Kinetics of high-temperature spreading

This paper reviews the recent advances in the experimental and theoretical analysis of the high-temperature spreading of molten metals and oxides. Results obtained in the analysis of simple non-reactive systems are compared with current theories developed for room-temperature liquids. These results outline the critical role in spreading at high-temperature of the local dissipation at the triple solid-liquid-vapor junction. However, in most high-temperature systems, the substrate cannot be described as an ideal solid - rigid and insoluble - and the movement of the triple junctions is accompanied by other phenomena such as ridging, interdiffusion, and chemical reactions (reactive spreading). The effect of these phenomena is outlined and a framework for the theoretical analysis of reactive spreading emerges. This framework is based on the division of the reactive spreading process into its constituent steps, and the identification of the step that drives spreading and controls its kinetics. A key aspect of the analysis is the description of the structure of the triple junction and the identification of the relative kinetics of the movement of the liquid and the other phenomena that accompany spreading.