42CrMo钢空气离子氮氧共渗研究

Surface Modification of AISI 4140 Steel by Co-Implantation of N and O Ions

采用不同空气流量对42Cr Mo钢进行离子氮氧共渗,并和常规离子渗氮进行对比。利用金相、显微硬度计、X射线衍射仪、电化学性能分析测试仪对复合渗层的显微组织、厚度、物相、表面硬度及耐蚀性进行了测试和分析。研究结果表明,普通空气可用作42Cr Mo钢离子氮氧共渗处理的氧气源;同样温度和时间条件下,离子氮氧共渗比常规离子渗氮的渗层厚,表面显微硬度提高,硬度梯度更加平缓。同时,渗层中物相含微量Fe3O4,起到提高耐蚀性的效果。同时,研究发现,空气流量0.3 L/min为最佳工艺参数。

A novel technique was developed to modify the surfaces of AISI4140 steel by plasma co-implantation of N＋and O-2ions with air as the O2 source. The impact of the modification conditions,including but not limited to the air flow-rate,substrate temperature and implantation time,on the microstructures,phase-structure and mechanical behavior of the modified surfaces was investigated with X-ray diffraction,metallurgical microscope,electrochemical workstation and mechanical probes. The results show that depending on the air flow-rate,the co-implantation significantly affects the mechanical properties. For example,as the air flow-rate increased,the thickness of the implanted layer changed in an increase-decrease mode; the thickest layer,implanted at an optimized air flow-rate of0. 3 L / mm,was 29,5 μm,being 50% higher than that modified by conventional N-implantation. The co-implantation outperforms the N-ion implantation because of a higher micro-hardness,better corrosion resistance due to formation of small amount of Fe3O4 and a thicker,more compact and more uniform implanted layer.