| 摘要 |
PURPOSE:To improve varistor voltage, nonlinear coefft. and surge resistance by incorporating Na2O, TiO2 and Bi2O3 into a specified base. CONSTITUTION:SrCO3 is mixed with TiO2, CaCO3 and the oxide of at least one kind of element selected among Nb, W, Ta, In, Y and rare earth elements. The mixture is calcined, pulverized, press-molded and sintered to obtain a compd. represented by the formula (where x+y<=0.25 and x>0). Semiconductor porcelain consisting of 98.0-99.9mol% of the obtd. compd. and 2.0-0.1mol% of the above-mentioned oxide is coated with 0.01-2.0mol% Na2O-TiO2-Bi2O3 (O<Na2O, O<TiO2, O<Bi2O3) mixture and sintered. |
