Effects of surface treatments on the corrosion and erosion-corrosion of 304 stainless steel in 3.5% NaCl solution

Effects of citric acid treatment, nitric acid treatment and potentiostatic treatment on the corrosion resistance and erosion-corrosion behavior of 304 stainless steel in 3.5 wt.% NaCl solution containing 2 wt.% sand particles have been investigated by electrochemical methods. The result indicates that all treatments contribute to a significant improvement of corrosion resistance due to the formation of a Cr oxide-rich passive film. However, only citric acid treatment increases the critical flow velocity and erosion-corrosion resistance of 304 stainless steel under impingement. Passive film formed on the nitric acid treated stainless steel is easily destroyed by sand particles.