Corrosion mechanism of H2O on Sm2Fe17 and nitrogenation process of corroded Sm2Fe17
来源期刊：Journal of Rare Earths2019年第6期
论文作者：Jianwei Xu Jingwu Zheng Haibo Chen Liang Qiao Yao Ying Wei Cai Wangchang Li Jing Yu Min Lin Shenglei Che
文章页码：638 - 644
摘 要：Sm2 Fe17 prepared by reduction-diffusion method needs to be washed with water to remove calcium oxide. Electrochemical corrosion occurs when Sm2 Fe17 powder is in contact with liquid water. Corrosion mechanism of H2 O on Sm2 Fe17 powder and nitrogenation process of corroded Sm2 Fe17 were studied by analyzing the structure and morphology. It is indicated that the metallic hydroxide forms and deposits on the Sm2 Fe17 powder surfaces during water corrosion. At the same time, oxygen and hydrogen enter the unit cell of Sm2 Fe17, causing a slight increase in Curie temperature. In the subsequent nitriding process,the hydroxide is dehydrated and hydrogen is desorbed. The resulting oxide reacts with Sm2 Fe17Nx to form a-Fe and Sm2 O3. Thermodynamic calculations using the HSC Chemistry 6.0 software indicate that the reaction can occur spontaneously. The effect of water corrosion on the magnetic properties of the nitride can be eliminated by hydrogen reduction prior to nitriding.
Jianwei Xu1，Jingwu Zheng1，Haibo Chen1，Liang Qiao1，Yao Ying1，Wei Cai1，Wangchang Li1，Jing Yu1，Min Lin2，Shenglei Che1
1. Research Center of Magnetic and Electronic Materials,College of Materials Science and Engineering,Zhejiang University of Technology2. Key Laboratory of Magnetic Materials and Devices,Ningbo Institute of Material Technology & Engineering,Chinese Academy of Sciences
摘 要：Sm2 Fe17 prepared by reduction-diffusion method needs to be washed with water to remove calcium oxide. Electrochemical corrosion occurs when Sm2 Fe17 powder is in contact with liquid water. Corrosion mechanism of H2 O on Sm2 Fe17 powder and nitrogenation process of corroded Sm2 Fe17 were studied by analyzing the structure and morphology. It is indicated that the metallic hydroxide forms and deposits on the Sm2 Fe17 powder surfaces during water corrosion. At the same time, oxygen and hydrogen enter the unit cell of Sm2 Fe17, causing a slight increase in Curie temperature. In the subsequent nitriding process,the hydroxide is dehydrated and hydrogen is desorbed. The resulting oxide reacts with Sm2 Fe17Nx to form a-Fe and Sm2 O3. Thermodynamic calculations using the HSC Chemistry 6.0 software indicate that the reaction can occur spontaneously. The effect of water corrosion on the magnetic properties of the nitride can be eliminated by hydrogen reduction prior to nitriding.
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