NATIONAL BUREAU OF STANDARDS REPORT

10 029

COMPATABILITY OF PROTECTIVE COATINGS, MATERIALS, AND LIQUID PROPELLANTS

QUARTERLY PROGRESS REPORT NO. 13

January 1 to March 31, 1969

For

Picatinny Arsenal Project

Order No. A1-8-RFO34-01-D1-GG

To

Commanding Officer

Picatinny Arsenal, Dover, N. J. 0780 1 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 Standards1 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 three broad program areas and provides central national services in a fourth. 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, and the Center for Radiation Research.

THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the

United States of a complete and consistent system of physical measurement, coor- dinates that system with the measurement systems of other nations, and furnishes

essential services leading to accurate and uniform physical measurements throughout

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of an Office of Standard Reference Data and a group of divisions organized by the

following areas of science and engineering:

Applied Mathematics—Electricity—Metrology—Mechanics—Heat—Atomic Physics—Cryogenics2—Radio Physics2 —Radio Engineering2—Astrophysics2—Time

and Frequency.2 THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research leading to methods, standards of measurement, and data needed by industry, commerce,

educational institutions, and government. The Institute also provides advisory and

research services to other government agencies. The Institute consists of an Office of

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Analytical Chemistry—Polymers—Metallurgy — Inorganic Materials — Physical

Chemistry.

THE INSTITUTE FOR APPLIED TECHNOLOGY provides for the creation of appropriate opportunities for the use and application of technology within the Federal Government and within the civilian sector of American industry. The primary functions

of the Institute may be broadly classified as programs relating to technological meas- urements and standards and techniques for the transfer of technology. The Institute

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problems of other agencies and institutions. The Center for Radiation Research consists of the following divisions:

Reactor Radiation—Linac Radiation—Applied Radiation—Nuclear Radiation.

1 Headquarters and Laboratories at Gaithersburg, Maryland, unless otherwise noted ; mailing address Washington. D. C. 20234.

2 Located at Boulder. Colorado 80302.

3 Located at 5285 Port Royal Road, Springfield. Virginia 22151.
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT

3120465 April 1, 1969

NBS REPORT

10 029

COMPATABILITY OF PROTECTIVE COATINGS, MATERIALS, AND LIQUID PROPELLANTS

By

J. P. Young and G. I. Reid

QUARTERLY PROGRESS REPORT NO. 13 January 1 to March 31, 1969

For

Picatinny Arsenal Project

Order No. A1-8-RFO34-01-D1-GG

To

Commanding Officer

Picatinny Arsenal, Dover, N. J. 0780 1 Attn: Code SMUPA DL-2

Liquid Rocket Propulsion Laboratory

IMPORTANT NOTICE NATIONAL BUREAU OF ST

for use within the Government, and review. For this reason, th whole or in part, is not authoi Bureau of Standards, Washingti

the Report has been specifically

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.

ss accounting documents intended

subjected to additional evaluation

listing of this Report, either in

e Office of the Director, National

)y the Government agency for which

:opies for its own use.

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

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 change in the activity of metals in contact

with MHF-3 at 1T0°F listed in Table 1. Several stainless steels were

giving considerably different rates for comparable units and a variation

in the oxide coating on otherwise similar specimens was suggested as the

cause. To check this idea, several stainless specimens and nickel were

oxidized in air before exposure to fuel. Initial indications were that

AM355 stainless and nickel were considerably less reactive in the oxidized state with MHF-3.

2. Experiments on kinetics of fuel decomposition

The rate of fuel decomposition decreased further for the Maraging

steel specimens partially coated with cadmium indicating continued protection of the exposed MS by the cadmium. A specimen with one-half of

the MS surface coated with electroless nickel gave a higher rate than

MS alone

.

A specimen of large area plated with electroless nickel gave the

same rate coefficient as those having one-tenth the area/volume-of-fuel

ratio.

3. Decomposition of Aerozine-50 fuel in contact with

various materials at l60°F

The background rate for this fuel continued to decline and the

high fuel decomposition rate for Teflon coated aluminum and Maraging

steel were confirmed.

U. Exposure of various materials to oxidizers at l60°F

Sudden rapid increases in the decomposition rate of IRFNA was

considered to result from gradual consumption of the HF inhibitor at l60°F.

A change in the system for evaluating IRFNA was considered necessary.

There was no significant change in units containing NTO.

C. Summary of Progress During Current Period

1. The rates of fuel decomposition of specimens exposed to MHF-3

at l60°F did not change significantly. Several units which had a high

rate, including some stainless steels, were discontinued. Sixteen new

units were assembled and testing started. These new units included

specimens of varying thicknesses of cadmium and electroless nickel,

solid specimens of cadmium and electroless nickel and specimens of

thermally oxidized Maraging steel and electroless nickel. Data on

these units containing MHF-3 are given in Table 1 and Figure 1.

2. Experiments on kinetics of fuel decomposition

Another unit was added to test the effect of porosity in coatings. It contained a Maraging steel specimen with end caps of cadmium

in mechanical contact with the steel (Figure 3). The fuel decomposition

2

rate is lower than that for Maraging steel alone and is decreasing.

Further testing to determine the effect of ratio of metal area to fuel

volume has been stopped. The results indicate that the rate coefficient

is independent of the A/V ratio, at least for electrolytic nickel and

electroless nickel, the two materials tested.

3. Decomposition of Aerozine-50 fuel

The units containing Maraging steel and Teflon coated aluminum

have been discontinued because of excessive rate of fuel decomposition.

The other units containing 301 stainless steel, titanium and Teflon did

not change in rate appreciably (Table 4). A new unit is being set up

containing MP35N high alloy steel.

4. Exposure of materials to UDMH fuel

Two units containing uncoated Maraging steel specimens show a

low rate of fuel decomposition at l60°F.

5 . Exposure of materials to oxidizers

The rate coefficient of gas evolution for specimens in NTO decreased slightly this period. The rate also decreased slightly for

specimens in IRFNA but the data was clouded by the uncertainty of the

concentration of the HF inhibitor. Modification of the test units to

lessen this difficulty is planned. Meanwhile the test temperature has

been reduced from l60°F to 90°F. At the lower temperature no reaction

is evident.

3

D. Details of Progress During the Current Report Period

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

materials at l60°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 decreased slightly from

3 3 0.0039 cm /day at the end of the preceding quarterly period to 0.0037 cm /

day at the end of the present period. Since units having a larger bulb

and manometer are used for specimens of larger surface area or thoae

expected to have a high fuel decomposition rate, a third "background"

unit of the larger size was set up. So far it shows no increase in the

background rate over the standard size units but was not included in

determination of the average value because of its relatively short test

period.

b . Effects of various metals

Table 1 and Figure 1 contain the cumulative results to the

end of March 1969 • The relative reactivity of the various specimens is

as follows

Low activity ; silver, cadmium, 50/50 lead-tin solder,

electroless nickel (standard acid bath), zinc, tin-nickel

alloy, tin, 3^7 stainless steel, tungsten, aluminum,

lead, titanium alloys 6A1-^V and 3 Al-llCr-13V, Teflon

coated Maraging steel, oxidized AM355 stainless steel,

oxidized nickel and 301 stainless steel.

Moderate activity : gold, nickel, stainless Maraging

steel and chromium.

high activity : cobalt, lQ% Maraging steel, molybdenum,

iron, AM 355 stainless steel, Inco-7l8.

k

(l) Behavior of recent units

The performance of the oxidized stainless steel, AM355,

in unit Hg-7^ lends credence to the theory that nonuniform oxide coatings

cause vide variation in the performance of otherwise similar stainless

steel specimens. In this case, a thermally oxidized specimen has a rate,

thus far, lower by a factor of twenty than the best untreated specimen.

The reduced rate of nickel after oxidizing is down in the range of that

for electroless nickel. Combined with its good ductility, this low rate

gives nickel possibilities as a collapsable liner material. The oxidized

stainless Maraging steel showed no improvement in rate. Oxidized

Maraging steel also showed no improvement in fuel decomposition rate.

(2) Deposit thickness tests on Maraging steel

Deposits of cadmium and electroless nickel of from 0.5

to 2 mils in thickness have given low rates. The initial tests of deposits of these metals, 0.1 mil thick, give rates in the low activity range

(Hg-8l, Hg-82)

.

(3) Other new tests

A Maraging st-eel specimen with zinc phosphate coating

gave no initial improvement over untreated MS. However, the 301 stainless steel specimen (Hg-89) gave a low rate. A Maraging steel specimen

dip-coated with 50-50 lead-tin alloy (Hg-9l) gave a very low rate. A

specimen plated with electroless nickel in the citrate type bath (Hg-78)

gave a higher initial rate than expected and probably should be confirmed by a check run. A unit containing oxidized electroless nickel

(Hg-90) showed no improvement over a similar untreated coating.

5

2. Results of experiments on the kinetics of fuel decomposition

a. The rate of fuel decomposition of the cadmium plated Maraging steel specimen with one-half of the steel surface exposed (Hg-5l) and

the cadmium plated Maraging steel specimen with pores drilled to expose

the steel (Hg-63) continued to decrease (Table 2). A third Maraging

steel specimen (Figure 3/ with the entire surface exposed except where

caps of cadmium were mechanically clamped (Hg-84) gave a rate about onehalf the average for uncoated Maraging steel alone. These tests show

the considerable cathodic protection afforded Maraging steel by cadmium

resulting in reduced decomposition of MHF-3 at l60°C.

The specimen consisting of electroless nickel on Maraging

steel with one-half of the steel surface exposed (Hg-7l) continued to

give a rate greater than that for either Maraging steel or electroless

nickel alone although its rate did decrease from the previous quarter.

b . Effect of ratio of metal area to fuel volume

The rate of fuel decomposition resulting from the exposure

of a large area of electroless nickel to fuel (Unit Hg-70, Table 3) continues to parallel the rate for much smaller specimens for the second

quarter. This further confirms the independence between the rate coefficient of fuel decomposition and the specimen-area fuel-volume ratio

for electroless nickel. This test series is being discontinued.

3. Fuel tanks plated for Picatinny Arsenal

Two one-half scale fuel tanks were plated, one with 0.88 mil

average thickness of electroless nickel and one with 1.2 mils average

thickness of cadmium and given to Mr. Ng to be tested at Picatinny Arsenal.

6

k . Decomposition of Aerozine-50 fuel in contact with various

materials at l60°F

Results of the exposure tests are given in Table k. The background

rate for this fuel in a test unit without a specimen has changed slightly

3 from a previous value of 0.0063 to 0.007^ cm /day. The units containing

Maraging steel and Teflon coated aluminum have been discontinued because

of excessive rate. At the request of Mr. Ng of Picatinny Arsenal a new

unit is being set up with MP35N high alloy steel as the specimen. There

was little change in the rates for 301 stainless steel, titanium and

Teflon (TFE).

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

Two units containing UDMH (unsymmetrical dimethyl hydrazine) fuel

were set up during the period of this report at the request of Mr. Ng

of Picatinny Arsenal. The specimen in each is 18% Maraging steel. So

far there has been very little reaction with the fuel. The results to

date are shown in Table 5

6. Exposure of various materials to oxidizers at l60°F

Results of the nine bomb-type test units are given in Table 6

and Figure 2. The two oxidizers used are NTO (nitrogen tetroxide inhibited with 0.6+0.

2

I of nitric oxide) and IRFNA (red fuming nitric acid

inhibited with 0. 7+0.1% hydrogen fluoride).

Because of the suspected gradual loss of the inhibitor in the

IRFNA units and subsequent rapid increase in pressure, only the data

obtained during the period after refilling the units and the start of a

sudden pressure was used. At the suggestion of Mr. Ng, the temperature

of the IRFNA units was reduced from l60°F to 90°F. At this lower

7

temperature no reaction has been observed. It has been learned that the

3-M Company markets an easily applied Teflon coating. It is planned to

coat a couple of the stainless steel units to try to reduce consumption

of the IRFNA inhibitor and to obtain longer uninterrupted tests of specimens at 160 °F. According to information from our mechanical design

group, bombs made wholly from Teflon would not be suitable for our application because of the problem of cold creep of the Teflon subjected to

the pressures necessary to insure leak-proof sealing of the bombs. In

the meantime the runs will be continued at 90°F.

The units containing NTO are relatively unchanged from the

previous period.

D. New Work

1. Tests of special materials

Materials in test units now being set up at the request of Mr. Ng

include: MP35N high alloy steel from Latrobe Steel Co. ; vapor deposited

aluminum coating on Maraging steel from Commonwealth Scientific Corp. ;

2021 aluminum from Alcoa; and 301 stainless steel (untreated). Other

new units will contain 50-50 cadmium-tin alloy dip coated, a duplicate

50-50 lead-tin alloy dip coated, and a blank (no specimen) "background"

unit containing UDMH.

In addition to the above, and also at the suggestion of Mr. Ng,

two companies have been contacted in regard to coating specimens with

aluminum by their processes. Dow Chemical Company has agreed to coat

two specimens with their solvated aluminum hydride electroless aluminum

process in return for a description of the test procedure and results.

8

Samples of Maraging steel have already been sent to Continental Oil's

Organometallic Division to be aluminum coated in their aduminum diethyl

hydride bath.

An inquiry to the Astro-Power Laboratory of McDonnell Douglas

Astronautics Company revealed that their Astro-coat-T fluocarbon polymer

coating process has not been tested on the type of material of interest

to us (Maraging steel) and will require further investigation on their

part before coated samples can be furnished.

2. Examination of terminated units

Fuel and metals in units for which there is no need for further

testing will be examined as necessary.

3. Coating fuel tanks

Two more one-half scale fuel tanks are on hand and will be modified and plated as required.

9

TABLE 1

Summary of Test Data for Materials

Exposed to MHF-3 at l60°F

* * ** Test

unit

number

Specimen Area of

specimen

cm2

Time

under

test

days

Gas

evolved

3 cm^

Rate

coefficient

cm 3 /day/ cm 2 previous present

Calculated

tank pressure

after 1 year

psig

Hg-2

Hg-15

Background

Background

-)

)av.

-)

8l8 3.04 0.0039 0.0037 —

Hg-48 Aluminum 12.5 475 1.1 0.00015 0.00019 2

Hg-31 Cadmium 14.7 6i4 1.1 0.00008 0.00012 1

Hg-16 Cadmium (thin) 9.4 770 11 0.0012 0.0015 16

Hg-2T Cadmium (thin) 10.6 629 6.1 0.0009 0.0009 10

Hg-8 l Cadmium (0.1 mil) 14.4 27 2.3 — 0.0059 62

Hg-80 Cadmium3- 13.4 64 5-1 — 0.0060 63

Hg-50 ChromiumX17.0 482xx113 0.0199 0.0201 213

Hg-12 Electroless nickel 22.2 788 17 0.00098 0.00097 10

Hg-i+9 Electroless nickel

(Alk) x 12.6 46i^ 169 0.228 0.2198 2319

Hg-52 Electroless nickel

( Alk) x 13.0 320

XX

42.5 0.0187 0.0125 132

Hg-58 Electroless nickel

(bh 4 ) x 14.2 390 113 0.0196 0.0203 214

Hg-6l Electroless nickel

( 8oo

° c ) 12.2 305 4.1 0.0011 0.0011 12

Hg-TT

Q Electroless nickel ' 15.0 57 4 — 0.0047 49

Hg-T 8 Electroless nickel

(citrate bath)

9-8 59 9.7 — 0.0169 178

Hg-82 Electroless nickel

( 0.1 mil)

15-3 63 7-5 — 0.0078 82

Hg-90 Electroless nickel

(oxidized)

14.4 40 3.5 — 0.0061 64

Hg-39 Inco ( 7 l8 ) a,X 12.0 482 207 0.1120 0.1142 1205

Hg- 8T Maraging steel

( oxidized)

15.0 34 42.6 — 0.0835 882

TABLE 1 ( cont .

)

Summary of Test Data for Materials

Exposed to MHF-•3 at l6o° F

Test

unit

number

Specimen Area of

speci- men

2 cirr

Time

lander

test

days

Gas

evolved

cm 3

* Rate

coefficient

cm 3 /day/cm2 previous present

Calculated

tank pressure

after 1 year

psig

Hg-57 Nickel l4.0 405 24 0.0050 0.0042 45

Hg-75 Nickel (oxidized) 3- 18.5 93 7 — 0.0041 43

Hg-29 Silver 14.5 626 2.3 0.0002 0.00025 3

Hg-22 Silver (thin) 16.0 709 128 0.0104 0.0112 119

Hg-33 Solder (Pb/Sn,

50-50

)

a 15.3 6l4 Zero Zero Zero Zero

Hg-91 Solder (Pb/Sn, l4.3

50-5O)(Dip coated)

19 0.4 — 0.0015 16

Hg-l4 Stainless steel

( 347

)

a 13.2 797 Zero Zero Zero Zero

Hg-28 Stainless steel

( 347

)

a 6.5 625 7-7 0.0020 0.0019 20

Hg-43 Stainless Maraging

steela 15-0 525 43.5 0.0058 0.0058 6l

Hg-55 Stainless Maraging

steela ’ x

l6.

6

398 77.2 0.0176 0.0171 180

Hg-44 Stainless steel

( AM355) a,x

11. b 398 148 0.0883 0.0920 972

Hg-54 Stainless steel

( AM355) a,x

11.5 398 75.6 0.0335 0.0391 413

Hg-74 Stainless steel

( AM355) a (oxidized in air at 500

18.5

°F)

105 4 " 0.0021 22

Hg-89 Stainless

(301, aged)

3- 14.7 40 2.5 — 0.0043 45

Hg-68 Teflon coated MS lb.

2

290 13.5 0.0041 0.0033 35

Hg-32 Tin 13.0 6l6 26.3 0.0035 0.0033 35

HG-30 Titanium3 ^ 15.0 456 Zero Zero Zero Zero

Hg-1+5 Titanium (6Al,4v) a 13.3 478 Zero Zero Zero Zero

* ^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.

Total days under test are not equal to number of days during which gas was collected, due to interrupted collection.

/These specimens are solid metal. All others are coatings on 18# Marging steel.

Titanium alloy, 13# V, 11# Cr, 3# Al. Similar to alloy B120VCA.

cVapor-deposited foil from Commonwealth Scientific Corp.

TABLE 2

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

in Special Tests

Effect of Porosity in Coatings of Cadmium on Maraging Steel

Test Time Gas Rate

unit under evolved coefficient

number Description test cm 3 /day /cm2 days cm 3 previous present

Hg-51 Cadmium on Maraging steel

with 1/2 of MS surface

exposed - 8 cm2

423 33.8 0.013 0.0100

Hg-63 Cadmium on Maraging steel

with 200 0 . 026 ” diam.

pores. MS area 1.04 cm 2

310 8

##

0.027 0.0248

Hg-71 Electroless nickel on Maraging steel with 1/2 of

MS surface exposed - l4 cm2

113 0.355 0.202

X

Hg-84 Maraging steel in* electricad.

contact with Cd end caps.

28 9.9 — 0.0410

*Rate coefficient is calculated on basis of exposed Maraging steel only.

** , o Rate coefficient based on pore area: 1.04 cm . XHighest rate for Maraging steel alone was 0.098 and for standard electroless nickel 0.0047. xxTotal days under test are not equal to days during which gas was collected.

Effect

of

Variation

of

Ratio

of

Metal

Area

to

Fuel

Volume

at

l60°F

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TABLE 4

Test Data for Materials Exposed to Aerozine-50

at l60 °F

Test

unit

number

Coating

or metal

Area of

specimen

cm 2

Time

under

test

days

#

Gas

evolved

cm 3

* Rate

coefficient

cm 3 /day/ cm 2 previous present

#*

Calculated

tank pressure

after 1 year

psig

Hg-53A

(

301 Stainless

steela cryogenic form)

lU.7 218 83.8 0.0290 0.0262 276

Hg-56A None

(Background)

368 2.71 0.0063 0.0074 —

Hg-59A Maraging steel

steela 5 x 15.2 0.8 41.2 — 3.39 35,760

Hg-60A . . a Titanium 14-5 370 0.3 Zero 0.00006 1

Hg-62A Teflon ( TFE

)

a 17.5 370 0.7 0.00002 0.00011 1

Hg-69A Teflon coated

7075-T6 Alx 14.2 0.33 9.4 — 2.01 21,170

#

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

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

^'hese specimens are uncoated, solid material.

X

Dis continued.

TABLE 5

Test Data for Materials Exposed to UDMH

at 160 °F

* #

Test Coating Area of Time Gas Rate

unit or speci- under evolved coefficient

number metal men test cm 3 day/cm2 cm2 days cm 3 previous present

Hg-85U Maraging steel

a

1 U .0 26 0.7 0.0019

Hg-92U Maraging steela

1 U .0 20 0.3 0.0011

* Cumulative total corrected to 1 atm. pressure, no background.

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

3/These specimens are uncoated, solid material.

** Calculated

tank pressure

after 1 year

psig

20

11

TABLE 6

Results of Tests of Materials Exposed to Oxydizers

at l60 °F in

Stainless Steel Bomb-Type Test Units

# * ** Test Specimen Area of Time Gas Rate Calculated

unit speci- under evolved coefficient tank pressure

number men test 3 cm J cm 3 /day/cm2 after 1 year

cm2 days previous present psig

Inhibited :red fuming nitric acid

RFN-1 Teflon (TFE) 14.5 202 14.4 0.0074 0.0049 52

RFN-2 Stainless steel

(301 Cryogenic form

aged)

14.7 210 13.4 0.0042 0.0043 46

RFN-3 Maraging steel 13.6 193 Zero Zero Zero Zero

rfn-4 Teflon on 6061-T6 A1

15.1 183 9.5 0.0026 0.0034 36

RFN-5 None (Background) 32 1.27

Nitrogen tetroxide

0.038

301-NT0 Stainless steel

(301 Cryogenic form

un- aged)

338 302 Zero Zero Zero Zero

NT0-1 None (Background) — 115 5.8 0.0417 — —

NT0-2 Teflon (TFE) 19.9. 246 23 0.0066 0.0047 50

NT0-3 Stainless steel

(301 Cryogenic form

aged)

14.7 265 2.8 0.0013 0.0007 8

nto-4 Maraging steel 13.6 238 2.4 0.00099 0.00090 9

NT0-5 Titanium

(6ai, 4v)

13.4 120 0.8 0.00097 0.00050 5

* 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.

Tested at 90°F.

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V Jf ip •rH

X • <0

H •O

p

"V - — P tO CP

d o o d

d P •rH P 0- -P s S *

•w

H

w P S

P-, o rH c H

H

dH o O

(A 0) •os <4

© *H

d

d •H

d

d S P g H (0 >

44 44 44d 44H _d

03

d rHd P H o m3

O o P o i*1 o

m3 c d •X

d 4/ •Hd

© •rH •rH CO •rH

•rH <0 ' S.

O 0j c o c c o\

d o g P d o P *H ^—*. w W 01 <0 a o 03 05 d 05 i—i

JC P. to o •rH 0} 05 •rH 05 » d 03 4-> •rH m d t—i X d O X! d

01 '—p

m3 CO

H <M o i—i H P H

d

d 0)

O

d

r

OO

V ' O

-H

p

r

—4 p

H P H P P p P d •H <0 a •H d d P d P P d P d > H s m) •rH O •* 44 o O f» o p m3 rH d m? H d 0) d O d d H d

•rH -p

d

O

p

H •rH •rH

HH •H

H 5®

e-< o U) 0 o CO CO

w

w cO tq

50

100

150

200

250

300

400

500

600

700

Calculated

tank

pressure

(psig/yr)

Figure 1

Rate

of

gas

evolution

from

MHF-3

in

contact

with

indicated

metals

at

160°F.

(Some

short

term

units

not

in

average)

N T 0

301 Stainless steel (90°F)

Titanium (6a1,4V)

301 Stainless steel

Maraging steel

Teflon (TFE)

IRFNA

Maraging steel

Teflon on aluminum

301 Stainless steel

Teflon (TFE)

10 20 30 40 50 60

Calculated tank pressure (psig/yr)

70 30

Figure 2

Cumulative gas evolution as indicated by pressure increase resulting from contact

of above materials with NT0 and IRFNA at 160°F.


Figure 3. At the left of center is the specimen chamber of a test unit containing a Maraging steel specimen

protected by caps of cadmium clamped on each end.

At the right is the mercury reservoir and the

manometer column. There is no fuel in the specimen

chamber and the mercury level is below the bottom

of the reservoir because the unit is being leak

tested under full manometer pressure.

Magnification - 2X.

ESI