Microwave dielectric properties of a temperature-stable and ultra-low sintering Li3AlMo3O12/Li0.5Bi0.5MoO4 composite ceramics for ULTCC application

Temperature-stable ULTCC composite (1-x)Li3AlMo3O12-xLi0.5Bi0.5MoO4 ceramics were prepared by solid-state reaction method. X-ray and EDS results showed that Li3AlMo3O12 phase and Li0.5Bi0.5MoO4 phase exist independently, and no other phase is generated. Due to the low sintering temperature of both two phases, the composite ceramics can obtain high density at 560 ℃. Microwave dielectric properties mainly depend on the ceramic Li0.5Bi0.5MoO4 content x, the addition of Li0.5Bi0.5MoO4 effectively increases the τf of Li3AlMo3O12 from −65.05 ppm/℃ to 4.96 ppm/℃, but caused the dielectric loss increase. When x=0.45 and sintered at 560 ℃, microwave dielectric properties of 0.55Li3AlMo3O12-0.45Li0.5Bi0.5MoO4 ceramics with close zero τf: εr = 15.32, Q×f = 13,158 GHz, τf = 4.96 ppm/℃. •The composite ceramics can obtain high density at 560 ℃.•Exhibits excellent chemical compatibility with metallic aluminum.•The τf value was adjusted to near-zero successfully (τf = 4.96 ppm/°C).•Optimum microwave dielectric properties (εr = 15.32, Q×f = 13158 GHz and τf = 4.96 ppm/°C) were achieved.