ORNL-2106 - the Molten Salt Energy Technologies Web Site

ANP PROJECT PROGRESS REPORT
to sodium was calculated by using the latter weight,
the density of 3.53 9/cm3* the weight of the
absorbed sodium, and a sodium density at 97.8OC
(the melting point of sodium) of 0.951 g/cm3.
As shown in Table 3.2.7, the losses of rare-
earth oxides by this low density (3.53 g/cm3)
body were greater than the losses by the higher
density (6.58 g/cm3) Lindsay Mix body, which is
in keeping with the general trend for the lower
density ceramics to have lower corrosion resist-
ance. There is no explanation for the relatively
large loss of Y,03. The exposure to sodium also
slightly weakened the body; its hardness, on the
Mohs' scale, changed from 3 to 2 during the test.
Long-term corrosion tests of finished ART control
rod Lindsay Mix shapes and sodium in lnconel
containers have been initiated to determine the
extent of the corrosion of these materials under
the most adverse operating conditions expected
and for periods equal to and greater than the pro-
posed operati ng ti me.
SOLID-PHASE-BONDING SCREENING TESTS
W. H. Cook
Molybdenum has been tested for 100-hr periods
for solid-phase bonding with itself, tungsten,
158
K150A (80% Tic-10% NbTaTiC,-10% Ni), and W
K152B (64% TiC-6% NbTaTiC3-30% Ni) with *
calculated contact pressures of 20,000 psi in the
fuel mixture (No. 30) NaF-ZrF,-UF, (50-464
mole %) at 150OoF. Bonding was absent only
for molybdenum vs tungsten and molybdenum vs
K15OA. The surface roughnesses of the contacting
surfaces of all specimens were 1.5 to 2 pin. rms,
as determined with a profilometer.
The contact pressure was reduced from the
standard 50,000 psi to 20,000 psi in an effort to
get below the yield strength of molybdenum at
150OOF. The 20,000-psi loading was not low
enough, inasmuch as the molybdenum deformed
slightly in all the tests. All examinations were
made with a low-power microscope.
In the test of molybdenum vs molybdenum, the
solid-phase bonding was accompanied by some
deformation and considerable upsetting. In the
bonding between molybdenum and K152B, a thin
film appeared to have been transferred from the
molybdenum surface to the K152B surface in the
contact area. This was probably a nickel-
molybdenum diffusion layer, but it has not yet
been identified.