Inhibitor Protection of Metals at the Corrosion Fatigue Crack Growth Stage

Previously published results of tests on the influence of corrosion inhibitors on electrochemical conditions at the corrosion fatigue crack (CFC) tip and specimen surface and on the cyclic corrosion crack growth resistance (CGR) of 0.44% carbon (C)-chromium (Cr) steel in water were reviewed. A direct interrelation has been shown to exist between electrochemical conditions at the CFC tip and the cyclic corrosion CGR of steel in inhibited and noninhibited water. On this basis, a methodology for evaluating inhibitor effectiveness in the presence of a crack in a structural element was developed. The electrochemical criteria for assessing the intensity of local anodic dissolution (LAD) and hydrogen embrittlement (HE) of a metal at the CFC tip were proposed. Averaged electrochemical parameters were used to develop methods of comparing different inhibitors more effectively and of determining optimal concentrations.