Room-temperature fabrication of microwave dielectric Li2MoO4–TiO2 composite ceramics

Abstract This paper presents the incorporation of large amounts of insoluble additives into a Li 2 MoO 4 ceramic matrix fabricated with a room-temperature densification method. Li 2 MoO 4 –TiO 2 composite ceramics were fabricated by a method based on the water-solubility of Li 2 MoO 4 , where the densification occurs at room temperature during sample pressing and is followed by further post-processing at 120 °C to remove residual water. As the amount of added rutile TiO 2 rose from 10 to 30 vol%, relative permittivity and loss tangent values at ~9 GHz increased from 6.9 to 10.1 and from 1.1×10 −3 to 3.8×10 −3 , respectively, and thermal coefficient of permittivity decreased from 180 ppm/°C to −170 ppm/°C. The Lichtenecker equation used in the analysis of relative permittivity was applicable in this study for Li 2 MoO 4 –TiO 2 composite ceramics with up to 20 vol% of TiO 2 . However, with 25 and 30 vol% additions of TiO 2 , correspondence decreased due to increased porosity in the composites. The low post-processing temperature made this material feasible for Ag electrode integration without formation of unwanted extra phases.