2001 Fiscal Year Final Research Report Summary
Investigation of Fine Biomachining of Metals by Using Microbially Influenced Corrosion
| Project/Area Number |
12650715
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | YAMAGUCHI UNIVERSITY |
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Principal Investigator |
KUMADA Makoto Yamaguchi University, Faculty of Engineering, Professor, 工学部, 教授 (60284262)
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| Co-Investigator(Kenkyū-buntansha) |
MIYUKI Hideaki Sumitomo Metal Industries Ltd, Group Manager, 総合技術研究所, 研究主幹(研究職)
MAEDA Syuji Yamaguchi Prefectual Industrial Technology Institute, Special Researcher, 生産システム部, 専門研究員(研究職)
KOBUCHI Shigetoshi Yamaguchi University, Center for Collaborative Research, Associate Professor, 教授 (30225560)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Iron oxidizing bacteria / Microbially influenced corrosion / Fine biomachining / Mild steel / Copper / Surface roughness / Inhibitor / インヒビター |
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| Research Abstract |
In order to use microbially influenced corrosion (usually MIC) for the fine biomachining of metals, influence of pH on both culture of Thiobacillus Ferrooxidans of a kind iron oxidizing bacteria and biomachining mass loss of mild steel and copper in 9K medium and the and the bacteria-cultured solution has been investigated. Furthermore, the biomachining mechanism of metaks has been investigated both by electrochemical measurements in 9K medium and the bacteria-cultured solution and observations of the surface fils.
The cells of bac-teria increased with culture time in 9k medium of pH 1.5. 2.0. 2.5 and 3.0. though they became maximum on 3 to 4 days at other pH except 1.5. The biomachining mass loss of mild steel and copper in the bacteria-cultured solution became larger at pH 1.5 than other pH and then after it became the least at pH 2.5, it increased again at pH 3.0. Fe_2 (SO_4)_3 whi-ch was produced through culture of bacteria accelerated biomachining mass loss of iron andcopper as oxi
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dizing agent. Biomachining mass loss of iron and copper were respectively about 30 mm/y and 6 mm/y of dissolution in 9K medium and the bacteria-cultured solution.
The surface of mild steel was rougher than copper's in 9K medium and the bacteria-cultured solution. The surface roughness of mild steel was about 30 μm after biomachining in bacteria-cultured solution. On the other hand, the copper's roughness was about 3 μm. Both mild steel and copper were generally attacked. But localized pitting attacks were observed on the surface microstructures of mild steel through low magnification in 9K medium and the bacteria-cultured solution. In all solution, copper was generally attacked. The biomachined surface of copper differed from that of mild steel in the point of the very fine structures.
Cathodic polarization curves of mild steel depolarized greatly in the region of -750 to -900 mV zs SCE in the bacteria-cultured solution. This depolarization caused by the reduction reaction of Fe^<3+> + e → Fe^<2+> accelerated the dissolution of metals. In 9K medium, the dissolution of mild steel and copper was prevented by FeSO_4 film, however, in the bacteria-cultured solution FeSO_4 film was not formed owing to the action of bacteria and the dissolution was accelerated by oxidizing effect of Fe^<3+> Less
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Research Products
(10 results)
