Characterization of a Novel Thermal Sprayed Composite Coating

Thermal spray coatings are known to enhance the surface properties of the components by imparting desired characteristics such as high hardness, toughness, corrosion protection etc. The commercialization of thermal spray coating methods has been mainly due to their versatile nature and capability to spray several kinds of materials. In erosive environments, composite coatings provide added advantage of better toughness along with desired hardness as compared to ceramic coatings. In this paper a novel composite coating prepared from sand and Ni as feedstock materials has been studied. This coating composition could provide an alternative to WC based cermets coatings. An in-depth characterization of the Sand/Ni based cermet coating has been performed using SEM/EDS, XRD, AFM and Micro-hardness tester. Coating was analyzed for its porosity content, micro-hardness, fracture toughness and residual stresses. SEM/EDS results show a nearly homogenous coating structure with SiO₂ reinforcement.XRD has confirmed the presence of SiO₂ and Ni phases in the coating. The coating was found to be intact with the substrate steel.