低温B_2O_3掺杂对Ba_4Sm_(9.33)Ti_(18)O_(54)微波介质陶瓷性能的影响

Effect of Low-Temperature B_2O_3 Doping on the Properties of Ba_4Sm_(9.33)Ti_(18)O_(54) Microwave Dielectric Ceramics

为降低Ba_4Sm_(9.33)Ti_(18)O_(54)(BST)微波介质陶瓷的烧结温度,研究了B_2O_3掺杂对其烧结性能、物相组成、显微结构及介电性能的影响。结果表明:少量B2O3的引入未改变陶瓷的晶相组成,主晶相为Ba_(6-3x)Sm_(8+2x)Ti_(18)O_(54)固溶体,适量B_2O_3不仅能显著地降低BST陶瓷的烧结温度至1180℃,而且能提高其介电性能;随着B_2O_3添加量的继续增加,有烧绿石结构的Sm_2Ti_2O_7相出现并逐渐增多。当B_2O_3添加量为0.25 wt%,在1180℃温度烧结3 h时,BST陶瓷获得优异的微波介电性能:ε_r=76.58,Q·f=6794.24 GHz,τ_f=-7.06×10^(-6)/℃。

The effects of B2O3 doping on the sintering behavior, phase composition, microstructure and dielectric properties of BST ceramics were investigated in order to reduce the sintering temperature of Ba4Sm9.33Ti18O54（BST） microwave dielectric ceramics. It was indicated that small addition of B2O3 didn’t change the crystal phase of BST ceramics, the main phase of samples was Ba6-3xSm8＋2xTi18O54 solid solution; Moderate addition of B2O3 could not only dramatically lower the sintering temperature which dropped to 1180 ℃, but also improve the dielectric properties; The Sm2Ti2O7 of pyrochlore structure appeared and increased gradually with increasing the content of B2O3. When the addition amount of B2O3 was 0.25 wt%, the BST ceramics sintered at 1180 ℃ for 3 h have excellent dielectric properties with εr of 76.58, Q·f of 6794.24 GHz and τf of -7.06×10-6/℃.