辉光等离子体氮化铀表面的氢腐蚀

摘要

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 crU2 N3+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.%采用辉光等离子体氮化方法制备铀表面氮化样品.俄歇电子能谱和X射线衍射对样品的分析表明,铀表面形成了厚约250 nm、主要成分为α-U2 N3+x的氮化层,氮化层与基体之间具有平缓的过渡层,且氮在金属铀的基体内有一定扩散.与轻微氧化样品氢腐蚀的对比实验表明,氮化处理使样品表面缺陷密度减少,改性层对氢吸附、扩散有阻挡作用,氢蚀形核较慢且其生长明显受到改性层的抑制,这表明铀表面辉光等离子体氮化可作为延缓氢腐蚀的有效手段.