Heat Treatment of Metals ›› 2022, Vol. 47 ›› Issue (7): 259-263.DOI: 10.13251/j.issn.0254-6051.2022.07.044

• SURFACE ENGINEERING • Previous Articles     Next Articles

Salt bath vanadium-nitrocarburizing process of AZ31B magnesium alloy

Zhou Liuyan1, Liu Liguo1, Ma Hui2, Chen Dongxu1   

  1. 1. College of Mechanical Engineering, Jiangnan University, Wuxi Jiangsu 214122, China;
    2. Yankuang Group Tangcun Industry Co., Ltd., Chucheng Shandong 273500, China
  • Received:2022-01-29 Revised:2022-05-09 Online:2022-07-25 Published:2022-08-12

Abstract: In order to improve the surface hardness, friction and wear properties and corrosion resistance of AZ31B magnesium alloy, a high hardness carbonitriding layer was prepared on the AZ31B magnesium alloy surface by salt bath vanadium-nitrocarburizing process. The surface microhardness, cross-section morphology, phase composition of the nitrocarburizing layer, and the wear resistance and corrosion resistance were analyzed by means of digital microhardness tester, optical microscope, X-ray diffractometer, X-ray energy spectrometer, friction and wear test and electrochemical test. The results show that a layer mainly composed of high hardness metal compounds such as VC and VN is formed on the AZ31B magnesium alloy surface after salt bath vanadium-nitrocarburizing treatment. The maximum surface hardness of the vanadium-nitrocarburizing layer is up to 283.1 HV0.05, which is increased by 280% and 62% respectively compared with that of the untreated and the carbonitriding treated. Comparing with the untreated alloy, the friction coefficient and wear mass loss of the alloy after vanadium-nitrocarburizing are reduced by about 30% and 50% respectively, the self-corrosion potential is increased by 60 mV and the self-corrosion current density is reduced by an order of magnitude, which showing that the salt bath vanadium-nitrocarburizing process can significantly improve the surface hardness, friction and wear properties and corrosion resistance of AZ31B magnesium alloy.

Key words: magnesium alloy, vanadium-nitrocarburizing, salt bath, microhardness, friction and wear, corrosion resistance

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