Effect of cavitation on corrosion behavior of HVOF-sprayed WC-10Co4Cr coating with post-sealing in artificial seawater

This study aims to further improve the cavitation-corrosion performances of high-velocity oxygen-fuel (HVOF) sprayed WC-10Co4Cr coatings by post-sealing treatment with epoxy resin using a vacuum impregnation method. Compared with the as-sprayed coatings with a porosity of 2.52%, the sealed WC-10Co4Cr coatings with a much lower porosity of 0.78% were successfully fabricated. The sealed coatings showed significantly enhanced corrosion and cavitation resistance tested in artificial seawater compared to those of the as-sprayed coatings. Further cavitation-corrosion testing under cavitation and quiescence conditions showed that the corrosion rate of both the as-sprayed coating and sealed coating was reduced under cavitation condition. Furthermore, a mechanism was suggested to illustrate the effect of cavitation on corrosion behavior of the coatings. The sealing treated WC-10Co4Cr coatings show encouraging promises as cavitation-corrosion resistance layers for marine structures.