Influence of the secondary phase on micro galvanic corrosion of low carbon bainitic steel in NaCl solution
By Wei, Jie; Dong, Junhua; Zhou, Yangtao; He, Xiaoyan; Wang, Changgang; Ke, Wei
Published in Materials Characterization
2018
Abstract
The corrosion behavior of lath bainitic and granular bainitic steels in 0.01 mol/L NaCl solution was studied by SEM and TEM observation, electrochemical monitoring and weight loss test. The results indicate that the micro galvanic couple forms between the steel matrix and the secondary phase, which causes non-uniform micro corrosion on surfaces of two steels. In lath bainitic steel, the secondary phase ? acts as the micro anode. While in granular bainitic steel, the secondary phase M acts as the micro cathode. Moreover, the corrosion acceleration caused by micro galvanic couple is obvious in the initial immersion stage, and then it becomes weak during the long term corrosion.