ORNL-1816 - the Molten Salt Energy Technologies Web Site

Fig. 6.8. A-Nickel T-Joint Brazed with 60%
Pd-37% Ni-3% Si and Exposed to Sodium Hy-
droxide for 100 hr at 15OOOF. Note surface attack
and small voids at interface between base material
and braze alloy. Unetched. 1OOX. Reduced 39%.
500X.
- .001
- ,002
- .003
- .004
- .005
er Exp
PERIOD ENDING DECEMBER 10,1954
The reasons for failure of the B,C to withstand
the corrosive actions of the sodium and lithium are
not known at this time; powder x-ray analyses of
the tested specimens of B,C indicate that B,C is
the primary phase and that a new, secondary,
unidentified phase is present as a result of both
the sodium and lithium corrosion tests. The attack
on the B,C by the fluoride mixture is not definite
or uniform. The 5 mils of attack found on one side
of the specimen was the maximum depth of attack
if the 14-mil-thick unidentified phase found an the
other side can be attributed to fluoride mixture in
a surface imperfection of the test specimen. Fur-
ther tests will be necessary to properly evaluate
B,C corrosion resistance to the fluoride mi Kture.
These screening, si ngl e-run, static corrosion
tests of B,C, Tic, ZrC, and Cr,C, indicate that
these carbides, except B,C in lithium or sodium,
warrant further and more severe tests in the in-
vestigation of materials to withstand the long-term,
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