Effect of dopants on synthesis of BaTi_4O_9 and Ba_2Ti_9O_(20) ceramics prepared by reaction-sintering process

摘要

The effect of dopants on BaTi_4O_9 (BT4) and Ba_2Ti_9O_(20) (B2T9) ceramics by the reaction-sintering process was investigated. CuO addition is more effective in lowering the sintering temperature of BT4 and B2T9 ceramics. MnO_2 and CuO addition are effective to obtain temperature stable BT4 ceramics. With MnO_2 addition, Q X f of BT4 ceramics could be raised. ZrO_2 addition is effective to obtain B2T9 ceramics with higher dielectric constant. With CuO addition, tau_f of B2T9 ceramics shifted toward negative values and 0 ppm/deg C could be obtained. Optimum properties in BT4 doped with MnO_2 of epsilon_r = 37.1, Q X f = 51,200 GHz (at 7 GHz) and tau_f = 0 ppm/deg C and in B2T9 doped with ZrO_2 of epsilon_r = 37.9, Q X f = 39,700 GHz (at 7 GHz) and tau_f = 5.9ppm/deg C were obtained.