2006 Fiscal Year Final Research Report Summary
Electrodeposition of Zn-Active Metals Composite for Surface Treatment of Steel Sheets
| Project/Area Number |
16360366
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | KYUSHU UNIVERCITY |
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Principal Investigator |
FUKUSHIMA Hisaaki Kyushu University, Faculty of Engineering, Professor, 大学院工学研究院, 教授 (50038113)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANO Hiroaki Kyushu University, Faculty of Engineering, Associate Professor, 大学院工学研究院, 助教授 (70325504)
OUE Satoshi Kyushu University, Faculty of Engineering, Research Associate, 大学院工学研究院, 助手 (90264085)
KAMIMURA Haruo Kyushu University, Faculty of Engineering, Research Associate, 大学院工学研究院, 助手 (40294897)
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| Project Period (FY) |
2004 – 2006
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| Keywords | vanadium / electrodeposition / oxide / current density / composite / corrosion current / zinc / polarization curve |
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| Research Abstract |
Electrodeposition of Zn with V was tried in un-agitated or agitated sulfate solutions containing Zn^<2+> and VO^<2+> at pH 0-3 and 40℃ under galvanostatic conditions. XPS spectra of deposits showed that V was involved in deposited Zn in form of V_2O_3 by hydrolysis of V^<3+> reduced from VO^<2+>. The content of V in deposits increased with increasing pH in solution and current density. These conditions appear to accelerate the hydrolysis of V ions as a result of an increase in hydrogen evolution in cathode layer. The partial polarization curve for Zn deposition was greatly polarized in solution containing VO^<2+> ions. This great polarization by addition of VO^<2+> ions is ascribed to the increase in resistance polarization as a result of formation of V_2O_3 resulting from hydrolysis of V^<3+>. SEM and EPMA images of deposits revealed that V in deposits segregated at edge of layered platelet crystals of Zn. The agitation of electrolyte decreased the content of V in deposits, but decreased the segregation of V_2O_3. The preferred orientation of deposited Zn was (0001) basal plane of hcp at the conditions where no V was involved in deposited Zn, while the orientation of (11 22) increased with increasing the content of V in deposits. The V_2O_3 codeposited with Zn seems to prohibit the growth of (0001) Zn basal plane. Anodic polarization curves for Zn dissolution in 3% NaCl solution were polarized by codeposition of V_2O_3 with Zn at V content less than 5 mass%. The corrosion current densities of deposits obtained from agitated solutions were smaller than those.from un-agitated solutions
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