Enthalpies of drop solution for a suite of substituted pollucites with the compositions CsTixAl1-xSi2O6+0.5x,; 0 ≤ x ≤, which are synthesized using the sol-gel method, have been measured in molten lead borate (2PbO·B2O3) at 701°C. As Ti4+ substitutes for Al3+, the enthalpies of drop solution become less endothermic and show exothermic heats of mixing within the composition range from x = 0.3 to 1. This nonideal mixing behavior is consistent with the trend seen in variation of lattice parameters, and we interpret it to be a result of the short-range order associated with the framework cations Al3+, Si4+, and Ti4+ in the structure. Using enthalpies of drop solution of SiO2, Al2O3, TiO2, and Cs2O, standard molar enthalpies of formation of these phases from their constituent oxides and from the elements are derived for the first time.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of the American Ceramic Society|
|State||Published - Mar 2001|
ASJC Scopus subject areas
- Ceramics and Composites
- Materials Chemistry