Effects of Flow Velocity and Sand Concentration on Hydro-Abrasive Erosion Behavior of HVOF-Sprayed WC-Cr3C2-Ni Coating in 3.5 wt.% NaCl Aqueous Solution

Abstract

To explore the hydro-abrasive erosion (HAE) behaviors of a high-velocity oxygen fuel (HVOF)-sprayed WC-Cr3C2-Ni coating in 3.5 wt.% NaCl aqueous solution, various flow velocities (FVs) and sand concentrations (SCs) were designed using a rotating disk rig facility. In comparison with 1Cr18Ni9Ti stainless steel, the WC-Cr3C2-Ni coating possessed higher hardness (H) and elastic modulus (E) values, worse anticorrosion properties, and superior HAE resistances in 3.5 wt.% NaCl aqueous solution. Higher FVs and SCs caused more severe HAE degradations for both the WC-Cr3C2-Ni coating and the 1Cr18Ni9Ti stainless steel, while FV had a greater influence on HAE resistances than SC. With an increase in the FV and SC, uncontinuous corrosion product films and erosion pits, the micro-cutting of the soft binder matrix and the fracturing of hard-phase grains, and crater formation and coating spalling were addressed as the HAE failure mechanisms in the 3.5 wt.% NaCl aqueous solution of the WC-Cr3C2-Ni coating.