温度对N80油套管钢CO_2腐蚀膜覆盖条件下阴极阻抗谱的影响

The Influence of Temperature on the Cathodic Impedance Spectra of N80 Steel Pipes Covered by Corrosion Film

利用极化曲线和电化学阻抗谱技术研究了温度对腐蚀膜覆盖条件下N80油套管钢在含饱和CO2的地层水中阴极阻抗谱的影响。结果表明:成膜温度升高阴极反应电阻增加,扩散导纳减小,表明阴极反应速率减小。说明温度升高有助于致密性膜的形成,对基体的保护作用增强。3MPa200℃下所成膜覆盖条件下N80油套管钢在不同温度的阴极过程阻抗谱主要由高频容抗弧、低频容抗弧和Warburg阻抗共同组成,随着温度升高,扩散过程增强。

The influence of temperature on the cathodic impedance spectra of N80 steel pipe, which was covered by corrosion film and was in stratum water with saturated CO2, was investigated by means of the technology of polarization curve and electrochemical impedance spectra. The results show that with the rising of film-forming temperature, the reaction impedance increased while the diffusion admittance decreased, thus indicating that the cathodic reaction rate decreased. It is also found that with the increase of temperature the compact film was easily formed and the film protection on the matrix was strengthened. The impedance spectra of N80 steel pipe, which was covered by corrosion film formed at 3MPa and 200℃ and measured at different temperatures, consisted of capacitance arc at high frequency, capacitance arc at low frequency and Warburg impedance. With the temperature increasing, the diffusion process was enhanced.