The evolution of oxide layer and its influence on nitriding after different decarburization time and holding time in grain-oriented silicon steel was investigated by field emission scanning electron mi-croscopy and energy dispersive spectrometer.The results indicate that oxide layer gets thicker with the decarburization time prolonging and is beneficial to nitriding,accompanying with the process of lamellar silica transform into spherical silica.The three-layer structure of oxide layer is beneficial to nitriding,the main contribution to nitriding comes from lamellar silica,while thicker spherical silica plays certain suppression role in nitriding,the nitriding content of oxide layer with solely spherical sil-ica structure is much less than that of three-layer structure.There are some influences on the mor-phology of nitride after nitriding process.%采用场发射电子扫描显微镜（FESEM）和能谱仪（EDS）研究取向硅钢经过不同脱碳和保温时间后氧化层的演变规律及氧化层对后续渗氮的影响。结果表明：随脱碳时间的延长，氧化层逐渐变厚，期间伴随着片状 SiO2向球状 SiO2的转变，而且脱碳后增厚的氧化层更有利于渗氮的进行。氧化层的三层结构有利于渗氮的进行，其中层片状 SiO2对渗氮起主要贡献，而球状 SiO2层较厚时对渗氮有一定的抑制作用，且当氧化层全为球状 SiO2时，渗入氮含量明显减少。氧化层的结构对渗氮后在铁基体中形成的氮化物形态也有影响。
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