Achieving excellent temperature-stable dielectric properties of Bi0.5Na0.5TiO3-based lead-free ceramics via doping AgNbO3
Lina Liu, Xiao‐Ming Chen, Xingxing Wang, Han‐li Lian
Abstract
The lead-free ceramics ([Formula: see text])(0.94[Formula: see text][Formula: see text][Formula: see text]TiO 3 -0.06BiAlO 3 )-[Formula: see text]AgNbO 3 (denoted as BNBTA-[Formula: see text]AN) were synthesized via a solid-state sintering method. The effect of AgNbO 3 doping amount on dielectric properties of the ceramics was studied systematically. X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectroscope were used to detect the structure of the ceramics. Temperature-dependent dielectric spectra, frequency-dependent dielectric constant and alternating current (ac) electric conductance at various temperatures were measured. The doping of AgNbO 3 greatly reduces dielectric constant around Curie temperature and thus enhances the temperature stability of the dielectric constant. The ceramic BNBTA-0.03AN exhibits excellent temperature-stable dielectric properties with temperature coefficient of capacitance (TCC) [Formula: see text]15% between 55 ∘ C and 418 ∘ C with temperature window 363 ∘ C and small changes of dielectric constant and dielectric loss from 100 Hz to 1 MHz at different temperatures. The obtained ceramics are expected to be used in high-temperature capacitors due to its excellent temperature stability.