Abstract: Diffusion couples, Fe-6.8 wt% Al-1.0 wt% Si/Fe and Fe-6.3 wt% Al-0.9 wt% Si/Fe were constructed and separately annealed at 1050°C for 3 h and at 1000°C for 64 h. The concentration profiles of Fe, Al and Si atoms in these couples were measured by electron probe micro-analysis (EPMA), while the diffusion behavior was also simulated by coupling thermodynamic and kinetic properties of Fe-Al-Si system. The simulation results were in good agreement with the measured concentration profiles showing the validity of dynamic parameters of Fe-Al-Si system. Calculation was made for Fe-7 wt% Al-1 wt% Si/Fe diffusion couples at 1000°C with different diffusion time. Silicon uphill was found under the in°uence of aluminum.

Key words: Diffusion kinetics, Fe-Al-Si system, Thermo-calc and DICTRA