The activation energy for the diffusion of C in Cr is 111,000 j/mol. Calculate the diffusion coefficient at 827°C, grven that D at 1127°C is 6.25 * 10^-11 m^2/s.

A thermal evaporator is used to deposit aluminum. The aluminum charge is maintained at a uniform temperature of 1100 o C. If the the vapor pressure of aluminum is about 1x10-3 torr at that temperature, calculate the evaporation rate of aluminum?

Problem 3. Phosphorus is diffused into a thick slice of silicon with no previous phosphorus in it at a temperature of 1100°C. If the surface concentration of the phosphorus is 1 x 10 atoms/cm and its concentration at 1 µm is 1 x 105 atoms/cm, how long must be the diffusion time? D = 3.0 x 10 cm?/s for P diffusing in Si at 1100°C.

You wish to carburize 0.2 wt% C steel ball bearings. The balls have a diameter of 2.5 mm. You anneal them at 930 °C in an atmosphere which fixes the surface carbon concentration at 1 wt% C. (a) How long will it take to raise the average C concentration to 0.6 wt% ? (b) What is the concentration at the centre of each ball at this time?