Dissolution kinetics of arbitrarily-shaped alumina in oxide melt: An integration of phase-field modelling and real-time observation study

A feasibility study of utilizing a phase-field model considering the convection effect is performed in this work to investigate the dissolution kinetics of arbitrarily-shaped alumina particle in the oxide melt. The established model has been benchmarked by high temperature confocal laser scanning microscope (HT-CLSM) to observe the polycrystalline sapphire dissolution in multicomponent oxide melt. The effects of alumina morphology and temperature on the dissolution kinetics were studied quantitatively. It is for the first time found that the dissolution of irregular alumina particle in oxide melt shows a double-fold smooth anisotropy behavior. The dissolution rate of alumina particle is governed by the interface interactions rather than the self-diffusion of dissolved component in oxide melt. Increasing the temperature, the interfacial mobility coefficient increases, and the effect of alumina particle shape on the dissolution rate decreases. The temperature variation has a minor influence on the shape evolution of alumina during dissolution process. The convection intensity affects both the dissolution rate and shape evolution of alumina particle. An increased convection intensity increases the dissolution rate. As the convection partially affects the contact area of alumina particle with oxide melt, a decreased alumina particle curvature increases the dissolution rate. When the convection affects the whole contact area of alumina particle with oxide melt, the contact area plays an important role on the dissolution rate. The obtained methodology can be applied to investigate a general dissolution phenomenon in the high temperature oxide melt in materials science. [Display omitted] •A novel approach to study dissolution kinetics of arbitrarily-shaped alumina particle in oxide melt was proposed.•The dissolution of irregular alumina particle in oxide melt presents double-fold smooth anisotropy.•The effect of alumina particle shape on the dissolution rate decreases with increasing temperature.•Temperature variation has a minor influence on the shape evolution of alumina particle during its dissolution.•Convection intensity of melt affects both the dissolution rate and shape evolution of particle.