NITRIDATION OF URANIUM AND RARE-EARTH-METALS IN LIQUID CD

The nitride formation reaction of liquid 2 wt% U-1 wt% Gd-1 wt% Ce-Cd alloys has been studied over the temperature range of 773-873 K using graphite and molybdenum crucibles. Uranium was preferentially nitrided to form U2N3, which were produced at the nitrogen gas-liquid alloy in terface. A little gadolinium was precipitated as nitrides, GdN or the (U, Gd)N phase. Almost all of the cerium and some gadolinium remained in the Cd phase as MCd11 intermetallic compounds. Resistance of Ce to nitridation is due to the lower activity coefficients in a Cd-rich sol ution at these temperatures. (C) 1997 Elsevier Science B.V.