Preparation of recycled WC-Co composite powder and high wear resistance cemented carbide coating

Using the cemented carbides WC-6Co scraps and Co3O4 powder as the raw materials, the recycled WC-12Co composite powder was prepared by a short-term recycling technique which contains the oxidation and reduction- carbonization procedures. The thermal spray feedstock powder was fabricated by the process consisting of spray drying and heat-treatment. The recycled WC-Co cemented carbide coating was fabricated by high velocity oxy fuel (HVOF) method. Moreover, the microstructure, wear resistance and its mechanism of the coating prepared by the recycled composite powder and the commercial feedstock powder were compared. The results show that when the carbon addition is 16.7% (mass fraction), the recycled WC-Co composite has the appropriate carbon content. The fabricated feedstock only contains WC and Co phases, with homogeneously distribution of spherical particles and average particle size of 23 μm. The recycled WC-12Co coating has a high density and a homogeneous WC grain distribution. Compared the microstructure and properties of the coating fabricated by commercial feedstock powder, the recycled coating has better wear resistance, which is caused by different wear mechanisms. © 2015, Central South University of Technology. All right reserved.