材料期刊网

用Kelvin探头电位分布测量技术研究了无机盐微粒沉积在大气腐蚀的发生与发展过程中的作用.结果表明，无机盐沉积诱发金属大气腐蚀的必要条件是环境相对湿度大于该无机盐与其饱和溶液平衡的相对湿度RHOSS.只有在这种条件下，无机盐微粒能够吸收环境中的水汽，在金属表面形成了薄电解质液层并改变电极表面的电位分布为不均匀的火山型电位分布.峰电位EP和谷电位EV会随环境相对湿度的变化而迅速变化，而金属基体电位EM不随环境湿度变化.增加干湿循环次数会增大峰电位EP和谷电位EV的差值即腐蚀电动势，从而增大了大气腐蚀速度.无机盐颗粒沉积金属表面化学分布与电位分布密切相关.提出了无机盐颗粒沉积金属表面不均匀电位分布模型，说明了无机盐颗粒沉积诱发大气腐蚀过程的机制.

The role of salt particle deposition in the initiation and propagation of atmospheric corrosion was studied using potential distribution measurement.The results showed that the necessary condition for the atmospheric corrosion initiation was the relative humidity higher than that over saturated solution of the salt particle,during which the salt particle absorbed water from the air and condensed rolyte layer on the metal surface.At the same time,non-homogeneous potential distribution with volcano type was formed around the place of salt deposition.The peak potential Ep and valley potential Ev changed drastically with rapid change of relative humidity,while the potential of the metal matrix remained.The difference of the peak potential and the valley potential Ep-Ev,the potential difference of the corrosion battery,increased rapidly with increasing the number of dry-wet cycles,which increased corrosion rate,too.It was also found out that the chemical distributions has close relationship with potential distribution on the metal surface with salt particle deposition.The model described the non-homogeneous potential distribution over the metal with salt deposition was proposed and the initiation and propagation of atmospheric corrosion caused by the salt deposition was elucidated,based on above findings.