Question

A block of pure iron needs to be converted to steel. The density of iron is 7.86x10^3kg/m^3, and the atomic weight is 0.0558kg/mol. The concentration of carbon at position A is 4x10^26 at/m^3. The carbon atomic weight is 0.012kg/mol. Carbon must be diffused into the iron to convert it to steel. It is desired to have 1025 atoms of carbon per m3 at point B. Position A is 1mm from position B. Assume that you have 1m^3 of iron. You heat the material uniformly to 1200oC. D0, carbon = 79x10-6 m2/sec, Ea = 83kJ/mol, and the density of carbon is 2260kg/m^3.

i. What is Dcarbon at 1200ºC in m2/sec?

ii. Calculate the FLUX (J) of carbon atoms in atoms per m2-sec at 1200ºC?

Answer 1