SURFACE CRYSTALLIZATION OF LEUCITE IN GLASSES

The aim of this paper was to study surface crystallization of leucite in glasses derived from an SiO2-Al2O3-K2O base glass in a comparative study with another glass based on SiO2-Al2O3-MgO. Monolithic samples a nd glass powder of SiO2-Al2O3-K2O glass were studied and phase formati ons were determined by using scanning electron microscopy. Heterogeneo us nucleation was promoted by seeding the surface of the monolithic gl ass samples with glass dust to produce a highly disordered crystal as the primary phase. In addition to leucite formation, growth of a highl y symmetric, flat, almost two-dimensional crystal phase with controlle d diffusion was also observed. In glass granules, leucite demonstrated rapid, almost dendritic growth, from the nucleating centers. Use of l eucite ceramic as a restorative dental product is considered.