Influence of sintering parameters on microstructure and electrical conductivity of La10Si6O27 ceramics

Abstract La 10 Si 6 O 27 ceramics powders were synthesized via the high temperature solid state reaction, and were then pressureless-sintered to obtain dense bulk ceramics by adjusting the sintering parameters. Crystal structure and electrical conductivity of La 10 Si 6 O 27 ceramics were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and complex impedance analysis. La 10 Si 6 O 27 ceramics obtained at sintering parameters of 1923 K and 10 h has the highest electrical conductivity of 1.28×10 −2  S cm −1 at test temperature of 1073 K. Sintering temperature have a distinct effect on the bulk density of samples and the content of La 2 SiO 5 second phase. The content of La 2 SiO 5 second phase is inversely proportional to electrical conductivity of as-sintered samples, while the bulk density is directly proportional to electrical conductivity of La 10 Si 6 O 27 ceramics.