Development of Scanning Interfacial Impedance Measuring Apparatus.

对于涂层和表面文件，已经提出了多种表征方法。其中，电化学阻抗谱不仅可以用于基础研究，还可以用于工业应用，因为它可以无损地测量薄膜的性质。然而，上述方法只能得到被测表面的平均值或平均值，从而无法获得缺陷及其在薄膜或局部退化区域中的分布信息。本研究旨在利用缝合在表面上的微探头来开发扫描界面阻抗测量仪，并制作二维阻抗图来识别涂层文件中的缺陷及其腐蚀速率及其分布。1988年，该仪器的主要部分已建成，该仪器由X-Y-Z工作台、频率响应分析仪和恒电位仪组成。1989年，购买了一台个人计算机，用来控制仪器，采集数据，最后在CRT屏幕或打印机上显示阻抗图。研制了一种由对电极和参比电极组成的薄管内微探针，并成功地测量了足够分辨率的阻抗图谱。分辨两点的分辨率约为200微米。定量表征了加速环境下钢表面涂层中的缺陷及其分布。对薄膜的降解过程进行了评价，观察了薄膜的毒性分布，发现降解程度最高的部位服从Gumbel分布。

Many kinds of characterization methods have been proposed for coating and surface files. Among them, electrochemical impedance spectrometry have been widely used not only for basic research, but also for industrial applications, because it could measure film properties without destruction. The above method, however, could obtain a mean or average value over the surface which was measured, so that information on defects and its distribution in the film or localized degradated area could not be obtained.In this study, "Scanning Interfacial impedance Measuring Apparatus" is aimed to develop by using a micro-probe which is seamed over the surface, and to make two dimensional impedance maps for identifying defects in coating files with corrosion rate and their distributions.In 1988, a main part of the apparatus which consists of X-Y-Z stage, frequency response analyzer, and potentiostat had been constructed. In 1989, a personal computer was purchased ard was used to control the apparatus, to make acquisition of the data, and finally to display impedance maps in a CRT screen or printer. A newly developed micro-probe which includes a counter electrode and a reference electrode within a thin tube was developed and succeeded to measure impedance maps with enough resolution. The resolution for distinguishing two points was proved to be about 200 mum. Defects and their distributions in coating film on steel in accelerated environments was characterized quantitatively. The process of degradation of the film was also evaluated.Poison distribution was observed and the distribution of the highest degradated sites was found to obey the Gumbel distribution.