1994 Fiscal Year Final Research Report Summary
Synthesis of Artificial Passivation Films by MOCVD
| Project/Area Number |
05453086
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Material processing/treatments
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
SUGIMOTO Katsuhisa Tohoku University, Engineering, Professor, 工学部, 教授 (80005397)
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| Co-Investigator(Kenkyū-buntansha) |
AKAO Noboru Tohoku University, Engineering, Research Assistant, 工学部, 助手 (80222503)
HARA Nobuyoshi Tohoku University, Engineering, Associate Professor, 工学部, 助教授 (40111257)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Chemical vapor diposition / Metalorganic / Artificial passivation film / Corrosion resistance / Ellipsometry |
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| Research Abstract |
A series of Fe_2O_3-Cr_2O_3-NiO composite oxide thin films were formed on Pt by a MOCVD method. The corrosion resistance of the films was examined in 5M-HCI by measuring the film thickness and the chemical analysis of the test solution. The decrease rates of film thickness as a function of potential were also examined in 1M-H_2SO_4 using insitu ellipsmetry under potentiostatic control. The dissolution rate of Fe_2O_3-Cr_2O_3 and NiO-Cr_2O_3 composite films decreased exponentially with an increase in the cationic mass fraction of Cr^<3+> ions, X_<Cr>, of the films. The reduction dissolution of Fe_2 O_3 and the oxidation dissolution of Cr_2O_3 proceeded in the cathodic and anodic polarization ranges, respectively. The intrinsic passivity range where no dissolution of Fe_2O_3-Cr_2O_3 films occurred was found between the above two dissolution ranges. The addition of Ta_2O_5 to Fe_2O_3-Cr_2O_3 films provided a beneficial effect to suppress the oxidation dissolution of the films. The activation time of Fe coated with Fe_2O_3-Cr_2O_3 (X_<Cr>>0.5) and Fe_2O_3-Cr_2O_3-Ta_2O_5 (X_<Cr>>0.3, X_<Ta>>0.3) films in H_2SO_4, HCI and NaOH solutions increased with increasing film thickness, and reached a maximum in the thickness range of 70-100 nm.
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