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由于粉末冶金零件具有突出的优点。使其应用比铸件和锻件明显增多。粉末冶金零件的主要优点是:一制成的复杂零件没有接缝;一可生产高精度公差的零件;一材料节省;一材料选择范围大;一生产成本低。用表面热处理可提高粉末冶金村料并不太好的磨损性能和腐蚀性能,以及疲劳性能。烧结钢的孔隙特性决定了所选择的热处理工艺。烧结零件的热处理适宜采用气体工艺方法,但气体反应常引起扩散层的深度超过用户的要求,因为活性分子通过与表面接近的孔隙扩散此氮和(或)碳通过基体扩散进行得快。在盐浴中处理之后,必须将孔隙中有毒性的和腐蚀性的残盐认真清理掉。辉光放电等离子热处理工艺能够克服上述困难。等离子渗氮和等离子氮一碳共渗,是改善粉末冶金零件的机械性能及摩擦性能很有发展前途的表面热处理工艺。等离子扩散处理中的很多单项参数,在工艺过程中可以准确控制,能生产出具有一定显微组织和性能的表面渗层。
As the powder metallurgy parts have outstanding advantages. Its application is significantly increased than castings and forgings. The main advantages of powder metallurgy parts are: a complex part made of no seams; a can produce high-precision tolerance parts; a material saving; a material selection range; a low production costs. Surface heat treatment can improve the powder metallurgy material is not very good wear and corrosion properties, and fatigue properties. The porosity of sintered steel determines the chosen heat treatment process. However, the gas reaction often causes the depth of the diffusion layer to exceed the user’s requirement since the active molecules diffuse through pores close to the surface and the nitrogen and / or carbon diffuse rapidly through the substrate. After treatment in a salt bath, the toxic and corrosive residual salts in the pores must be carefully removed. Glow discharge plasma heat treatment process can overcome the above difficulties. Plasma nitriding and plasma nitriding is the surface heat treatment process to improve the mechanical properties and friction properties of powder metallurgy parts. Many individual parameters in the plasma diffusion process can be accurately controlled in the process and can produce the surface layer with certain microstructure and properties.