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

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 degrees C with less micro pores and cracks. In addition, the densification temperature of slightly A-site nonstoichiometric ceramics have been successfully reduced to 1050 degrees 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 epsilon(r) = 23.2, Q x f = 56 400 GHz, and a tau(f) = 38.4 were achieved in Li2+xTiO3.