不同CO_2压力下形成的N80钢腐蚀产物膜特征

Characteristics of N80 steel corrosion scales forming under different CO_2 pressures

对N80钢在不同CO2压力下进行高温、高压腐蚀实验,根据失重法计算N80钢的腐蚀速率,利用扫描电镜观察腐蚀产物膜的微观形态,分析腐蚀产物膜的厚度和Ca元素含量,利用电化学阻抗谱和极化曲线法测试了腐蚀产物膜的电化学性能,并对腐蚀产物膜与基体间的剪切强度进行了测试.结果表明,随CO2压力增加,N80钢腐蚀速率增大;腐蚀产物膜晶粒尺寸基本不变,膜中微观缺陷数量逐渐增多;腐蚀产物膜电阻和反应电阻呈逐渐增加的趋势;腐蚀产物膜与N80钢基体结合的剪切强度下降,促进了N80钢的腐蚀.

Corrosion experiments of N80 steel were conducted under different CO2 pressures by a high temperature and high pressure autoclave. The corrosion rate of N80 steel was calculated by the mass-loss method, the micrograph, thickness and Ca content of the corrosion scales were observed by scanning electron microscopy, and the electrochemical properties were measured and analyzed by electrochemical impedance spectra and potentiodynamic polarization. The shear strengths between the corrosion scale and the N80 steel substrate were measured. The results show that with the increase of CO2 pressures the corrosion rate of N80 steel increases, the grain sizes of the corrosion scales show no obvious difference, and the amount of microcosmic flaws in the corrosion scales increases gradually. The resistance of the corrosion scale and the reaction resistance show the increase tendency. The shear strength between the corrosion scale and the N80 steel substrate decreases with the increase of CO2 pressure, leading to the increase in corrosion rate.