This is an interesting question. here is what I think:

I would say it is relative in cases like nucleation of new phases (like intermetallics) in the interface. It directly affects wetting and has to be considered as a determining state. Thermodynamically speaking, the interface energy can assist a reaction in the way of lowering the energy barrier. Also, it should be considered that after the formation of a new phase in the interface between A and B, two new interfaces would be added to the system: A/C and B/C.

If we are trying to make a joint by solid-state processes like diffusive couples, parameters like the diffusion coefficient are determining at a level that neglects interfacial energy.

Dear Mehdi,

Thanks.

In fact I try to link the interface energy to nucleation of a solid phase in liquid on a solid substrate. Although there are some description in thermodynamics, at atomic level, the links are not clear.

Giving your previous works (which I have followed eagerly), it should be something like nucleation of a second oxide layer beneath the primary oxide, as the case for Spinel under the MgO layer. Am I right? If it is so, I would say that thermodynamics plays a major role. The Gibbes free energy of formation is so low that any effect of the interfacial energy can be neglected. Also, based on multiple XPS profiles which I have recently got from surface oxide samples of Al-Mg, Al-Mg-Be, and Al-Mg-Ca systems, There is no clear interface between oxide layers. It is more of a gradient change.

Dear Mehdi,

Thank you very much for your quick response and interest in our work.

I did some ab initio md simulations for liquid-metal/oxide interfaces. We revealed formation of a metal layer terminating the substrates. These newly formed metallic layer has ordering and the atoms are bonded to the substrate. Thus they become part of the substrate. Structurally, we can consider these terminating metallic atoms/ions forming a two-dimensional compound (2DC).

Generally, I agree with you that thermodynamics should play a major role for the whole system. However, since the 2DCs at the interfaces are at atomic level, I am not sure how to apply thermodynamics rules.

The simulations also revealed that the atomic density and atomic ordering decreases with the distance from the substrate. Therefore, the simulations are in line with the experimental observations with considering the differences that simulations produce only idealised situations whereas there are many factors in experiments.

It will be my pleasure to have more discussion with you about the comparison between experimental observations and theoretical modelling.

Please send me some your your work to me if possible. Thank you very much in advance.

Dear Mohammad,

Thanks for your comments on the importance of interfacial energy on heterogeneous nucleation.

Changming