Synthesis and dielectric properties of strontium substituted calcium niobate ceramics

Highlights: • HCa_2(1-x)Sr_2xNb₃O₁₀ ceramics were prepared by cation exchange. • Cation exchanged ceramics facilitate great dielectric properties. • The structural properties were investigated by SEM, XRD, FT-IR, and Raman analysis. • The improved dielectric permittivity was obtained by strontium substitution. - Abstract: Layered perovskite KCa_2(1-x)Sr_2xNb₃O₁₀ 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 KCa_2(1-x)Sr_2xNb₃O₁₀ system were investigated. Also, potassium ions were exchanged with proton ions to obtain HCa_2(1-x)Sr_2xNb₃O₁₀. 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)Sr_xNb₂O₆-Ca_2(1-x)Sr_2xNb₂O₇ mixtures, which were obtained from HCa_2(1-x)Sr_2xNb₃O₁₀ 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 HCa_2(1-x)Sr_2xNb₃O₁₀