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HYDROGEN ABSORPTION AND IRON PASSIVE FILM BREAKDOWN IN ALKALINE ENVIRONMENTS

碱性环境中的氢吸收和铁钝化膜击穿

基本信息

批准号：
07650850
负责人：
YAMAKAWA Koji
金额：
$ 1.22万
依托单位：
OSAKA PREFECTURE UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
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

项目摘要

By using the scanning vibrating electrode technique, hydrogen permeation technique and polarization technique, the relation between the breakdown of the iron passive film and hydrogen absorption was investigated in mainly alkaline solutions containing H_2S and CO_2. Through two years'project, the following results were obtained :(1) In alkaline solution carbon steel showed no hydrogen absorption. However the abrupt increase in hydrogen absorption took place after a certain induction time by the addition of KCN,corresponding to the sudden decrease in corrosion potential. It was considered that KCN led to the breakdown of the iron sulfide film to expose bare surface.(2) In alkaline solution without CO_2, little hydrogen absorption was detected. On the other hand, the existence of CO_2 in the solution led largely to the increase in hydrogen absorption. This was explained in terms of the formation of iron carbonate film and the dissolution of the film.(3) Surface morphology was observed using the scanning vibrating electrode. Under the H_2S environment anodic part localized moved with time, whereas the anodic part under the CO_2 environment appeared to be uniformly distributed over the whole area.It was found that the surface morphology was different at both environments.(4) In general, it has been considered that the alkaline environments do not lead to the hydrogen absorption into materials. However, the present results showed that hydrogen embrittlement was possible to take place in alkaline environments with (H_2S+KCN) and CO_2.

利用扫描振动电极技术、氢渗透技术和极化技术，研究了在主要含H_2S和CO_2的碱性溶液中，铁钝化膜的击穿与吸氢的关系。通过两年的实验，得到以下结果：(1)在碱性溶液中，碳钢没有吸氢现象。但在一定的诱导时间后，KCN的加入使吸氢量急剧增加，与腐蚀电位的突然降低相对应。认为KCN导致了硫化铁薄膜的击穿，暴露在裸露的表面。(2)在无CO_2的碱性溶液中，几乎没有检测到吸氢。而溶液中CO_2的存在在很大程度上增加了吸氢量。这与碳酸铁膜的形成和膜的溶解有关。(3)利用扫描振动电极观察了碳酸铁膜的表面形貌。在H_2S环境下，阳极部分的局域化随着时间的推移而移动，而在CO_2环境下，阳极部分似乎均匀地分布在整个区域内，发现两种环境下的表面形貌不同。(4)总的来说，碱性环境不会导致材料吸氢。然而，目前的结果表明，在(H_2S+KCN)和CO_2的碱性环境中可能发生氢脆。