Y. Wang et Wj. Thomson, KINETIC-STUDIES OF TRICALCIUM SILICATE FORMATION FROM SOL-GEL PRECURSORS, Journal of Materials Science, 31(5), 1996, pp. 1319-1325
Reaction kinetic studies of Ca3SiO5 formation from sol-gel-derived pre
cursors were carried out in situ using dynamic X-ray diffraction. Infr
ared spectra data, TEM experimental results, and X-ray diffraction pat
terns, all confirmed that CaO and Ca2SiO4 are the only compounds forme
d from a stoichiometric gel prior to Ca3SiO5 formation (<1250 degrees
C). The kinetic data for Ca3SiO5 formation are consistent with an Avra
mi nucleation and growth mechanism but with a sudden drop in the time
exponent at higher conversion. The sharp drop of the exponent is attri
buted to the impingement of grain growth in the longitudinal direction
and this is confirmed by SEM observations of the fully converted gels
. The presence of 10% steam did not change the mechanism nor the activ
ation energy of the reaction but significantly enhanced the nucleation
and grain growth rate at both stages of the reaction.