Preparation of pure MgTiO3 powders and the effect of the ZnNb2O6-dope onto the property of MgTiO3-based ceramics

Magnesium titanate (MgTiO3) powders have been prepared and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of calcination temperature and MgO: TiO2 ratios on phase formation, morphology and particle size distribution of the proposed powders are examined. Single-phase MgTiO3 can be synthesized by heating the non-stoichiometrically 1.03MgO-1TiO2 at 1100 oC for 3 h. The densification, microstructural evolution and microwave dielectric characteristics of 0.935MgTiO3-0.065CaTiO3 (935MCT) compound are developed. It is found that the content of ZnNb2O6 has an apparent effect on the physical properties and the microwave dielectric characteristics of 935MCT ceramics. The 935MCT sample with 5 wt% of ZnNb2O6, sintered at 1300 oC for 2 h, was measured to show excellent microwave dielectric properties: εr equal to 22.5, Q x f value equal to 93,561 GHz (at 9 GHz) and τf equal to 6.2 ppm/oC.