中文摘要：

基于XRD、OM、STM、TEM分析与显微硬度和磨损测试研究了17-4PH钢在500℃有无稀土添加时脉冲等离子体氮碳共渗动力学、渗层的组织结构和性能。结果表明，添加稀土不改变共渗层的表面相结构，但提高了渗层中γ-Fe4N相的比例，使表面氮浓度提高7％，渗层深度最大可增加55％，表层显微硬度提高100～200HV；无稀土添加共渗层在抛光研磨过程中发生了粘着磨损；此外，在渗层中观察到了位错、层错等晶体缺陷。

英文摘要：

The growth kinetics, microstructure and mechanical properties of the surface layer of steel 17-4PH subjected to pulse plasma nitrocarburizing at 500℃ with or without rare earth （RE） addition were investigated based on a series of analysis of XRD,EDS,OM,STM and SEM as well as microhardness and wear measurements. The results show that the incorporation of RE does not change the surface phase structure but, instead, increases the proportion of γ＇-Fe4N phase in modified layer and leads to the increases of 7% , 55% and 100 -200 HV in the surface nitrogen concentration, nitrocarburized layer thickness and surface microhardness, respectively. The adhesion wear ocuurs in the nitrocarburized layer without RE addition during grinding. In addition, the crystal defects such as dislocation and fault have been observed in the plasma RE nitrocarburized layer.