NATIONAL BUREAU OF STANDARDS REPORT

9893

C0MPATABIL1TY OF PROTECTIVE COATINGS, MATERIALS, AND PROPELLANTS

QUARTERLY PROGRESS REPORT No. 10

April 1 to June 30, 1968

For

Picatinny Arsenal Project

Order No. A1-8-R F034-01-D1-GG

Picatinny Arsenal, Dover, N. J. 07801

Attn: Code SMUPA DL-2

Liquid Rocket Propulsion Laboratory

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

To

Commanding Officer
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards1 was established by an act of Congress March 3,

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NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT

3120465 July 1, 1968

NBS REPORT

9893

COMPATABILiTY OF PROTECTIVE COATINGS, MATERIALS, AND PROPELLANTS

By

J. P. Young, G. I. Reid, and V. A. Lamb

QUARTERLY PROGRESS REPORT No. 10

April 1 to June 30, 1968

For

Picatinny Arsenal Project

Order No. A1-8-R FO34-01-D1-GG

To

Commanding Officer

Picatinny Arsenal, Dover, N. J. 07801

Attn: Code SMUPA DL-2

Liquid Rocket P ropulsion Laboratory

IMPORTANT NOTICE NATIONAL BUREAU OF ST;

for use within the Government, and review. For this reason, the whole or in part, is not author! Bureau of Standards, Washingto

the Report has been specnically

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST) on October 9, 2015

is accounting documents intended

subjected to aoditionai evaluation

listing of this Report, either in

; 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 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

a. Decomposition rates due to various metals at l60°F.

Metals in the activity ranges of low, intermediate

and high remained essentially the same with 3^7 stainless and the

titanium alloys in the low activity classification. Stainless

Maraging steel had intermediate activity while AM 355 stainless and

Inco-7l8 were in the high activity range. Of the latter two types

it was thought that either the passive film had been lost or some

component had an accelerating action. A duplicate of the AM 355

stainless was set up.

Electroless nickel from a proprietary borohydride

bath was less active than that from the bath prepared from the

formula in the literature ,

•

1
*
Electroless nickel from the alkaline hath caused

rapid decomposition of fuel. These results were to be checked with

duplicate tests.

2. Results of experiments on kinetics of fuel decomposition

a. Effect of porosity of coatings

The results of the continuing experiments confirmed

the preliminary conclusion that Maraging steel exposed to fuel

through pores in silver coatings caused decomposition of fuel at a

rate qualitatively proportional to the pore area. A cadmium coating

that partially covered a Maraging steel base had a marked inhibiting

action on decomposition of fuel by the Maraging steel.

b . Effect of area of glass and fuel volume

The continued test results confirmed the general conclusions reached previously that decomposition at the glass-vapor

interface is negligible and that the homogeneous liquid phase decomposition is predominant.

c. Effect of contact between metal and fuel vapor

The increase in the rate of decomposition indicates

that condensation of liquid on the metal surface results in an increasing rate of fuel decomposition with increase in time.

d. Effect of ratio of metal area to fuel volume

No conclusions can be drawn from tests of large areas

of pure nickel and electroless nickel because of erratic performance.

New units were to be set up.

2

3. Decomposition of Aerozine-50 in contact with

various materials at l60°F

Units were set up with specimens of 301 stainless steelaged cryogenic form, titanium (6A1, kv ) , and lQ% Maraging steel and

Teflon (TFE) in contact with aerozine-50 , hut data were not obtained

due to the short period of exposure.

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

Tests were started on rates of corrosion of various materials in contact with two oxidizers, IRFNA and NTO and on rates of

decomposition of the oxidizers.

5 . Examination of specimens and MHF-3 fuel after tests at l60 °F

a. Corrosion of metals

Out of a large number of metals examined after prolonged exposure to the fuel, only zinc and nickel underwent extensive

corrosion. All others at most lost a few milligrams , corresponding

to a few microinch in thickness.

) b. Effects of exposure to metals on MHF-3 fuel

Except in one experiment with nickel, the concentrations of metallic salts dissolved in the fuel were very small. The

composition of the dissolved salts were not determined, but they

were separated by evaporation and dried. The dried salts did not

detonate under a, hammer blow (as might be possible if they were

azides )

.

3

C. Progress During Current Report Period

1. Decomposition of MHF-3 fuel in contact with

various materials at ?1°C (l60°F)

a. "Background" rate

The rate of evolution of gas from MHF-3 fuel in

"blank” (no specimen) mercury manometer test units has continued a

3 slow decrease. The average is now 0.00^3 cm /day for units Hg-2 and

o Hg-15 with little change from 0.004U cm /day at the end of the preceding quarterly period.

b. Effects of various metals

Table 1 contains the cumulative results to the end

of June 1968. The relative reactivity of the various specimens is

as follows

Low activity : silver, cadmium, electroless nickel,

zinc, tin-nickel alloy, tin, 3^7 stainless steel,

50-50 lead-tin solder, tungsten, titanium-6Al-^V

,

aluminum foil, titanium-3Al-llCr-13V, lead.

Intermediate activity : gold, nickel, stainless

Maraging steel, electroless nickel (prop, borohydride) , Teflon coated Maraging steel.

High activity : Cobalt, lQ% Maraging steel. Molybdenum,

iron, AM 355 stainless steel, electroless nickel

(alkaline bath), Inco-7l8 , chromium.

The behavior of some of the metals and coatings require

special comment.

(l) Type AM 355 stainless steel . The two units containing specimens of this steel, Hg-44 and Hg-5^, have been set up

for 20U and 117 days, respectively. Although the decomposition rate

3 2

for Hg-5^- has increased slightly from.0.0087 cm /day/cm at the end

u

3 2

of the last report period to 0..010 cm /day/cm at the present time,

2

it is much less than the rate attained by Hg-Ul+ of 0.0 66 cm/3/day/cm

in' about the same period of time. During this reporting period the

rate of gas evolution in Hg-44 has further increased to 0.072 cm /-

day/cm . As noted in the preceding report, the rate for unit Hg-U4

was in agreement with that for Hg-5^ during the first several weeks

of its life, after which the anomolous acceleration started. No

explanation for the discrepancy has been found. A third unit is

planned for rate confirmation.

(2) Stainless Maraging steel . A discrepancy also

exists between the two units containing stainless Maraging steel.

The decomposition rate of Hg-1+3 is nearly three times that of Hg-55

set up some five months later. A third test is therefore planned.

(3) Electroless nickel from borohydride type

baths . A duplicate specimen of the non-proprietary borohydride

electroless nickel (Report No. 9, p. k) was tested and an extremely

high rate was also obtained. The average coefficient for the two

3 2 units was 51 cm /day/cm , corresponding to a tank pressure after one

year, calculated as in Table 1, of 532,000 psi. Confirmation of the

high catalytic effect with this coating indicates that it is a characteristic of the material and is not due to accidental causes.

In contrast, the rate of decomposition of fuel in contact with the

proprietary borohydride electroless nickel is much lower (Table 1,

Unit Hg- 58 ). The non-proprietary deposit is reported to contain

several percent of boron, whereas it is claimed that the proprietary

5

deposit is nearly pure nickel. Such a difference might account for

the differing catalytic effects.

(U) Electroless nickel from the alkaline type

hath . A second specimen from the alkaline hath has heen under

test (Table 1, Unit Hg-52) . It shows a considerably reduced rate of

decomposition compared to the first specimen tested from this hath.

Before placing this specimen in a test unit it was placed in boiling

water for 60 min. , dipped in 10 % HC1, rinsed and soaked in fuel for

two weeks to remove trace residues that might contaminate the surface

The rate of decomposition of fuel is about one-eighth that obtained

with the first specimen plated in the alkaline electroless nickel

bath in unit Hg-^9 , but still much higher than that for electroless

nickel plated from the acid-type bath (Table 1, Hg-12)

.

Other specimens placed under test this period with

initial data reported in Table 1 are electroless nickel from the

standard acid bath but heated to 800°C before testing to simulate

the effect of a welding operation after plating (Hg-6l) , 301 cryogenic form stainless steel (Hg-53) , and Teflon coated Managing

steel (Hg-68).

2. Results of experiments on the kinetics of fuel

decomposition

a. Effects of the porosity of coatings

The tests of silver plated specimens with synthetic

pores have been terminated. However, two cadmium plated Managing

6
4
steel specimens are under test. One was started during this report

period to compare results with those of the silver plated specimens.

The data are given in Table 2. The results with the cadmium plated

specimens thus far are different than those obtained with the silver

where the gas accumulation is roughly proportional to the area of

Maraging steel exposed and is greater than for Maraging steel alone.

The contrary effect is evidenced by the cadmium plated specimens

which have a qualitatively lower accumulation for the area of Maraging

steel exposed than for Maraging steel alone. Thus, it appears that

in these couples, there is a bi-metallic electrolytic effect, with

silver, which is cathodic to Maraging steel, exerting an accelerating

effect on both corrosion and fuel decomposition, and cadmium, which

is anodic to Maraging steel, having the opposite effect.

b . Effect of ratio of metal area to fuel volume

Three new units have been set up to check the effect

of the ratio of metal area to fuel volume (Table 3). Units Hg-65

^ ' 2 and Hg-66 contain electroformed nickel sheet 100 cm as the metal

specimen. The data show that, for a range of A/V from 0.5 to 6.8,

there is no significant difference in the rate coefficient.

3* De compos it ionn of Aerozine-50 fuel in contact

with various materials at T1°C (l60 QF) . Initial results for these exposure tests are given in

Table 4. The background rate is 0.0147 cm /day for the glass

manometer unit. As will be noted in the table, the rates for titanium (Hg-60) and for solid Teflon (Hg-62) are zero after deduction

7

of the background value. The rates for Maraging steel (Hg-59) and

the Teflon coated aluminum (Hg-79) are quite high. The color of

the latter specimen has changed from a reddish brown to a light

grey which may indicate some reaction with the fuel or leaching of

some constituent from the sprayed Teflon. Such effects might cause

the difference between the rates for Hg-59 and Hg- 62 .

4 . Exposure of various materials to oxidizers

at 71°C (l6Q°F)

Nine bomb type units have been loaded with oxidizers and

specimens of various materials as shown in Table 5* The oxidizers

used are NTO (nitrogen tetroxide inhibited with 0.6+0. 2j nitric

oxide ) and IRFUA (inhibited red fuming nitric acid. The inhibitor

is 0. 7+0.1% hydrogen fluoride). Also two background units have been

set up, one with each oxidizer. The bombs are similar in design to

that shown in Report No. 1, Figure 1. Bodies are type 3l6 stainless

steel, fittings type 304L, and gage tubes type 316 and 3 ^7 .

The background unit containing IRFNA was erratic and will

be disassembled and restarted. Thus there is no background deduction

in the data for RFN-2. The other units containing IRFNA showed no

increase in pressure so are indicated in Table 2 as having zero

reaction. ~ ~~~ — ~ - “”TM' "" —————— - 0.6! nitric oxide was added by the supplier, Matheson Co., Inc. It.

was requested by Picatinny Arsenal that we verify the composition

by chemical analysis. Consultation with analytical staff at NBS

disclosed no suitable method. The literature on the chemistry of

the nitrogen oxides shows that complex labile equilibria exist between N02, N20i^, NO, N2O

5

, N2O3 , O2 } and N2 , dependent on temperature and pressure. A meaningful determination of NO therefore

appears to be impractical.

8

A thin walled tank of 301 stainless steel-cryogenic form,

unaged, furnished by Picatinny Arsenal, has been loaded with NTO and

is being tested at 32°C (90°F). The tank volume is 385 ml; it was

filled with oxidizer to 90% of capacity. This tank is designated

as 301-NT0 in Table 5* There is no appreciable decomposition of NTO

thus far.

3 The background rate for NTO is 0.0126 cm /day. This figure

is used in computing the data for this oxidizer given in Table 2.

It is interesting to note that the rate for Teflon is greater than

that for Maraging steel.

5 . Examination of specimens and MHF-3 fuel

after tests at T1°C (l60°F) . Four more units were disassembled during this period.

Results of examination of specimens and fuel are summarized in Table 6.

The fuel from Hg-38 was lost so no salt concentration test could be

made

.

a. Corrosion of metals

Only the nickel plated Maraging steel from Unit PA-26

showed evidence of attack by the fuel. The nickel was slightly pitted, but since pitted areas did not appear to be large enough to

account for the total weight loss , general corrosion of the nickel

surface must have occurred. A cross-section of a pit is shown in

Figure 1 and of 'an unpitted area in Figure 2. The surface roughness

in the latter indicates general corrosion.

9
i
The insignificant weight loss from molybdenum, iron,

and Maraging steel would imply no visible corrosion, and none was

observed.

b . Effects on MHF-3 fuel caused by exposure

to the metals in the test units

As might be expected, the fuel exposed to the nickel

specimen contains a significant amount of dissolved salts. The

amount in the fuel, exposed to Mo is in agreement with the blank.

The very small amount in the fuel exposed to iron is consistent with

the very minor corrosion loss of the iron specimen.

Salts obtained from the fuel and scraped from the

specimens could not be detonated by impact.

D. New Work

1. Tests of special metals

Duplicates of several of the special interest metals and

coatings will be set up for tests as indicated in other sections of

this report

.

2 . Tests with oxidizers

The background unit for the test with IRFNA is being dismantled, cleaned and reassembled.

3. Examination of terminated units

Several more units for which there is no need for further

testing will be dismantled and examined during the next quarter.

10
'
• TABLE 1

Summary of Test Data for Materials

Exposed to MHF-3 at 71°C Cl60°F)

* * #*

Test

unit

number

Coating

or

metal

Area of

specimen

cm^

Time

under

test

days

Gas

evolved

cm

3

Rate

coefficient ^ cm/ day/ cm

Calculate*

tank pressafter 1 ye

;

psig***

present previous

Hg-12 Electroless

ni ckel

22.2 522 12.1 0.0011 0.0011 11

Hg-lU 3 1+7 Stainless

steela 13.2 519 Zero Zero Zero Zero

Hg-l6 Cadmium

(thin)

9-b h$2 2.5 0.0005 0.0001 6

Hg-22 Silver

(thin)

16.0 1*57 53.3 0.0073 0.0066 77

Hg-23X

18° Maraging

steela 17.0 46i 50l+ 0.081 0.097 85 !+

Hg-2lt

x SL Molybdenum 4.8 1+58 235 0.111 0.123 1 , 171* Hg-25X

Iron

a b.k 455 63.7 0.033 0.037 349

Hg-27 Cadmium

(thin)

10.6 353 2.9 0.0008 0.0007 8

Hg-28 3*+7 Stainless

steela 6.5 351 6.1 0.0027 0.0030 28

Hg-29 Silver lb.

5

353 0.6 0.0001 Zero 1

Hg-30 Titaniuma (l3V,llCr,3Al)

15.0 183 0.2 0.00007 0.0002 1

Hg-31 Cadmium lit.

7

335 Zero Zero Zero Zero

Hg-32 Tin 13.0 353

^

18.3 0.001*1 0.001+5 1+3 Hg-33 Solder 50/50

lead-tina 15-3 335 Zero Zero Zero Zero

Hg-39 Inco 7l8

a 12.0 199 131 0.095 0.092 996

Hg-U3 Stainless Mar*

aging steel

- 15.0 251 23.5 0.0062 0.0072 66

Hg-UU Stainless steel

type AM 35

5

a 11.1+ 20 b** 87.3 0.072 0 .066 763

Continued
*

.

•
TABLE 1 (Cont'd.

Test Coating

unit or

number metal

Summary of Test Data for Materials

Exposed to MHF-3 at 71°C Cl60 °F)

Area of

specimen

cm^

* Time Gas

under evolved

test "5 days cm^

* Rate

coefficient ^

cni /day/ cm

Calculated

tank pressure

after 1 year

psig***

present previous

Hg-U5 Titanium3, alloy, 6A1,4V

13.3 200 Zero Zero Zero Zero

Hg-48 Aluminum3, 5 C

12.5 197 0.9 0.0004 0.0006 4

Hg-i(9 Electroless

nickel

(Alkaline bath)

12.6 30 9b.

0.249 0.23 2,630

Hg-50 Chromium 17.0 205

XX

bb.9 0.0145 0.012 253

Hg-52 Electroless

nickel

(Alkaline bath)

13.8 25 11.3 0.033

'

346

Hg-53 Stainless

steel-301

(Cryogenic form)

lU.7 56 19.5 0.024 250

HG-54 £L Stainless

steel AM 355

11.5 82 8.4 0.010 0.0087 103

Hg-55 Stainless Maraging steela

16.6 87 33.1 0.0229 0.0230 242

Hg-57 Nickel l4.0 117 17 A 0.0106 0.0101 112

Hg-58 Electroless 14.2

nickel

(Proprietary borohydride)

117 29 0.0176 0.0177 185

Hg-61 Electroless

ni ckel

(Heated to 800°C)

12.2 43 0.5 0.001 10

Hg-68 Teflon (on

(Maraging steel)

14.2 lb 2.5 0.0126 — 133

3^T-^ l8% Maraging l4.0 385 b31 0.084 0.075 882

(bomb unit) steela

y — — - • — . — - - — — Cumulative total, corrected for background rate and to 1 atm. pressure.

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

x

Dis continued.

^-^otal days under test are not equal to number of days during which gas

was collected, due to temporary leaks, or to interrupted collection due

to high rate.

^These specimens are solid metal. All others are coatings on 18 Maraging

steel.

"^Titanium alloy, 13% V, 11% Cr, 3% Al. Similar to alloy B120VCA.

cVapor-deposited foil from Commonwealth Scientific Corp.
Iff
TABLE 2

Data on Decomposition of MHE-3 Fuel at T1°C (l60°F)

in Special Test Units

Effect of Porosity in Coatings of Cadmium on Maraging Steel

Test

unit

number Description

Time

under

test

days

Gas

evolved

3

cm

Rate

coefficient ^ cm/ day/ cm

of exposed MS

present previous

Hg-51

Cadmium on Maraging steel

with 1/2 of MS surface

exposed - 8 cm^

155 15-3 0.017* 0.017

Kg- 63

Cadmium on Maraging steel

with 200 0 . 026 " diam.

pores. MS area 1.0 4 cm^

36 3.4

** 0.09

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

(Total specimen area; 15-4 cm^; exposed Maraging steel; 8 cm2.)

Rate coefficient based on pore area; 1.04 cm2.

Effect

of

Variation

in

Ratio

of

Metal

Area

to

Fuel

Volume

•H -P \ o\ OJ o oo 0 Jh S3 >> vo -=t -=f LTV 00

-P Ch 0 aj o o o o o aJ O *H *d • K O O \ o OO o o o o o § 0 vo -=t 0-

CQ > oo • • •

0} iH s 0J oo LTV oo 00 o o o ON vo LTV -=t ON > H oo 1—

0 i—

u 0 0 -p 0 B 0 CO t— -=t oo vo

•H c 0 rcf OJ 1—

rH CO LT\ EH 3 -p T3 CM -=X H

<l>'so

t— CO vo LT\ 00

oo vo 00 o iH < 1—

CM o o o vo CM

a3 aj S o o o rH CO

•p 0 o 1—

1—1—

0 H S <uo on

Qt So >

Td•H 00 a1 o

•H

t— LT\

lt\ go vo I—1 I—

OJ00 OJ

-=t

E—

OJ VOI—

CO

CM

OJoo

LT\ -=f

530 a3 CJ i—

i—

o o 1—1 o

•H a3 0 -p -p 0 -p

,-P u -P -p -p +3

a5 o 0 O •H •H o •H O B •H nd nd •H Td O & U •H

-p -P 0 vo LTN vo vo S

CQ •H X vo VO CM 1 0 1 1 1 1 E—

EH p p 520 530 530 <; -=J- a w w w PL, 00 p00

Xi

CQ Td0B£o

-po0I—

TABLE 4

Test Data for Materials Exposed to Aerozine-50

at 71°C (l60°F)

* * Test Coating Area of Time Gas Rate

unit or

speci- under evolved coeffimen test 0 cient

number metal cm^ days 0

cm cm

0

/ day/ cm'

** Calculated

tank pressure

after 1 year

psig

Hg-56 None

(background)

9k 1.38 0.147

Hg-59 Maraginga steel

15.2 0.8 41.2 3.39 35,760

Hg-60 Titanium8, 14.5 94 zero zero zero

Hg-62 Teflon8, (TFE)

17.5 94 zero zero zero

Hg-69 Teflon coated Ik.

0.33 9.4 2.01 21,170

7075-T6 A1

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.

aThese specimens are uncoated, solid material.
"
TABLE 5

Results of Tests of Materials Exposed to Oxy&izers

at T1°C (l60°F) in

Stainless Steel Bomb-Type Test Units

Test

unit

number

Coating

or

metal

Area of

specimen

2 cm

Time

under

test

days

* Gas

evolved

3

cm

* Rate

coefficient ^ cm / day/ cm

** Calculated

tank pressure

after 1 year

psig

Inhibited red fuming nitric acid

RFN-1 Teflon (TFE) 14.5 Ik zero zero zero

RITJ-2

(301

Stainless steel 14.7

Cryogenic form-aged)

Ik 1.48 0.0072 7 6

RFN-3 Maraging steel 13.6 Ik zero zero zero

RFN-4 Teflon on

6o6i-t6 A1

15.1 17 zero zero zero

Nitrogen tetroxide

301-NT0

X Stainless steel 338

(301 Cryogenic form-unaged)

2k zero zero zero

NT0-1 None

(background) — 53 0.67 0.0126 —

NTO-2 Teflon (TFE) 19.9 30 2.7 0.0045 48

NT0-3 Stainless steel lU •

(301 Cryogenic form-aged)

53 zero zero zero

NT0-4 Maraging steel 13.6 39 0.2 0.0004 4

*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 32°C (9Q°F)
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vo £ vo 1—P 0 t— o * p d ON O oo £ 00 £ p-

,£ •H t—

vo P vo d OO £ bC -P bD CM 0 oo H •H vo o i—

•H •H • -P . £ » 0 • •H d 0 £ t- rH o •H o 0 p"

-p £ •H i—

d d P CQ 0 £ £ P d • H S b£ 1 rH 0 H £ 0 ON * d P 3 d •H . • O 0 H i—

0 0 O * 0 P l> H 0 -H o £ H w bO d d r£ £ £ o d O O £ O -P • •H £3 O

«H O O o 0 0 0 0 o rH 0 £ £ -P £ O rH H o • O P o

CQ Pt £ £h 0 £3 bD s

-P Ph •H ,£ o P4 £ •H

rH -P bD 00 H d rH £ •H •H bD t— d •H 0 0 £ 0 • Q 0 0 0 +3 H > o 0 H K -P < • P d 1 £ O •H o o 0 0 £ £3 PI •H <CH Pc oo O CO LON CM U o * £ d CO H vo vo i—

0 0 0 d CM P oo * OO • CM Pc 0 0 £ -P P 0 •H •H

t»0 0 P P £ P p £ >

•H 0 o bD o 1 O 1 P- 0 -P r- o u ON U CM • 0 d •H LCV oo d OO d P- p d U 0 U H 0 0 0 o Pc d H H O d O O H

t50 rH 3 H i—

H £ rH 0 £ 0 0 bD 0

•H d rH £ 0 £ £ £ 1—

£ p -P 0 £ d Ph Pc •H 0 £ d o 0 • ^ P £ bD 0 O £ a ;>> O d p o •H •« H H • • H CQ •• £3 0 O 0 H 0 d 0 P S -P P P O o O O S £3 £h & P 0 vo P" LON CO

*H rg CM CM CM OO s 3 <! bD 1bD bD £ PH W W m

Original

fuel

contained

0.04

g/1

of

dissolved

solids.

Tabulated

data

are

not

corrected

for

this

factor.


Figure 1

Figure 2

Cross-section of pit in nickel coating on

Maraging steel (bottom). Modified Fry’s

etchant. 250 X

Cross-section of nickel on Maraging Steel

(bottom) showing some attack on the nickel

surface. Modified Fry's etchant. 250 X