In the steel system, additives are often alloyed into the material for certain p
ID: 932464 • Letter: I
Question
In the steel system, additives are often alloyed into the material for certain properties. An example of this is the common rare-earth magnet Neodymium-Iron-Boron. So for Pure Iron, calculate the following
1.From a Neodymium source that is 45% by weight, find the concentration at a depth of 100 micron from the surface after 1 minute at 1200oC. The pre-exponential factor for calculating the Diffusion coefficient is 1.8e-4 m2/s and the activation energy is 261 kJ/mole.
2.From a Boron source that is 45% by weight, find the concentration at a depth of 100 micron from the surface after 1 minute at 1200oC, the pre-exponential factor is 5e-7 m2/s and the activation energy is 77 kJ/mole.
3.Does one show faster diffusion than the other? If so, how can you account for this difference in diffusion rate?
Explanation / Answer
3. The second shows faster diffusion because it has lower activation energy.