MICROSCOPIC CHARACTERIZATION OF SOL-GEL PROCESSED CORDIERITE

Different analytical techniques have been used to characterize green a nd sintered sol-gel processed cordierite on a microscopic scale. The s intered material, although identified macroscopically as alpha-cordier ite, contains many small precipitates of different chemical compositio n. Larger precipitates, characterized by an increased Mg concentration , result from inhomogeneities in the precursor gel. Smaller precipitat es, identified as mullite and spinel, could not be related to gel hete rogeneities. The amorphous phase surrounding the cordierite grains and the precipitates is Mg depleted and Si enriched. Neither mu-cordierit e nor beta-cordierite were observed; slight variations of the alpha-co rdierite lattice parameters are attributed to some local perturbations due to a slight departure from stoichiometry or Si, Al ordering on ti ny domains.