渗氮层的微观结构对渗层脆性的影响

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。

Effect of The Microstructure of Nitrided Case on Case Brittleness

It has been studied that the microstructure of plasma nitrided case and gas nitrided case and effeet of the microstructure on case brittleness with Xray diffractometer and transmission electron microscope.The results show that the content of phase is more and the grains are smaller in plasma nitrided compound layer than those in the gas nitrided compound layer;the carbides take shape of particles in plasma nitrided diffusion layer,however the carbides take shape of intemittent strips and are distributed in certain direction in gas nitrided diffusion layer.These are important reasons that the case brittleness of plasma nitriding is lower than the case brittleness of gas nitriding.