Analytical expressions have been found for ridge growth and spreading velocities, depending on the ridging mechanisms. Unlike most low temperature wetting experiments, we found that in high temperature systems, spreading kinetics is controlled by the movement of the ridge. We have identified the limited conditions in which wetting results can be interpreted in terms of one-dimensional equilibrium, allowing us to accurately use contact angle results to measure interfacial energies. Our experiments have shown a close relationship between the infiltration and colloidal behavior of high temperature melts. This can alternately be stated as the tendency of the liquid to infiltrate grain boundaries or dense compacts.
Liquid infiltrates the grain boundaries of a dense preform.
Systems with non-zero dihedral angle. By control of oxygen partial pressure or addition of active elements, contact angles can be manipulated so that molten metals infiltrate porous ceramic preforms. However, these metals do not penetrate grain boundaries and the preform keeps its structural stability. In parallel, metal particles dispersed in molten silicate glass flocculate and sinter. Silicon nitride particles dispersed in silicate glasses flocculate, leaving an equilibrium layer.