316L不锈钢在醋酸溶液中的钝化膜电化学性质

Electrochemical properties of passivation film formed on 316L stainless steel in acetic acid

通过电化学阻抗方法测量316L不锈钢在25～85℃的醋酸溶液中的EIS曲线和Mott-Schottky曲线,并测量各温度点下的循环伏安曲线,研究了钝化膜的电化学性质.研究结果表明:在醋酸溶液中的阻抗谱表明316L不锈钢在25～85℃温度范围内均能形成稳定的钝化膜,随温度升高极化阻力下降而界面电容增大.温度对于316L不锈钢钝化膜的半导体本征性质没有根本的影响:在-0.5～0.1V电位区间内钝化膜呈p型半导体特征;在0.1～0.9V电位区间内钝化膜呈n型半导体特征;在0.9～1.1V电位区间内钝化膜呈p型半导体特征.钝化膜的循环伏安曲线显示当温度低于55℃时,钝化膜结构比较稳定;当温度为55℃时,钝化膜稳定性趋向恶化;当温度超过55℃时,钝化膜稳定性下降.

The electrochemical properties of passivation film on 316L stainless steel were investigated by electrochemical impedance spectroscopy （EIS）, Mott-Schottky analysis and cyclic voltammetry graph under the corresponding conditions. The result shows that passivation film on 316L stainless steel is steady in 60 % acetic acid solution from 25 ℃ to 85 ℃, the polarization resistance decreased but the interface capacitance increased with increasing temperature. There is no obvious relation between temperature and semiconductor intrinsic properties. The passivation film represents the n-semiconductor characteristic in the potential interval of -0.5 - 0.1 V, the p-semiconductor characteristic in the potential interval of 0.1 - 0.9 V, and the n-semiconductor characteristic in the potential interval of 0.9 - 1.1 V. The graph of cyclic voltammetry shows that when the temperature is lower than 55 ℃ the passivation film＇s structure is more steady, when the temperature is 55 ℃ its stability tends to worsen and when the temperature exceed 55 ℃ its stability declines.