Low-firing Li4Mg3Ti2O9–CaTiO3 composite ceramics with temperature stable microwave dielectric properties

Abstract

The nanopowders of Li4Mg3Ti2O9 (LMT, 37 nm) and CaTiO3 (CT, 110 nm) compounds were synthesized through a sol–gel method and calcined at 600 °C, about 450 °C lower than that required by conventional ball-milling method. The (1 − x)LMT-xCT (0.05 ≤ x ≤ 0.2) composite ceramics doped with 4 wt% LiF were prepared for low-temperature co-fired ceramics (LTCC). A near-zero τf value was obtained by adjusting composition x of CT. 4 wt% LiF-doped 0.85LMT-0.15CT ceramics sintered at 850 °C possess optimum microwave dielectric properties: er = 19.5, Q × f = 25,790 GHz, τf = − 5.8 ppm/°C. Such sample was compatible with Ag electrodes, which indicates the ceramic is a promising material for LTCC application.