Correlation between microstructure and Young’s modulus of porous ceramics using three-dimensional mesoscale analysis and FIB-SEM reconstruction method

Abstract

One of the engineering challenges in developing more reliable electrodes in solid oxide fuel cells is to reduce residual stresses generated during electrode fabrication. The Young's modulus of porous ceramic materials employed in the electrodes is a fundamental property essential for evaluating the residual stresses of electrodes. In this study, the correlation between Young's modulus and the microstructure of the cathode material La0.6Sr0.4Co0.2Fe0.8O3-δ was evaluated numerically using a voxel-based finite element method in conjunction with the three-dimensional mesoscale techniques, including a kinetic Monte Carlo and a discrete element method. The results of simulations utilizing the FIB-SEM reconstructed microstructures are in good agreement with those of micro-indentation experiments, indicating that our methodology is effective for estimating the Young's modulus of porous ceramics at room temperature. Furthermore, we reveal that the porosity dependence of Young’s modulus can be well described by an empirical power law based on the percolation model. In particular, our findings indicate that the dependencies on porosity are highly related to the homogeneity of the initial powder microstructures before sintering. Finally, our results suggest that the effective Young’s modulus of the porous materials at any porosity has a correlation with the tortuosity factor.

Keywords

• solid oxide fuel cells
• sintering
• young’s modulus
• porous matrerials
• fib-sem
• toruosity factor
• discrete element
• kinetic monte carlo
• finite element method