High-performance ZnTiNb2O8 microwave dielectric ceramics produced from ZnNb2O6-TiO2 nano powders

Ixiolite-structured ZnTiNb2O8 (ZTN) ceramics were prepared by the simple but effective route of reaction sintering ZnNb2O6 and TiO2 nano powders. The effect of sintering temperature and soaking time on the densification behavior, microstructure evolution and microwave dielectric properties of the synthesized ZTN ceramics were systematically studied. Nano ZnNb2O6 and TiO2 raw materials were mixed, pressed and sintered directly into ceramic bodies without any calcination step involved. The sintered samples were characterized by Field-Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), and microwave dielectric measurements. Single-phase ZnTiNb2O8 ceramics with relative densities up to 97% theoretical density were achieved by sintering at 975-1075 degrees C. The ixiolite ZTN ceramics reaction sintered at 1050 degrees C for 3 h exhibited excellent microwave dielectric properties with a dielectric constant (epsilon(r)) = 35.5, quality factor (Q x f(0)) = 52,500 GHz and a temperature coefficient of resonant frequency (tau(f)) = -60 ppm/degrees C. These results demonstrate that high-performance ZTN microwave dielectric ceramics can be successfully produced by the simple and efficient reaction-sintering method. (c) 2020 Elsevier B.V. All rights reserved.