Nitridation of chromium powder in ammonia atmosphere
来源期刊：International Journal of Minerals Metallurgy and Materials2015年第3期
论文作者：Ling Li Qiang Zhen Rong Li
文章页码：319 - 324
摘 要：CrN powder was synthesized by nitriding Cr metal in ammonia gas flow, and its chemical reaction mechanism and nitridation process were studied. Through thermodynamic calculations, the Cr-N-O predominance diagrams were constructed for different temperatures. Chromium nitride formed at 700-1200°C under relatively higher nitrogen and lower oxygen partial pressures. Phases in the products were then investigated using X-ray diffraction（XRD）, and the Cr2 N content varied with reaction temperature and holding time. The results indicate that the Cr metal powder nitridation process can be explained by a diffusion model. Further, Cr2 N formed as an intermediate product because of an incomplete reaction, which was observed by high-resolution transmission electron microscopy（HRTEM）. After nitriding at 1000°C for 20 h, CrN powder with an average grain size of 63 nm was obtained, and the obtained sample was analyzed by using a scanning electron microscope（SEM）.
Ling Li1，Qiang Zhen1,2，Rong Li1
1. Nano-Science and Technology Research Center, Shanghai University2. School of Materials Science and Engineering, Shanghai University
摘 要：CrN powder was synthesized by nitriding Cr metal in ammonia gas flow, and its chemical reaction mechanism and nitridation process were studied. Through thermodynamic calculations, the Cr-N-O predominance diagrams were constructed for different temperatures. Chromium nitride formed at 700-1200°C under relatively higher nitrogen and lower oxygen partial pressures. Phases in the products were then investigated using X-ray diffraction（XRD）, and the Cr2 N content varied with reaction temperature and holding time. The results indicate that the Cr metal powder nitridation process can be explained by a diffusion model. Further, Cr2 N formed as an intermediate product because of an incomplete reaction, which was observed by high-resolution transmission electron microscopy（HRTEM）. After nitriding at 1000°C for 20 h, CrN powder with an average grain size of 63 nm was obtained, and the obtained sample was analyzed by using a scanning electron microscope（SEM）.
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