Papers by Keyword: WC-Co Spraying Coating

Abstract: Residual strains and stresses associated with the processing steps of the industrial high-velocity oxygen-fuel (HVOF) thermal spray technique, was non-destructively characterised in both the coatings and substrates. A range of substrates, having coefficients of thermal expansion different to that of the as-coated WC-Co material, have been considered to assess the potential role of the thermal misfit associated with the coating procedure. Surface and depth resolved studies of the in-plane and normal components of residual strains have been investigated by exploiting the penetrating capabilities of high energy synchrotron X-rays in conjunction with micron sized gauge volumes to enable strain gradient determination with high positional resolution. Results reveal the presence of large residual strain/stress mismatches at the interface region in all the substrate materials, whereas the strains/stresses in the as-coated material are small, seemingly independent of the substrate material. The different contributions due to the HVOF process are qualitatively assessed in terms of an eigenstrains (plastic deformation) approach.

Abstract: HVOF WC-Co spraying coating can enhance greatly the anti-wear performance of workpiece, but it is just the high hardness of spraying coatings that makes the polishing of workpiece very difficult, the application of HVOF was limited. In this paper, we discuss the feasibility of apply ECP(electrochemical polishing) to spraying coatings, include the study of electrolyte, the optimization of machining parameters et al., the experiment results show that it is not only feasible that apply ECP to machining spraying coatings, but also high machining efficiency, high quality surface can be obtained. The surface roughness can be reduced from Ra=4.0μm to Ra=0.7μm with suitable machining parameters during a very short time.