Equilibrium for diffusion of gases in metals

In summary, the conversation is about the possibility of hydrogen moving from one metal to another when in contact with each other, similar to osmosis. The contact between the metals must be excellent for this to occur and there must be a driving force. The start of the reaction between titanium and hydrogen occurs at 300 C and requires a contact between the metals. Diffusion processes in semiconductors also support this idea.
  • #1
hannaha
1
0
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!
 
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  • #2
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.
 
  • #3
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.
 
  • #4
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
 
  • #5


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.
 

FAQ: Equilibrium for diffusion of gases in metals

1. What is equilibrium in the context of diffusion of gases in metals?

Equilibrium in this context refers to a state where the concentration of a gas in a metal is constant and there is no net movement of gas particles between the metal and its surroundings. This means that the rate of gas diffusion into the metal is equal to the rate of gas diffusion out of the metal.

2. What factors affect the equilibrium for diffusion of gases in metals?

The equilibrium for diffusion of gases in metals is affected by factors such as temperature, pressure, and the type of gas and metal involved. Higher temperatures and pressures tend to increase the rate of diffusion, while the type of gas and metal can also impact the diffusion rate.

3. How does the concentration gradient affect equilibrium for diffusion of gases in metals?

The concentration gradient, or the difference in concentration of a gas between the metal and its surroundings, is a driving force for diffusion. As the concentration gradient decreases, the rate of gas diffusion will also decrease until equilibrium is reached.

4. Can equilibrium for diffusion of gases in metals be reached in all cases?

No, equilibrium may not be reached in some cases, such as when there is a large difference in temperature or pressure between the metal and its surroundings. In these cases, diffusion may continue until the temperature or pressure equalizes, or until the metal reaches its solubility limit for the gas.

5. How is equilibrium for diffusion of gases in metals affected by the structure of the metal?

The structure of the metal, such as its grain size and composition, can affect the diffusion of gases. For example, a metal with a finer grain size may have a higher diffusion rate due to a larger surface area for gas particles to diffuse into. Additionally, the composition of the metal can impact its solubility for different gases, thus affecting the equilibrium for diffusion.

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