The effects of resin sealing on WC-NiCr HVOF sprayed coatings were studied using the anodic polarization measurements and the potentiostatic polarization measurements in sulfuric acid aqueous solution. Three types of coatings, without sealing, with sealing applied once and twice were prepared. Regarding the anodic polarization measurements the current densities of the coatings with sealing were less than that of the coating without sealing in the potential range of 0.1 V to 1 V (vs. Ag/AgCl, sat. KCl). According to the potentiostatic polarization measurements the current densities of the coatings with sealing were also less than that of the coating without sealing. Fe was detected in the electrolyte which the coating without sealing was immersed in on the potentiostatic polarization measurements. This meant that the substrate dissolved into the electrolyte because the coatings contain Fe less than 0.13 wt%. In addition, the coating sealed once were compared with that sealed twice. And it became clear that sealing effectively prevents substrates from dissolving and improves corrosion resistance of coating in sulfuric acid aqueous solution, which agreed with the result of salt spraying test.