Zhang Hao, Du Nan, Wang Shuaixing, Zhao Qing, Zhou Wenjie
National Defense Key Discipline Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang 330063, China.
Materials (Basel). 2020 Feb 5;13(3):726. doi: 10.3390/ma13030726.
Potassium ferricyanide and potassium ferrocyanide were used to observe and monitor the pitting corrosion of 304 stainless steel (SS) at anodic polarization in situ. The results show that there are Fe ions around the corrosion pit when pitting occurs on 304 SS in NaCl aqueous solution. The effect of Fe surrounded pits on the pitting corrosion was also studied by testing the electrochemical behavior of 304 SS in different Fe/Fe solutions. The presence of Fe leads to the positive shift of corrosion potential and the increase of corrosion rate of 304 SS. There are two possible reasons for this phenomenon. On the one hand, Fe hydrolysis results in the decrease of pH value of solution. At the same iron ion concentration, the higher the Fe ion concentration, the lower the solution pH value. On the other hand, Fe may reduce on the electrode surface. The decrease of solution pH and the reduction of Fe resulted in the acceleration of the corrosion rate.
采用铁氰化钾和亚铁氰化钾原位观察和监测304不锈钢（SS）在阳极极化时的点蚀情况。结果表明，当304不锈钢在NaCl水溶液中发生点蚀时，腐蚀坑周围存在铁离子。通过测试304不锈钢在不同Fe/Fe溶液中的电化学行为，研究了铁包围的蚀坑对点蚀的影响。铁的存在导致304不锈钢的腐蚀电位正向移动，腐蚀速率增加。这种现象可能有两个原因。一方面，铁水解导致溶液pH值降低。在相同铁离子浓度下，铁离子浓度越高，溶液pH值越低。另一方面，铁可能在电极表面发生还原。溶液pH值的降低和铁的还原导致腐蚀速率加快。
