Effects of pH on Cavitation Corrosion of Medium Carbon Steel in Distilled Water and Sodium Chloride Solutions

Abstract

Abstract Effects of pH on cavitation corrosion of 0.23% carbon steel in distilled water and in NaCl solutions with a concentration in the range of 3 to 20% were investigated at a frequency of 6.5 kHz with a double amplitude of 95 µm. The pH was controlled with HCl and KOH in the range of 1 to 12. Tests were conducted for 2.0 h, including four periods of 0.5 h each. Results in distilled water indicated that the corrosive factor was important. The results obtained in a dilute salt solution such as a 3% NaCl solution, which corresponded to having nearly maximum corrosivity of the salt solutions in the stagnant state, indicated the corrosive factor was also important. For cavitation corrosion in a concentrated salt solution, e.g., 20% NaCl solution, the density that enhances the erosive factor was thought to be more important than the corrosive factor.