The erosion behavior of Ni-base self-fluxing alloy, thermally sprayed coating on a metal substrate is affected by several factors, including the microstructure of the coatings, the porosity, the angle of impingement of solid particles and the hardness of the coatings. In this study, the erosion properties of thermally sprayed coatings with different tungsten carbide contents were investigated. Reinforced by tungsten carbide in the Ni(γ) matrix, the erosion resistance of the coating has been modified. With increasing tungsten carbide content, an erosion mechanism that involved a large amount of plastic deformation in the Ni(γ) matrix was found to represent the brittle fracture of carbides. Test results showed that an NiWC coating with an optimum composition ratio of Ni-base alloy to WC of 65:35 has the highest microhardness and improved erosion resistance compared with coatings of other compositions.