铜基体低压等离子体钨喷涂层激光重熔后的结构与性能

Microstructure and Properties of Laser Remelted Low Pressure Plasma Sprayed Tungsten Coating on Copper Substrate

在紫铜上直接喷涂的金属钨(W)层容易出现早期剥落。采用低压等离子体技术制备了Ni-Cu底层、Ni-W中间层和W层;利用大功率CO2激光束对W涂层重熔,研究了激光重熔处理对W涂层显微组织、致密度、结合强度及显微硬度的影响。结果表明:低压等离子喷涂的W层主要呈层状结构,W颗粒熔化不充分,涂层中存在大量的孔洞等缺陷;激光重熔后,W涂层表面的W颗粒已完全熔化,并在激光冷效应的作用下形成了一层厚度约为300μm的细晶组织,W涂层的致密度、结合强度得到了明显的提高。

Bottom layer of Ni-Cu and intermediate layer of Ni-W were prepared on the surface of Cu substrate by using low pressure plasma spraying ( LPPS) technique,followed by deposition of W layer via the same route.The resulting W coating was then remelted using high-power CO2 laser beam.The effect of laser remelting on the microstructure,compactness,ad-hesion to substrate and microhardness of W coating was investiga-ted.Results show that the W coating prepared by LPPS has lay-ered structure and contains incompletely melted W powders and a large amount of pores.After laser remelting,the W particulates on the coating surface were completely melted,and a fine crystal layer with a thickness of 300μm was formed under laser quench-ing effect,resulting in remarkably increased compactness and ad-hesion to substrate.