Foreign body indued kinetic roughening: Kinetics and observations

摘要

A new and novel phenomenon: kinetic roughening induced by foreign particles at a growing crystal face was observed for the first time. Beginning with relatively low supercoolings, when foreign particles are in contact with the crystal surface, the faceted growth of the {110} faces of naphthalene crystals from its melt reveals a transition from smooth growth to rough growth, followed by an increase in the growth rate. This is due to the vanishing of the two-dimensional (2-D) nucleation barrier at the particle contact area. At high supercoolings, the particle-indued kinetic roughening will be suppressed. To describe this unusual phenomenon, the thermodynamic and kinetic criteria for this type of kinetic roughening were derived. The effect of particles on kinetic roughening is determined in terms of the step correlation parameter f, which is 0.035 for the naphthalene crystallization system. This is the first quantitative measurement for the interaction (or contact) parameters between the crystal steps and foreeign particles.