成型工艺和烧结温度对CaTiO_3-LaAlO_3微波介质陶瓷结构与性能的影响

Effects of molding process and sintering temperature on structure and properity of CaTiO_3-LaAlO_3 microwave dielectric ceramics

采用传统固相反应法制备了CaTiO_3-LaAlO_3(CTLA)陶瓷,借助XRD、SEM和电性能测试手段,系统研究了干压、注塑两种成型工艺和烧结温度对CTLA陶瓷结构与性能的影响。结果表明,成型工艺和烧结温度不会改变CTLA陶瓷材料的主晶相,与干压成型相比,注塑成型的试样密度均匀性更好,其烧结密度、收缩率和相对介电常数略高,Q·f值下降,综合性能一般。相同成型工艺下,致密性、晶粒尺寸和相对介电常数均随烧结温度的增加而增加。烧结温度为1380℃时,干压成型试样具有最佳的性能:径向收缩率为15.02%,ε_r=44.01,Q·f(5 GHz)=41648 GHz,τ_f=1.24×10^(-6)℃^(-1)。

The CaTiO 3-LaAlO 3 ceramics were prepared by the conventional solid state reaction method. The effects of molding process and sintering temperature on structure and property of CaTiO 3-LaAlO 3 microwave dielectric ceramics were studied systematically through XRD, SEM and electrical properties characterization. The results show that the main phase of CTLA ceramics is not changed with the variation of the molding process and sintering temperature. Compared with dry molding, the density uniformity of injection molding is better, the sintering density, shrinkage and relative permittivity are increased slightly, and Q·f value is decreased. Under the same molding process, the compactness, grain size and relative permittivity are increased with increasing sintering temperature. When the sintering temperature is 1380 ℃, the dry pressing has the best performance: the radial shrinkage is 15. 02%, relative permittivity is 44. 01, Q·f (5 GHz) value is 41648 GHz,τ f value is 1. 24×10^-6 ℃^-1 .