Modeling the aging kinetics of zirconia ceramics

TL;DR

This study investigates the aging process of yttria-stabilized zirconia ceramics at 134°C, combining experimental analysis and numerical simulation to accurately predict transformation kinetics.

Contribution

It introduces a comprehensive approach using the MAJ formalism and numerical modeling to understand and predict zirconia aging behavior based on microstructure and kinetic parameters.

Findings

Aging kinetics are governed by nucleation and growth mechanisms.

Numerical simulation improves the fit of aging models.

Surface nucleation and growth rates predict aging progression.

Abstract

Yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) with different microstructures were elaborated. The isothermal tetragonal to monoclinic transformation was investigated at 134 {\deg}C in steam by X-ray diffraction, Atomic Force Microscopy (AFM) and optical interferometry. The aging kinetics were analyzed in terms of nucleation and growth, using the Mehl-Avrami-Johnson (MAJ) formalism. Numerical simulation of the aging of zirconia surfaces was also conducted, and the results were used to better fit the aging kinetics. The simulation shows that the exponent of the MAJ laws is controlled not only by the nucleation and growth mechanisms, but also - and mainly - by their respective kinetic parameters. Measurements of nucleation and growth rates at the surface, at the beginning of aging, and the use of numerical simulation allow the accurate prediction of aging kinetics.