S. Laruelle et M. Figlarz, HIGH-ENERGY MILLING OF WO3 OXIDES - AMORPHIZATION AND REACTION WITH CS2CO3, Journal of solid state chemistry, 111(1), 1994, pp. 172-177
Three WO3 oxides with ReO3-, pyrochlore-, and hexagonal-type structure
s have been studied in nonreactive and reactive grinding conditions by
high-energy ball milling. In nonreactive grinding conditions, pyrochl
ore- and hexagonal-type WO3 oxides amorphize by collapse of the oxide
structure. Monoclinic WO3 cannot be amorphized in these experimental c
onditions: the effect of high-energy ball milling is to decrease the c
rystallite size to a limit value. In reactive grinding conditions WO3
+ Cs2CO3 mixtures lead to the formation of a lacunar cubic pyrochlore-
type cesium tungstate. The reaction kinetics are strongly influenced b
y the WO3 oxide structure and its behavior in nonreactive grinding. Th
e mechanochemical reactivity is higher for monoclinic WO3 and seems to
depend on the presence of intercrystallite boundaries rather than on
the amorphous oxide phase. (C) 1994 Academic Press, Inc.