a) For a diffusion analysis where the temperature is not a fixed variable, calculate the diffusivity of nickel in iron at 800 degrees C.
b) Given the situation in part a, estimate the flux of Ni atoms into the Fe if there is a drop in concentration from 8 - 6 at % between 3 and 4 mm from the surface. P y-Fe at 800 degrees C = 7.92 g/cm^3 Please show all work for both parts and do not answer with a link.