Phase structure and microwave dielectric properties of 0.85(0.74CaTiO 3 –0.26SmAlO 3 )–0.15Ca 1.15 Sm 0.85 Al 0.85 Ti 0.15 O 4 composite ceramics prepared by reaction-sintering process

0.85(0.74CaTiO 3 –0.26SmAlO 3 )–0.15Ca 1.15 Sm 0.85 Al 0.85 Ti 0.15 O 4 (CSC) composite ceramics were prepared by a reaction-sintering method. The phase structure, sintering behavior and microwave dielectric properties of CSC ceramics were investigated. The preparation process of reaction-sintering route (RS) is simple. XRD patterns show that Ca 0.74 Ti 0.74 Sm 0.26 Al 0.26 O 3 (similar to CaTiO 3 ), SmAlO 3 and Ca 1.15 Sm 0.85 Al 0.85 Ti 0.15 O 4 phases are formed in the CSC ceramics. The grain size and dielectric constant of CSC ceramics increase with rising the sintering temperature. As the sintering temperature increases, the quality factor ( Q × f ) and τ f value of the CSC ceramics increase to the maximum values first and then decrease. The bulk density fluctuates up and down around a value, but little change. The ceramics sintered at 1500 °C got the best microwave dielectric performances with ε r = 35.9, Q × f = 49,221 GHz, τ f = − 0.53 ppm/°C.