Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Modeling of diffusion

Please login with a confirmed email address before reporting spam

Hello!
I would like to model the diffusion of dopants into a bulk material from a thin layer on its surface . As I understand, in my COMSOL version (4.4) I should use the module "Transport of Diluted Species". But during the diffusion the dopant layer should decrease. How could I build the model?

5 Replies Last Post 20.12.2016, 11:07 GMT-5

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 27.01.2015, 03:56 GMT-5
You have thin layer with some initial dopant concentration. Assign the "No flux" condition on the boundary which is facing the "outside world", and at boundary between the layer and bulk no condition is necessary as COMSOL assumes continuity across inner boundaries. Of course, if you have some specific condition on that boundary, use it. I could attach a model but I am using version 5.0. Yet, attached the report file which may help you.

br
Lasse
You have thin layer with some initial dopant concentration. Assign the "No flux" condition on the boundary which is facing the "outside world", and at boundary between the layer and bulk no condition is necessary as COMSOL assumes continuity across inner boundaries. Of course, if you have some specific condition on that boundary, use it. I could attach a model but I am using version 5.0. Yet, attached the report file which may help you. br Lasse

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 27.01.2015, 03:58 GMT-5
And the attachments
And the attachments


Please login with a confirmed email address before reporting spam

Posted: 9 years ago 27.01.2015, 12:09 GMT-5
Well, but in such model the dopant layer won't decrease. It will be only a part of diffusion area. However, in the reality dopants diffuse in, and specially created conditions prevent outdiffusion.

If a have misunderstood your idea, please send me your model, it doesn't matter which version it has.
Well, but in such model the dopant layer won't decrease. It will be only a part of diffusion area. However, in the reality dopants diffuse in, and specially created conditions prevent outdiffusion. If a have misunderstood your idea, please send me your model, it doesn't matter which version it has.

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 28.01.2015, 02:29 GMT-5
If you mean that the thickness of the dopant layer does not decrease you are right. In my model only the concentration of the dopant in the layer decreases. If you want the thickness to decrease, I do not know how to do it.
If you mean that the thickness of the dopant layer does not decrease you are right. In my model only the concentration of the dopant in the layer decreases. If you want the thickness to decrease, I do not know how to do it.

Please login with a confirmed email address before reporting spam

Posted: 8 years ago 20.12.2016, 11:07 GMT-5
Could you please send me the diffusion model I need to study the diffusion between a gas and a liquid either in 3d or in 2d
Could you please send me the diffusion model I need to study the diffusion between a gas and a liquid either in 3d or in 2d

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.