| 摘要 |
PURPOSE:To obtain a composition capable of obtaining a voltage-dependent nonlinear resistor whose varistor voltage is high, whose nonlinear coefficient alphais large and whose surge-resistant amount is high by a method wherein Na2O, SiO2 and CuO whose amounts are specific are contained in a semiconductor porcelain which is composed of the following: (Sr1-xCax)TiyO3; and an oxide of Nb, W, In or a rare-earth element. CONSTITUTION:A total of 0.01 to 1.0mol% of Na2O, SiO2 and CuO (where 0<Na2O, 0<SiO2 and 0<=CuO) is contained in a semiconductor porcelain which is composed of the following: 98.0 to 99.9mol% of (Sr1-xCax)TiyO3 (where 0<=x<=0.25 and 0.996<=y<=1.003); and 0.1 to 2.0mol% of an oxide of Nb, W, Ta, In or a rare-earth element. When the total of Na2O, SiO2 and CuO as said oxidizing agents is less than 0.01mol%, a nonlinear coefficient is small; and when the total exceeds 1.00mol%, a surge-resistant amount is lowered. When the oxide of Nb, W, Ta, In or the rare-earth element as said semiconductor- forming agent is at 0mol%, a varistor characteristic is not displayed; and when it exceeds 2.0mol%, the surge-resistant amount is lowered. |
