用等距离电位法修正Q345钢在稀NaHCO_3溶液中极化曲线  

AMENDING THE POLARIZATION CURVES OF THE Q345 IN NaHCO_3 SOLUTION THROUGH THE METHOD OF EQUIDISTANCE VOLTAGE

作　　者：聂向晖[1] 杜翠薇[1] 李晓刚[1] 

机构地区：[1]北京科技大学材料科学与工程学院腐蚀与防护中心,北京100083

出　　处：《中国腐蚀与防护学报》2009年第3期167-171,共5页Journal of Chinese Society For Corrosion and Protection

基　　金：国家自然科学基金重大项目(No.5049933);科技部国家科学基础条件平台建设项目(No.2005DKA10400)

摘　　要：利用等距离电位法对Q345钢在6 mmol/L、3 mmol/L、1.5 mmol/L的NaHCO_3a溶液中的阳极极化曲线进行了修正,消除了溶液电阻R_(sol)对测量结果的影响,利用修正后的结果可以方便地求出Q345钢在三种不同浓度NaHCO_3溶液中的Tafel斜率b_a和腐蚀电流密度I_(corr)等动力学参数.与电化学阻抗谱拟合得到的溶液电阻R_(sol)相比,发现在极化作用下,其R_(sol)由于溶液中离子运动速度的增加以及电极表面附近离子浓度的变化而减小.利用等距离电位法计算出的R_(sol)在相应的电位范围内是适用的,而不能将其推广到整个极化曲线测量区间,否则将会引起较大的误差。由于受扩散作用的影响,这种等距离电位法不适合对其阴极过程进行修正.The polarization curves of the Q345 were measured in NaHCO3 solution, and the concentration is 6 mmol/L, 3 mmol/L and 1.5 mmol/L respectively. The anodic polarization curves were amended by means of equidistance voltage. By this way, the influence of the solution resistance to the measurement was eliminated. By the modified results, the kinetic parameters, such as ba and Icorr could be got easily. Comparing with the results from EIS, under the effect of the polarization, because of the shifting of the iron concentration near the electrode surface and the movement speed of the ions is much fast under the effect of the electric field ,solution resistance is less than the resistance at the corrosion potential. Furthermore, the Rsol that calculated by the method of equidistance voltage is reasonable for the calculation range, but it can not be extended to the whole range of the measurement. Otherwise, a big error will be aroused. Being the effect of diffusion process, this method is not suitable for cathodal course.

关 键 词：溶液电阻 极化曲线 等距离电位法 

分 类 号：TG172.5[金属学及工艺—金属表面处理]