Microwave dielectric properties of (Mg0.4Zn0.6)2SiO4-CaTiO3 ceramics sintered with Li2CO3-H3BO3 for LTCC technology

The effects of different adding methods of Li2CO3, H3BO3, Li2CO3-H3BO3 glass (B-Li glass) and Li2CO3-H3BO3 (LB) additives on the microstructure and microwave dielectric properties of 0.88(Mg0.4Zn0.6)2SiO4-0.12CaTiO3 (MZS-C) ceramics were investigated. Of all the adding methods, the addition of LB is the most effective way to lower the sintering temperature of MZS-C ceramics with good microwave dielectric properties. With LB addition, the MZS-C ceramics can be well sintered below 950 °C. The phase formation, microstructure, chemical compatibility with silver and microwave dielectric properties of MZS-C composite ceramics with LB addition were also systematically studied. The dielectric constant and Q×f value were related to the amount of the LB addition and sintering temperature. The near zero τf value can be obtained by adjusting the amount of LB addition. The MZS-C ceramics with 4.0 wt.% LB sintered at 950 °C/2 h exhibited excellent microwave dielectric properties of εr = 7.12, Q×f=28,600 GHz and τf = −6 ppm/°C. Meanwhile, the material was compatible with silver, which made it a promising candidate material for LTCC application.