Enhancing effects of nahso3 on corrosion of t91 steel

Abstract

In the paper, corrosion behavior of T91 steel in different concentrations of NaHSO3 solution was studied in combination with scanning electron microscope (SEM) and electrochemical measurements. The results showed that the steel exhibited active anodic dissolution characteristics in the solution, and NaHSO3 concentration affected both cathodic and anodic behav-iors. The steel surface was covered by intact corrosion products in the solutions, but the compactness and mechanical properties of the corrosion products degraded with the increase of NaHSO3 concentration. In low-concentration NaHSO3 solution the steel tended to undergo uniform corrosion with slight corrosion pits, but its corrosion mode gradually transited to localized corrosion as the NaHSO3 concentration increased. The mechanical property degradation of the corrosion products caused by sulfur compounds and the pH decrease of the solution are the important factors to accelerating its corrosion process.