Microwave dielectric properties of Li2TiO3 ceramics sintered at low temperatures

Li2TiO3 ceramics were prepared at the sintering temperatures from 1050 to 1250 degrees C. The optimal microwave dielectric properties were epsilon(r) = 23.29, Q x f = 15,525 GHz (5.9 GHz), and tau(f) = 35.05 ppm/degrees C for the sample sintered at 1200 degrees C. The microwave dielectric properties were improved obviously when the Li2TiO3 ceramics were sintered at low temperatures with small additions of H3BO3 (B2O3 in the form of H3BO3). Only monoclinic Li2TiO3 was found in the pure or H3BO3-doped Li2TiO3 ceramics. About 1.0 wt.% H3BO3 addition aided the sintering of Li2TiO3 ceramics effectively while excessive H3BO3 (>2.5 wt.%) was not favorable. Typically the best microwave dielectric properties were epsilon(r) = 23.28, Q x f = 37,110 GHz (6.3 GHz), and tau(f) = 30.43 ppm/degrees C for the 1.0 wt.% H3BO3-doped Li2TiO3 ceramic sintered at 920 for 3 h, which is promising for LTCC applications. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.