Vacuum carburization of 12Cr2Ni4A low carbon alloy steel with lanthanum and cerium ion implantation

• Published in: Journal of rare earths Vol. 35; no. 11; pp. 1164 - 1170
• Main Authors: Dong, Meiling, Cui, Xiufang, Zhang, Yuhui, Jin, Guo, Yue, Caiwen, Zhao, Xin, Cai, Zhaobing, Xu, Binshi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2017
• Subjects: carburization; Cerium; Diffusion; implantation; Ion implantation; Lanthanum; lon; Vacuum; Vacuum carburization; Cerium; Ion implantation; Lanthanum; Diffusion; Vacuum carburization
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/j.jre.2017.04.004

As bearing parts, 12Cr2Ni4A is expected to have high hardness and excellent fatigue strength, socarburizing is employed to improve the inherit properties of 12Cr2Ni4A. However, the traditionalcarburizing is limited by poor microstructure distribution and low rate of carburizing. The rare earth ionimplantation is known to help improving the properties of tribology, corrosion resistance and oxidationresistance of metal. In this article, the RE implantation is employed to assist the carburizing. Lanthanumand cerium ion implantations are initially used to assist 12Cr2Ni4A low pressure vacuum carburization.The microstructure, content of retained austenite, hardness, thickness of layer and carbon diffusion wereanalyzed by optical microscopy （OM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD） andRockwell]Vickers hardness tester, respectively. It was shown that lanthanum and cerium implantationscan improve structure of the vacuum carburizing layer, and enhance the uniformity of carbon elementdistribution on the carburized surface. Meanwhile the RE implantation plays a positive role in promotingthe surface hardness and carburized rate. The lanthanum element has more significant effect on surfacehardness and content of retained austenite than cerium element. The surface hardness of lanthanumelement implanted layer was 62.9 HRC with 9.13% content of retained austenite, while the carburizing rateof cerium implanted layer increased by 12.4%.