Influence of Sintering Temperature and CaTiO3 Doping on Structure and Dielectric Properties for Instability Layered Can+1TinO3n+1 (n = 1) Ceramics

Abstract

Ca2TiO4+xwt% CaTiO3 (x=0, 0.8, 1.6 and 3.2) ceramics were prepared by solid state reaction technique. The relation between phase compositions and structures, microstructures, sintering temperatures, and microwave dielectric properties of these ceramic systems were accordingly studied. XRD patterns revealed that the main phase of the undoped CaTiO3 in Ca2TiO4 ceramic systems was closely related with the sintering temperature, and the crystal phase transited from the orthorhombic CaTiO3 phase (as sintered at 1400℃) to tetragonal Ca3Ti2O7 phase (as sintered at 1420℃). In addition, the CaTiO3-doping in various amounts resulted in the change of main phase with the sintering temperature increasing from 1420℃ to 1450℃. Wherein, the stability and high-content Ca3Ti2O7 phase could be obtained by doping 1.6wt%-3.2wt% CaTiO3. The microwave dielectric properties test showed that the undoped Ca2TiO4 multiphase systems got a great reduction in the εr, Q×f and τf values from 59.04, 2340 GHz and 93.13×10-6/℃ (as sintered at 1400℃) to 59.04, 2340 GHz and 93.13×10-6/℃ (as sintered at 1420℃), respectively. Additionally, the various amounts of CaTiO3-doping could keep the Q×f values stably to some extent for the Ca2TiO4 ceramic systems.