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ANP PRQJECT QUARTERLY PROGRESS REPORT
Pd-3% Mn alloy. As a result of this
investigation, it was found that a
brazing alloy in contact with one base
metal may be severelyoxidized, whereas
it may be relatively unattacked when
in contact with another base metal.
This might be explained by the fact
that the least oxidation -resistant
constituents of the brazing alloy may
diffuse more readily into certain base
metals than into others.
Corrosion af Braz%ng Alloys by
Sodium Hydroxide. Since A nickel is
relatively unattacked by molten sodium
hydroxide at 15Q0°F, it serves as a
suitable base metal for testing the
corrosion resistance of brazing alloys
in this medium. Examination of a
joint brazed with 60% Pd-40% Ni alloy
and tested in NaOH for 100 hr showed
168
that no attack is present. Several
other alloys were attacked, and the
joints brazed with the Cr-Ni-Si-Mn and
the Cr-Ni-Si alloys fractured during
removal from the test capsule.
Corrosion of Brazing Alloys by
Sodium and Li thiom. Because brazing
operations may be proposed for as-
sembling fuel plates into subas-
semblies for certain types of reactors,
it was of interest to study the static
corrosion resistance of brazed joints
in contact with sodium or lithium.
The 60% Pd-4QX N i alloy, which ex-
hibited excellent corrosion resistance
to all other media tested, was severely
attacked by the liquid metals. The
extreme attack of sodium on brazed
Inconel is illustrated in Fig. 12,7,
which is the photomicrograph of a
Fig. 12.7. Inconel Brazed with 60$ Pd-4Q% N i After 100 hr at 15QO0F in
Sodium, Etched with aqua regia. 15QX.