Towards the Validation of a Phase Field Model for Ni Coarsening in Solid Oxide Cells

Ni coarsening in the Ni/yttria-stabilized zirconia (YSZ) fuel electrode of solid oxide cells (SOCs) is a major cause of long-term performance degradation. Phase-field modeling is a powerful tool for studying Ni coarsening in the complex 3D structures of SOC fuel electrodes. In this work, we present a study aimed at validating a phase-field model, comparing simulation results with time-dependent ex-situ tomographic data. Three equilibrium Ni/YSZ contact angles are examined: 97 degrees, 120 degrees, and 150 degrees. Simulated microstructures are characterized through quantities such as the Ni mean radius, triple-phase boundaries, and interface shape distribution. The phase-field model reproduces the improved pore connectivity in the first stage of Ni coarsening observed in the tomography data. This model also indicates that the contact angle plays a key role in the microstructural evolution during Ni coarsening, and the best match to the experiment was obtained with the equilibrium contact angle of 120 degrees, close to a measured value in literature. Finally, the limitations of the model are discussed. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study validates the role of contact angle on microstructural evolution during Ni coarsening using a phase-field model, with an equilibrium contact angle of 120 degrees showing the best match to experimental results.