Synthesis and dielectric properties of strontium substituted calcium niobate ceramics

Layered perovskite KCa2(1−x)Sr2xNb3O10 ceramic (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) materials were prepared by a conventional solid-state reaction method, and the effects of Sr substitution for Ca on the crystal structure and dielectric properties of the KCa2(1−x)Sr2xNb3O10 system were investigated. Also, potassium ions were exchanged with proton ions to obtain HCa2(1−x)Sr2xNb3O10. Then, X-ray diffraction, infra-red spectra, and energy dispersive detector analysis were carried out to verify immaculate substitution. Unlike alkali cations intercalated powder, the dielectric properties of 2Ca(1−x)SrxNb2O6-Ca2(1−x)Sr2xNb2O7 mixtures, which were obtained from HCa2(1−x)Sr2xNb3O10 by sintering, showed high dielectric permittivity with increasing amounts of strontium, and remained unaffected by frequency change from 1 kHz to 1 MHz. Its compositional dependence behavior was analyzed through Raman spectral analysis. X-ray diffraction, differential thermal analysis, and thermogravimetry observation revealed the phase transition on sintering of HCa2(1−x)Sr2xNb3O10.