EFFECT OF AL SI RATIO ON CRYSTALLIZATION OF CORDIERITE CERAMICS PREPARED BY THE SOL-GEL METHOD/

The application of cordierite ceramics as the electronic materials has recently extended immensely, because of their superior heat resistanc e, low dielectric constants, etc, In this study, the cordierite cerami cs, which can be sintered at low temperature without any nucleation ag ents, were prepared by the sol-gel method, The effect of Al/Si ratio o n the crystallization behavior and sintering was investigated, Metal a lkoxides, Si (OC2H5)(4), Al(OC4H9s)(3), and Mg(OC2H5)(2) were hydrolyz ed in 2-methoxyethanol, resulting in gelation, The obtained gel powder s were heat-treated at various temperatures, As the Al/Si ratio decrea sed, the deposition of mu-cordierite occurred at lower temperatures, T he initial transformation of alpha-cordierite phase from mu-cordierite phase took place by heat treating at 950 degrees C for Ih, However, t he complete transformation to single alpha-cordierite phase was retard ed and achieved at higher temperatures, >1050 degrees C, With the incr ease of Al/Si ratio, the initial transformation to alpha-cordierite fr om mu-cordierite occurred at higher temperatures, while the complete t ransformation took place rapidly at lower temperatures, about 1000 deg rees C.