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为提高17-4PH不锈钢的耐水蚀性能,利用激光熔覆方法在其表面制备了Stelite6合金涂层。研究了涂层的微观组织形貌、相组成以及元素扩散行为,分析了涂层的硬度分布和耐水蚀性能。结果表明,Stellite6涂层微观组织由平面晶、胞状和柱状晶、树枝晶以及等轴晶组成,物相组成包括面心立方(FCC)结构的γ-Co固溶体和M_(23)C_6、Cr_7C_3、CoC_x等,Fe、Co元素在基体和涂层间的扩散明显。Stellite6涂层的最高硬度为561HV,平均硬度约为基材的1.4倍。多道多层熔覆时,搭接区存在软化现象,横向硬度分布出现周期性波动。在压力为80 Mpa、温度为80℃、水流冲蚀时间为30h的条件下,基材表面发生了严重的材料破坏,而Stellite6涂层表面基本保留了初始形貌,涂层的耐水蚀性能相比基材的有了显著提高。
In order to improve the corrosion resistance of 17-4PH stainless steel, a Stelite6 alloy coating was prepared on the surface by laser cladding. The microstructure, phase composition and element diffusion of the coating were studied. The hardness distribution and corrosion resistance of the coating were analyzed. The results showed that the microstructure of Stellite6 coating consisted of planar crystalline, cellular and columnar crystals, dendrites and equiaxed grains. The phase composition of the coating consisted of the γ-Co solid solution of FCC and the structures of M 23 C 6, Cr 7 C 3, CoC_x, etc., Fe, Co element diffusion between the substrate and coating obvious. Stellite6 coating has a maximum hardness of 561 HV and an average hardness of about 1.4 times the substrate. Multi-channel multi-layer cladding, the overlap zone there softening phenomenon, the horizontal distribution of hardness appears cyclical fluctuations. Under the conditions of pressure 80 Mpa, temperature 80 ℃ and water erosion time 30h, the material surface of the substrate was damaged seriously, while the surface of Stellite6 basically retained the initial morphology. The corrosion resistance of the coating Than the substrate has been significantly improved.