N80油套管钢钝化膜的光电化学性能

采用电容测试法研究了N80油套管钢在浓度为0.5 mol/L NaHCO3溶液中形成钝化膜的半导体性能,结合Mott-Schottky方程分析了测试频率,成膜电位和C l-浓度对钝化膜半导体性能的影响。电容测试结果表明,钝化膜呈n型半导体特性,Mott-Schottky曲线的斜率随着测试频率的增加、成膜电位的正移和溶液中氯离子浓度的增加而增加,相应地膜内的施主密度减小。光电化学实验结果表明,光电流强度随成膜电位的正移及成膜时间的延长而增加,这主要归功于高电位和长时间下所成的钝化膜具有比较均匀的组成,光激发所成的空位或电子在膜内的迁移率的增加。

Photo-electrochemical Characteristics of Passive Film Formed on N80 Tubular Steel

The semi-conductive properties of the passive film formed on N80 tube steel in 0.5 mol/L NaHCO3 solution were investigated via capacitance measurement.Based on Mott-Schottky equation,the factors,such as measuring frequency,formation potential and Cl-concentration,which affect the semi-conductive performance of the passive films,were analyzed.The results show that the passive film exhibited n-type semi-conductive character.The donor density of the passive film decreased with the increase of the measurement frequency,the formation potential,and Cl-concentration.The photo-electrochemical experiments revealed that the photo-current increased with the increase of the formation potential and the formation time,which was attributed to the increasing mobility of the photo-generated holes or electrons.