Effects of LiF on sintering behavior and properties of CaO-B2O3-SiO2 dielectric ceramics obtained by solid-state reaction

Li-added CaO-B2O3-SiO2 (CBS) dielectric microwave substrates for low temperature co-fired ceramic (LTCC) applications were prepared using a solid-state reaction, and the effect of the LiF additive on the sintering behavior, dielectric performance and mechanical properties of the product was investigated. In this presently reported work, we found that the LiF additive could effectually reduce the sintering temperature of the CBS ceramics and also substantially improved the densification, dielectric and mechanical properties of it. The experimental results showed that an addition of 3 wt% LiF to the sample sintered at 790 degrees C resulted in a main crystalline phase of beta-CaSiO3 which had excellent proprieties. These included an excellent degree of densification, epsilon(r) of 6.43, tan delta of 5.9 x 10(-4) and a volume resistivity of 8.20 x 10(11) Omega cm at 1 MHz, and flexural strength of 241 MPa.