Hydriding Behavior of Glow-Discharge Plasma Nitrided Uranium Surface

Surface nitrided uranium was prepared using glow-discharge plasma nitriding method. The surface layer was examined and a comparison between surface nitrided and oxidized against hydrogen corrosion was monitored with a digital microscope. AES depth profile and XRD spectrum show that the surface-nitrided layer is about 250 nm in sputtering depth and mainly consists of α-U₂N_3+x, with a mild nitride-substrate interface and nitrogen diffuses into the metal bulk. SEM micrographs show that pulsed glow-discharge plasma nitriding can reduce the number of polishing scratches and other defects. Surface nitride layer retards hydrogen diffusion into bulk, delays the nucleation and restrains hydride growth. Glow-discharge plasma nitriding can passivate uranium surface against hydrogen corrosion effectively.