Green gelcasting of CaCu₃Ti₄O₁₂ ceramics

CaCu₃Ti₄O₁₂ (CCTO) ceramics with desirable dielectric properties were prepared by a green gelcasting forming method combined with pressureless sintering. A non-toxic natural macromolecule, glutinous rice flour (GRF) was used as the gelling agent for the gelcasting process. The significant parameter, namely, the dosage of gelling agent was carefully studied so as to optimize the gelcasting process. The results showed that the dosage of GRF had evident effect on both gelcasting process and the final dielectric properties of CCTO ceramics. CCTO ceramics from the green body solidified with 3.5 wt% GRF showed relatively optimal dielectric properties, namely a dielectric constant up to 1.60 × 10⁴ and a loss of only 0.063 (at 1 kHz test frequency). CCTO ceramics fabricated by this green gelcasting method have superior dielectric properties compared with that of the ceramics obtained by the dry pressing method.