Investigation on phase composition and microwave dielectric properties of MgO-SiO₂-TiO₂ system

The microwave dielectric properties of MgO-SiO₂-TiO₂ system were investigated through the solid sintering method. A detailed analysis was conducted to investigate the effects of SiO₂ content and holding time on the phase composition, microstructure, sintering characteristics and dielectric properties of MgO-SiO₂-TiO₂ ceramics. In this study, it was discovered that for all compositions, a three-phase composite of Mg₂SiO₄, Mg₂TiO₄ and MgO was observed. Furthermore, as the SiO₂ content increased, there was a gradual increase in the amount of Mg₂SiO₄ phase, while the amounts of Mg₂TiO₄ and MgO phases decreased. Although holding time did not change the phase type, it influenced the intensity of diffraction peaks of each phase. The variation of holding time affected reaction efficiency and crystallization behavior of the samples. The MgO-SiO₂-TiO₂ system exhibited wide tunability in terms of dielectric constants, and higher quality factors were observed at lower dielectric constant values. The MgO-SiO₂-TiO₂ system, composed of 50.44 wt% MgO, 30.28 wt% SiO₂ and 14.28 wt% TiO₂, were sintered at 1500 ℃ for 2 h. Remarkable dielectric properties were achieved, with the dielectric constant measured at 7.7, the quality factor recorded as 89,798 GHz (11 GHz), and the temperature coefficient of the resonant frequency calculated as − 32.5 ppm/℃.