Study On Microstructure Of WC/Ni-based Alloy Coatings And Interfaces Produced By High Velocity Oxy-fuel Flame Spraying On Copper Surface

High Velocity Oxy-Fuel(HVOF) spraying technique was used in this article to achieve the Ni-based alloy coatings(WC/Ni, NiCrBSi) on C11300 copper surface. In order to study the relationships between the spraying technics, coatings microstructure and mechanics property, the microhardness of coatings and interfaces with which the HVOF Ni-based alloy coating and copper substrate combine, coatings microstructure, phase structure and the alloy element concentration in the interface were analyzed.The microhardness distribution of coatings and interface were studied using micro-hardness instrument. The results indicated that the microhardness of WC/Ni coatings was different remarkably with the difference of WC content in WC/Ni powders in coating landscape orientation, microhardness of WC35/Ni coating was the lowest(about HM760 averagely), the highest microhardness was belong to the WC45/Ni coating(about HM960), microhardness of WC50/Ni coating was between WC35/Ni and WC45/Ni coating(about HM898). As for the NiCrBSi coating, the microhardness distribution is quite symmetrical, the average microhardness is about HM940. In the lengthways coating section, the microhardness increases gradually from coating surface to interior, which indicates that surface coating is loose, interior coating is compact correspondingly.The microstructure of coatings and interfaces was analyzed by means of optic microscope(OM) and scanning electronic microscope(SEM). The results indicated that the coating was compact, the powder particles distorted greatly by HVOF spaying. Many hard phases enchase in the coating substrate or distribute on the coating substrate surface hardly. There are some transition of particles between sublaye and working layers. The combination condition between sublayer and copper base is interlaced, and exists at the copper side near the interface, which indicates that the...