2 0 0 0 OA 高濃度硫酸中におけるステンレス鋼の腐食機構解析
- 著者
- 松橋 亮 安保 秀雄 阿部 征三郎 紀平 寛
- 出版者
- Japan Society of Corrosion Engineering
- 雑誌
- 防食技術 (ISSN:00109355)
- 巻号頁・発行日
- vol.36, no.9, pp.578-585, 1987-09-15 (Released:2009-10-30)
- 参考文献数
- 7
- 被引用文献数
- 5 8
The mechanism of corrosion of stainless steels in highly concentrated sulfuric acid was studied by the electrochemical method and surface analysis as EPMA and Laser-Raman Spectroscopy. Cyclic potential changes occured in this system about between -0.2V (SCE) (active state) and 0.2V (SCE) (passive state). The anodic reaction was determined as the metal dissolution in both the active and the passive state. The cathodic reaction in the active state near -0.2V (SCE) was mainly dominated by the reduction of hydrogen ion which was clearly indicated by the evolution of hydrogen gas. On the other hand, catholic reaction at the passive state about 0.2V (SCE) was determined as the reduction of molecular sulfuric acid resulting in the formation of sulfur and water. By the analysis of EPMA, precipitated sulfur was found on the specimen surface polarized at 0.2V (SCE) potentiostatically. The in-situ observation of corroding surface by Laser-Raman spectroscopy indicated the formation of precipitated sulfur on the metal surface at the corrosion potential. Cyclic changes in corrosion potentials were considered due to the following mechanisms; dissolved metal ion at the active state formed metal sulfate films on the metal surface, leading the corrosion potential to the passive state. Inversely at the passive state, water as the product of the cathodic reaction accelerated the dissolution of the metal sulfate film to move the corrosion potential to the active state.
1 0 0 0 OA 自然海水中に浸漬したステンレス鋼の電位貴化メカニズムの検討
- 著者
- 伊藤 公夫 松橋 亮 加藤 敏朗 三木 理 紀平 寛
- 出版者
- Japan Society of Corrosion Engineering
- 雑誌
- Zairyo-to-Kankyo (ISSN:09170480)
- 巻号頁・発行日
- vol.50, no.6, pp.285-291, 2001-06-15 (Released:2011-12-15)
- 参考文献数
- 20
- 被引用文献数
- 6 5
Potential ennoblement for stainless steel in natural seawater was analyzed. Open circuit potentials (OCPs) of platinum, gold, palladium, chromium, titanium and nickel ennobled in natural seawater as well as stainless steel, SUS 304 (18Cr-8Ni). Potential ennoblement is not a specific event to only stainless steel. Marine biofilm clearly caused potential ennoblement. Cathodic polarization curves for the ennobled stainless steel elucidated that there were two distinct reduction current increases. One is the limited diffusion current of dissolved oxygen reduction below -500mV vs. Ag/AgCl (KClsat). The other reduction current around 0mV vs. Ag/AgCl (KClsat) was considered to be hydrogen peroxide reduction current in acidic condition. Synergistic effect of hydrogen peroxide and low pH in artificial seawater carried out high OCP of stainless steel like that in natural seawater. Therefore, we concluded that synergistic effect of hydrogen peroxide production and low pH by marine microorganisms is possible cause for potential ennoblement in natural seawater.
1 0 0 0 OA 耐候性鋼の腐食減耗予測モデルに関する研究
- 著者
- 紀平 寛 田辺 康児 楠 隆 竹澤 博 安波 博道 田中 睦人 松岡 和巳 原田 佳幸
- 出版者
- 公益社団法人 土木学会
- 雑誌
- 土木学会論文集 (ISSN:02897806)
- 巻号頁・発行日
- vol.2005, no.780, pp.780_71-780_86, 2005 (Released:2006-04-07)
- 参考文献数
- 42
- 被引用文献数
- 14 13
耐候性鋼の超長期にわたる腐食減耗予測法について研究を行った. さび安定化概念にもとづく思想を体系的に展開し, 腐食速度パラメータを推定するアルゴリズムや数式モデルの立案, 地域気象情報のデータベース化, 簡易な飛来塩分量および硫黄酸化物量の推定法などを策定した. 複雑な計算過程を容易に操作できるよう, 内桁条件における腐食減耗予測シミュレーションソフトウェアも開発した. 前記の思想展開により, 設計にて考慮すべき予測腐食減耗量を見極めるための工学的指標群を初めて具体的かつ体系的に整理・提案し, 長期耐久性の実現に関わる数多な構成技術要素保障項目の関連性を明確にした. 今後の進化へ向けて検討すべき点を明らかにしつつ, 現在までの進捗内容を詳細に報告する.