Equilibrium for diffusion of gases in metals

[hannaha]

Hi there,

This could be absolute nonsense but I just got thinking about this. Say you had a certain metal into which a quantity of hydrogen had diffused, and then you placed it in communication with another hydrogen-free metal (say, titanium), would it be possible that the hydrogen would move into the titanium metal, out of the other metal? Coming from a a biology background I was thinking about osmosis (well, any concentration gradient-type process) - does the same apply to gases in metals i.e. would an equilibrium be reached? Or is there no driving force created by the "empty" metal?

Any ideas would be appreciated, thanks!

 

[Enthalpy]

I understand it just as you suggest, and this is backed by diffusion processes in semiconductors. Not just for hydrogen, but as well for dopants.

You need an excellent contact between the solids so (1) the diffusing species don't need to pass through air in between (2) hydrogen doesn't go away through the slit.

Also interesting: solids have some affinity for the diffusing species, so the equilibrium between contacting solids is not at identical concentrations.

 

[chill_factor]

there is a driving force indeed. there is a driving force even for a hydrogen permeated metal in empty space. its just the kinetics that's a problem.

if you weld 2 alloys together, even the alloys start diffusing into one another; however, it may be extremely slow.

 

[mzain]

there are certain conditions that needs to be fulfilled for a specific reaction to occur. for example for titanium and hydrogen the start of reaction takes place at 300 C. and for the reaction to occur the there must be a contact between the metals in your case. and it will be diffusion controlled process.

i hope it will help u to some extent

 

[alphy]

I find this to be a very interesting question. The diffusion of gases in metals is a well-studied phenomenon and there are certain principles that apply to this process. One key concept is the idea of equilibrium, which is the state in which there is no net movement of particles between two systems. In the case of diffusion in metals, equilibrium can be reached when the concentration of the gas in both metals is equal.

In your scenario, it is possible for the hydrogen to diffuse from one metal to the other, as long as there is a concentration gradient present. This means that the hydrogen concentration is higher in one metal compared to the other. However, the rate of diffusion will depend on various factors such as the temperature, pressure, and the type of metal involved. In some cases, the diffusion may not occur at all if the driving force (concentration gradient) is not sufficient.

It is also important to note that the process of diffusion in metals is not exactly the same as osmosis in biology. Osmosis involves the movement of water molecules across a semi-permeable membrane, while diffusion in metals occurs through the interstitial spaces between metal atoms.

In summary, the diffusion of gases in metals can reach an equilibrium state, but this will depend on various factors and may not always occur. Further research and experimentation would be needed to fully understand the dynamics of this process. Thank you for bringing up this interesting topic.