Determination of model parameters under sharp and thin interface limits of the phase-field model to study cation interdiffusion in SOFC

A systematic procedure is presented to determine the gradient energy coefficient and height of double-well potential (phase-field model parameters). The well-known Allen-Cahn equation is used to investigate cation interdiffusion in solid oxide fuel cell (SOFC). An established procedure that commonly applied in the study of solidification is adapted. The phase-field model parameters are determined under sharp as well as thin interface limits. The upper limit of the interface thickness is deduced for the thin interface limit. Effect of variation of interface thickness for a particular value of interfacial energy is evaluated on the cation interdiffusion in terms of interdiffusion length of the cations under thin interface limit and this is compared with that of sharp interface limit. Effect of variation of interfacial energy at the upper limit of the interface thickness is also studied under the thin interface limit. Further, the reason behind the variation of interdiffusion length is also presented under the thin interface limit for different values of interfacial energy. Under a large variation of interfacial energy, no significant changes are found in the interdiffusion length of the cations. From this study, it can be deduced that for a considerable range of interfacial energy, a wider range of model parameters can be selected for the phase-field model with reasonable accuracy.