不锈钢载波钝化膜的生长过程

FORMATION OF PASSIVE FILM ON 304 STAINLESS STEEL UNDER ALTERNATING VOLTAGE ELECTRIC FIELD

运用电化学交流阻抗分析(EIS)、电量测定并结合原子力显微镜(AFM)研究了304不锈钢载波钝化膜的生长过程.研究了在交变电场下钝化膜层中微孔的产生及其对膜层生长的作用;并运用钝化膜生长过程中的电量-时间响应和原子力显微镜扫描分析对不锈钢载波钝化膜的生长机理进行验证分析.结果表明:载波钝化膜具有很高的生长速度是由于交变电场对膜层的作用改变了膜层的生长方式,使之不同于直流钝化条件下钝化膜的生长过程.

An investigation on the growth of passive film on 304 stainless steel by using alternating voltage (A.V.) passivation was carried out by electrochemical impedance spectroscopy (EIS), coulometry measurement and atomic force microscopy (AFM). EIS was performed on 304 stainless steel electrode, which is covered by A.V. passive film, to identify the formation of pore as a function of higher potential parts (Eh) in alternating square wave electric field. Coulomb-time curves were measured during the growth of passive film on different conditions. A new concept, probability of pore formation, which describes the behaviour of the pores during the growth of film, was presented. Results indicate that the growth mechanism of A.V. passive film is different from that of D.C. passive film, which makes the AV. passive films have a faster growth rate. Coulomb-time curves and AFM analysis confirmed the growth mechanism of A.V. passive film.