Extracting interdiffusion coefficients from binary diffusion couples using traditional methods and a forward-simulation method

Abstract

A MatLab program is developed to allow effective extraction of both interdiffusion coefficients and impurity diffusivities from concentration profiles of binary diffusion couples. In addition to implementing the Boltzmann–Matano method, the Sauer–Freise method, the Hall method, and the Wagner method, a forward-simulation method was developed and implemented in the program. Eight binary systems (Fe–Ni, Co–Ni, Nb–W, Ni–W, Ni–Mo, Co–Mo, Fe–Nb and Ni–Nb) were used to test the program and to evaluate the advantages and disadvantages of the various methods. The forward-simulation method shows advantages including the ability to extract the impurity diffusion coefficients. Valuable impurity diffusivities and interdiffusion coefficients data at 1100 °C for the eight binary systems are obtained and they are in good agreements with available literature data. The successful diffusivity extraction from several complicated composition profiles with several intermetallic compounds demonstrates the reliability and robustness of the program.