Influence of Co substitution on the phase, microstructure, and microwave dielectric properties of MgSiO3 ceramics

Solid-state sintering method was used for the synthesis of Mg 1−x Co x SiO 3 (x = 0–0.25) ceramics. Phase, microstructure and microwave dielectric properties of the ceramics were investigated. With increase in Co 2+ content, the increase was observed in the lattice parameters. The Q u f o value of MgSiO 3 was enhanced from 103,453 to 145,846 GHz with increasing the value of x content from 0 to 0.15. The Co 2+ substitution also led to an obvious decrease in the sintering temperature by ~ 100 °C. Clino-enstatite phase formed for the composition with x = 0 while Proto-enstatite formed as the major along with minor clino-enstatite phase for the compositions with x > 0. Good dielectric properties at microwave frequencies i.e. ε r  ~ 8.11, Q u f o ~ 145,846 GHz and τ f ~ − 12 ppm/°C were obtained for the composition with x = 0.15 sintered at 1350 °C for 9 h. This is suggested to be a very favorable dielectric material for millimeterwave applications.