Effect of passivity on electrochemical corrosion behavior of alloys during cavitation in aqueous solutions

摘要

The effect of cavitation on free corrosion potential, potentiodynamic polarization curves for 20SiMn low alloy steel and 0Cr13Ni5Mo and CrMnN stainless steels in HCl, NaCl, NaCl + Na{sub}2NO{sub}2 solutions, was investigated. Cavitation was produced by using a magnetostrictive-driven apparatus. Experimental results showed that the effect of cavitation on cathodic and anodic reactions was much different in given media. Cavitation shifts the free corrosion potential in cathodic direction, and mainly affects the anodic process, i.e. increases anodic current densities by two or three orders of magnitude for self-passivating systems. Cavitation shifts the free corrosion potential in noble direction and mainly affects the cathodic process, i.e. increases cathodic current densities for non-passivating systems. These results show a higher dependence on passivity of materials in given environments. The above phenomena were explained by the ideal polarization curves.