采用固相反应法制备了xSrTiO3-(1-x)LaAlO3(x=0.4~0.7)介电陶瓷, 分析了不同x值陶瓷的结构和介电性能。结果表明: 该陶瓷主相为钙钛矿固溶体, x= 0.4~0.5时, 为正交钙钛矿结构, 在x=0.55~0.7时, 为赝立方钙钛矿结构; 赝立方结构的陶瓷具有较高的介电常数(ε＞50)和低介电损耗(10-3~10-4)及近零的温度系数; 陶瓷从赝立方结构转变成正交结构时, 介电常数明显下降(ε=34~45), 介电损耗迅速增大(约10-2); x=0.6,0.7的陶瓷具有优良的介电性能, ε＞55, tanδ在10-3~10-4之间(f=1 MHz);x=0.4时陶瓷具有优异的微波介电性能, ε =30.5, Qf=40 177 GHz, τf= -22.9×10- 6 ℃-1。

xSrTiO3-(1-x) LaAlO3(x=0.4-0.7) dielectric ceramics were prepared by solid state reaction method, the structure and properties of ceramics with different x value were discussed. The results show that perovskite solid solution was the main phase of this ceramics. The perovskite were orthogonal structure and constrain cubic structure when x were 0.4-0.5 and 0.55-0.7 respectively. The ceramics with the pseudocubic structure exhibited the higher dielectric constant (ε＞50), lower dielectric loss(10-3-10-4)and near-zero temperature coefficient. The dielectric constant decreased obviously (ε=35-45) and dielectric loss increased rapidly (about 10-2)when the ceramics transformed from orthogonal structure to the constrain cubic structure. Good dielectric properties (ε＞55, tan δ of the ceramics was about 10-3-10-4 at 1 MHz)were achieved when x was 0.6 and 0.7. Excellent microwave dielectric properties of ceramic (x=0.4) were achieved as following: ε =30.5, Qf=40 177 GHz, τf = -22.9×10- 6℃-1.