1992 Fiscal Year Final Research Report Summary
"Measurements of a Trace Amount of Indoor Corrosion Using Kelvin Probe and QCM Methods"
| Project/Area Number |
03453066
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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 |
金属材料(含表面処理・腐食防食)
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
TSURU Tooru Tokyo Institute of Technology, Department of Metallurgy, Professor, 工学部, 教授 (20092562)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIKATA Atsushi Tokyo Institute of Technology, Department of Metallurgy, Associate Professor, 工学部, 助教授 (90180588)
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| Project Period (FY) |
1991 – 1992
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| Keywords | ATMOSPHERIC CORROSION / ELECTROLYTE THIN LAYER / KELVIN METHOD / DIFFUSION LIMITING CURRENT / WATWER LAYER / ELECTRONIC MATERIALS / QUARTZ CRYSTAL MICROBALANCE / QCM |
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| Research Abstract |
New methods for measuring a trace amount of corrosion, which are based on Kelvin prove and quartz crystal microbalance (QCM) methods, have been developed to clarify the mechanisms of indoor corrosion in electronic equipments.
This study is divided into three chapters.
(1) "Development of a Vibrating reference electrode system" A new technique for measuring the potential distribution on a metal without touching the surface has been developed. We found that the use of parasitic capacitance is effective to reduce to time for measurement. By using this equipment, the surface potential of aluminum embedded in a copper sheet was measured.
(2) "oxygen reduction under thin water layer" The reduction mechanisms of oxygen on metals with thin water layer have been investigated by Kelvin probe method. Particular attention has been given to the dependence of the oxygen reduction rate on the thickness of water layer. It was found that the reduction rate increases with decreasing the thickness of water layer down to the thickness of several tens mum. When the thickness is decreased further, it is independent of the thickness. It can be explained by a decrease of oxygen solvability and a pH change of water film.
(3) "Impedance characteristics of metal corrosion under thin water layer"
The impedance characteristics of steels and copper have been monitored in wet/dry cycle condition. This is capable of monitoring the corrosion rate simultaneously with the thickness of water layer. We found that the corrosion rate increases sharply, immediately after the dried surface is reimmersed into a solution and shortly before the surface dried out, and that it exhibits a maximum around the water layer thickness of 20 mum.
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