不锈钢过钝化－二次钝化的研究

通过对３０４不锈钢在较高电位下过钝化和二次钝化的稳态过程和电化学交流阻抗（ＥＩＳ）的分析，认为不锈钢过钝化和二次钝化现象与膜／溶液（ｆ／ｓ）界面上的电化学反应有密切关系，并通过理论模型分析，解释了过钝化和二次过钝化膜在高电位下溶解速度高，而在开路自腐蚀电位下反而有较好的稳定性这一现象．

ON THE TRANSPASSIVATION-REPASSIVATION OF TYPE 304 STAINLESS STEEL IN HIGH POTENTIAL RANGE

n investigation on the transpassivation-repassivation of type 304 stainless steel in 0. 5 mol/ L H2SO4 was carried out, and a model concerned with electrochemical processes of the electrode was proposed With the aid of analyses of the steady process and the EIS of the electrode on the basis of the model, it is found that in the high potential range the transpassivation process is closely related with the electrochemical dissolution occurring on the interface between surface film and solution, and the repassivation is due to the sharp decrease in lower valence chides; while at the open circuit potential, the inverse electrochemical reaction plays an important role in maintaining the film formed in the high potential range, and makes the film more stable than normally passivated film.