低温取向硅钢渗氮工艺对表面氧化层的影响  

Effect of Nitriding Process on Surface Oxide Layer of Low Temperature Grain-Oriented Silicon Steel

作　　者：肖水方 戴方钦[1] 郭悦[1] 曾曦灿 XIAO Shuifang;DAI Fangqin;GUO Yue;ZENG Xican(Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室

出　　处：《热加工工艺》2019年第22期137-142,共6页Hot Working Technology

摘　　要：采用场发射电子扫描显微镜(SEM)分析渗氮前后取向硅钢试样表层形貌,采用辉光放电光谱仪(GD-OES)分析表层元素分布。在GD-OES中用AT离子溅射试样表面,通过控制溅射时间、溅射深度使试样达到表面不同深度位置。并利用光电子能谱(XPS)分析渗氮前后不同深度元素组成及价态,采用SEM观察渗氮后不同深度形貌特征,探究渗氮过程反应机理。结果表明:渗氮前,试样表面形成约3 pm厚的氧化层,外表面由FeO和Fe2SiO4组成,中间层为球状SiO2,靠近基体一侧为带状SiO2,氧化层中还残留有少量的单质硅。渗氮过程中,NHs分解产生的出会将钢带表层部分FeO和Fe2SiO4还原成单质Fe和Si02o[N]进入钢带表面,并在浓度梯度的作用下在钢带中发生扩散,与钢带中合金元素Si等结合以Si3N4形式析出,SisNq在整个氧化层中及靠近氧化层/基体界面的铁基中都有析出,即渗氮层厚度大于氧化层厚度。The surface morphologies of the grain-oriented silicon steel samples before and after nitriding were analyzedby field emission electron scanning microscope (SEM) and the surface element distribution was analyzed by glow dischargespectrometer (GD-OES). The surface of the sample was sputtered by Ar ion in GD-OES. By controlling the sputtering time,different spattering depth from the surface of the sample was obtained. The composition and valence of elements in differentdepth before and after nitriding were analyzed by photoelectron spectroscopy (XPS). The morphologies of different depthsafter nitriding were observed by SEM, and the reaction mechanism of nitriding process was explored. The results show that,the oxide layer is about 3 |xm thick on the surface of the sample before nitriding, and the outer surface is composed of FeO andFe2SiO4. The intermediate layer is spherical SiO2, there is banded SiO2 near the substrate side, and there is still a small amountof silicon in the oxide layer. During nitriding, H2 produces by NH3 decomposition will reduce part of FeO and Fe2SiO4 in thesurface layer of steel strip to simple Fe and SiO2. [N] enters the steel strip surface, diffuses in the steel band in the role ofconcentration gradient, bonds with the Si in the steel and precipitates in the form of Si3N4. Si3N4 is precipitated in the wholeoxidation layer and the iron base near the oxidation layer/matrix interface, that is, the nitriding layer thickness is larger than theoxide layer thickness.

关 键 词：低温取向硅钢 渗氮 氧化层 GD-OES XPS SEM 

分 类 号：TG156.82[金属学及工艺—热处理] TG161[金属学及工艺—金属学]