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Development of Multi-Probe Scanning Environmental Microscope and In Situ Observation of Initiation of Corrosion Damage

多探头扫描环境显微镜的研制及腐蚀损伤萌生的原位观察

基本信息

批准号：
07555347
负责人：
KOMAI Kenjiro
金额：
$ 1.66万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07555347/
关键词：
Environmental Microscope Corrosion In Situ Observation pH Chloride Ion Localized Corrosion Multi-Probe Scanning Microelectrode 腐食き裂

项目摘要

In order to perform in situ observation of an initiation stage of corrosion damage including pitting corrosion and stress corrosion cracking, we have developed a multi-probe scanning environmental microscope, which enables us observe local distribution of pH and chloride ion concentration. To measure precise distribution of pH and chloride ion concentration, the measuring system must be electrically isolated from the sample. For this purpose, we have developed a specially designed potentiostat and an electrometer. By using the developed measuring system, we have utilized a micron size Ag/AgCl microelectrode. The microelectrode is insensitive to local pH value, and therefore, a precise measurement of local chloride ion concentration becomes possible. We also developed a so called chronoamperometric method, where a micron size Pt microelectrode is cyclically polarized, and an associated electric current is measured : local concentration of chloride ion and pH values can be measured by using a current density by anodically, and cathodically polarized. Advantage of this method is that the reaction time of the microelectrode is faster than an microelectrode such as a Ag/AgCl electrode, which enables us measure faster ; this method is a kind of a multielectrode that can measure both pH and chloride ion concentration at a time. We discuss the ability and usefulness of these methods.

为了对点蚀和应力腐蚀开裂等腐蚀损伤的初始阶段进行原位观察，我们开发了一种多探针扫描环境显微镜，它使我们能够观察局部pH值和氯离子浓度的分布。为了精确测量pH值和氯离子浓度的分布，测量系统必须与样品电隔离。为此，我们研制了专门设计的恒电位仪和静电计。通过使用开发的测量系统，我们已经利用了微米尺寸的Ag/AgCl微电极。该微电极对局部pH值不敏感，因此可以精确测量局部氯离子浓度。我们还开发了一种所谓的计时电流法，其中微米尺寸的Pt微电极被循环极化，并且测量相关的电流：可以通过使用阳极极化和阴极极化的电流密度来测量氯离子的局部浓度和pH值。该方法的优点是微电极的反应时间比Ag/AgCl电极等微电极更快，使我们的测量速度更快;该方法是一种可以同时测量pH和氯离子浓度的多电极。我们讨论这些方法的能力和实用性。