Plasma sprayed WC-12% Co coatings have been used in various engineering applications such as wear-resistant nozzles, cutting tools, and drill bits due to their excellent mechanical properties. However, the corrosion properties of these coatings leave much to be desired because of the higher percentage of porosity, which allows the corrosive media to travel through the coating surface and reach the metallic substrate. This work is aimed at sealing the pores in plasma-sprayed WC-12% Co coatings by the sol-gel method to increase their corrosion resistance. The percentage of porosity in the as-sprayed and sealed coatings was estimated by the ASTM standard method. Moreover, the presence of sealant in the pores was confirmed by scanning electron microscopy (SEM) and the energy-dispersive X-ray spectroscopy (EDS) analysis. The electrochemical tests were employed to study the corrosion resistance of as-sprayed and sealed coatings in 3.5 wt % NaCl solution. The porosity estimation results revealed a significant decrease (>75%) in the porosity of the coating after the sealing treatment. The electrochemical tests demonstrated that the sealed coating had a noble corrosion potential (-452 mV vs. Ag/AgCl), lower corrosion current density (3.07 μA/cm 2 ), and higher polarization resistance (162.649 kΩ cm 2 ) relative to the as-sprayed coating, hence, was more corrosion resistant.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.