Microwave sintering of Ca_0.6La_0.2667TiO₃ microwave dielectric ceramics

Ca_0.6La_0.2667TiO₃ ceramics were prepared by conventional and microwave sintering techniques and their sinterability, microstructure, and microwave dielectric properties were investigated in detail for comparison. Densified Ca_0.6La_0.2667TiO₃ ceramics were obtained by microwave sintering at 1350℃ for 30 min and by conventional sintering at 1450℃ for 4 h. An unusual phenomenon was found that some larger grains (grain size range:8-10 μm) inclined to assemble in one area but some smaller ones (grain size range:2-4 μm) inclined to gather in another area in the microwave sintered ceramics. The microwave dielectric properties of Ca_0.6La_0.2667TiO₃ ceramics prepared by microwave sintering at 1350℃ were as follows:dielectric constant (ɛ_r)=119.6, quality factor (Qf)=17858.5 GHz, and temperature coefficient of resonant frequency (τ_f)=155.5 ppm/℃. In contrast, the microwave dielectric properties of the ceramics prepared by conventional sintering at 1450℃ were ɛ_r=117.4, Qf=13375 GHz, and τ_f=217.2 ppm/℃.