Isothermal Crystal Growth Behavior of CaSiO$lt;inf$gt;3$lt;/inf$gt; in Ternary Oxide Melts

The process of isothermal wollastonite (CaSiO 3 ) crystallization in the CaO-Al 2 O 3 -SiO 2 system was simulated using a phase field model coupled with the FACTSage Toxide thermodynamic database. The effects of composition and temperature on the crystallization behaviour were studied. The simulations show that for the considered cases, the wollastonite morphology is mainly determined by anisotropy in the interface energy and hardly affected by anisotropy in the interface kinetics. In agreement with the observations from in-situ experiments, the simulations show a transition from planar to dendritic growth with decreasing temperature and the dendritic structure becomes finer when the temperature is decreased in further. The growth rates and dendrite tip radii obtained in the simulations agree well with Ivanstov's theory and are of the same orders of magnitude as those measured experimentally.