利用Ｘ射线衍射仪和透射电镜研究了离子渗氮层和普通气体渗氮层的微观结构及其对渗层脆性的影响。结果表明，离子渗氮化合物层中γ′相的含量比普通气体渗氮的要多，且γ′相晶粒较小；离子渗氮扩散层中的碳化物呈粒状，而普通气体渗氮扩散层中的碳化物呈断续的长条状，且分布有一定的方向性。这是离子渗氮的渗层脆性低于普通气体渗氮的重要原因。 The microstructure of ion nitriding layer and common gas nitriding layer were investigated by X-ray diffractometer and transmission electron microscope. The results show that the content of γ ’phase in ion nitriding compound layer is more than that of ordinary gas nitriding, and the grain size of γ’ phase is small. The carbide in ion nitriding diffusion layer is granular, while the nitriding diffusion Carbide layer was intermittent strip, and the distribution of a certain directionality. This is an important reason for nitriding nitriding brittleness lower than ordinary gas nitriding.