Structural, conductive and dielectric properties of silicon phosphate SiP2O7 synthesis from activated clay

Abstract The purpose of this study is the manufacture of SiP2O7 powder, using low-cost material, namely, phosphoric acid and activated metakaolin (AMK).The mineralogical characterization by X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) analysis showed that SiP2O7 has a well-crystalline structure. The conductivity and dielectric behavior have been studied over a frequency range from 40 Hz to 5 × 106 Hz and at temperatures ranging from 20 °C to 300 °C. The results indicate that the SiP2O7 synthesized by activated metakaolin have a high ionic electrical conductivity of 2.96 × 10−6 Scm−1 at room temperature, which increases to 8.8 × 10−3 Scm−1 at 300 °C. Furthermore, the powder exhibited a high dielectric constant (120 × 105) and loss factor (350 × 105) at 300 °C, which both decreased with increasing frequency. The imaginary electric modulus (M") showed that the dielectric relaxation time (τ) varies nearly linearly with temperature.