氯化钠溶液中铜丝尺寸效应对腐蚀行为的影响

为了研究半径变化对铜丝腐蚀行为的影响, 通过极化曲线和交流阻抗测试方法研究了半径为0.04-0.82 mm的铜丝在自然通气的0.5 mol·L-1 NaCl(pH=7.4)溶液中的腐蚀行为. 结果表明, 当铜丝半径小于氧的扩散层厚度(0.56 mm)时, 随着半径减少, 非线性扩散的存在加速了电化学反应的传质过程, 其影响由慢到快迅速增大, 使得受扩散过程控制的阴、阳极反应速率增大, 铜丝的腐蚀电流密度显著增加. 对铂丝、不锈钢丝的氧阴极还原反应过程研究也得到了类似的反应特征. 上述现象表明铜丝腐蚀行为的尺寸效应具有一定的普遍性.

Size Effect on the Corrosion Behavior of Copper Wires in NaCI Solution

The influence of wire radius (0.04-0.82 mm) on the corrosion behavior of copper wires was investigated in naturally aerated 0.5 mol·L-1 NaCl solution (pH=7.4), by means of polarization and electrochemical impedance spectroscopy method. The results showed that the mass transfer process was significantly accelerated by non-linear diffusion when radius of copper wire was less than the thickness of diffusion layer (0.56 mm), and consequently, the cathodic and anodic reaction rates controlled by diffusion, as well as the corrosion current density, increased rapidly. It showed that the influence was accelerated with the decrease of wire radius. By comparing cathodic oxygen reduction reaction of platinum and stainless steel wires, the same results were obtained. Therefore, the size effect on corrosion behavior of copper wires is a widespread phenomenon.