The phase diagrams of CaO-SiO2-CaF2 and CaO-SiO2-CaF2-NaF systems were determined as a base system of mold fluxes. The commercial fluxes have been composition in which cuspidine first crystallizes. The thermodynamic stability of cuspidine was examined from the standard Gibbs energy of formation of cuspidine, which was measured, by two methods of the Galvanic cell method and the transpiration method. The effect of fluorine to silicate network was investigated. It is indicated that CaF2 behaves as a neutral solvent for silicate slag. The crystallization in mold fluxes was measured by a high temperature XRD. Cuspidine predominantly appears because the construction of silicate glass with CaF2 has CaF+ ion pair near non-bridging oxygen. The over addition of Na2O to mold flux prevents cuspidine from crystallizing.
|Number of pages||5|
|Publication status||Published - 2003 Jan 1|
ASJC Scopus subject areas
- Metals and Alloys