Transport of impurities out of a two-phase crystal layer into a melt under the effect of a temperature gradient: Mechanisms and kinetics

Possible mechanisms and kinetics of removal of eutectic-forming impurities from a two-phase crystal layers with a transverse temperature gradient are considered. Mathematical models are suggested for various mechanisms of impurity transport out of a crystal layer into the surrounding melt. Equations for estimating the purification rate of layers with open and closed pores are derived and analyzed. These equations are intercompared and are checked against the results of numerical solution. It is shown that, in the case of the migration of closed inclusions, the purification rate is higher than in the case of the diffusion of impurities out of open pores.