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Unformatted text preview: MatSc503 Kinetics of Materials Processes HW #2 Due January 30, 2002 1. Hydrogen in a very large slab of nickel of thickness 1 cm is removed by subjecting it to a vacuum at 600C. The diffusion coefficient of hydrogen in nickel at 600C is approximately 1.0 10- 6 cm 2 /s. The initial concentration of hydrogen in the nickel is 1 . × 10- 5 g/cm 3 . (a) Calculate the concentration profile of hydrogen in nickel across the thickness after 100 s. (b) (10 points) What is the flux of hydrogen at the nickel surface at 100 s? (c) (10 points) How much hydrogen has been removed from the slab per unit area after 100 s? (d) (10 points) How long will it take to reduce the average concentration of hydrogen in the nickel to 1 . × 10- 6 g/cm 3 ? 2. A sensitive infra-red detector is made by vapor depositing alternate 13 nm thick layers of HgTe and CdTe on a substrate. It is found that the detector loses its sensitivity due to interdiffusion after 55 hr at 162 ◦ C or after 250 hr at 110 ◦ C....
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This note was uploaded on 01/19/2010 for the course MAT SCI 503 taught by Professor Chen during the Spring '02 term at Pennsylvania State University, University Park.
- Spring '02