1993 Fiscal Year Final Research Report Summary
Corrosing Prevention of Insoluble Anode for Steel Strip Electroplating
| Project/Area Number |
04650643
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 | Institute of Industrial Science, The University of Tokyo |
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Principal Investigator |
MUSHIAKE Katsuhiko The University of Tokyo, Institute of Industrial Science, Research Assistant, 生産技術研究所, 助手 (10092347)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Insoluble Anode / Durability / Acidic Sulfate Bath / Electroplating / Iridium Dioxide / Titanium Substrate / Glass Coating |
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| Research Abstract |
Conventional metal electrodes for oxygen evolution (IrO_2-Ta_2O_5-coated titanium electrodes) are impractical in steel strip electroplating because of their poor durabiblity. The purpose of the present study is to extend the service life of the electrodes by forming protective glass coatings on titanium substrates. The glass coatings were prepared by sintering an admixture of frit and silicide. Ohmic losses in the coatings were estimated to be about 1.2mV and have little influence on cell voltage. Immersion test in boiled sulfuric acid solutions showed that the glass coatings prevent titanium from corroding. The glass-coated substrates were painted with H_2IrCl_6 solutions containing some inorganic additives and fired repeatedly. The metal electrodes thus prepared were tested as anodes in sulfuric acid solutions containing organic brighteners. The service life increased with increasing number of catalyst paintings and decreased with increasing content of the organic agents. The glass coatings and the inorganic additives exert a noticeable effect on the extension of the service life. The observations were described in the forms of straight lines on logarithmic graph paper. The relations make it possible to predict the magnitude of the long-term service life. A novel use of insoluble anodes in the purification of electrolytic solution was also studied. Chloride ion, a common contaminant in zinc sulfate solutions from recycled resources, must be removed prior to the succeeding electrolysis. In a recirculation cell equipped with such anodes of large area, the anion may be effectively eliminated.
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