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| Teaching Since: | May 2017 |
| Last Sign in: | 408 Weeks Ago |
| Questions Answered: | 66690 |
| Tutorials Posted: | 66688 |
MCS,PHD
Argosy University/ Phoniex University/
Nov-2005 - Oct-2011
Professor
Phoniex University
Oct-2001 - Nov-2016
5.25  The  steady-state  diffusion  flux  through  a metal  plate  is  7.8 X 10-8  kg/m2-s  at  a  tem- perature  of  1200°C  (1473  K)  and  when  the concentration gradient is -500 kg/m4. Calcu- late the diffusion flux at 1000°C (1273 K) for
Â
1473
1673
2.2 X 10-15
4.8 X 10-14
the same concentration gradient and  assum-
ing an activation energy for diffusion of 145,000 J/mol.
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(a)Â Â Â Â Determine the values of D0 and the acti- vation energy Qd.
5.26Â Â At approximately what temperature would a specimen of g-iron have to be carburized for
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(b) What is the magnitude of D at (1573 K)?
1300°C
4 h to produce the same diffusion result as at 1000°C for 12 h?
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5.22 The diffusion coefficients for carbon in nickel are given at two temperatures:
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T(°C)              D(m2/s)
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