Preparation of Neptunium Mononitride by Carbothermic Reduction

Abstract

Neptunium mononitride with carbon and oxygen contents of less than 1, 000 ppm was prepared by the carbothermic reduction of Np_O2 in flowing N₂ gas at 1, 823 K, followed by the removal of excess carbon in a N2-H2 mixed gas stream at 1, 723 K. It is suggested from the present result and also the consideration on the chemical form of residual carbon in actinide mononitrides synthesized by carbothermic reduction that the removability of carbon by hydrogen might strongly depend on the solubility of carbon in the nitrides. It was also confirmed that sintering behavior of NpN is similar to that of UN and PuN.