In order to improve the zinc corrosion resistance of rollers used for hot-galvanization,WC-12Co coating was prepared with high velocity oxygen fuel (HVOF) spraying method,and the corrosion resistance and failure mechanism of the coating in liquid zinc at 450 ℃ were studied.The liquid zinc corrosion tests were performed for the 316/WC-12Co coating.The microstructural change and phase constituent of specimens without corrosion as well as specimens corroded respectively for five and ten days were analyzed with SEM-EDS and XRD.The results show that the Co-Zn compounds generate on the Co matrix of the coating after the liquid zinc corrosion,which causes the transversal cracks and leads to the flaking of the coating.When the coating entirely flakes off,the protection effect of the coating will disappear,and thus,the base metal is seriously corroded by liquid zinc and some zinc slag (Fe-Zn13) forms finally.%为了提高热镀锌用辊件的耐腐蚀性,试验采用超音速火焰喷涂方法制备WC-12Co涂层,研究了涂层在450℃锌液中的耐腐蚀性能以及失效机制.将316L/WC-12Co涂层进行液锌腐蚀,以扫描电镜能谱分析、x-射线衍射方式分析对比了未经过腐蚀试件、腐蚀5天试件、腐蚀10天试件的组织变化和相组成,结果显示涂层基体Co受液锌腐蚀生成Co与Zn化合物,引发横向裂纹,导致涂层剥落.涂层全部剥落后保护失效,使母材被液锌直接严重腐蚀,最终生成锌渣FeZn13.
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