MECHANISMS OF INCIPIENT CHEMICAL REACTION BETWEEN CA(OH)(2) AND SIO2 UNDER MODERATE MECHANICAL STRESSING .3. CHANGES IN THE SHORT RANGE ORDERING THROUGHOUT THE MECHANICAL AND THERMAL PROCESSES

摘要

The structure of mechanically induced precursor in an amorphous state between Ca(OH)(2) and SiO2 was determined by solid state MAS and CP/MAS Si-29 NMR spectroscopies, and the changes in the behavior of crystallization by linear heating were studied by X-ray diffractometry. a large broad Q(0) peak due to the short-range order of hydrated calcium silicates appeared in the Si-29 NMR spectra of mechanically induced precursors, The formation of the new ordering is confined in the near-surface region of SiO2 particles, as confirmed by comparing MAS and CP/MAS NMR spectra, When the amorphous precursor obtained above was subsequently heated, a rapid solid state reaction led to single phased alpha-CaSiO3 as the final product, (C) 1997 Academic Press. [References: 19]