Energy Landscape of Zirconia Phase Transitions

Abstract

The solid-phase transitions of zirconia are important phenomena for many industrial applications. Because of the lack of tools for resolving the atom displacement pattern, the transition kinetics has been disputed for over 60 years. Here, first-principles-based stochastic surface walking (SSW) pathway sampling is utilized for resolving the mechanism of ZrO2 tetragonal-to-monoclinic solid-phase transition. Two types of lattice and atom correspondence allowed in phase transition are determined for the first time from energy criterion, which are originated from two nearly energy-degenerate lowest-transition pathways and one stress-induced ferroelastic transition channel of tetragonal phase. An orthorhombic crystal phase (Pbc2/1) is discovered to be a trapping state at low temperatures in phase transition, the presence of which does not create new orientation relation but deters transformation toughening significantly. This new finding may facilitate the design of new functional oxide materials in ceramic industry.

Atomic Structure of Domain and Interphase Boundaries in Ferroelectric HfO2

“…Furthermore, the local Hf-O bonding configuration across the boundary may also play a role. Furthermore, this finding is in good qualitative agreement with studies that show the (100) m habit is the more favorable habit planes for related zirconia phase transformations 41. Strain and displacements of the Hf sub-lattice needed to form certain rumpled boundaries (i.e.…”

Real-time atomistic observation of structural phase transformations in individual hafnia nanorods

“…Insight may be gleaned, therefore, from examining the case of ZrO 2 , which has been successfully stabilized in the tetragonal phase at room temperature in nanocrystalline form71213. This represents a suppression of the ZrO 2 transition temperature by over 1000 °C from its bulk value of 1050 °C (refs 16, 17, 18, 19). Even for such classical martensitic transitions, however, the atomistic details of the transition and their specific size dependence remain to be elucidated.…”

“…The interplay between deformation, creation of twin boundaries, bond stretching and phase transformations has thus remained unexplored even for the classical displacive transition characterized by this simple binary oxide system. Indeed, despite considerable attempts to map energy landscapes1819, much of the work in this area remains theoretical, and there exists no precedent for real-space and real-time examination of the phase transformation at the atomic scale.…”

Structure and water oxidation activity of 3d metal oxides

“…The SSW method is originally developed for molecules and clusters, and is recently extended to crystal systems by coupling the degrees of freedom of lattice. The method has been successfully utilized for predicting the structure of C 100 ‐fullerene, B 40 ‐clusters, the pathway of TiO 2 (B)‐to‐anatase, anatase‐to‐rutile, and ZrO 2 t‐m transitions . A key feature for SSW method is the small displacement of atoms when exploring the PES, which allows it to maintain the one‐to‐one correspondence between two connecting minimum structures.…”

“…The method has been successfully utilized for predicting the structure of C 100 -fullerene, 36 B 40 -clusters, 39 the pathway of TiO 2 (B)-to-anatase, 40 anatase-torutile, 41 and ZrO 2 t-m transitions. 42 A key feature for SSW method is the small displacement of atoms when exploring the PES, which allows it to maintain the one-to-one correspondence between two connecting minimum structures. The detail of the algorithm can be found in our previous publications.…”