drybox while mixing and casting are carried out in the humidity-controlled pro-cessing room of LPC's High Energy Laboratory. A given propellant prepara-tion is considered satisfactory only when tes: specimens exhibit at least 98% oftheoretical density after cure.
(U) Surveillance specimens are prepared by vacuum castingpropellant into lined, -cylindrical stainless steel cans. The primary specimensare contained in 1.1 -inch lID cans with propellant depths (maximum diffusionpath length) of Z, 3, and 6 cm. A minimum of 3 such specimens of each depthare prepared for each surveillance temperature or formulation variation. Such"case-bonded grains" have rather high length-to-diameter ratios and conse-quently may possess significant cure and thermal shrinkage-induced stresseswhich would complicate any- quantitative interpretation of shelflife solely interms of the gas generation-diffusion processes. Therefore, a limited numberof specimens are also prepared in 4-inch lD cans of Z.5-cm depth. The middleportion of these large diameter specimens should possess very little cure or
vmal ~ ~ ~ ~ ~ ~ P 1hikg te!ad~ud ~L.tl affe - ilby minor propelant-liner debonding which might greatly alter the diffusion process in. the smalldiameter specimens.
(U) After cure the specimens are stored in ovens with a veryslow nitrogen purge to maintain the exposed propellant surfaces essentially atsero hydrogen concentration. Periodically, specimens are removed brieflyfrom the ovens and tested for the presence of voids by determining whetherany dilation occurs under vacuum. For this test a specimen is placed in a belljar with the plunger of a standard thickness gage resting on its top surface;any movement of the plunger upon brief evacuation is taken as evidence for thepresence of voids. To minimise possible effects of this evacuation upon theintegrity of the specimens, and hence upon measured shelflives, this vacuumdilation, test is initiaUy performed upon only one or twn of those specimensexpected to fail first, e. S., 6-cm and 4-cmr deep.. After void formation hasbeen observed in this fashion. periodic X-rays of the specimens are obtainedto provide a more concrete demonstration of the presence of voids, and to assistin determining the locus of failure.
(U) Three formulations are used in this surveillance program.The first of these is a double-base system to be employed primarily as a vehiclefor studying the physical chemistry of the gas generation-diffusion-shelilife
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AFRPL-TR-66-114 THIS PAGE UNCLASSIFIED 716-:1-2
process, e.g., correlation of the parameters by means of the mathematicalanalysis and determination of such detailed factors as the influencq of solidscontent upon diffusion rates, and hence upon shelflife. The basic formulationis designated A23-06 (24.6f PNC, 9.17%TEGDN, 29.51 TMETN, 1.6% stabilizers,24.6% LMH-1). The other two basic formulations are a UTC polyester systemand an ABL crosslinked double-base system. Samples of these latter systemsare to be supplied to LPC by UTC and ABL for measurements of gas generationrate, diffusion/solubility constants, and shelflife of laboratory specimens.
(U) (2) Results
(U) Stainless steel surveillance containers were fabricated andsand blasted and the appropriate number shipped to UTC and ABL for the prepa-ration of surveillance specimens from their formulations. The necessaryquantity of LMH-l from blend 97-131 was also shipped to UTC and ABL. Pro-pellant samples are scheduled to be returned to LPC during the month of May.
(U) Table VII presents some preliminary surveillance data ob-tained at 115 0 F for propellant A23-06 (LMH-l blend 97-131) in copper containersand in a plastic container. Although failure times are very short, obviouseffects of diffusion path length and exposed surface area can be seen in thelonger life of S-2 cm and P compared to that of S1-6 cm and S'-4 cm. After the48-hour tests had indicated voids in all metal containers by vacuum dilation butnone by X-rays, attempts were made to deterrmine whether the vacuum dilationincreased regularly with time in the hope that a correlation might be made be-tween extent of dilation and first appearance of voids by X-ray. No trend indilation readings became apparent, however, even though an effort was made toreproduce evacuating time and final pressure. In all subsequent experime-ntstherefore, the vacuum dilation test is to be regarded as qualitative in nature andevacuation times are kept at a minimum (- 15 seconds) in order to preclude anydamages to the specimens.
(U) Surveillance data obtained to date for propellants A23-06 andA23-06C (control propellant with equal volume of aluminum substituted for blend97-131 LMHdI) in the stainless steel containers are presented in Table VIIIThe following comments may be made.
(U) The reason is not clear for the apparently shorter life ofthese 6 and 4-au specimens compared with those of Table VII. In general,however, failure occurs too rapidly at 1 159F with this formulation and theLMH-I sample to permit any sensible study of the effects of variables orcorrelation with parameters. Subsequent measurements with this system will
be restricted to 756F storage or to the use of the more stable LMH-l samplessoon forthcoming from Dow.
(U) As in past experiments, the vacuum dilation test possessesgreater sensitivity for voids than does X-ray. Since no other obvious correla-tion appears, both techniques must continue to be employed. It should be
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TABLE Vt!
PRELIMINARY SURVEILLANCE DATA AT I 15OFFOR FORMULATION A23 - 0 6 a)
Time to Observe Voids (H~ours) (c)ame(b)________
Sample_ Vacuum Dilation X-Ray
S t-6 cm: > 0; < 24 3w 48; < 600
S'-4 crn >0;< 24 3w48;< 600
S'-2 cm >Z4,< 49 3w48; <600
P >48 ,4;< 600
(a). Propellant density after cure in P container 98% of theoretical.
(b) S' samples in copper can@ 1.0-inch MD and designated depth ofpropellant. P sample in. polyethylene container, 3.8-cmdiameter and 5-cm deep.,
(c) Time beyond 17-hour cure at 1 150F%
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"g 96 414 ~..-' 4'o5lob
r4 a4'
*f k s
in n1 i. qto4 U J4_
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LOCKUEED PROPULSION COMPANY -
AFRPL-TR-66-114 THIS PAGE UNCLASSIFIED 716-Q-Z
pointed out that holei 1/3a, 1/16 and 1/s inch in diameter and depth were drilledinto the top surface of some of the control samples. Top-view X-rays showedthe 1/16 and '/a -inch holes but not the i/3z-incb.
(U) The observed upward "plug" movement of the propellantmust be a consequence of the combined effects of the presence of maximum gasconcentration at the bottom, of maximum cure and thermally-induced stressesin that region, and of rather poor liner-propellant bonding. Since this mode offailure creates new paths for difussional losses of hydrogen, the interpretationof failure time and mode becomes cloudy for the central region of the L (4-inchdiameter) samples, where cure and thermally induced stresses should be verysmall. It may be desirable, therefore, in the future to cure large diameterspecimens of that depth, cut out the central portion and pot it into S-4-cmcontainers.
(U) From the composition of propellant A23-06 it can be cal-
culated that a hydrogen solubility of 2 x 10"6 (c. f., Table VI) requires
a total hydrogen generation of 4 x 10-6 This in turn can be seeng LMH- Vfrom Figure 11 to require about 10 hours at 140OF and Z5 hours at 1000F in theabsence of diffusional losses. Plotting the logarithm of these times versusreciprocal absolute temperature yields a first approximation the corresponding"saturation times" at ll 50 F and 75OF of 17 and 50 hours, respectively. Theselast rumbers are both approximately 1/3 the observed shelflife of the 6-cm deepsurveillance specimens. Considering the rather preliminary nature of thevarious data and the fact that swunr ,fusional losses will have occurred in thesurveillance specimens4 , such agreement at this stage must be "onsideredencouraging.
(U) Exact analysis of surveillance data with the diffusion-gasgeneration equations necessitates having an analytic function for gas generationrate at the surveillance temperatures plus subsequent computer calculations ofgas concentration as a function of time and geometry. In view of the prelimi-nary status of all the data, such analyses are not yet warranted.
____ _I'
* Diffusion may be neglected in general when Dt/ <0.0S. At ll5* fora Dofl I X10" cmr/sec, t ofl SOhours, and I of6fm, Dt/a a 0.15. At 7SFfora D of 5 x 10"6 cma/sec, t of 50 hours and L9of 6 cm, Dt/,a a 0.25. Thus,•thin our certainty in D some amount of diffusion almost certainly has taken
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"LoCKH690 PROPULSION COMPANY
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REFERENCES - TASK II
1) LPC 716-Q-1, AFRPL-TR-66-48, March 1966.
2) Crank, 3. , The Mathematics of Diffusion, Clarendon Press, Oxford, 1956.
3) M'-haels, A. S., Veith, W. R.., Bixler, H. 3., Polymer Letters 1, 19, 1963.
4) Lundberg, J. L., Wilk, M. B., Huyett, 3., 3. Polymer Sci., 57, 275, 1962.
5) DiBenedetto, A. T., 3. Polynm. Sci. Al, 3477, 1963.
6) Meares, P., JACS 67, 3415, 1954.
7) Norton, F. 3., 3. AppI. Polym. Sci., 1649, 1963.
8) Lawson, C.G., ER.DE, 8/M/58, June 1958.
9) UTC 2068-FR, 15 July 1965.
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AFRPL-TR-66-114 THIS PAGE C SSID716-0-2
S*SECTION IV
BERYLLIUM HEALTH PHYSICS PROGRAM
(U) A summary of all monitoring sample data taken during February,March, and April is given in Table IX.
(U) During this period, air monitors in Building 11 9A laboratory wererun during all working hours, the filters being analyzed for Be every 1, 2or 3 weeks, depending upon the work load in the laboratory. During low workperiods the monitors were allowed to run for a longer time period betweenanalyses to enhance the detection of possible contamination.
(U) The strand burner equipment and operation (Building 114) were modifiedto accommodate Be propellant strand burning. An absolute filter was mnstailedin the hood exhaust system with a corresponding increase in air flow -,.• of theexhaust. The bomb vent was also adapted with an abaSelute filter to minimizeair contamination. The burning procedure was modified to maintain surfacecontamination within the hood.
(U) Two motors containing beryllium hydride were tested at LPC'a PotreroProduction and Test Facility during this period. On April Zgth. a 20-poundmotor overpressurized and the propellant buzrned slowly out in the openConsiderable air contamination was detected downwind from the teas site, butthe contamination was not considered serious because berylliuma motors aretested only when the wind carries possible contaminat ion away from personnelareas and into the unused portion of LPC's Potrero facility.
'Although this motor firing was conducted under a different program, allmonitoring data are reported here.
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TABLE IX
BERYLLIUM MONITORING DATA
Feb IS - Mar 4 lFib 2h .Mar 4 Mar 19-. MarZI Uar2-Apr? AprS- MayLaboratory, Building 119A (S daye) (6 day.s) (9 days) Mar daye1 (Ap daye,
Sample Satllon No. I
m' air eampled 30 36 30 101 90
on so 3.. ail sil 1. 1.0
0 a Be/mr 0.13 .... 0.02 0.04
Sample Station No. 2
m, air sampled 30 36 30 100
pg3 Be '0.1 nU ril nil Nil
0 g Be/mr nil ....
Sample .tation No, 3
m' air sampled - 30 36 30 100 90
pea Bc o0. I nil all 1.0 vi0it 3./rn nil ..a. 0.0 sit0.S
Sample Station No, 4
mn'air sampled 30 34 10lO49
I& B3
0.6 nil 1.3 nil
e a l/r/m' 0.0 ... 0.01
Sample Station No. 5
m' air sampled 30 36 30 100 90
IBe nl nil o ll sitIe I Be/rn......
Sample Station No. 6
m's ir sampled 30 34 0 101 00
t b.e all all nil 3.6 nil
e g 3./mrn 0.0J
r-meenenl r-gCitly. •UtlIOtII Itli
Mis No. o37/3ll
!tM* April 21
-'~air ol 9w g 1e/rn'
Pro essimt Room
Static. I - upper head 4.0 si t.
Stati. a * lower bed 4.0 1.3 0.81
Control Room
Station c 4.0 sli
Strand atroing. Building 114
DaeApril 12 May &
rno air u a, a. se/rn' - 1 air Ej~a l, eg 3./rn'
Heed 34 W90 ".5 34 1.2 0.04
Deow e**bow 34 all o- 34 0.1 0.34
Potrero Open Air nring.. Be•ylillen Meagre
Dale AW SMUy)
Sample Time 10 misiles S mi111100
Creeewlnd Sampl*
m5
, air 9.6 LU
o ISo 9.0 All
pg 6 Was, 0.M0
Deonwind Sample
m, ,r 9.6 LS
pas g . 50 4.2J ge/rn' P29.0 L3
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W__l LOCKHEKO PROPULSION COMPANY
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UNCLASSIFIEDSmcufty Classification
DOCUMENT CONTROL DATA - R&D(S.I..'A41 oE*1kl.p fl. not* .boo o bf ,. *"#- ..d .. _eff~ .# so .pe..d hon.. am O.64.Wo -~. PON .. 4
Lo$ he OropINAo TON A1ýo' = - Anay1C9" sc"r 111FCTDivis•ion o f Lockhe ed Ai rc raft Co rpo rationI a ON6IDENTARedlands, California 92374 a ,o 4
11 "apoT TITLE
CHARACTERIZATION AND EVALUATION OF LIGHT METAL HYDRIDES (U)
4 oESciNPTIVE NO-aS (Tr,"s mo- e6. 1..e.. do.)
Quarterly R•-port No. 2, covering period I February through 30 April 19665 AV TNO S1S fLoa. n40. R.0 ff5 .• 56460
Baumgartner. W.E. and Myers. G.
6 11E1PONT OATS Y0@A6 MID. PAGE 0=7 76, ". 01 EVPS
June 1966 47 9S. CON ?WACV @ 00a. ff0." "o, 610146IN&eaNs OEPT "W"ORMqS1
AF 04(611)-I 1219a -. sejatc No. LPC Report No. 716-Q-2
Air Force Program Structure No. 75OG
Project No. 3148, Task No. 314804 No-,
IS 0 AV IL AGSLITV'INIAYTtOff NOTICES
Qualified requesters may obtain copies of this report from DDC.Foreign announcement and dissemination of this report by DDC is not authorized.
II SUPPLE•ENTARY NOTES Ii. SPONSORING WIUTARY ACIMTY
Air" Force Rocket Propulsion LaboratoryResearch aid Technology DivisionAir Force Systems CommandTTni•4mg Stom,* Ai y- o ', -. g•lf
I AGITRACT T
Evaluation of Beany material of recent production shows distinct improvementsin the material's particulate structure. Propellant mixes using the newermaterials gave low mix viscosity prior to ball milling. Analytical data aresummarized.
A Beany double-base propellant was fired in a small motor at low chamber pres-sure. A significantly lower efficiency was obtained than was measured in a cont-rol motor fired under closely similar (mass flow rate., pressure) conditions.
Experimental work was continued in obtaining basic data for LMH-I propellantshelf-life prediction. Initial data on gas generation rates, gas diffusion andsolubility are reported.
DD FO°N" 1473 UNCLASSIFIEDsaet Cle|sedc,,,ion
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Characterization and Evaluation of Light MetalHydrides
Solid Rocket Propellants
Fuel s
Solid Propellant Applications
Propellant She-if Life
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