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the maximum concentration of metal oxyde

Posted Mar 31, 2015, 6:41 a.m. EDT Version 5.0 2 Replies

Feng Song
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I have question on the surface reaction

I have done a model on Metal oxidation reaction and diffusion process.
and I have get some results on the concentraion of metal oxyde.
but the concentration of metal oxyde on the surface of metal can vary from small to very large number, whihc is larger than the maximum value. it is impossible in nature.

the question is how to control the concentraion under the maximum value in the reaction and diffusion process.


thanks
2 Replies Last Post Mar 31, 2015, 8:34 a.m. EDT
Lasse Murtomäki
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Posted: 10 years ago Mar 31, 2015, 7:57 a.m. EDT
Use a reversible reaction with an equilibrium constant that prevents too high concentration:

rate = kf*c_O*c_M - kb*c_MO

Since the activity of pure solid metal is 1, this reduces to

rate = kf*c_O - kb*c_MO

and the equilibrium constant is K = kf/kb where kf and kb are the forward and backward reaction rate constants.

Lasse
Use a reversible reaction with an equilibrium constant that prevents too high concentration: rate = kf*c_O*c_M - kb*c_MO Since the activity of pure solid metal is 1, this reduces to rate = kf*c_O - kb*c_MO and the equilibrium constant is K = kf/kb where kf and kb are the forward and backward reaction rate constants. Lasse
Feng Song
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Posted: 10 years ago Mar 31, 2015, 8:34 a.m. EDT
thanks,

I know the problem is from the false constant.
thank you very much.
thanks, I know the problem is from the false constant. thank you very much.

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