Effect of Cobalt and Chromium Content on Microstructure and Properties of WC-Co-Cr Coatings Prepared by High-Velocity Oxy-Fuel Spraying

Abstract

To explore the Co/Cr ratio impact on the high-velocity oxygen fuel (HVOF)-sprayed WC-Co-Cr coatings microstructure and performances, three kinds of WC-Co-Cr coatings, namely WC-4Co-10Cr, WC-7Co-7Cr, and WC-10Co-4Cr, were prepared by using a high-velocity oxygen fuel (HVOF) spraying process. The three coatings' phase composition, microstructure, basic mechanical properties, abrasive wear, and corrosion resistance were investigated. The results show that all three WC-Co-Cr coatings comprise the main phase WC, minor W₂C, and amorphous W-Co-Cr phase, besides the WC-4Co-10Cr coating containing a small amount of Cr_xC_y phase. In addition, WC-7Co-7Cr coating exhibited the highest hardness and abrasive wear resistance, followed by WC-10Co-4Cr and WC-4Co-10Cr coatings. The corrosion resistance as a hierarchy was found to be WC-10Co-4Cr > WC-7Co-7Cr > WC-4Co-10Cr.

Keywords: WC-Co-Cr; abrasive wear; corrosion; high-velocity oxygen fuel spraying.