Correlation of sol-gel processing parameters with microstructure and properties of ceramic product

Abstract

Very high purity MgAI2O4 spinel precursor can be prepared via the low temperature process called “Oxide One Pot Synthesis Process (OOPS)”. Sol-gel processing of such precursors offers the opportunity to prepare spinels with controlled microstructures, which is key to optimizing their properties for application as humidity sensors. Sol-gel processing of a double alkoxide precursor was carried out in buffer solutions in the range pH 8-12, to investigate the effect on the physical properties of the sintered ceramic products. The structure and morphology of the latter were characterized using FTIR, XRD, SEM and BET surface area measurements. Sol-gel processing results in a sintered product with narrow pore size distribution and containing a spinel phase of high crystallinity. At higher pH values, increasing amounts of an α-Al2O3 phase are formed. At all pH values, the sintered product exhibits high water adsorption, up to 0.31 g H2O/g sample.