AISI 420F不锈钢表面等离子渗Zr层组织及性能研究

Surface Modification of AISI 420FStainless Steel by Plasma Zr-Alloying

采用等离子合金化技术,在含一定碳量的AISI 420F马氏体不锈钢表面制备Zr/Zr C合金层。研究了等离子渗Zr合金化温度和时间对Zr/Zr C合金层组织、相结构、渗层厚度以及硬度和摩擦磨损性能的影响。利用扫描电镜和光导放电光谱分析仪分析Zr/Zr C合金层表面和截面的形貌及成分分布,用X射线衍射表征渗层的物相组成。结果表明：AISI 420F不锈钢渗Zr后,得到组织连续且致密的渗Zr合金层,合金层由表面富Zr层/富Zr C层/Fe-Cr-Zr-C扩散层组成。在900~1000℃合金化范围内,形成的Zr合金层厚度随渗Zr温度的升高由17μm增加至23μm。在950℃渗Zr时,合金层和富Zr C层厚度随着渗Zr时间的延长分别呈直线和抛物线规律增加;渗Zr后试样的硬度最大值为865HV0.025,与基体（269HV0.025）相比有显著提高;摩擦磨损检测表明,与基材相比,AISI 420F不锈钢经渗Zr处理后,划痕宽度由540降低至360μm,摩擦系数由0.8明显降低为0.4左右,耐磨性得到改善。

The surfaces of AISI 420F stainless steel were Zr-alloyed by double glow plasma alloying. The im- pact of the Zr-alloying temperature and time, thickness, and voltage of Zr-source and workpiece, on the microstruc- tures, phase-structures and mechanical behavior was investigated with X-ray diffraction, energy dispersive spectros- copy, scanning electron microscopy, glow discharge optical emission spectroscopy and conventional mechanical probes. The results show that the compact Zr/ZrC surface layers ,Zr-alloyed in 900 - 1000℃ for 4 h and 20 μm in thickness, significantly improved the mechanical properties of the substrate. As the Zr-alloying temperature and time increased, the ZrC thickness increased. The Zr-alloying reduced the friction coefficient from 0.8 to 0.4 ; the micro- hardness increased from 269HV0.025to 865HV0.025 ,accompanied by a decrease of the wear-rate. Possible mechanisms responsible for the surface Zr-alloying were tentatively discussed.