Effects of Acidity on Passive Film-Breakdown and Repassivation Processes in Alloy-Molten Salt Interface

酸度对合金-熔盐界面钝化膜破坏和再钝化过程的影响

基本信息

批准号：
10450268
负责人：
NISHIKATA Atsushi
金额：
$ 5.44万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10450268/
关键词：
Strain electrode Type 304 stainless steel Strain Stress Acidity Passivation

项目摘要

In the previous research work which was carried out under Grant-in-Aid for Science Research (B-2, Project # 07555665) in 1995-1996, a strain electrode system for use in high temperature molten salt environments had been developed.However, the serious problem of how to prevent the leakage of molten salts through gap between the specimen (SUS304 plate) and crucible (alumina) was still left. In the present research work, a rod of SUS304 stainless steel was used as the specimen and the crucible which was made of the same materials as the specimen was utilized. The specimen and crucible were screwed together and then the screw part was sealed with alumina cement. By this method, the leakage problem was almost solved.The new strain electrode system was applied to investigation of the passive film breakdown and repassivation of SUS304 stainless steel in molten nitrates at 300 C. The following results were drawn ;1. In the elastic region, the current response to the applied strain was not observed, which indicates that the oxide film is not broken down by the elastic deformation.2. Plastic deformation provided the strain current due to the formation of slip steps on the surface which leads to the breakdown of passive films.3. When the strain was increased stepwisely by 2%, amount of electric charge, which was used for the passivation of newly formed surface, decreased with increasing the strain. Large plastic deformation increases the number of the slips teps per unit length, as a result, decreases the distance between the slip steps, which leads to reduction of newly-formed surface area.

在先前的研究工作中，在1995 - 1996年在1995年至1996年的《科学研究授予》（B-2，Project＃0755665）下进行的研究中，已经开发了用于高温熔融盐环境的应变电极系统。如何通过样品（SUS304板）和坩埚（氧化铝）之间的间隙来防止如何防止熔融盐泄漏的严重问题。在本研究工作中，将SUS304不锈钢杆用作标本和坩埚，该标本由与标本相同的材料制成。将试样和坩埚拧在一起，然后用氧化铝水泥密封螺钉部分。通过这种方法，几乎解决了泄漏问题。新的应变电极系统用于研究被动膜崩溃和SUS304不锈钢在300 C中的熔融硝酸盐中的不锈钢的重新持续。在弹性区域中，未观察到当前对施加应变的反应，这表明氧化物膜未被弹性变形分解。2。塑性变形提供了应变电流，这是由于表面上滑动台阶的形成，从而导致被动膜的崩溃3。当应变增加继承2％时，用于钝化新形成的表面的电荷量随着应变的增加而降低。因此，大型塑性变形增加了单位长度TEP的数量，因此减少了滑动步骤之间的距离，从而导致新形成的表面积减少。