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ANP PROJECT PROGRESS REPORT
RARE-EARTH-OXIDE COMPACTS FOR ART
CONTROL RODS
J. A. Griffin L. M. Doney
The design of the ART control rods calls for a
porous compact of rare-earth oxides. The pores of
the compact are to be filled,with metallic sodium,
and the compacts are to be canned in Inconel. The
following process was developed for the fabrication
of the compacts. The as-received rare-earth-oxide
material (Code 920 from Lindsay Chemical Co.)
was pressed at 4000 psi into compacts, which
were calcined at 1325OC for 1 hr. The calcination
step was carried out to reduce the shrinkage of the
oxide during the final sintering. These compocts
212
3.6. CERAMIC RESEARCH
L. M. Doney
were crushed to pass an 80.mesh screen. The
final mixture was compounded from 75% of the
80.mesh calcined material and 25% of the as-
received Lindsay Code 920 oxide. This combi-
nation was thoroughly mixed and pressed, with no
binder, at a pressure of 4000 psi. These compacts
were then sintered at 1425°C for 55 min in air.
Samples of the sintered compacts are shown in
Fig. 3.6.1.
The compacts were oversize in all dimensions
so that they could be ground accurately to size
and so that no difficulty would be encountered
during canning. The grinding was carried out by a
commercial ceramic firm. The inside and outside
Fig. 3.6.1. Sintered Rare-Earth Compacts Before Being Ground to Desired Dimensions.
L" t
.