Oxides in an oxygen potential gradient: coupled morphological stability of the multiple phase boundaries

TL;DR

This paper presents a comprehensive formal analysis of how oxygen potential gradients influence the morphological stability of multiple phase boundaries in oxides, highlighting transport processes and degradation mechanisms.

Contribution

It introduces a formal framework for understanding coupled morphological stability of phase boundaries in oxides under potential gradients, advancing the theoretical understanding.

Findings

Transport processes are coupled at phase boundaries.

Morphological stability is affected by oxygen potential gradients.

Degradation mechanisms like unmixing are linked to boundary stability.

Abstract

In materials that are exposed to thermodynamic potential gradients, i.e., gradients of chemical potentials, electrical potential, temperature, or pressure, transport processes of the mobile components occur. These transport processes and the coupling between different processes are not only of fundamental interest, but are also the origin of several degradation processes, such as kinetic unmixing and decomposition. In addition, changes in the morphology of the material surfaces and interfaces may appear. In this paper, a comprehensive formal treatment of the coupled morphological stability of multiple phase boundaries will be given for oxides that are exposed to an oxygen potential gradient.