Enhanced dielectric properties of Mg4Nb2O9 ceramic by Ti substitution
Abstract
In this paper, the strategy of substituting Ti4+ for Nb5+ in Mg4Nb2O9 microwave dielectric ceramic was employed to improve the microwave dielectric properties. Specifically, a maximum Q ×?f value of 137,462?GHz was obtained at x = 0.15, resulting in a nearly 30% increase in the quality factor (Q ×?f) for the Mg4Nb2?xTixO9?x/2 sample. Moreover, we investigated the phase composition, micromorphology, and the relationship between structural characterization and dielectric properties. The X-ray diffraction (XRD) patterns indicated that only a single Mg4Nb2O9 phase with a trigonal corundum-type structure was formed in all the samples. The ?r was related to the ionic polarizability, and the τf value was dependent on the B–O bond valence (VB–O) and BO6 octahedral distortions. Ultimately, the Mg4Nb1.85Ti0.15O8.925 ceramic sample exhibited microwave dielectric properties with ?r?=?13.89,?Q?×?f?=?137,462?GHz, and τf?= ??55.1?ppm/°C.