SYNTHESIS AND FABRICATION OF REFRACTORY URANIUM COMPOUNDS. Quarterly Report No. 4 for March 1 to April 30 and July 31, 1960

Additional work on the synthesis and fabrication of uranium nitride produced an improved product free of oxide contamination as indicated by x-ray analysis. Further work to increase the density of the sintered pellets is needed. A stock of several pounds of stoichiometric uranium monocarbide was prepared by carbon reduction of uranium dioxide. Pellets having bulk densities ranging from 93 to 96% theoretical were obtained by cold pressing and sfntering. Initial experiments on the fabrication of bars, 3 by 1/2 by 1/4 in., by cold pressing and sintering, resulted in sound but somewhat low-density bodies. A few experiments were conducted on the production of uranium monocarbide from ammonium diuranate. The results indicate that considerable addftional work may be necessary to consistently produce a stoichiometric product. The simultaneous synthesis ard hot pressing of uranium monocarbide was funther studied and pellets with balk densities as high as 96.6% theoretical (based on 100% UC) were produced. However, metallographic examination disclosed the presence of some free uranium metal in all pellets. The synthesis of 1-lb batches of U/sub 3/Si/sub 2/ of improved quality was successfully carried out by a nonquench method. Using the U/ sub 3/Si/sub 2/ so produced, sound pellets with bulk densities up to 98.5% theoretical were prepared by cold pressing and sintering. The sintering technique was also used to produce 3- by 1/2- by 1/4-in. bars for physical- property tests. (auth