超级13Cr油管钢在含Cl^-溶液中的腐蚀行为及其表面腐蚀膜的电化学特性

Corrosion Behavior of Super 13Cr Tubing Steel in Cl^- Solution and Electrochemical Characteristics of Corrosion Film on Its Surface

在室温不同质量分数(5%～35%)NaCl溶液中对超级13Cr油管钢进行浸泡腐蚀试验,研究了该钢的腐蚀形貌、腐蚀速率、腐蚀产物及其表面腐蚀膜的电化学特性。结果表明:试验钢在NaCl溶液中具有较好的耐蚀性;随NaCl质量分数的增加,其耐蚀性降低,当NaCl质量分数大于25%时变化尤为显著,腐蚀形式由局部腐蚀发展为全面腐蚀,腐蚀产物主要为Fe_3O_4,腐蚀膜疏松不致密;腐蚀膜的极化曲线存在钝化区,具有钝化特性,在低频区的电极过程为扩散控制,在高频区则为电荷传递控制,其阻抗由一个时间常数确定。

Immersion corrosion tests in NaCl solutions with different NaCl mass fractions(5%-35%) were conducted on super 13Cr tubing steel at room temperature.Corrosion morphology,corrosion rate,corrosion products of the steel and electrochemical characteristics of its surface corrosion film were studied.The results show that the tested steel had relatively good corrosion resistance in NaCl solution.The corrosion resistance decreased with increasing mass fraction of NaCl and the decline was obvious when the NaCl mass fraction increased over 25%.With increasing NaCl mass fraction,the corrosion form changed from local corrosion to general corrosion.The corrosion products were composed of Fe3O4,and the corrosion film was loose and not dense.The polarization curves of the corrosion film had a passivation zone,indicating that the film had passivation characteristics.The electrode process in the low-frequency zone was diffusion control,and that in the high-frequency zone was charge transfer control.The impedance of the corrosion film was determined by a time constant.