Microstructure and corrosion resistance of the brazed WC composite coatings in aerated acidic chloride media

The paper presents the corrosion behavior of the brazed WC composite coatings by using a combination of weight loss method and electrochemical polarization measurement. The brazed WC composite coatings have lower corrosion current densities compared with the 316L stainless steel and show a superior corrosion-resistance property. A further decrease of corrosion current densities is observed for the brazed WC composite coatings with the extending of etching time. The X-ray diffusion (XRD) analysis shows that WC, γ-Ni solid solution and γ-Ni + Ni3B eutectic solution were presented in the coating surface. The surface morphology observation and composition analysis were conducted by scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) spectroscopy. The insoluble oxidation products were deposited on the corroded coating surface.

► The brazed WC composite coatings exhibit superior corrosion resistance compared with the 316L steel in acidic chloride media.
► The polarization curves of the brazed WC composite coating show an active dissolution anodic process.
► The microstructure of the corroded specimens consists of insoluble oxidation products.