等离子喷涂WC-Ni涂层的组织结构及力学性能

Microstructure and mechanical properties of plasma sprayed WC-Ni coatings

采用等离子喷涂技术在不同的喷涂工艺条件下制备WC-Ni涂层。采用X射线衍射(XRD)和扫描电镜(SEM)表征和观察涂层的相结构和显微组织,同时运用压痕法对涂层的显微硬度、弹性模量和断裂韧性进行测试。结果表明,等离子喷涂工艺参数对涂层的组织结构和相结构有显著影响,等离子喷涂功率增加,粒子的熔化程度增加,适当的喷涂距离下沉积形成的涂层致密;等离子功率增加,喷涂过程中会产生WC粒子的失碳,相对于W_2C相,WC_(1-x)相的增加可以同时提高涂层的显微硬度和断裂韧性;与涂层的相组成相比,致密的组织结构对涂层显微硬度、弹性模量和断裂韧性的综合性能的提高更显著。

Plasma sprayed WC-Ni coatings were prepared at different spraying parameters.Phase structures and microstructures of the coatings were characterized by means of X-ray diffraction(XRD)and scanning electron microscope(SEM).The Vickers microhardness,elastic modulus and fracture toughness were also tested by using indentation method.The results show that the plasma sprayed parameters have significant effect on phase structures and microstructures of WC-Ni coating.With the increase of plasma power,the melting degree of particles is increased,which results in dense coatings with proper spraying distance.With the increased plasma power,the carbon loss of WC particles will occur during spraying.Compared to W2C phase,the increased WC1-x phase will improve micorhardness and fracture toughness of WC-Ni coatings.Compared to phase composition,the dense microstructure of coatings can significantly improve the mechanical properties.