| 摘要 |
PURPOSE:To improve varistor voltage, non-linear coefficient and surge resistance by incorporating Na2O, SiO2 and Co2O3 into a specific semiconductive porcelain. CONSTITUTION:A mixture is obtained by mixing SrCO3, TiO2, CaCO3, Ta2O5 and oxide of Nb, W, Ta, In or rare earth element and resultant mixture is calcined, then crushed to obtain crushed powder. Next, said crushed powder is shaped and burned to obtain semiconductive porcelain composed of 98.0-99.9mol% (Sr1-xCax)TiyO3 (0<=x<=0.25; 0.996<=y<=1.003) and 0.1-2.0mol% said oxide. Then, 0.01-2.0mol% in total of Na2O, SiO2 and Co2O3 (with a proviso that 0<Na, 0<Si and 0<Co) is added to said porcelain. |
