温度对X80管线钢在0.5mol/L Na_2CO_3+1.0mol/L NaHCO_3溶液中电化学腐蚀性能的影响  

Influence of Temperature on Electrochemical Corrosion Behavior of X80 Pipeline Steel in 0.5 mol/L Na_2CO_3+1.0 mol/L NaHCO_3 Solution

作　　者：齐季[1] 谢飞[1] 王丹[1] 宋志国[1] 孙岩[1] 肖辉宗 

机构地区：[1]辽宁石油化工大学石油天然气工程学院,辽宁抚顺113001

出　　处：《材料保护》2017年第5期28-32,共5页Materials Protection

基　　金：国家自然科学基金项目(51604150);辽宁省博士启动基金项目(201601324)资助

摘　　要：目前,有关温度对CO_3^(2-)-HCO_3^-环境下X80管线钢腐蚀行为的影响规律尚无统一的认识。为了探究高强度钢在不同温度的0.5 mol/L Na_2CO_3+1.0 mol/L NaHCO_3溶液中的腐蚀行为,采用动电位极化、电化学阻抗技术,并结合金相显微镜观察研究了温度对X80管线钢在0.5 mol/L Na_2CO_3+1.0 mol/L NaHCO_3溶液中电化学腐蚀行为的影响规律,并通过Mott-Schottky曲线对不同温度下钝化膜的半导体性质进行探讨。结果表明:温度从30℃上升至75℃时,X80钢的点蚀电位和电荷转移电阻均逐渐减小,腐蚀现象越明显;当温度达到90℃时,点蚀电位和电荷转移电阻反而增大,腐蚀程度有所减缓;在0.3~0.7 V内,钝化膜呈现出典型的n型半导体特征;随着温度的升高,钝化膜内的施主电流密度和平带电位呈现先降低后增加的趋势,钝化膜稳定性先减弱后增强;在75~90℃之间存在一个临界温度,此温度下钝化膜的缺陷密度最大,保护性最差。In order to explore the corrosion behavior of high strength steel in 0.5 mol/L Na2CO3＋ 1.0 mol/L NaHCO3 solution of different tem- perature, the effects of temperature on electrochemical corrosion behavior of X80 pipeline steel in 0.5 mol/L Na2CO3 ＋ 1.0 mol/L NaHCO3 solu- tion were investigated by potentiodynamie polarization, electrochemical impedance spectroscopy（EIS） and metallographie microscope, and the semiconductor properties of passive films at different temperatures were studied by Mott-Sehottky curves. Results showed when the temperature rose from 30 ℃ to 75℃, the pitting potential and charge transfer resistance of X80 steel decreased gradually, and the corrosion phenomenon became more obvious. When the temperature reached 90 ℃, the pitting potential and charge transfer resistance increased, and the corrosion degree reduced gradually. In the range of 0.3 V to 0.7 V, the passivation film exhibited n-type semiconductor characteristics. With the increase of temperature, the current density of donor and fiat band potential of passive film decreased firstly and then increased, and the stability of pas- sive film declined firstly and then increased. A critical temperature existed between 75 ℃ and 90 ℃, and at this temperature, the defect densi- ty of passive film was the maximum and the protection was the worst.

关 键 词：X80管线钢 温度 腐蚀电化学 Mott-Schottky曲线 

分 类 号：TG178[金属学及工艺—金属表面处理]