Investigation of impact of Zr-doping on the structural and microwave dielectric properties of CaTiO3 ceramics

A new lead-free composition of Ca(Ti1-xZrx)O3, 0.0 ≤ x ≤ 1.0 ceramics was fabricated by a conventional method. The effects of B-site Zr substitution on the structure and microwave dielectric properties of CaTiO3 ceramics were investigated using X-ray diffraction, scanning electron microscopy, and impedance analyzers. Rietveld's refinement of the XRD pattern revealed that all the ceramics has an orthorhombic structure with space group Pbnm. The SEM micrographs revealed that the samples have a dense microstructure and spherical grain shape. The dielectric constant value (ϵr) decreased to 27 with increasing Zr4+ concentrations and the maximum dielectric constant (175) was reported for CaTi0·5Zr0·5O3 ceramics. The quality factor (Q) value of CaZrO3 ceramics reached 3267 GHz even though pure CaTiO3 ceramics possesses relatively smaller quality factor values equal to 2622.0 GHz and the maximum quality factor (∼8400 GHz) was achieved for x = 0.5.