| 摘要 |
PURPOSE:To obtain the title material with improved electrical properties by diffusing to the crystal grain boundary of a semiconductive porcelain a diffusive material comprising TiO2 and one compound or a mixture of at least two compounds selected from Bi. Pb, Cu, B, Na and K ones to form a dielectric layer. CONSTITUTION:Firstly, the main component SrTiO3 is admixed with each ca.0.05-2mol% of Nb2O3 and CuO followed by forming and then baking in a mixed atmosphere of H2 and N2 at ca.1440-1540 deg.C to produce a semiconductive porcelain. Second, one of the surfaces of this porcelain is coated with a diffusive material comprising (A) 1-30mol% of TiO2 and (B) 70-99mol% of one compound or a mixture of at least two compound selected from Bi, Pb, Cu, B, Na and K ones followed by heating at ca.1000-1300 deg.C for about 1-2hr to effect thermal diffusion if said material to form a dielectric layer. Thence, a silver paste is printed on both the surfaces of the semiconductive porcelain material thus obtained, followed by baking at about 80 deg.C into a silver electrode, thus obtaining a grain boundary insulation-type semiconductive porcelain capacitor. |
