The study of corrosion behavior of WC-MgO composite in H2SO4 and NaOH solution

Abstract

The corrosion behavior of WC-MgO composite in H2SO4 and NaOH solution has been studied with electrochemistry and microstructure analysis method. The aim of this work is to explore the corrosion behavior and mechanism of WC-MgO whisker composite in acid and alkali solution. The result suggests that WC-MgO composite possesses higher corrosion resistance in H2SO4 solution than in NaOH solution. The key reason for better corrosion resistance in H2SO4 solution is the stable WO3 passive film. The oxidation of WC leads to corrosion induced crack along with grain boundaries. It can be attributed to the preferential corrosion of grain boundary and volume expansion caused by WC phase oxidation. The corrosion induced crack on the surface may decrease mechanical properties of WC-MgO composite. In NaOH solution, the main corrosion mechanism is the dissolution of WC phase but MgO is relatively stable.