Problem 5 An iron-carbon alloy initially containing 0.35 wt% C is exposed to an oxygen-rich and Virtually carbon-free atmosphere at 1127C. Under these circumstances the carbon diffuses from the alloy and reacts at the surface with the oxygen in the atmosphere; that is, the carbon concentration at the surface position is maintained essentially at 0 wt% C (this process of carbon depletion is termed decarburization). At What position will the carbon concentration be 0.15 wt% after a 10-h treatment? Iron has FCC crystal structure above 912C. The gas constant is 8.31 J/mol-K