Enhanced sintering characteristics and microwave dielectric properties of Li2TiO3 due to nano-size and nonstoichiometry effect

Abstract

Ultrafine Li₂TiO₃ nanopowder was synthesized by a sol–gel method. The effect of a slight A- and B-site cation nonstoichiometry on the structure, densification and microwave dielectric properties of Li₂TiO₃ was investigated. The phase presence and surface morphology were determined by XRD and SEM techniques, respectively. The average particle size calculated from the TEM micrograph of the powder was 6–12 nm. Compared with the conventional solid-state method, Li₂TiO₃ nanopowder synthesized by the sol–gel method could be densified at 1250 °C with less micro pores and cracks. In addition, the densification temperature of slightly A-site nonstoichiometric ceramics have been successfully reduced to 1050 °C. Also, it is found that a slight cation defect can improve density and microwave dielectric properties, while the addition of excess ions deteriorated them. When x = 0.08, well-densified ceramics with uniform grains and good dielectric microwave dielectric properties of ε_r = 23.2, Q × f = 56 400 GHz, and a τ_f = 38.4 were achieved in Li_2+xTiO₃.