Mechanochemistry of hydrothermally prepared Al-free and Al-substituted 1.1 nm tobermorite was studied using 29Si NMR, XRD, and TGA-DTA. Tobermorite has a double-chain structure and Al/Si substitution occurs preferentially at bridging tetrahedra. By using the vibration mill, both tobermorites were observed to decompose as a function of milling time to form amorphous C-S-H-like phases. The decomposition rate was higher for the Al-substituted tobermorite. The decomposition process occurs mainly at the bridge portion of the silicate double chain. In the Al-substituted tobermorite, the breakage seems to occur preferentially at the points where Al has replaced Si. On heating the amorphous C-S-H-like phase, wollastonite is formed. However, no decrease was observed at the wollastonite formation temperature.
|Number of pages||6|
|Journal||Journal of the American Ceramic Society|
|Publication status||Published - 1996 Jan 1|
ASJC Scopus subject areas
- Ceramics and Composites
- Geochemistry and Petrology
- Materials Chemistry