High-Energy Milling of WO3 Oxides: Amorphization and Reaction with Cs2CO3

✍ Scribed by Stéphane Laruelle; Michel Figlarz

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 228 KB
• Volume: 111
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1994.1214

✦ Synopsis

Three (\mathrm{WO}{3}) oxides with (\mathrm{ReO}{3}^{-}), pyrochlore-, and hexagonal-type structures have been studied in nonreactive and reactive grinding conditions by liigh-energy ball milling. In nonreactive grinding conditions, pyrochlore- and hexagonal-type (\mathrm{WO}{3}) oxides amorphize by collapse of the oxide structure. Monoclinic (\mathrm{WO}{3}) cannot be amorphized in these experimental conditions: the effect of high-energy ball milling is to decrease the crystallite size to a limit value. In reactive grinding conditions (\mathrm{WO}{3}+\mathrm{Cs}{2} \mathrm{CO}{3}) mixtures lead to the formation of a lacunar cubic pyrochlore-type cesium tungstate. The reaction kinetics are strongly influenced by the (\mathrm{WO}{3}) oxide structure and its behavior in nonreactive grinding. The mechanochemical reactivity is higher for monoclinic (\mathrm{WO}_{3}) and seems to depend on the presence of intercrystallite boundaries rather than on the amorphous oxide phase. 1994 Academic Press, Inc.