Improved mechanical performance and electrochemical corrosion of WC-Al2O3 composite in NaCl solution by adding the TiC additives

Abstract

In this study, 85-xWC-xTiC-15wt%Al2O3 (x = 0, 5, 10 and 20 wt%) composites were fabricated via hot pressing sintering technology. The influences of TiC additives on the mechanical performance and electrochemical behavior of WC-Al2O3 composite in NaCl solution were investigated. The mean size of WC grain showed a downward trend with the increase of TiC content. The relative density, hardness and fracture toughness of WC-based composites were improved by TiC additives. The maximum values of mechanical performance were obtained when TiC content was 10 wt%. Moreover, the research results indicated that TiC additives significantly increase the corrosion potential and decrease the corrosion current density in NaCl solution. When TiC content increased, the charge-change resistance (Rct) value presented an uptrend, and then decreased obviously when the TiC content reached 20 wt%. The XPS spectrum and SEM images proved that TiO2 passivation film was formed on the surface of WA15-10TiC composite. Therefore, it could be concluded that TiO2 passive film could inhibit further corrosion of the composite.