NATIONAL BUREAU OF STANDARDS REPORT

10 069

COMPATIBILITY OF PROTECTIVE COATINGS, MATERIALS, AND LIQUID PROPELLANTS

QUARTERLY PROGRESS REPORT NO. 14

April 1 to June 30, 1969

For

Picatinny Arsenal Project

Order No. A1-8-RF034G01-D1-GG

To

Commanding Officer

Picatinny Arsenal, Dover, N. J. 07801

Attn: Code SMUPA DL-2

Liquid Rocket Propulsion Laboratory

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards ' was established by an act of Congress March 3, 1901. Today,

in addition to serving as the Nation’s central measurement laboratory, the Bureau is a principal

focal point in the Federal Government for assuring maximum application of the physical and

engineering sciences to the advancement of technology in industry and commerce. To this end

the Bureau conducts research and provides central national services in four broad program

areas. These are; (1) basic measurements and standards, (2) materials measurements and

standards, (3) technological measurements and standards, and (4) transfer of technology.

The Bureau comprises the Institute for Basic Standards, the Institute for Materials Research, the

Institute for Applied Technology, the Center for Radiation Research, the Center for Computer

Sciences and Technology, and the Office for Information Programs.

THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United

States of a complete and consistent system of physical measurement; coordinates that system with measurement systems of other nations; and furnishes essential services leading to accurate and

uniform physical measurements throughout the Nation’s scientific community, industry, and commerce. The Institute consists of an Office of Measurement Services and the following technical

divisions:Applied Mathematics—Electricity—Metrology—Mechanics—Heat—Atomic and Molecular Physics—Radio Physics -—Radio Engineering -—Time and Frequency -—Astrophysics -—Cryogenics.-

THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research leading to im- proved methods of measurement standards, and data on the properties of well-characterized

materials needed by industry, commerce, educational institutions, and Government; develops,

produces, and distributes standard reference materials; relates the physical and chemical properties of materials to their behavior and their interaction with their environments; and provides

advisory and research services to other Government agencies. The Institute consists of an Office of Standard Reference Materials and the following divisions: Analytical Chemistry—Polymers—Metallurgy—Inorganic Materials—Physical Chemistry.

THE INSTITUTE FOR APPLIED TECHNOLOGY provides technical services to promote

the use of available technology and to facilitate technological innovation in industry and Government; cooperates with public and private organizations in the development of technological

standards, and test methodologies; and provides advisory and research services for Federal, state, and local government agencies. The Institute consists of the following technical divisions and

offices; Engineering Standards—Weights and Measures — Invention and Innovation —Vehicle Systems Research—Product Evaluation—Building Research—Instrument Shops—Measurement Engineering—Electronic Technology—Technical Analysis.

THE CENTER FOR RADIATION RESEARCH engages in research, measurement, and application of radiation to the solution of Bureau mission problems and the problems of other agencies and institutions. The Center consists of the following divisions; Reactor Radiation—Linac Radiation—Nuclear Radiation—Applied Radiation. THE CENTER FOR COMPUTER SCIENCES AND TECHNOLOGY conducts research and

provides technical services designed to aid Government agencies in the selection, acquisition, and effective use of automatic data processing equipment; and serves as the principal focus

for the development of Federal standards for automatic data processing equipment, techniques,

and computer languages. The Center consists of the following offices and divisions; Information Processing Standards—Computer Information — Computer Services — Sys- tems Development—Information Processing Technology.

THE OFFICE FOR INFORMATION PROGRAMS promotes optimum dissemination and

accessibility of scientific information generated within NBS and other agencies of the Federal government; promotes the development of the National Standard Reference Data System and a system of information analysis centers dealing with the broader aspects of the National Measure- ment System, and provides appropriate services to ensure that the NBS staff has optimum accessibility to the scientific information of the world. The Office consists of the following

organizational units:

Office of Standard Reference Data—Clearinghouse for Federal Scientific and Technical Information ' —Office of Technical Information and Publications—Library—Office of Public Information—Office of International Relations.

' Headquarters and Laboratories at Gaithersburg. Maryland, unless otherwise noted; mailing address Washington, D.C. 20234. Located at Boulder. Colorado 80302.

^ Located at 5286 Port Royal Road, Springfield. Virginia 22151.
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT

3120465 July 1, 1969

NBS REPORT

10 069

COMPATIBILITY OF PROTECTIVE COATINGS, MATERIALS, AND LIQUID PROPELLANTS

By

J. P. Young and G. I. Reid

QUARTERLY PROGRESS REPORT NO. 14

April 1 to June 30, 1969

For

Picatinny Arsenal Project

Order No. A1-8-RF034-01-D1-GG

To

Commanding Officer

Picatinny Arsenal, Dover, N. J. 07801

Attn: Code SMUPA DL-2

Liquid Rocket Propulsion Laboratory

IMPORTANT NOTICE NATIONAL BUREAU OF S

for use within the Government, and review. For this reason, tl whole or in part, is not authc Bureau of Standards, Washing

the Report has been specificall

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.

ess accounting documents intended

s subjected to additional evaluation

e listing of this Report, either in he Office of the Director, National

by the Government agency for which

copies for its own use.

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
f >5- I' i^A ; -« fi ^rr :« ^ \h%

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COMPATIBILITY OF PROTECTIVE COATINGS, MATERIALS, AND LIQUID PROPELLANTS

A. Objectives of Project

1. To investigate the effect of various coatings and materials for

their ability to withstand the corrosive effects of hydrazine fuels and

oxidizers, and for freedom from catalytic effect on the decomposition of

fuels and oxidizers.

2. To develop procedures for applying coatings, disclosed as satisfactory under part (l), to the interior surfaces of rocket and missile

fuel tanks of complex shape.

B. Summary of Progress in Preceding Quarter

1. Decomposition of MHF-3 fuel in contact with various materials

There was little chainge in the activity of any of the metals in

contact with MHF-3 at l60°F. Tests of some materials, including some

stainless steels, were discontinued because of a persistent high rate of

fuel decomposition. Sixteen new specimens were assembled in test units

and testing started.

2. Experiments on kinetics of fuel decomposition

A unit containing uncoated Managing steel with end caps of

cadmium was added to the group to test the effect of exposed steel.

The activity was lower than for Managing steel alone and was decreasing.

Results of the effect of metal area to fuel volume indicated

that the volume of gas produced per unit area per day by a metal is independent of the A/V ratio for the two coatings tested, electrolytic

nickel and electroless nickel.

3. Decomposition of Aerozine-^0 fuel

Tests of Managing steel and Teflon coated aluminum with this

fuel were discontinued because of excessive activity. Other materials,

including 301 stainless steel, titanium. Teflon and MP35N steel, were

still under test at l60°F.

U . Exposure of materials to UDMII fuel

Two units containing uncoated Managing steel specimens show

little activity at l60°F.

5 . Exposure of materials to oxidizers

There was a slight decrease in the activity of specimens in NTO

(Nitrogen Tetroxide) at l60°F. Activity of specimens in IRFNA (red

fuming nitric) at 90°F was practically nil.

C. Summary of Progress During Current Period

1. The rates of fuel decomposition caused by specimens exposed to

MHF-3 at i 60°F remained substantially the same as in the previous quarter.

Several units with higher rates were discontinued at the end of this

quarter. Fourteen new units were started, including MS coated aluminum

by three different companies, two types of steel, and a vaporizedalurainum coated cylinder of Maraging steel. Data on the lonits containing

MHF-3 are given in Table 1 and Figure 1.

2. Effect of porosity of coatings on MS

Tests of the effects of pores in coatings and exposed areas of

Maraging steel adjacent to coating metals were continued. Rates for

specimens plated with cadmium are low and decreasing while the rate for

one speicmen partially coated with electroless nickel is high, as shown

in Table 2.

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3. Decomposition of Aerozine-^0 fuel

The unit containing 301 stainless was terminated because of a

consistent high rate of fuel decomposition. Rates for titanium and

Teflon did not change significantly. The MP35N alloy steel has a high

rate of fuel decomposition (Table 3).

k. Exposure to UDMH fuel

A background unit containing no specimen has been added to the

two units with UDMH and Managing steel which have a low rate of fuel

decomposition (Table ^).

5 . Exposure of materials to oxidizers

Table 5 shows that the rate of gas evolution for 301 stainless

steel. Teflon, Managing steel, and titanium in contact with NTO remained

very low for the current period.

Specimens of Teflon and 301 stainless steel have very little

reaction with IRENA at 90°F. Managing steel shows some activity.

D. Details of Progress During the Current Report Period

l. Decomposition of MHF-3 fuel in contact with various materials

at i60°F

a. "Background" rate .

The average rate of evolution of gas in blank (no specimen)

mercury manometer test units Hg-2 and Hg-15 has remained the same at

3 0.0037 cm /day during the present period. The rate of the large size

background unit has also remained about the same and is close to the

value for the standard sized units above. Therefore, it was not considered necessary to use a separate value in calculating results in the

3

larger units. This result is consistent with previously obtained

fuel-volume/surface-area relationships in the decomposition of fuel.

It was determined that decomposition occurred mainly in the fuel itself and very little at the fuel-glass interface,

b. Effects of various metals

Table 1 and Figure 1 contain the cumulative results to the

end of June 1969 . The relative reactivity of the various specimens is

as follows

Low Activity : solder ( 50/50-Pb/Sn) , titanium, aluminum,

silver, 3^7 stainless cadmium, 355 stainless, electroless

nickel (std. acid bath), zinc, tin-nickel alloy, tin,

tungsten, lead, dip coated solder ( 50/50-Pb/Sm) , Teflon

coated MS, oxidized nickel, 301 stainless, dip coated

lead-tin alloy.

Moderate activity : gold, nickel, stainless Managing steel,

chromium, electroless nickel 0.1 mil thick on MS, silver

0.5 niil thick on MS and GE aluminum on MS.

High activity : cobalt, l8^ Managing steel, molybdenum,

iron, AM 355 stainless, Inco 718, Commonwealth Scien. vapor

aluminum on MS , Dow Chemical aluminum on MS.

( l) Behavior of recent units

The performance of several coatings of aluminum on

Managing steel (MS) specimens was disappointing. The high rate of fuel

decomposition (see Table l) must be attributed to porosity or incomplete

coverage of the MS as aluminum itself has little reaction with fuel.

The types of application and the companies who furnished specimens are

as follows

Hg-9^-97 Vapor deposition. Commonwealth Engineering, Inc.

Hg-lOU Electrodeposited from organic (ether) bath. General

Electric Company.

Hg-105 Electroless plated, Dow Chemical Company.

U

Of these three coatings, the electrodeposit from the ether bath was by

far the least reactive. This is most likely because of its thickness

of about 2 mils. The two other deposits were less than 0.2 mil thick.

The surface of the vapor deposited coating was quite rough, as shown in

Figure 3. The appearance of the electroless coating was dark, dull and

uneven. Only the electrodeposited coating had the normal white color of

aluminum.

A test was developed to check the continuity of a coating on Managing steel. It consisted of boiling a specimen in distilled

water for bne-half to two hours and then letting the specimen stand in

the water overnight. Any porosity was indicated by rust spots. Of the

three aluminum coatings listed above, only the electrodeposited alimainum

showed no rust spots.

A second specimen of electroless nickel from the citrate

bath on MS (Hg-99) resulted in a low rate, normal for this type of

deposit

.

A new high alloy, steel, MP35N (Hg-99) > produced by the

Latrobe Steel Company, had a very low reaction rate with MHF-3. Another

steel, 301 stainless, had been exposed to oxidizers (NTO IRFNA) previously

but not to MHF-3. Two specimens in units Hg-lOO and 101 indicate very

low reaction rates

.

A cadmium-tin alloy dip-coated MS specimen was prepared

and exposed to fuel in unit Hg-102. It had a very low reaction rate.

Results to date show that lead-tin or cadmium-tin alloys have among the

lowest rates of fuel decomposition. They are inexpensive and may be

5
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applied to the steel by mechanical methods. For these reasons they show

much promise as fuel tank coatings for missile tankage systems produced

on a volume basis.

The special aluminum alloy, 2021, furnished by the

Aluminum Compary of America (Hg-96 , 98 ) gave no reaction with the fuel

during the first 80 dt^ys of testing.

( 2) Deposit thickness tests on Managing st eel

Although the fuel decomposition rates for thin cadmium

deposits of from 0.1 and 0.2 mil (Hg-l6 ,27 ,8l) are in the low range and

are decreasing, the rates for similar thin deposits of electroless nickel

(Hg- 82 , 103 ) are substantially higher than for thicker deposits of 1 to

2 mils (Hg-12 ,6l)

.

( 3 ) Aluminum coated MS cylinder

A 1 " diam. J" long cylinder of MS furnished by Mr. Ng

(Picatinny Arsenal) was vapor coated with aluminum on the inside surface

by Commonwealth Scientific Corporation. The deposit was in the order

of 0.6 mil average thickness. The cylinder was fitted with aluminum

end-plugs and Teflon gaskets. One end-plug was machined to allow attachment of a valve and pressure gage. The cylinder was cleaned and filled

to 10^ ullage with MHF-3 and tested at l60°F. Data are given in Table 1,

No. 110. Initial results indicate a low reaction rate with the fuel in

spite of the poor showing of the above mentioned MS specimen with a

thinner coating by the same process.

6
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fli
2. Results of experiments on the effects of porosity

in coatings on MS

The rate of fuel decomposition of the cadmium plated Managing

steel specimens with one-half of the steel surface exposed (Hg-5l)

,

the cadmium plated MS specimen with pores drilled to expose the steel

(Hg- 63 ) and the MS specimen with end caps of cadmium (Hg-8i+) continued

to decrease. This considerable reduction from the normal rate of decomposition of MHF-3 by MS is attributed to the cathodic protection afforded by the cadmium. The rates in Table 2 are based on the area of

exposed MS.

The specimen consisting of electroless nickel on MS with onehalf of the steel surface exposed (Hg-7l) continued to have a rate

nearly ten times that for MS in contact with cadmium. The rate did

decline somewhat from that of the previous quarter, however.

3. Fuel tanks to be plated for Picatinny Arsenal

Two one-half scale fuel tanks have been modified and heat treated

by the NBS shops. One tank is to be coated inside with aluminum.

General Electric Company, which has large facilities for plating aluminum

from the ether bath, is now preparing an estimate for the aluminum coating job. The other tank is to be dip coated with a 50/50-lead/tin

solder coat. An initial attempt at tinning the tank by coating with

zinc chloride flux, heating and pouring in molten solder did not give

a satisfactory coating. Two other methods are now iinder consideration

for covering the inside surface of the tank with a continuous coat of

solder.

7
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U. Decomposition of Aerozine-50 fuel in contact with various

materials at l60°F

The ’’background" rate for this fuel in a unit with no specimen

has increased further from 0.007^ to 0.008^ cm /day. The fuel decomposition rates for titanium and Teflon increased very slightly. The new

unit containing MP35N alloy steel showed a rather high rate of decomposition during the first U8 days of testing. The data are shown in Table 3.

5 . Decomposition of UDMH in contact with specimens at l60°F

The results of the exposure of two specimens of MS to UDMH

(unsymmetrical dimethyl hydrazine) fuel are shown in Table The reaction rate is low.

6. Exposure of various materials to oxidizers

Results of the tests in nine bomb-type units are given in Table 5

and Figure 2. The four units containing NTO (Nitrogen Tetroxide inhibited

with 0.6 0.2^ of nitric oxide) at l60°F containing 301 stainless.

Teflon, MS and titanium changed very little during the quarter and all

had a low reaction rate. Also, the small 301 stainless tank containing

NTO at 90°F did not change from its previous zero reaction rate.

During this quarter the units containing IRFN (red fuming nitric

acid inhibited with 0.7 ± 0 . 1% hydrogen fluoride) were run at 90°F because

of the relatively rapid loss of the inhibitor at l60°F and the resultant

attack on the stainless steel units. At this temperature the reaction

rate is very low except for MS which showed some activity on a new specimen started when a previous specimen failed after eleven months of exposure. A sudden increase in pressure in the unit resulted when the

8

first MS specimen was attacked by the IRFNA. The 60 mil thick specimen

was perforated and lost about one-half its weight. It is shown in

Figure U.

Two fluorocarbon resin dispersions were obtained for use in

coating the inside of the metal test units to reduce reaction with the

oxidizers and for possible testing as tank coatings. The materials

are TFE-30 fluorocarbon resin dispersion manufactured by DuPont, and

Kel-F dispersion grade KF-633 produced by the 3M Company. The disper1 sions may be applied by dipping or spraying and in the case of TFE-30

by electrodeposition. However, initial attempts to obtain a pore-free

coating by electrodeposition that did not crack on sintering at 760°F

were not successful. Stainless steel tubular specimens were dip coated

and sintered and the resxilting coating withstood IRFNA for several days

at room temperature with no visible effect. The main difficulty was

obtaining good adhesion to the stainless steel surface. However, it

was felt that these fluorocarbon resin coatings were sufficiently effective to be used for protection of the inner surfaces of test bombs

used with IRFNA.

D. Summaiy

The results of the compatibility tests thus far show that different

coatings in the acceptable low reaction range have different benefits

as follows

Ease of application - electroless nickel

Greatest protection of MS in fuel - cadmium

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aluminum

Widest range of protection from both

fuels and oxidizers

Best possibilities for use as thin-film

collapsable fuel tank liners oxidized nickel

Low cost protection of steel - solder ( 50/50-Pb/Sn)

Other materials which our tests show might be used alone or in conjunction with others and are acceptable for use with fuels and/or

oxidizers are: titaniijm, stainless steels 301, 3^T» 355AM (oxidized),

lead, tin, silver and Teflon.

E. Further Work

It is recommended that further work be done to complete the investigation of materials for possible use in the tankage for the four liquid

propulsion systems imder consideration. This would include the following:

Compatibility tests of the most promising coatings with

Aerozine-50, UDMH and MHF-5.

Stress corrosion tests of the best coatings on MS and

the four fuels

.

Tests of aluminum coatings with oxidizers.

Metallurgical examination of exposed specimens.

Experimental plating or coating of one-half scale and full-size

fuel and oxidizer tanks.

USCOMM-NHS-DC 10
I 1

I
TABLE 1

Summary of Test Data for Materials

Exposed to MHF-3 at 160 °F

Test Specimen Area of Time

* Gas

* Rate

** Calculated

unit (Deposits are 2 mils speci- under- evolved coefficient tank pressure

number min. unless other- men test cm^ cm^/day/ cm^ after 1 year

wise noted) cm^ days previous present psig

Hg-2

Hg-15

Background

Background

--)

__)av. 909 3.35 0.0037 0.0037 —

Hg-48 3- C Aluminum ’ 12.5 566 1.7 0.00019 0.00024 3 Hg-94 c Aluminum on MS

( 0.2 mil thick)

14 43 53.6 — 0.0890 940

Hg-97 Q Aluminum on MS

(0.2 mil thick)

14.3 26 57.4 — 0.1544 1629

Hg-96 Aluminum^, Type 2021 11.8 80 0.1 — 0.00011 1 Hg-98 Aluminum^, Type 2021 11.8 80 Zero — Zero Zero

Hg-104 Aluminum on MS

by General Electric Co.

14 10 1.5 — 0.0107 113

Hg-105 Aluminum on MS

(0.2 mil thick)

by Dow Chemical Co.

14 10 10.8 0.0771 814

ho. 110 Aluminum coated MS 114.4

cylinder^ (0.6 mil)

4 2.2 — 0.0048 51

Hg-31 Cadmium 14. 7 705 1.9 0.00012 0.00018 2 Hg-16 Cadmium (0.5 mil) 9.4 861 13.4 0.0015 0.0017 18

Hg-27 Cadmium (0.5 mil) 10.6 720 7 0.0009 0.0009 10

Hg-81 Cadmium (0.1 mil) 14.4 94 5.7 0.0059 0.0042 44

Hg-80 3 Cadmium 13.4 148 7.9 0.0060 0.0040 42

Hg-102 Cadmium-tin alloy

(Dipped coating on MS)

14 49 1.5 — 0.0022 23

Hg-12 Electroless nickel 22.2 879 19.1 0.00097 0.0010 10

Hg-61 Electroless nickel

(800°C

12.2 396 5.6 0.0011 0.0012 12

Hg-77 Electroless nickel 15.0 141 9.9 0.0047 0.0047 49

Hg-82 Electroless nickel

(0.1 mil)

15.3 151 23.8 0.0078 0.0103 109

Hg-90 Electroless nickel

(oxidized)

14.4 126 8 0.0061 0.0044 47

Hg-103 Electroless nickel

(0.3 mil thick)

15 47 14.4 — 0.0204 216

Hg-106 Electroless nickel

from citrate bath

13.6 17 0.5 — 0.0022 23

Hg-87 Maraging steel

(oxidized)

15.0 89 90 0.0835 0.0674 712
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TABLE 1 (cont.)

Summary of Test Data for Materials

Exposed to MHF-3 at 160°F

Test

unit

number

Specimen Area of

(Deposits are 2 mils specimin. unless other- men wise noted) cm^

Time

under

test

days

* Gas

evolved

cm^

* Rate

coefficient

cm Vday/ cm^

previous present

•k'k Calculated

tank pressure

after 1 year

psig

Hg-57 Nickel 14.0 496 27 0.0042 0.0039 41

Hg-75 Nickel (oxidized) 18.5 179 13.9 0.0041 0.0042 44

Hg-29 Silver 14.5 716 3.5 0.00025 0.00037 4 Hg-22 Silver (0.5 mil)^ 16.0 774 138.9 0.0112 0.0172 181

Hg-33 Solder (Pb/Sn,

50-50)^

15.3 705 Zero Zero Zero Zero

Hg-91 Solder (Pb/Sn,

50-50) (Dip coated)

14.3 110 0.7 0.0015 0.00045 5

Hg-107 Solder (Pb/Sn,

50-50) (Dip coated)

14.1 3 Zero — Zero Zero

Hg-14 Stainless steel

(347)a

13.2 888 Zero Zero Zero Ze ro

Hg-28 Stainless steel

(347)3

6.5 716 9.6 0.0019 0.0021 22

Hg-43 Stainless Managing

steel3

15.0 605 48.9 0.0058 0.0054 57

Hg-74 Stainless steel

(AM355)^

(oxidiaed in air at 500°

18.5

F)

196 7.1 0.0021 0.0019 21

Hg~89 Stainless

(301, aged)3

14. 7 131 13 0.0043 0.0069 72

Hg-100 Stainless steel

(301

)^

11.9 80 0.4 — 0.00042

h,;-101 Stainless steel

(301)^

10.3 80 0.8 — 0.00097 10

Hg-99 MP35N steel^

(by Latrobe Steel Co.)

1. 855 80 0.1 — 0.00067 /

Hv,-68 Teflon coated MS 14.2 381 15.3 0.0033 0.0028 30

ti, -”2 Tj-n 13.0 707 29.1 0.0033 0.0032 3 3

Ilg-30

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litanium 15.0 547 0.1 Zero 0.00001 Zero

llg-45 Titanium (6A1,4V)^ 13.3 569 Zero Zero Zero Ze ro

,,^t:uiuu i ai. Ive total, corrected for background rate and to 1 atm. pressure.

Based on a tank in the form of a cube, 1 cu. ft. volume, 10% ullage.

Discontinued.

These specimens are solid metal. All others are coatings on 18% Managing steel.

T'Laniuin alloy, 13% V, 11% Cr, 3% Al. Similar to alloy B120VCA.

V.ipor- deposited from Commonwealth Scientific Corp.

TABLE 2

Data on Decomposition of MHF-3 Fuel at l60 °F

in Special Tests

Effect of Porosity in Coatings of Cadmium on Managing Steel

* Test

unit

number Description

(Deposits 2 mils thick)

Time

under

test

days

Gas

evolved

cm^

Rate

coefficient

cm^/day/cm^

previous present

Hg-51 Cadmium on Managing steel

with 1/2 of MS surface

exposed - 8 cm^

509 1+0 0.0100 0.0098

Hg-63 Cadmium on Managing steel

with 200 0.026" diam.

pores. MS area l.OU cm^

koi 9.8 O.O2I+8 0.0235

Hg-Ti'" Electroless nickel on Managing steel with 1/2 of

MS surface exposed - 1^+ cm^

252^ ITT .

3

0.2020 0.1835^

Hg- 8U Managing steel in electrical

contact with Cd end caps

118 39 0 . Ol+lO 0.0383

Rate coefficient is calculated on basis of exposed Managing steel only.

Rate coefficient based on pone area: l.OU cm^

.

Highest rate for Managing steel alone was 0.098 and for standard electroless nickel O.OOU7.

XXTotal days under test are not equal to days during which gas was collected.

"''Discontinued.

TABLE 3

Test Data for Materials Exposed to Aerozine-50

at 160 °F

» * ** Test

unit

number

Specimen

Area of

specimen

cm^

Time

under

test

days

Gas

evolved

cm^

Rate

coefficient

cm ^ /day/ cm^

previous present

Calculated

tank pressure

after 1 year

psig

Hg- 5 bA None

(Background)

U59 3 . 8 U 0 . 007 ^+ 0 . 008U —

Hg- 60A

3i Titanium lh .5 U55 1.8 0.00006 0.00027 3

hg-62A Teflon (TFE)^ 17.5 U61 1.3 0.00011 0.00016 2

Hg-95A MP35N steel^’^ 1.869 kd 6.9 — 0.0769 812

Cumulative total, corrected for background rate and to 1 atm. pressure.

Based on a tank in the form of a cube, 1 cu. ft. volvime, 10 ^ ullage,

^hese specimens are uncoated, solid material.

^Latrobe Steel Co., Latrobe, Pennsylvania.

i

j TABLE h

I Test Data for Materials Exposed to UDMH

at 160 °F1

* * ** Test Area of Time Gas Rate Calculated

unit Specimen speci- under evolved coefficient tank pressure

number men test cm ^ /day/ cm^- after 1 year

cm^ days 3

cni'^ previous present psig

Hg-85U Si Maraging steel li+.O 117 0.7 0.0019 O.OOOU 3 5

Hg-92U Maraging steel^ lii.O 111 l.U 0.0011 0.0011 12

Hg-93U Background — 80 0.31 — 0.0039 —

Cumulative total corrected to 1 atm. pressure.

**Based on a tank in the form of a cube , 1 cu. ft. volume

,

10^ ullage.

^'hese specimens are uncoated, solid material.
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TABLE 5

Results of Tests of Materials Exposed to Oxydizers

Stainless Steel Bomb-Type Test Units

Test

unit

number

Specimen

Area of

speci men

cm2

Time

under

test

days

* Gas

evolved

3 cm"^

* Rate

coefficient

cm^/ day/ cm^

previous present

** Calculated

tank pressure

after 1 year

psig

Inhibited :red fuming nitric acid at 90°E

RFN-1 Teflon (tee) lU.5 11+.1+ 0.001+9 Zero Zero

REN

Stainless steel

(301 Cryogenic form

aged)

li+.T 381"“ 13.1+ 0.001+3 Zero Zero

RFN-3 Maraging steel

(New specimen)

25 25 2.0 — 0.0038 1+0

RFN-1| Teflon on

6o6i-t6 A1

15.1 38i+"“ 9.5 O.OO 3

I+ Zero Zero

RFN-5 None (Background) — 369^“ 6.2 0.038 Zero Zero

Nitrogen tetroxide at 90°^E

301-NT0 Stainless steel

(301 Cryogenic fom

un-aged)

338

Nitrogen

393 Zero

tetroxide at l60

Zero

°E

Zero Zero

NTO-1 None (Background) — 115 5.8 O.OI+I7 — —

WTO

Teflon (tee) 19.9 397^ 23 O.OOi+7 O.OOl+l 1+3 WTO3

Stainless steel

(301 Cryogenic form

aged)

li+.7 1+20 6 . 6 0.0007 0.0008 8

NT0-1+ Maraging steel 13.6 l+ 06

"“

3.7 0.0009 0.0015 16

WTO5

Titanium

(6ai, i+V)

13.

273^x 0.8 0.00050 0.00035 1+

Cumulative total, corrected for background rate and to 1 atm. pressure.

Based on a tank in the form of a cube, 1 cu. ft. volume, 10^ ullage.

Discontinued.

XXTotal days under test are not equal to days during which gas was collected.

Figure

1

Rate

of

gas

evolution

from

MRF-3

in

contact

with

indicated

metals

at

l60°F.
t
Calculated tank pressure (psig/yr)

Figure 2

Cumulative gas evolution as indicated by pressure increases resulting from

contact of above materials with NTC and IRFNA

FIGURE 3. As -deposited surface of Maraging steel specimen coated with

aluminum by the vapor deposition process of Commonwealth

Scientific Corporation. Thickness of deposit about 0.2 mil.

tl

ii

!

i

l!

I
'4

s

• Vorsin

L

\

Hi

II

|i

ij

m

"’‘3

j?r-x^

• *^7**‘^S

V*:'

FIGURE 4. Maraging steel specimen (uncoated) exposed to IRFNA

for eleven months at l60°F. Note complete perforation

near center of 60 mil thick specimen. Magnification 5X.
. ‘ V \V"r »» ,.r., - ;

A.'- '.