Development of Scanning Interfacial Impedance Measuring Apparatus.

涂层和表面锉的表征方法有很多种。其中，电化学阻抗法不仅广泛应用于基础研究，而且由于它可以在不破坏薄膜的情况下测量薄膜的性质，因此在工业应用中也得到了广泛的应用。然而，上述方法只能得到被测表面的平均值或平均值，因此无法获得缺陷及其在薄膜或局部降解区域中的分布信息。在本研究中，“扫描界面阻抗测量仪”的目的是利用一个缝在表面上的微探针，制作二维阻抗图，用于识别涂层文件中具有腐蚀速率及其分布的缺陷。1988年，研制完成了由X-Y-Z级、频响分析仪和恒电位器组成的仪器主体部分。1989年，购买了一台个人电脑，用于控制仪器，采集数据，最后在CRT屏幕或打印机上显示阻抗图。研制了一种新型微探针，该探针包括一个对电极和一个细管内的参比电极，并成功地以足够的分辨率测量阻抗图。结果表明，分辨两点的分辨率约为200 μ m。对加速环境下钢涂层中的缺陷及其分布进行了定量表征。并对膜的降解过程进行了评价。观察毒性分布，发现最高降解位点的分布服从甘贝尔分布。

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.