Phase-field modeling of solute precipitation and dissolution

A phase-field approach to the dynamics of liquid-solid interfaces that evolve due to precipitation and/or dissolution is presented. For the purpose of illustration and comparison with other methods, phase-field simulations were carried out assuming first order reaction (dissolution/precipitation) kinetics. In contrast to solidification processes controlled by a temperature field that is continuous across the solid/liquid interface (with a discontinuous temperature gradient), precipitation/dissolution is controlled by a solute concentration field that is discontinuous at the solid/liquid interface. The sharp-interface asymptotic analysis of the phase-field equations for solidification [A. Karma and W.-J. Rappel, Phys. Rev. E 57, 4323 (1998)] has been modified for precipitation/dissolution processes to demonstrate that the phase-field equations converge to the proper sharp-interface limit. The mathematical model has been validated for a one-dimensional precipitation/dissolution problem by comparison with the analytical solution. (C) 2008 American Institute of Physics.