【作者】 马燕；

【导师】 林冠发；

【作者基本信息】 西安石油大学 ， 材料加工工程， 2014， 硕士

【摘要】 本文利用高温高压腐蚀试验设备、电化学测试并辅以SEM、EDS及XPS等现代分析技术，研究了超级13Cr不锈钢在高温高压CO2环境下的腐蚀机理。实验结果表明，超级13Cr不锈钢CO2腐蚀速率随主要影响因素的变化有如下特征：在气相中随着温度的升高而增大，而在液相中先增大，达到140℃后趋于平缓；无论在气相中还是在液相中都随着CO2分压的升高先增大后减小，在CO2为2.5Mpa时达到最大值；气相中随着Cl-浓度增加而增大，液相中当浓度超过50g/L时，腐蚀受到抑制有所减缓。气液两相中超级13Cr不锈钢的点蚀深度和点蚀速率随着温度和Cl-浓度的升高而分别增大。超级13Cr不锈钢主要是依靠Cr在表面富集形成以Cr2O3为主的钝化膜来起到耐蚀作用的。在电化学测试中，从极化曲线可以看出：随着温度与Cl-浓度的升高，超级13Cr不锈钢的自腐蚀电位与点蚀电位都有所降低，耐蚀性能降低，腐蚀产物膜的稳定性降低。在酸性条件下比在碱性条件下更容易发生腐蚀，金属表面的钝化膜更容易被局部破坏而使基体发生点蚀。从阻抗谱可以看出：随着温度的升高，扩散系数增大，容抗弧减小，双电层电阻与腐蚀产物膜电阻都有所降低，耐蚀性能下降。极化电阻（R2+R3）随着Cl-增加而减少，钝化膜变疏松，耐蚀性能降低。当pH发生变化时，钝化膜电容大于双电层电容发生吸附现象，在pH为2时表面最为粗糙， pH的升高可以有利于超级13Cr不锈钢表面的腐蚀产物膜均匀致密，材料的耐蚀性增强。更多还原

【Abstract】 With autoclave, electrochemical test and SEM, EDS, XPS, the corrosion mechanism of super13Cr stainless steel under the high temperature and pressure CO2environment was investigated.The results showed that:corrosion rate of super13Cr stainless steel under CO2environment, exacerbated with temperature increasing in the gas phase, and in the gas phase increased firstly then stabilized after140℃. The corrosion rate exacerbated with CO2partial pressure increasing and reduced after2.5MPa; With the increase of concentration of Cl", the rate exacerbated constantly in the gas, but it was inhibited after50g/L in liquid phase. The pitting corrosion rate and depth of the steel exacerbated as the increase of temperature and Cl-concentration.The occurrence of corrosion could be resisted because the Cr element existed in the form of Cr2O3in the surface scale of super13Cr stainless steel.In electrochemical tests, it could be seen from the polarization curve that as the temperature and the concentration of Cl-rised, the corrosion potential and pitting potential of super13Cr stainless steel has been reduced, corrosion resistance was poor, and the stability of the corrosion product films reduced. In addition, it is more prone to corrosion under acidic environment than under basic environment, and the passivation film of the metal is more easy partially destroyed and occure pitting corrosion. It was seen from the impedance spectra that as the temperature increased, the coefficient of diffusion increased, the impedance of the electric double layer and corrosion product film were reduced, and resistance corrosion of the material dropped. Polarization resistance (R2+R3) of the steel decreased with Cl-increasing, and the film became loose, the resistance corrosion reduced. When the pH changed, the capacitor of the passive film was greater than electric double layer, the adsorption phenomena occurred, and the surfaces was most rough.The corrosion product film of super13Cr stainless steel could be more dense as pH increases, and the corrosion resistance of the steel enhanced.更多还原