温度和硫离子对N80钢CO_2腐蚀电化学行为的影响

INFIUENCE OF TEMPERATURE AND SULFUR ION ON CARBON DIOXIDE CORROSION BEHAVIOR OF N80 STEEL

应用电化学阻抗谱(EIS)、扫描电镜(SEM)及能谱(EDS)研究了温度和硫离子交互作用下,N80钢的CO2腐蚀电化学行为及腐蚀膜的形貌与组成.结果表明:温度和硫离子对N80钢CO2腐蚀电化学行为影响显著;硫离子加入后试样表面吸附着一层腐蚀膜;随着油田地层水中S2-浓度的增加,传递电阻R1、膜电阻R2及扩散阻抗W增加,膜电容Q2减小;腐蚀膜主要由FeS及少量FeCO3组成;其致密性随硫离子含量增加和温度升高而增强.

The joint effect of temperature and sulfur steel was investigated by eleetrochemical impedance ion on the carbon dioxide corrosion behavior of N80 spectra（EIS）. The microstrueture and composition of the corrosion scale was observed and analyzed by scanning electron microscopy（SEM） and energy desper- sive spectra（EDS）. The results showed that temperature and sulfur ion have significant effect on the cor- rosion behavior of N80 steel. With the addition of sulfur ion, the sample surface was covered by a corrosion seale ,which was mainly composed of FeS and a little amount of FeCO3. With the increase of the sulfur ion concentration of the stratum water from oilfield, the transfer resistance R1 , film resistance R2 and diffusion impedance W increased, the film capacitance Q： decreased. The compactness of the corrosion scale increased with the increment of sulfur ion concentration and temperature.