双辉等离子涂层对机械曲轴耐磨耐蚀性能的影响

采用双辉等离子技术在机械曲轴表面制备了SiC/Ta复合涂层,研究了合成温度对复合涂层显微形貌、物相组成、耐磨和耐腐蚀性能的影响。结果表明,当合成温度从750上升至900℃时,复合涂层表面形貌由花纹状逐渐演变成细小颗粒团簇状,截面形貌中可见不同合成温度下复合涂层厚度和内部质量存在一定差异,不同合成温度的复合涂层中都出现了SiC、Ta、Ta₂C和TaC衍射峰。机械曲轴基体的摩擦系数都高于不同合成温度下的复合涂层,合成温度800℃时复合涂层的摩擦系数最小且最为稳定;随着合成温度升高,磨痕深度、磨痕宽度、磨损体积和比磨损率都呈现先减小后增大的特征,在合成温度为800℃时磨损体积和比磨损率最小;极化曲线和电化学阻抗谱测试结果保持一致,即复合涂层的耐蚀性能都优于基体,且合成温度为800℃时复合涂层的耐蚀性能最好;机械曲轴表面适宜的复合涂层合成温度为800℃,此时复合涂层具有最佳的耐蚀和耐磨性能。

Surface Modification of Crankshaft with SiC/Ta Composite Coating

The surfaces of 4 Cr13 stainless steel, a crankshaft material, were modified and reconditioned with SiC/Ta coatings by double glow discharge plasma alloying.The influence of the surface alloying temperature and Ta-transition layer on the tribological behavior of the coatings was investigated with X-ray diffraction, scanning electron microscopy, conventional mechanical probes and electrochemistry work station.The results show that the alloying temperature had a major impact.To be specific, the Ta-transition layer considerably enhanced the interfacial adhesion and improved the toughness;as the alloying temperature increased from 750℃ to 900℃,the wear-resistance and corrosion-resistance changed in an increase-decrease mode, peaking at 800℃.Moreover, alloyed at 800℃,the coatings had the lowest friction coefficient, because of the refinement of texture and grain size.Abrasive wear was found to account for the wear mechanism.