X80钢在含有SRB的海水溶液中阴极保护准则适用性

通过表面观察及电化学方法研究X80钢在含有SRB的海水溶液中阴极保护准则的适用性,测试结果表明:腐蚀控制因素为阳极控制,对金属施加阴极极化第5天降低金属腐蚀速度主要通过增大金属表面SRB的附着电阻和电荷转移电阻实现;而施加阴极极化第10天,阴极保护主要通过改变金属表面电荷转移电阻控制腐蚀速度,且阴极极化电位越大控制效果越好。无阴级保护的金属试样腐蚀产物较多且附着力差,施加阴极保护的金属试样腐蚀产物较少且附着力较强。阴极保护的确能对存在SRB的海水溶液环境中X80钢起到阴极极化作用,但极化5 d时传统的阴极保护准则中-850 mV_CSE(即-770 mV_SCE)电位未达到85%的保护要求,-950 mV_CSE(即-870 mV_SCE)电位刚刚能满足保护要求;而极化10 d时2种极化电位下保护度都有所下降且都不能满足保护要求,因此还需要进一步实验确定其合适的阴极保护电位。

Study on the cathodic protection criteria applicability of X80 steel in seawater solution containing SRB

The applicability of cathodic protection criteria was studied by surface observation and electrochemical method while the X80 steel was immersed into seawater solution containing SRB. The results revealed:The corrosion was anode control. The corrosion rate was reduced by increasing the SRB adhesion resistance and the charge transfer resistance on the metal surface in the fifth day. While the metal was protected mainly through changing the charge transfer resistance on the metal surface in the tenth day, and the cathodic polarization potential was more negative, the effect was better. The corrosion products were more and poor adhesion on the metal with no-cathodic polarization, and the corrosion products were less and strong adhesion on the metal surface with cathodic protecting. The cathodic polarization could indeed protect the X80 steel in the presence of SRB. In the fifth day, the protection degree was not up to 85% when the metal was polarized to -850 mV_CSE, and it just could meet the protection requirement while polarized to -950 mV_CSE. And in the tenth day the protection degree was declined, it did not meet the requirement while polarized to -850 mV_CSE and -950 mV_CSE. So it was needed to continue to determine the appropriate cathodic protection potential in the presence of SRB.