An aluminum film was deposited at a rate of 1 μm/min in vacuum at 25 °C. It was found that the oxygen content in the film was 0.01 at% (remember that is only O). What was the total air pressure in the system (assuming air is 20% O2)?

.Nitrogen from a gaseous phase is to be diffused into pure iron at 669 °C. If the surface concentration is maintained at 1.0 wt% N, what will be the concentration (wt%) 0.9 mm from the surface after 6 hours? Given: Qd = 58 kJ/mol and Do = 6.2 x 10-7 m2/s. %3D

3. Mention how freezing increases food storage time.

Problem 1 A sheet of BCC iron 1 mm thick was exposed to a carburizing gas atmosphere on one side and a decarburizing atmosphere on the other side at 725°C. After having reached steady state, the iron was quickly cooled to room temperature. The carbon concentrations at the two surfaces of the sheet were determined to be 0.012 and 0.0075 wt%. Compute the diffusion coefficient if the diffusion flux is 1.4 x 108 kg/m2-s. Hint: Use Equation 4.9(Text Book) to convert the concentrations from weight percent to kilograms of carbon per cubic meter of iron.