| 摘要 |
PURPOSE: ZPCCY-based varistor ceramics for high voltage are provide to maintain high breakdown field, low current leackage, and high nonlinearity by adding a small quantity of indium oxide to ZPCCy-based varistor ceramics, thereby assuring improved current-volatage characteristic for long term use. CONSTITUTION: ZPCCY-based varistor ceramics for high voltage comprise ZPCCY-based varistor ceramics and indium oxide (In2O3). ZPCCY-based varistor ceramics include zinc oxide (ZnO), praseodymium oxide (Pr6O11), cobalt oxide (CoO), chrome oxide (Cr2O3) and yttrium oxide (Y2O3). The indium oxide is added in a quantity of 0.001 mol% to 0.01 mol%. The ZPCCY-based varistor ceramics maintain the breakdown field at higher than 1000 V/cm and the nonlinearity at equal to or higher than 40. The method for manufacturing ZPCCY-based varistor ceramics comprises the steps of : (1) weighing zinc oxide (ZnO), praseodymium oxide (Pr6O11), cobalt oxide (CoO), chrome oxide (Cr2O3) and yttrium oxide (Y2O3) (2) pulverizing the weighed mixture in a ball mill, calcining the produced dry powder, and mixing the powder with polyvinyl alcohol (3) molding and sintering the mixed composition and polishing both the surfaces of the sinter (4) applying a silver electrode to the polished sinter and packaging the produced ZPCCY-based varistor ceramics. [Reference numerals] (AA) Electric field E; (BB) The amount of an indium oxide added; (CC) Current density
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