| 摘要 |
<p>PURPOSE:To make it possible to easily obtain a ceramic capacitor having excellent varistor characteristics by a method wherein, after a sintering accelerator, a specific semiconductor accelerator, an oxygen good conductive solid electrolyte and a grain boundary depletion layer forming agent have been added to the oxide powder mainly composed of SrTiO3 and the above-mentioned material has been sintered, sintering, reduction and heat treatment operations are conducted. CONSTITUTION:A sintering accelerator of 0.1 to 5.0wt.%, a semiconductivity accelerator of 0.05 to 2.0wt.% which will mainly be brought into the state of solid solution of perovskite phase, a good oxygen conductive solid electrolyte ZrO2, which performs an additional function as a grain growth control agent, of 0.1 to 10.0wt.%, and a grain boundary depletion layer forming agent Sr (Cu1-3Nb2/3)O3, which performs an additional function as a grain growth control agent, of 0.2 to 4.0wt.%, are added to the perovskite type oxide powder mainly composed of SrTiO3. After the above-mentioned material has been mixed and molded by applying pressure, sintering and reducing operations are conducted at 800 to 1500 deg.C. Subsequently, a heat treatment is conducted at 900 to 1150 deg.C in an oxidizing atmosphere, and an electrode 5 is formed. For example, the above-mentioned sintering accelerator is selected from a TiO2- MgO-SiO2 system, TiO-MnO-SiO2 system and TiO2-Al2-O3-SiO2 system, and the semiconductor accelerator is selected from WO3, Nb2O5, La2O3 and Y2O3.</p> |
