激光重熔等离子喷涂WC颗粒增强镍基涂层组织及高温磨损性能

High temperature wear behavior of WC particles reinforced Ni-based plasma-sprayed coating by laser remelting

为了提高等离子喷涂WC颗粒增强镍基涂层的性能,采用激光重熔工艺对涂层进行处理,研究了激光重熔对涂层微观组织和性能的影响.用扫描电镜(SEM)、X射线衍射仪(XRD)和显微硬度计分析了涂层表面形貌、微观结构、相组成和显微硬度,同时对涂层的高温摩擦磨损特性进行了考察.结果表明,激光重熔消除了等离子喷涂层的层片状结构、孔隙等缺陷,涂层致密度提高;另外在激光高能量密度作用下,WC颗粒部分熔化,并在周围析出枝晶结构.激光重熔处理后涂层的显微硬度明显提高,其磨损性能也显著高于原等离子喷涂层.

To improve the properties of tungsten carbide(WC) particles reinforced Ni-based coating prepared by plasma spraying,laser remelting experiment was carried out and the effects of laser remelting on microstructure and properties on coating were studied.The surface morphology,microstructure,phase and microhardness of coatings were investigated by using scanning electron microscopy(SEM),X-ray diffractometry and microhardness measurement.Meanwhile,the high temperature fiction and wear behavior for both coatings were comparatively studied.The results showed that the defects of as-sprayed coating like lamellar stacking microstructure and pores were eliminated by laser remelting,and the remelted coating possessed a denser microstructure.In addition,WC particles partly dissociated at the edge,and the dendrite grew from the surface of the partially melted WC particles under high energy density laser.The laser-remelted sample had higher hardness,better wear resistance than the as-sprayed coating.