Reaction Kinetics in Hydriding-Nitriding of Metallic Cerium

The metallic cerium was employed as raw material to investigate the parameters of reaction kinetics in hydriding-nitriding reaction. The influence of initial reaction temperature, initial gas pressure and the thickness of cerium in hydriding-nitriding of metallic cerium were investigated. The results show that the increased initial reaction temperature is in favor of shortening induction period in hydriding process, but has no remarkable influence in reaction rate of hydriding process. With the increasing of H₂ initial pressure and decreasing of the thickness of cerium, the reaction rate is significantly enhanced. Furthermore, as proved by XRD, SEM and other characterization, the cerium hydride reacts with N₂ and gets cerium nitride and H₂. The initial reaction temperature and initial N₂ pressure accelerate the nitriding reaction successfully. As a result, an initial reaction temperature of 350 ℃ and an initial N₂ pressure of 60 kPa are chosen as the relatively optimal conditions proposed for the nitriding of cerium hydride.