Effects of different carbides content and brazing process on the electrochemical behaviour of vacuum brazed WC-10Ni+NiCrBSi coatings

Abstract This study prepared a WC-10Ni/NiCrBSi composite coating on Q235 steel employing flexible coating cloth and vacuum brazing technologies. The surface hardness and corrosion resistance of the coating were characterised by the Vickers hardness, electrochemical, and micro-electrochemical tests. The results show that the corrosion resistance of the coating improved with the increase in cladding temperature. Moreover, with the increase in WC-10Ni content, the corrosion resistance of the coating decreased. Through transmission electron microscopy, scanning electron microscopy, and energy dispersive spectroscopy analysis, it is shown that there is galvanic corrosion in the micro-zone corrosion, where the WC particles are protected as cathodes, and the hardness of the coating is not affected by electrochemical behaviour. Thus, the hardness of the coating is not affected when it is applied in a corrosive environment.