| 摘要 |
PURPOSE:To reduce varistor voltage and increase voltage-current nonlinear index and extent of surge resistance by constructing a varistor from a composition composed of Ca-substituted SrTiO3 which is a principal component, the second and third components of specific metal oxide groups and the fourth component of MgTiO3-SiO2 in a specified proportion. CONSTITUTION:A varistor is produced by calcining a composition composed of a mixture of 100 pts.wt. principal component containing (1) 90.000-99.998mol% Sr1-xCaTiO3 (0.001<=x<=0.300), (2) 0.001-5.000mol% one or more of Nb2O5, Ta2O5, etc., and (3) 0.001-5.000mol% one or more of Al2O3, Sb2O3, etc., with 0.001-10.000 pts.wt. additive prepared by calcining (4) a mixture of 60.000-32.500mol% MgTiO3 with 40.000-67.500mol% SiO2 at >=1200 deg.C. The resultant element has a low varistor voltage, a high dielectric constant and voltage-current nonlinear index due to a large particle diameter, a homogeneous flow of surge current due to small dispersion in particle diameter and a great extent of surge resistance due to effectively increased resistance of grain boundaries with Ca. |
