Effect of Li~+ and Mn~(2+) Doping on the Electrical Properties of SrTiO_3- Based Varistor Ceramics

摘要

Effect of Li~+ and Mn~(2+) doping on the electrical properties of SrTiO_3-based varistor ceramics was investigated. The results showed that the varistor ceramics cannot possess ideal electrical properties when only Li~+ or Mn~(2+) was doped. However, when Li~+ and Mn~(2+) were properly doped together, the samples acquired excellent electrical properties: V_(1mA) = (5.7 ～ 11.7)V/mm; α = 6.8 ～ 11.0; ε_r= (2.4 ～ 4.4) x 10~5; tanδ= (7.1 ～ 10.4)%. When the contents of Li_2CO_3 and MnCO_3 were 1.00 mol% and 0.05 mol% respectively, the nonlinear coefficient a reached the largest value of 11.0. Compared with only Mn~(2+) doping, the addition of Li~+ increases the a value significantly.