Influence of strontium substitution on the dielectric properties of Ca(1 - x)SrxTi0.9Zr0.1O3 solid solutions

A conventional solid-state reaction has been used to synthesize the perovskite Ca(1 - x)SrxTi(1 - y)ZryO3 (y=0.1). The aim of this study is focused on the development of new materials with complex perovskite structure and on their dielectric property improvement. The temperature and substitutional ratio effects on the different phase evolutions is investigated by X-ray diffraction (XRD) and scanning electron microscope observations. These ceramics sintered at 1500 degrees C, present a density higher than 95% and their dielectric properties are significantly affected by the substitution. The CaTiO3 ceramic present a relative permittivity of 190 and the temperature coefficient of the permittivity of -1828 ppm/C degrees. The substitution with zirconium (for x=0 and y=0.1: Sigma=145; vertical bar Sigma = -917 ppm/C degrees). Both permittivity and temperature coefficient values decrease; however, an opposite effect is observed when substituting with the strontium. With increasing an x value and maintaining a y value constant (y=0.1), the dielectric constant increases and the temperature coefficient remains constant. Therefore, the dielectric properties of CaTiO3 ceramics are improved with the combined substitution. (C) 2010 Elsevier B.V. All rights reserved.