阵列电极法测量聚合物/金属界面电位分布

CORROSION POTENTIAL IMAGING AT INTERFACE OF POLYMERIC COATING/METAL BY ARRAY ELECTRODETECHNIQUE

提出一种微计算机控制的阵列电极技术,用于原位测量金属/聚合物界面电位分布。阵列电极由64根金属丝组成,它们相互绝缘、紧密排列,形成8×8阵列电极。由此可研究有关腐蚀物质如O_2、H_2O等在聚合物涂层中的传输过程,研究聚合物涂层的不均一性及缺陷分布以及研究聚合物/金属界面的腐蚀破坏的电化学机理。

An array electrode composed of 64 steel wires and a potential imaging system were developed as a new electrochemical technique for probing the corrosion potential distribution at interface of polymeric coating/metal. The measuring technique was described, and the availability of the technique was examined. The novel data related to the corrosion behavior at the interface were obtained and the effects of defects in the coating on its degradation were discussed. The potential imaging demonstrated the existence of inhomogeneities in the coatings, including intrinsic defects or damage in service (artificial defects). Corrosion preferentially initiated at the defect sites. The anodic sites surrounding cathodic area and the development process of corrosion reaction were in situ imaged for the first time for organically coated steel system. The relevant and direct information provided by this unique technique would be very helpful for further understanding some important physicochemical processes associated with degradation of coated metals.