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-1TiO(2) at 1100 degrees C for 3 h. The densification, microstructural evolution and microwave dielectric characteristics of 0.935MgTiO(3)-0.065CaTiO(3) (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 degrees C for 2 h, was measured to show excellent microwave dielectric properties: epsilon(r) equal to 22.5. Qxf value equal to 93,561 GHz (at 9 GHz) and tau(f) equal to 6.2 ppm/degrees C. (C) 2009 Elsevier B.V. All rights reserved.