【摘要】 利用金相显微镜、扫描电镜和X射线衍射仪对经氮气-甲烷离子氮碳共渗的40Cr钢进行了分析,并测定了渗层中沿层深方向的显微硬度分布。结果表明:渗层可分为3层,即化合物层、扩散层和基体组织。表面渗层物相结构主要由氮(碳)ε化合物和Fe3C构成;在适当的工艺条件下,可以获得表层硬度高达525HV(0·1),沿层深方向硬度分布合理、脆性低的渗层;与常规离子渗氮相比,以氮气-甲烷混合气体作为气源的离子氮碳共渗工艺成本低廉,绿色环保。更多还原

【Abstract】 This paper deals with metallographic micro-analysis, SEM-analysis and XRD phase composition ana-lysis on Steel 40Cr which was treated by compound treatment method of N, C co-diffusing, and determined microscopic hardness distribution along the direction of depth of the compound layer. The result shows that the composite layer can divide into three layers. The surface layer is chiefly N, C compound. The second layer is diffused layer. The third layer is basic structure. Phase composition of the composite layer is made of Fe3C and ε phase (N, C compound); Under suitable technological conditions, compound layer which surface hardness was raised to 525 HV(0.1), hardness distribution along the direction of depth of compound layer was more reasonable, and brittleness was low can be obtained. Compared with traditional plasma nitriding using NH3 or N2-H2, this process is cheap and friendly to environment.更多还原