Modeling and simulation of grain growth in Si3N4. III. Tip shape evolution

Abstract Simulations based on the anisotropic Ostwald ripening model have been performed for the tip shape evolution of the β-Si 3 N 4 crystal in the liquid phase. It was found that tip shape is a function of the liquid concentration and the relationship between the interfacial reaction and diffusion constants. Depending on the concentration of the liquid phase, a convex, almost flat, or concave surface appeared at the tip surface. The following two factors are crucial for understanding the development of concavity at the tip surface of the β-Si 3 N 4 crystal: (1) strong growth anisotropy of the β-Si 3 N 4 crystal that is the interfacial reaction and diffusion controlled kinetics of the (100) and (001) surfaces, respectively, and (2) supersaturation of the liquid phase.