Study on residual stresses of Ni-based WC coating by laser remelting based on XRD

The morphologies of Ni-based WC coating by flame spraying and laser cladding respectively were observed with scanning electric microscope (SEM), respectively, and residual stresses were measured with XRD (X-ray diffraction). At the same time, the spectra of WC coating were analyzed by XRD, and the forming mechanisms of residual stress were analyzed. Experimental results are shown that residual stresses of Ni-based WC coating by flame spraying are all tensile while those by laser cladding are compressive, chemical-physical reaction of the coating is the cause to result in material volume change, which makes residual stress into compressive from tensile; when residual stress is changed into compressive from tensile, micro-cracks on the coating surface greatly decrease, which is illustrated that the effect of residual stress on micro-crack is obvious; XRD spectra peak of WC coating is only contained Ni and W, and has no impurity and other reaction productions.