CO_2饱和的0.5mol/L NaCl溶液中温度对3Cr低合金钢腐蚀行为的影响  

Effect of Temperature on Corrosion Behavior of 3Cr Low-Alloy Steel in Aqueous Solution of Sodium Chloride Saturated with Carbon Dioxide

作　　者：贾志军[1,2] 张新[3] 杜翠薇[2] 李晓刚[2] 

机构地区：[1]清华大学化工系,北京100084 [2]北京科技大学腐蚀与防护中心,北京100083 [3]环境保护部核与辐射安全中心,北京100082

出　　处：《材料保护》2012年第3期23-26,2,共4页Materials Protection

基　　金：国家高技术研究发展计划项目(2009AA063405-04)

摘　　要：低合金钢在含CO2的NaCl溶液中的腐蚀行为受温度影响很大。利用动电位极化和电化学阻抗(EIS)技术研究了CO2饱和的NaCl溶液中温度对3Cr低合金钢腐蚀过程的影响。结果表明:温度的升高促进了腐蚀过程的阴阳极反应,合金钢的腐蚀速率增大;随着温度的升高,阳极塔菲尔斜率逐渐减小,阴极塔菲尔斜率逐渐增大,电极表面的阳极区面积逐渐增大,而阴极区面积逐渐减小;温度升高对阴极过程的促进作用大于阳极过程,使Ecorr发生正向移动;温度升高提高了合金钢的腐蚀速率,但极化曲线形状基本相同,即腐蚀机理未发生变化;合金钢在CO2饱和的0.5 mol/L NaCl溶液中的电化学阻抗谱均出现2个时间常数,高频和中频段出现由双电层界面电容和电荷转移电阻引起的容抗弧,低频段出现与钝化膜相关的容抗弧,但都随着温度的升高而减小。The effect of temperature on the corrosion behavior of 3Cr low-alloy steel in aqueous solution of NaCl saturated with CO 2 was investigated by potentiodynamic polarization technique and electrochemical impedance spectroscopy(EIS).It was found that increasing temperature contributed to accelerated cathodic and anodic processes and increased corrosion rate of the alloy steel.With increasing temperature,the Tafel slope of anodic polarization curves decreased and the cathodic Tafel slope increased,accompanied by gradual increase of anodic zone and gradual decrease of cathodic zone on electrode surface.In the meantime,increasing temperature was more effective in accelerating the cathodic process than the anodic process,leading to shift of corrosion potential towards the positive direction.Increasing temperature led to increased corrosion rate of the alloy steel,but had almost no effect on the shape of the polarization curves.Namely,it had almost no effect on the corrosion mechanism.Moreover,the EIS pattern of the alloy steel in 0.5 mol/L NaCl solution saturated with CO 2 showed two time constants: the high and medium frequency capacitance related to the capacitance of the double layer and transfer resistance,and the low frequency one related to the passivation film.However,both the two time constants reduced with increasing temperature.

关 键 词：腐蚀行为 CO2腐蚀 3Cr低合金钢 温度 NACL溶液 动电位极化曲线 电化学阻抗谱 

分 类 号：TG172.5[金属学及工艺—金属表面处理]