Synthesis of Mullite-Silica Ceramics with Enhanced Electrophysical Properties

Abstract

This study presents the synthesis of mullite–silica ceramics with enhanced electrophysical properties from natural kaolinite sourced from the Orenburg region. The work focuses on the influence of heat treatment and raw material dispersion on the phase formation process. The phase composition was characterized using differential thermal analysis (DTA), thermal process simulation during firing, and x-ray diffraction (XRD). The results indicate that an optimal temperature regime, combined with preliminary mechanical activation (grinding) and chemical activation with oxalic acid, stabilizes the mullite phase and reduces the maturing of residual silica. This process yields materials with low dielectric loss across a wide frequency range, along with high thermal stability and improved insulating properties. The obtained samples exceed the stipulated requirements of GOST 20419–83 for key parameters, including thermal conductivity and dielectric loss, thereby confirming their potential for use in electrical insulation and thermal barrier applications in the energy and engineering sectors.