机械加工表面粗糙度对4130 X钢在0.5%NaCl溶液中的腐蚀性能影响

Effect of Surface Roughness on Corrosion Behavior of 4130X Steel in 0.5% NaCl Solution

本文采用动电位极化、电化学阻抗谱、微观形貌观测等方法研究了不同表面粗糙度的4130X钢在质量分数为0.5%NaCl溶液中的腐蚀行为。实验结果表明,随表面粗糙度下降,试样表面积变化不大,其自然腐蚀电位下降,然腐蚀电流密度降低,电荷转移电阻降低,腐蚀反应剧烈程度整体有所下降。微观形貌显示,在反应发生初期,试样表面首先于凸起位置发生腐蚀,并且随腐蚀反应的进行逐渐扩展至试样整体表面。表面粗糙度对腐蚀反应影响主要来源于试样表面的几何形状差异、电化学活性差异和表面状态差异。

In this paper, the corrosion behavior of 4130 X steel with different surface roughness in 0.5% NaCl solution was studied by means of dynamic potential polarization, electrochemical impedance spectroscopy and microscopic morphology observation. The experimental results showed that when the surface roughness decreased, the specimen surface area had no obvious change, the corrosion potential decreased, the corrosion current density decreased, the charge transfer resistance decreased, and the corrosion reaction intensity overall declined. The micro morphology showed that in the initial stage of the reaction, the sample surface is corroded at the raised position, and gradually extended to the whole surface of the sample with the corrosion reaction. The influence of surface roughness on the corrosion reaction is mainly derived from the geometry difference, the difference of the electrochemical activity and the difference of the surface state of the sample.