Zhou Zhenpeng, Chen Xiao, Hu Xiaozhen, Li Sheng, Lv Menglong, Xie Yiting, Yao Hailong, Wang Hongtao, Bai Xiaobo
Jiangxi Province Engineering Research Center of Materials Surface Enhancing & Remanufacturing, School of Materials Science and Engineering, Jiujiang University, Jiujiang 332005, China.
Xinyu Key Laboratory of Materials Technology and Application for Intelligent Manufacturing, School of Mechanical and Electrical Engineering, Xinyu University, Xinyu 338004, China.
Materials (Basel). 2022 Sep 27;15(19):6721. doi: 10.3390/ma15196721.
The influence of post-process heat treatment on cold-sprayed Zn coatings on the Mg alloy substrate was investigated at different temperatures (150, 250, and 350 °C) and times (2, 8, and 16 h). Phase, microstructure, microhardness, and tensile strength of Zn coatings were analyzed before and after heat treatment. Corrosion properties of Zn coatings after heat treatment were investigated in simulated body fluid by using potentiodynamic polarization and immersion testing. Results show that although the heat treatment presented little effect on phase compositions of Zn coatings, the full width at half maxima of the Zn phase decreased with the heat temperature and time. Zn coatings presented comparable microstructures before and after heat treatment in addition to the inter-diffusion layers, and the inter-diffusion layer was dependent on the heat temperature and time. Both the thickness and the microhardness of inter-diffusion layers were increased with the heat temperature and time, with the largest thickness of 704.1 ± 32.4 μm and the largest microhardness of 323.7 ± 104.1 HV at 350 °C for 2 h. The microhardness of Zn coating was significantly decreased from 70.8 ± 5.6 HV to 43.9 ± 12.5 HV with the heat temperature from the ambient temperature to 350 °C, and was slightly decreased with the heat time at 250 °C. Although the tensile strength of Zn coating was slightly increased by heat treatment, with the highest value of 40.9 ± 3.9 MPa at 150 °C for 2 h, excessive heat temperature and time were detrimental to the tensile strength, with the lowest value of 6.6 ± 1.6 MPa at 350 °C for 2 h. The heat temperature and heat time presented limited effects on the corrosion current and corrosion ratio of the Zn coatings, and Zn coatings before and after heat treatment effectively hindered the simulated body fluid from penetrating into the substrate. The corrosion behavior of Zn coatings was discussed in terms of corrosion products and microstructures after immersion.
研究了后处理热处理对镁合金基体上冷喷涂锌涂层在不同温度（150、250和350℃）和时间（2、8和16小时）下的影响。分析了热处理前后锌涂层的相、微观结构、显微硬度和拉伸强度。通过动电位极化和浸泡试验研究了热处理后锌涂层在模拟体液中的腐蚀性能。结果表明，尽管热处理对锌涂层的相组成影响不大，但锌相的半高宽随加热温度和时间的增加而减小。除了互扩散层外，热处理前后锌涂层的微观结构具有可比性，互扩散层取决于加热温度和时间。互扩散层的厚度和显微硬度均随加热温度和时间的增加而增加，在350℃下加热2小时时，互扩散层的最大厚度为704.1±32.4μm，最大显微硬度为323.7±104.1 HV。随着加热温度从室温升高到350℃，锌涂层的显微硬度从70.8±5.6 HV显著降低到43.9±12.5 HV，在250℃下，显微硬度随加热时间略有降低。尽管热处理使锌涂层的拉伸强度略有增加，在150℃下加热2小时时，拉伸强度最高值为40.9±3.9 MPa，但过高的加热温度和时间对拉伸强度不利，在350℃下加热2小时时，拉伸强度最低值为6.6±1.6 MPa。加热温度和加热时间对锌涂层的腐蚀电流和腐蚀速率影响有限，热处理前后的锌涂层有效地阻碍了模拟体液渗透到基体中。根据浸泡后的腐蚀产物和微观结构讨论了锌涂层的腐蚀行为。
