B. Ammundsen et al., A STUDY OF THE FORMATION OF SILICA-SUPPORTED MIXED MAGNESIUM-MANGANESE SPINEL OXIDES FROM MULTICOMPONENT GELS, JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY, 4(1), 1995, pp. 23-29
The effects of thermal treatment on composite materials prepared by th
e gelation of sols comprising large concentrations of metal oxide prec
ursor salts have been investigated, in order to determine the composit
ional and thermal requirements for forming spinel magnesium manganates
in such systems. The preparative technique has been found to give ris
e to derived gel materials in which the metal oxide phase, in the form
of regular spherical particles, is dispersed throughout a continuous
silica matrix. Silica-supported mixed magnesium and manganese spinel o
xide phases were obtained for systems comprising at least 30 wt% metal
nitrate after heating to temperatures between 700 and 850-degrees-C,
but not without concomitant formation of Mn2O3 and modification of the
silica network by magnesium.