Metastable Nanocrystalline Zirconia in Light of the Nucleation Theory

Abstract

It is demonstrated that the theoretical foundation for the existence of metastable nonmonoclinic zirconia due to nanocrystallinity contradicts the fundamental aspects of the classical nucleation theory. As a consequence, the stabilization of the thermodynamically less stable zirconia modifications cannot be related to metastability. The experimental findings suggest that nonmonoclinic zirconia at room temperature results from chemical reactions, the products of which slightly deviate from pure monoclinic zirconia in terms of composition and, hence, in terms of structure.