Effect of ZnO on Mg ₂ TiO ₄ –MgTiO ₃ –CaTiO ₃ microwave dielectric ceramics prepared by reaction sintering route

ZnO-doped Mg2TiO4–MgTiO3–CaTiO3 microwave dielectric ceramics were successfully prepared by the reaction sintering route. The compact samples consisted of MgTiO3, Mg2TiO4 and CaTiO3, which was confirmed by X-ray diffraction and energy-dispersive spectra. ZnO efficiently lowered the sintering temperature and promoted the densification, as well as the improvements in the dielectric constant and the quality factor. At the level of ZnO = 1 wt-%, the ceramics exhibited optimum microwave dielectric properties: a dielectric constant of 20.3, a high quality factor of 64,740 GHz (at 9.9 GHz) and a near-zero temperature coefficient of resonant frequency (–1.3 ppm/oC) after sintering at 1320oC for 4 h.