Finite Size Effect on the Sinterability and Dielectric Properties of ZnNb2O6–ZBS Glass Composites

Abstract

ZnNb2O6 (ZN) is a columbite‐structured niobate compound showing excellent dielectric properties and comparatively low sintering temperatures (∼1200°C). Hence it is a good candidate for possible low‐temperature cofired ceramics (LTCC) applications. In the present investigation, ZnNb2O6 was synthesized in the form of micrometer‐sized powder using a conventional solid‐state ceramic synthesis route as well as in the form of nanosized powder by a polymer complex method. The finite size effect of ZN particles on sinterability and microwave dielectric properties of sintered pellets was evaluated. The phase formation was confirmed from the X‐ray diffraction (XRD) analysis. The particle size distribution of the nanoparticles was found to be of the order of 18–20 nm by using high‐resolution transmission electron microscopy analysis and 30 nm by analyzing the XRD patterns using Debye Scherrer's formula, after correcting for the instrument broadening effects. A ZN–60ZnO–30B2O3–10SiO2 (ZBS) composite was made by adding predetermined amounts of glasses. The microstructures of the sintered pellets of ZN and ZN–ZBS composites were examined using scanning electron microscopy and analyzed using image analysis. The nano‐ZN–ZBS composites were sintered to 93% of the reported density at 925°C/2 h, with microwave dielectric properties of ɛr=22.5, Q×f∼12 800 GHz, and τf=−69.6 ppm/°C, emerging as a potential material for possible LTCC applications.