工艺参数对激光重熔等离子喷涂Ni基WC复合涂层影响

Effect of Process Parameters on Plasma-Sprayed Ni-Based and WC Composited Coatings by Laser Remelting

采用激光重熔工艺对等离子喷涂预置Ni基WC复合涂层进行处理,研究了激光工艺参数对涂层微观组织和性能的影响。用扫描电镜(SEM)、显微硬度计和球-盘式摩擦磨损机分析了涂层微观结构、显微硬度和高温摩擦磨损特性。结果表明,激光重熔消除了等离子喷涂层的片层状结构、孔隙等缺陷,涂层致密性提高;随着激光功率的增加,WC颗粒烧损和溶解增多,同时涂层稀释率变大;激光重熔处理后涂层的显微硬度和磨损性能显著高于原等离子喷涂层,但激光功率对其有较大的影响,工艺参数的合理选择有利于WC颗粒适当熔化,从而在涂层中保留较高比例的硬质相,同时使WC颗粒与Ni基体的结合较强,达到较高的显微硬度和耐磨性能。

The effects of laser remelting parameters on microstructure and properties of nickel（Ni）-based and tungsten carbide（WC） composited coatings prepared by plasma spraying were studied.The microstructural characteristics,microhardness,fiction and wear behaviour of the coatings were investigated using scanning electron microscopy（SEM）,microhardness measurement and a ball-ondisk tribometer.The results show 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.With the increase of the laser power,the burning loss and dissolve of the WC particles is increased,while the dilution of the coating becomes large.The laser-remelted samples had higher hardness,better wear resistance than the as-sprayed coating.Laser power has a great impact on the coating and an optimized process parameter is help to achieve appropriate melting of WC particles,which lead to retain a high proportion of hard phase in the coating,good combination between the WC particles and the Ni-base matrix alloy,so that the coating owns high microhardness and wear resistance.