PRECERAMIC POLYMER ROUTE TO AMORPHOUS AND CRYSTALLINE POTASSIUM ALUMINOSILICATE POWDERS AND THEIR ELECTRORHEOLOGICAL PROPERTIES

The oxide one-pot synthesis (OOPS) process was used to synthesize a po lymer precursor to potassium aluminosilicate, KAlSiO4 (KASp). A KAlSiO 4 gel (KASg) also was produced via a sol-gel route using the same prec ursor, The two routes to KAlSiO4 were explored to compare the effects of the two processing methods on powder properties, The KASp and KASg powders both transformed on heating (>500 degrees C) to amorphous, hig h-surface-area powders with narrow pore-size distributions (4-24 nm, T hese anhydrous, amorphous powders were intrinsic electrorheological (E R) materials, Both materials crystallized at similar to 1070 degrees C , and thermogravimetric analysis, differential thermal analysis, and I i-ray diffractometry suggested that they were identical, Diffuse refle ctance infrared Fourier transform spectroscopy and scanning electron m icroscopy proved that the KASp powders were homogeneous, whereas the K ASg powders were heterogeneous and segregated, The KASg powders exhibi ted better ER properties that mere associated with the segregated phas es.