by Janson Montaner (resume). Modified by R.D. Kriz (5/19/95).
A diffusion couple is formed between stainless steel and nickel. The atmosphere is brought to a temperature of 1500 degrees Celsius and held there for twelve hours. The initial concentration of nickel in the steel is 0.30 wt%, and the surface concentration is 0.80 wt%. How long will it take for the steel to reach a nickel content of 0.50 wt% at a distance of 0.5 mm into the steel? The diffusivity of nickel in stainless steel is 4.34E-13 m^2/s at 1500 degrees Celsius.
Fick's second law should be used to solve this equation.
Interpolating from the erf function table leads to:
End of Nonsteady-State Diffusion Example