Development of laser Enhanced Electrochemical Microscopy

激光增强电化学显微镜的发展

基本信息

批准号：
02555152
负责人：
SHIBATA Toshio
金额：
$ 7.81万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

For evaluation of localized corrosion susceptibility, metallography for structure or composition, and laser etching/plating, a Scanning Laser Enhanced Electrochemical Microscopy (SLEEM) has been developed. Solid state semiconductor laser of AlGaAs which is small and easily controlled was used as a scanning laser source. In 1990, a 40 mW output power type laser was used and later 80 mW type was introduced in 1991. Laser out put was Chopped by bias voltage into 10 Hz to 100 Hz square wave and irradiated to the metal specimen which is kept at a constant potential in the electrolytic solution. Change in electrolytic current by laser irradiation is detected by a lock in amplifier and make a scanning image by using microcomputer. Current change induced by laser irradiation at the constant potential is found to be proportional to the electrolytic current without irradiation. Decrease in frequency of irradiation induces the current increase because of temperature increase at the metal surface as a theoretical model predicts. Characteristic increase in current for Fe, Cr and Ni which are constituents elements of stainfess steels was observed at a specified potential region for each element, so that current change of stainless steel by irradiation at the constant potential depends on its composition. Resolving power of the SLEEM is the same size of about 10 mum as the spot size of the laser beam. Based on the above analysis, the chromium depleted grain boundary image of sensitized stainless steel could be obtained succesfully at the potential that is active for Fe but passive for Cr. At the trans passive potential, the compositional image of Cr in two phase stainless steel could be obtained. Fine image etching can be made at the active and transpassive potential.

为了评估局部腐蚀易感性，结构或组成的金相图以及激光蚀刻/镀层，已经开发了扫描激光增强的电化学显微镜（SLEEM）。小且容易控制的藻类的固态半导体激光用作扫描激光源。在1990年，使用了40 MW的输出功率类型激光器，后来在1991年引入了80 MW类型。激光输出推杆被偏置电压切成10 Hz至100 Hz平方波，并被照射到金属样品中，金属样品在电解溶液中保持恒定电位。通过放大器中的锁检测到通过激光照射的电流电流变化，并使用微型计算机进行扫描图像。在恒定电势下激光照射引起的电流变化与无辐射的电流电流成正比。作为理论模型预测的金属表面的温度升高，辐射频率的降低会导致电流增加。在每个元素的指定电势区域中观察到Fe，Cr和Ni的电流的特征增加，这是污渍钢的成分元素的特征增加，因此，在恒定电势下通过辐射通过辐射的当前不锈钢变化取决于其组成。 Sleem的分辨能力与激光束的斑点大小相同约10妈妈。基于上述分析，可以在Fe活跃但被动的Cr的电势下成功获得敏感不锈钢的铬颗粒晶界图像。在反式被动势下，可以获得两相不锈钢中Cr的组成图像。精细的图像蚀刻可以在主动和跨性电位上进行。