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.

著者

天藤 雅之 竹下 哲郎 中澤 崇徳 木村 英隆 安保 秀雄

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.79, no.1, pp.98-104, 1993-01-01 (Released:2009-06-30)

参考文献数

14

被引用文献数

14 21

---

Room temperature creep behavior has been investigated for typical stainless steels (SUS304, SUS430, SUS410L). The mechanism of creep is discussed in comparison with creep data on a carbon steel (SM400).The results are summerized as follows:1) Stainless steels showed creep deformation at a stress around 0.2% proof stress. Though creep rate decreased monotonously with increase in time, deformation did not ceased even at a time 1000 h. The creep curve of SUS304 steel followed a logarithmic creep law.2) No creep was observed in steel SM400 below a critical strain rate at around 10-8S-1.3) The facts that interstitial free steels showed room temperature creep, and that SUS304 steel showed no creep at 300°C suggest that the suppression of creep can be attributed to the dynamic strain aging due to the interaction between dislocation and interstitial carbon and nitrogen atoms.