X70钢在含H2S的弱酸性溶液中的腐蚀行为的电化学研究

用动电位扫描法和电化学阻抗谱研究了X70钢在含H2S弱酸性溶液中的腐蚀行为,讨论了酸度、温度、浸泡时间、极化电位对X70钢腐蚀行为的影响。结果表明,恒温下,随着溶液酸度的增加,促进了腐蚀反应阴极过程的进行;当酸度一定时,随着温度的增加,X70钢的自腐蚀电流逐渐增大,自腐蚀电位先负移后正移;随着浸泡时间的延长,FeS保护膜变得更加稳定,抑制作用增强;FeS保护膜在一定电位范围内可对电极反应起到抑制作用,当电位增加到更高的数值时,这种保护膜就会被破坏而失去保护作用。

ELECTROCHEMICAL STUDY ON THE CORROSION BEHAVIOR OF X70 STEEL IN ACID SOLUTIONS WITH H2S

The influences of the acidity of solution,temperature,immersion time and polarization potentials on corrosion behavior of X70 steel in weak acidic solutions with H_2S were studied by means of potentiodynamic polarization curves and electrochemical impendence spectroscopy.With the increasing of the acidity of the solution promoted the cathodic process,thus accelerated the corrosion rate of X70 steel.With the increasing of temperature,the corrosion current increased gradually,the corrosion potential became negative firstly and then positive.With the extension of immersion time,FeS film became more steady and inhibition was strengthened.The FeS protective film could suppress the electrode reaction with the increasing of electrode potential in a certain region,however,when the electrode potential rised to more pasitive values,this kind of protective film would be destroyed and lost protective function.