Phase formation in copper and calcium titanate dielectric ceramic obtained by polymeric precursor method

Abstract

The polycrystalline ceramic named calcium and copper titanate is a dielectric ceramic with very high dielectric constant applicable in several electronic devices. The powder form for that advanced ceramic can be synthesized through chemical route, like the Polymeric Precursor Method at relative lower temperatures the presence of alkaline earth cations harms the structural homogenization during the crystallization process. In this work, the calcium and copper titanate powder was obtained by Polymeric Precursors Method by imposing a slow thermal decomposition of polymeric precursor and several crushing steps before the calcination at 800 °C for 4 hours. The entire process was observed by thermogravimetric analysis and FTIR spectrometry, including the nitrogen adsorption-desorption isotherms and X-ray diffractometry techniques for calcined power samples. It was observed the crystallization of the cubic Im-3 Ca1/4Cu3/4TiO3 phase only starts after organics removal and full calcium carbonate elimination above 700 ºC, which is followed by pore elimination and particle sintering. The chemical synthetic route used in this work shows the ability to prepare CCT powders sample with very structural homogeneity, which characteristics are required to manufacturing many electronic devices.