Microwave dielectric properties of B₂O₃-added Li₂MgTiO₄ceramics for LTCC applications

Abstract

Li2MgTiO4 (LMT) ceramics which are synthesized using a conventional solid-state reaction route. The LMT ceramic sintered at 1250°C for 4 h had good microwave dielectric properties. However, this sintering temperature is too high to meet the requirement of low-temperature co-fired ceramics (LTCC). In this study, the effects of B2O3 additives and sintering temperature on the microstructure and microwave dielectric properties of LMT ceramics were investigated. The B2O3 additive forms a liquid phase during sintering, which decreases the sintering temperature from 1250°C to 925°C. The LMT ceramic with 8 wt% B2O3 sintered at 925°C for 4 h was found to exhibit optimum microwave dielectric properties: dielectric constant 15.16, quality factor 64,164 GHz, and temperature coefficient of resonant frequency -28.07 ppm/°C. Moreover, co-firing of the LMT ceramic with 8 wt% B2O3 and 20 wt% Ag powder demonstrated good chemical compatibility. Therefore, the LMT ceramics with 8 wt% B2O3 sintered at 925°C for 4 h is suitable for LTCC applications.