ORNL-1771 - Oak Ridge National Laboratory

ANP QUARTERLY PROGRESS REKIRT
TABLE 6.2. RESULTS OF TTATHC TESTS OF SPECiAL STELLITE HEATS BN S ~ ~ l ~ ~
AND IH NaF-ZrF4-UF4 (50-46-4 mole '7) AT 1500°F FO
.......... ___. .........
Weight Change
(din. 2 )
Bath .............
As received
Sodium
No F- Pr F4- U F4
Metallographic Notes
Heot B Heat C Heat B Heat C
+0.008
+0.016
-0.05 2
-0.060
+0.002
+0.003
-0.045
-0.057
Structure consisted of large, fairly
equiaxed particles of complex
carbide (Cr7Cg) surrounded by a
eutectic structure in a cobolt-
rich matrix
No attack; however, no globular
particles nf the carbide phase in
a 1- to 2-mil area adjacent PO the
surface; carbide porticles in this
area completely transformed to n
very fine precipitate; precipitn-
tion also occurred in matrix, es-
pecially near the, exposed surface
Same as above
Attack on carbide phose varied
from 8 to 19 mils; minimum at-
tack of 8 mils occurred on speci-
men where dendrites of cobalt-
rich solid solution surrounded by
carbide porticles were oriented
porallel to the specimen surfoce;
maximum attack of 19 mils oc-
curred where dendrites were
oriented perpendicular to ?he
specimen surface; large amount
of fine precipitation in matrix
during test due to aging
Same as above
container, and the plug was welded in place in a
dry box under a purified helium atmosphere. The
nominal composition of Hastelloy R is 45% Ni, 14%
Cr, 10% Fe, 6% Mol 3% Ti, 2% AI. The specimens
were exposed to the various media for 100 hr at
1500°F. The test results are presented in Table
6.3,
The specimens showed good resistance to attack
by NuF-ZrF,-UF, (50-44-4 mole %), Fig. 4.7, and
by lithium. Surprisingly, this alloy had better re-
sistance to attack by lithium than by sodium; the
attack by lithium on high-nickel-content alloys (for
example, Inconel) at 1500°F is usuully heavy and
is greater than the attack by sodium. The sample
tested in sodium was attacked slightly, while the
specimen tested in lead was heavily attacked. The
specimen tested in sodium hydroxide was attacked
throughout its entire thickness.
__ ~
Carbide particles which sur-
rounded the dendrites of the
cobalt-rich solid solution hod a
very fine structure; only a few of
the equiaxed carbide particles
seen throughout Heat B could be
found
No attack; very little difference in
as-received and tested structures
Same os above
Carbide network attacked to a
depth of 7 to 20 mils, depending
on orientation of the network
Same as above
.........
Inconel in Molten Rubidium
Tests were candiicted on rubidium metal in con-
nection with an ORSORT project. Rubidium has a
low melting point, 92"F, and a low boiling point,
129O0F, and therefore is being considered as a
possible reactor coolant, The rubidium metal used
in the experiments was prepared by calcium re-
duction of the rubidium fluoride salt by the Stable
Isotope Research and Production Division,
An initial attempt to determine die vapor pressure
vs temperature relationship up to 1650°C was m-
successful. However, the test equipment has been
redesigned and another attempt will be made in the
near future, lneonel has been tested in contact
with static rubidium for 100 hr at 1650°F. The at-
tack varied from 0.5 mil in the vapor zone to a
maximum of 1.5 mils at the liquid-gas interface, as
shown in Fig. 6.8. The rubidium used was not dis-
tilled and is known to have contained several per