处理温度对1Cr18Ni9Ti钢脉冲直流等离子渗氮的影响

Effects of Treatment Temperature on DC-Pulsed Plasma Nitriding of 1Cr18Ni9Ti Steel

利用脉冲直流辉光等离子技术，在不同的温度下对1Cr18Ni9Ti奥氏体不锈钢进行了渗氮处理。利用光学显微镜、显微硬度计、XRD以及电化学工作站对渗氮层进行了分析。结果表明，处理温度显著影响1Cr18Ni9Ti钢渗氮层的结构与性能。处理温度≤440℃时，渗层为纯S相结构；处理温度在460～540℃之间时，为S相＋CrN＋Fe4N的混合组织；处理温度≥560℃时，为CrN＋Fe4N的化合物层。可在较宽的温度范围内对该钢进行脉冲直流等离子渗氮，获得表面硬度高于基底5～6倍的渗氮层。渗氮层的厚度随处理温度的升高而增加，而抗腐蚀性能随着处理温度的升高呈下降趋势。

The effect of DC-pulsed glow discharge plasma nitriding technique on 1Cr18Ni9Ti austenitic stainless steel at different temperatures was introduced. The microstructures, microhardness and corrosion resistance of the nitriding layer were investigated by optical microscopy, microhardness tester, X-ray diffraction and electrochemistry work station. The results show that the microstructures and properties of the nitriding layers are considerably affected by the treatment temperatures. The nitriding layers are composed of pure S phase when treated below 440℃ ,S phase ＋ CrN ＋ Fe4N when treated in the range of 460 - 540℃ and CrN ＋ Fe4N when treated above 560℃. The microhardness of nitriding layers obtained in a wide range of treatment temperature is 5 -6 times higher than that of the substrate. More over,the depth increases and the corrosion resistance of the nitriding layers decreases with the increase of treatment temperature.