Electrical properties of cordierite obtained by non-hydrolytic sol–gel method

Cordierite ceramic material, due to its properties such as low thermal expansion coefficient, low dielectric constant and high specific resistivity, could be used as an insulating material in high-frequency electronics, as well as a substrate for integrated circuits and electronic modules. In this paper, cordierite (2MgO·2Al2O3·5SiO2) was synthesized by the non-hydrolytic sol–gel process combined with solvothermal treatment starting from aluminium chloride, TEOS and magnesium chloride dissolved in absolute ethanol. Crystallization of μ-cordierite from gel occurred at temperatures between 900 and 1000 °C and a higher calcination temperature resulted in the transformation of μ-cordierite to α-cordierite. Cordierite material obtained by sintering of powder in the temperature range from 1400 to 1450 °C showed values of the dielectric constants from 7.93 to 3.78 and values of dielectric loss tangents from 0.049 to 0.001.