Influence of Feldspar Addition on the Properties of CaCu3Ti4O12 Ceramic

Abstract

The colossal dielectric permittivity of calcium copper titanate (CaCu3Ti4O12, CCTO) provides a vast potential in miniaturizing electronic devices but become limited due to high dielectric loss. Hence, feldspar was introduced to reduce the dielectric loss by fill in the air gap between CCTO boundaries during the sintering process. The CCTO powder was prepared by the solid-state reaction method. The study focused on the phase formation and dielectric properties of CCTO with the addition of feldspar. The raw materials were weighed based on stoichiometric ratios for CCTO, while the weight percentage ratio opted for feldspar added (1%, 3%, 5%, 7% and 10%). The mixed powders were ball mixed for 24 hours using dry mixing. Then, it was calcined at 900°C for 12 hours and sintered at 1040°C for 10 hours after being pressed into a pellet with 6 mm diameter. The X-ray Diffractometer (XRD) and impedance analyzer were utilized to observe the phase formation and dielectric properties. A single-phase CCTO was obtained after the sintering process except for CCTO without feldspar (0 wt%) and 1wt% of feldspar addition, and it still has remaining CuO in the ceramic system. Even though feldspar can reduce the dielectric loss of the CCTO from 0.6 (CCTO without feldspar) to 0.4 (10 wt%) at 1 MHz, it is also hard to maintain the high dielectric constant. The dielectric constant of 1wt% of feldspar addition recorded the highest value, up to 4000 at 1 MHz, while the lowest dielectric constant owned by 10 wt% of feldspar addition, ~700 at 1 MHz.