On the analysis of composition profiles in binary diffusion couples: systems with a strong compositional dependence of the interdiffusion coefficient

TL;DR

This paper introduces a new method for accurately analyzing composition profiles in binary diffusion couples, especially when the interdiffusion coefficient varies strongly with composition, improving reliability over traditional techniques.

Contribution

A novel fitting approach for composition profiles in systems with strong compositional dependence of interdiffusion coefficients is proposed and validated with Fe-Ga data.

Findings

Improved fitting accuracy at diffusion couple ends.

Enhanced reliability in systems with variable interdiffusion coefficients.

Validated method against experimental Fe-Ga data.

Abstract

Diffusion couple technique is an efficient tool for the estimating the chemical diffusion coefficients. Typical experimental uncertainties of the composition profile measurements complicate a correct determination of the interdiffusion coefficients via the standard Boltzmann-Matano, Sauer-Freise or the den Broeder methods, especially for systems with a strong compositional dependence of the interdiffusion coefficient. A new approach for reliable fitting of the experimental profiles with an improved behavior at both ends of the diffusion couple is proposed and tested against the experimental data on chemical diffusion in the system Fe-Ga