Analysis of oxide layer structure in nitrided grain-oriented silicon steel
来源期刊：International Journal of Minerals Metallurgy and Materials2019年第12期
论文作者：Xiao-long Wu Xia Li Ping Yang Zhi-wei Jia Hai-li Zhang
文章页码：1531 - 1538
摘 要：The production of low-temperature reheated grain-oriented silicon steel is mainly based on the acquired inhibitor method. Due to the additional nitriding process, a high nitrogen content exists in the oxide layer, which changes the structure of the oxide layer. In this study, the structure of the surface oxide layer after nitriding was analyzed by scanning electron microscopy（SEM）, electron back-scattered diffraction（EBSD）, glow discharge spectrometry（GDS）, and X-ray diffraction（XRD）. The size and orientation of ferritic grains in the oxide layer were characterized, and the distribution characteristics of the key elements along the thickness direction were determined. The results show that the oxide layer of the steel sample mainly comprised particles of Fe2SiO4 and spherical and lamellar SiO2, and Fe4N and fcc-Fe phases were also detected. Moreover, the size and orientation of ferritic grains in the oxide layer were different from those of coarse matrix ferritic grains beneath the oxide layer; however, some ferritic grains exhibited same orientations as those in the neighboring matrix. Higher nitrogen content was detected in the oxide layer than that in the matrix beneath the oxide layer. The form of nitrogen enrichment in the oxide layer was analyzed, and the growth mechanism of ferritic grains during the oxide layer formation is proposed.
Xiao-long Wu1，Xia Li1，Ping Yang1，Zhi-wei Jia2，Hai-li Zhang2
1. School of Materials Science and Engineering, University of Science and Technology Beijing2. Iron and Steel Research Institute,Angang Group
摘 要：The production of low-temperature reheated grain-oriented silicon steel is mainly based on the acquired inhibitor method. Due to the additional nitriding process, a high nitrogen content exists in the oxide layer, which changes the structure of the oxide layer. In this study, the structure of the surface oxide layer after nitriding was analyzed by scanning electron microscopy（SEM）, electron back-scattered diffraction（EBSD）, glow discharge spectrometry（GDS）, and X-ray diffraction（XRD）. The size and orientation of ferritic grains in the oxide layer were characterized, and the distribution characteristics of the key elements along the thickness direction were determined. The results show that the oxide layer of the steel sample mainly comprised particles of Fe2SiO4 and spherical and lamellar SiO2, and Fe4N and fcc-Fe phases were also detected. Moreover, the size and orientation of ferritic grains in the oxide layer were different from those of coarse matrix ferritic grains beneath the oxide layer; however, some ferritic grains exhibited same orientations as those in the neighboring matrix. Higher nitrogen content was detected in the oxide layer than that in the matrix beneath the oxide layer. The form of nitrogen enrichment in the oxide layer was analyzed, and the growth mechanism of ferritic grains during the oxide layer formation is proposed.
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