Microwave dielectric properties of the low-temperature-fired Li_2ZnTi_3O_8-Li_2TiO_3 ceramics for LTCC applications

摘要

In this work, 0.73Li~(2)ZnTi~(3)O~(8)–0.27Li~(2)TiO~(3)ceramics were prepared through a traditional solid-state process. The effects of Li~(2)O–B~(2)O~(3)–SiO~(2)–CaO–Al~(2)O~(3)(LBSCA) glass addition on phase formation, microstructure, sintering characteristic and microwave dielectric properties of the ceramics were investigated. A small amount of LBSCA glass addition significantly reduced sintering temperature of the ceramics. X-ray diffraction analysis revealed that Li~(2)ZnTi~(3)O~(8)and Li~(2)TiO~(3)phases coexisted without producing any other crystal phases in the sintered ceramics. Dielectric constant and Qf values were related to the amount of LBSCA addition and sintering temperatures. The specimens obtained near-zero temperature coefficient (τ~(f)) values through the compensation on the positive τ~(f)of Li~(2)TiO~(3)and the negative τ~(f)of Li~(2)ZnTi~(3)O~(8). The 0.73Li~(2)ZnTi~(3)O~(8)–0.27Li~(2)TiO~(3)ceramic with 0.75 wt% LBSCA addition and sintered at 900 °C for 3 h exhibited excellent microwave dielectric properties of ɛ ~( r ) = 23.907, Qf  = 63050 GHz and τ ~( f ) = 1.2 ppm/°C, which was very suitable for LTCC (low temperature co-fired ceramics) applications.