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

摘要

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 centre dot 2Al_2O_3 centre dot 5SiO_2) 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 mu-cordierite from gel occurred at temperatures between 900 and 1000 deg C and a higher calcination temperature resulted in the transformation of mu-cordierite to alpha-cordierite. Cordierite material obtained by sintering of powder in the temperature range from 1400 to 1450 deg 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.