Dielectric properties of nanocrystalline CaCu3Ti4O12 (CCTO) ceramics fabricated from Algerian limestone raw material

Algerian natural limestone was used to fabricate the perovskite CaCu3Ti4O12 phase (CCTO) to replace com-mercial calcium carbonate (CaCO3) powder by a solid-state method. X-ray diffraction analysis of CCTO ceramics sintered at 1010 degrees C manifested the formation of well-crystallized pure (CCTO) phase with narrow crystallite size (43-99 nm) without any additional phases after sintering beyond 4 h. Thermal analysis by DSC indicated that CCTO phase is stable up to 1151 degrees C, afterwards it decomposes into CaTiO3 and TiO2 and accompanied by the segregation of the CuO/Cu2O phase. Scanning electron microscopy observations of the ceramics sintered at 1010 degrees C showed that most of the grains have an average particle size in the narrow range of 1-2 mu m. The sintered pellet at 1010 C degrees for 14 h showed the optimum density (>94%). This study highlights the importance of using natural calcium carbonates (extracted from Guelma limestone in Algeria) as potential replacement to commercial counterpart for the fabrication of dense well-crystallized perovskite-type ceramics with controlled particle size distribution as promising candidates for electronic applications.