Microstructural and electrical properties of CaTiO3–CaCu3Ti4O12 ceramics

This study investigates the microstructure and dielectric properties of (CTO)1−x–(CCTO)x ceramics. X-ray diffraction (XRD) patterns show that the crystal phases of polycrystalline CCTO exhibit a (2 2 0) preferential orientation at the molar fraction x = 1. For (CTO)2/3–(CCTO)1/3 or (CTO)1/3–(CCTO)2/3 ceramics, the crystalline structures of CTO and CCTO coexist at x = 1/3 and 2/3, respectively. Surface scanning electron microscope (SEM) morphologies show that the CCTO with x = 1 sintered above 1010 °C exhibits liquid-phase secondary recrystallization (LPSR) regions, and these regions expand as the sintering temperature increases. Therefore, the grain size and ceramics density depends on the sintering temperature and composition. This suggests that CCTO prepared at x = 1 can be a good candidate for capacitor applications because of its high ɛ value. The dielectric properties of CCTO sintered at 1100 °C include a dielectric constant (ɛ) of 23,600, dielectric loss (tan δ) of 0.406 at 10 kHz, leakage current density (J) of 6.11 × 10−6 A/cm2 and conductivity (σ) of 6.11 × 10−9 Ω cm−1 at 1 kV/cm.