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试验研究

真空热处理对HVOF制备的WC-CoCr涂层组织结构和性能的影响

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  • 1. 湖南工业职业技术学院汽车工程学院; 2. 中南大学材料科学与工程学院
古 一,副教授, 主要研究方向为材料表面涂层制备工艺,电话:0731 - 88877698,E - mail:guyi@csu.edu.cn

收稿日期: 2022-01-17

  修回日期: 2022-02-24

  录用日期: 2022-03-08

  网络出版日期: 2024-01-08

基金资助

湖南省自然科学基金项目(2019JJ70082)资助

Effect of Vacuum Heat Treatment on the Microstructure and Properties of WC - CoCr Coating Prepared by HVOF

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  • 1. College of Automotive Engineering, Hunan Industry Polytechnic, Changsha 410208, China;2. School of Materials Science and Engineering, Central South University, Changsha 410075, China

Received date: 2022-01-17

  Revised date: 2022-02-24

  Accepted date: 2022-03-08

  Online published: 2024-01-08

摘要

为改善WC - CoCr涂层的耐磨性能,采用X射线衍射(XRD)、扫描电镜(SEM)、显微维氏硬度仪、摩擦试验机等,研究了超音速火焰喷涂(HVOF)方法制备的WC - CoCr涂层经不同温度真空热处理后的相结构、显微组织、硬度以及摩擦磨损性能。结果表明:涂层经600 ℃热处理的相组成与未热处理的一致,但当热处理温度在750 ℃及以上时,涂层中生成Co6W6C相和Co25Cr25W8C2相,且热处理温度越高,上述两相含量越多。随着热处理温度的升高,涂层孔隙率先减小后增大、涂层硬度先升高后下降,其中在750 ℃×1 h热处理时涂层硬度达到最大值1 535 HV0.5 N;涂层平均摩擦系数先迅速下降后趋于稳定,与未热处理涂层的平均摩擦系数相比,当热处理温度在750 ℃及以上时下降了约51.8%;涂层磨损率呈现出先快速下降后升高的趋势,涂层经750 ℃热处理后的磨损率最小,约为1.91 μg/m,与未热处理涂层相比,下降了约93.9%。

本文引用格式

王志辉, 古一, 简忠武 . 真空热处理对HVOF制备的WC-CoCr涂层组织结构和性能的影响[J]. 材料保护, 2022 , 55(5) : 1 -9 . DOI: 10.16577/j.issn.1001-1560.2022.0117

Abstract

In order to improve the wear resistance, the WC - CoCr coating prepared by HVOF with a vacuum heat treatment at different temperatures was studied in the aspects of phase structure, microstructure, hardness and friction and wear properties by means of XRD, SEM, micro - Vickers hardness tester and friction tester. Results showed that the phase composition of the coating with a heat treatment at 600 ℃ was consistent with that without heat treatment. However, when the heat treatment temperature was euqal to or higher than 750 ℃, the Co6W6C phase and Co25Cr25W8C2 phase were formed in the coating, and the contents of such phases increased with the rising of heat treatment temperature. While the temperature increased, the porosity of the coating decreased first and then increased, the hardness of the coating increased first and then decreased, and the coating with a heat treatment at 750 ℃ for 1 h obtained the maximum hardness value of 1 535 HV0.5 N. Moreover, the average friction coefficient of the coating first decreased rapidly and then tended to be stable. When the heat treatment temperature was equal to or higher than 750 ℃, the average friction coefficient of the coating decreased by about 51.8% compared with that of the untreated coating. Besides, the wear rate of the coating decreased rapidly first and then increased, and the coating with a heat treatment at 750 ℃ obtained the minimum wear rate of about 1.91 μg/m, which decreased by about 93.9% compared with that of the untreated coating.
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