Low temperature sintering densification and properties of CaO-B2O3-SiO2-ZrO2 glass/Ca0.99Cu0.01SiO3 composites for LTCC application

The sintering shrinkage behavior, viscosity, microstructures, phase composition, dielectric properties and chemical compatibility with Ag of a novel low-temperature co-fired ceramic (LTCC) material, (1-x) CaO-B2O3-SiO2-ZrO2(CBSZ) + x Ca0.99Cu0.01SiO3 (x = 0, 5, 10, 15 and 20 wt%) glass/ceramics were discussed. The partial dissolution of the Ca0.99Cu0.01SiO3 ceramic powder in CBSZ glass will form additional liquid phase and make viscosity decrease, which could promote the densification of CBSZ/Ca0.99Cu0.01SiO3 composite. The introduction of Ca0.99Cu0.01SiO3 will form heterogeneous nucleus and promote the crystallization of samples. The CBSZ/Ca0.99Cu0.01SiO3 composite with 10 wt% Ca0.99Cu0.01SiO3 content sintered at 875 ºC for 30 min has a dielectric constant εr = 6.05, a dielectric loss tanδ = 1.18 × 10-3@13.76 GHz, flexural strength = 176 MPa, CTE = 7.7258 × 10-6/ºC, and shows good chemical compatibility when co-fired with Ag electrode. These results indicate that CBSZ glass/Ca0.99Cu0.01SiO3 ceramic composites have a potential to meet the demand of LTCC applications.