The sintering behavior and microwave dielectric properties of 0.67CaTiO3–0.33LaAlO3 ceramics sintered at medium temperatures with the additives of H3BO3–Li2CO3

0.67CaTiO3–0.33LaAlO3 (CTLA) microwave dielectric ceramic materials with the additives of H3BO3, Li2CO3 or H3BO3–Li2CO3 were prepared by a conventional solid-state reaction method. The effects of the sintering additives on the densification behavior, phase compositions, microstructures, and microwave dielectric properties of the CTLA ceramic samples were investigated. It was found that the binary additive of H3BO3–Li2CO3 effectively promoted the densification and lowered the sintering temperature of the CTLA ceramic samples without a significant decrease in their Q × f values. For example, with an addition of 0.2 wt% H3BO3–0.1 wt% Li2CO3, the optimal microwave dielectric properties of er = 45.5, Q × f = 31,771 GHz and a near-zero τf of 2.43 ppm/℃ were obtained in the CTLA ceramic sample sintered at only 1175 ℃, which is significantly lower (~ 225 ℃) compared to the sintering temperatures of conventionally sintered CTLA ceramics.