Phase constitution, structure analysis and microwave dielectric properties of Zn0.5Ti1−xZrxNbO4 ceramics

The phase constitution and phase structure of Zn0.5Ti1−xZrxNbO4 ceramics were analyzed by multiphase structure refinement. The diffraction patterns of Zn0.5Ti1−xZrxNbO4 showed that the ixiolite phase ZnTiNb2O8 and rutile phase Zn0.15Nb0.30Ti0.55O2 were obtained. The distortion of oxygen octahedron, bond valence of Ti-site and volume of oxygen octahedron were calculated. For the main phase ZnTiNb2O8, with substitution of Zr4+ for Ti4+, the distortion of oxygen octahedron and the bond valence of Ti-site increased. The increase of Ti-site bond valence led to a harder rattling of Ti cations of the specimens. As a result, the contribution of the rattling effect to the polarizabilities of the specimens decreased, and subsequently the dielectric constant decreased. With increasing fraction of Zn0.15Nb0.30Ti0.55O2, the Qf value decreased. The decrease of τf was mainly attributed to the increase of Ti-site bond valence. With the Ti-site bond valence increasing, the bonding strength between oxygen ion and Ti4+ ion became stronger, and the dilution of the average ionic polarizability decreased.

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► Quantitative determination was performed by multiphase refinement.
► The distortion of oxygen octahedral, bond valence of Ti-site and volume of oxygen octahedral were calculated.
► The excellent microwave dielectric properties were: ɛ = 49.8, Qf = 42,000 GHz, τf = 27.4 × 10−6/°C.