What is the Difference Between Self Diffusion and Interdiffusion?

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The key difference between self-diffusion and interdiffusion lies in the types of atoms that are involved in the diffusion process:

  • Self-diffusion refers to the diffusion of atoms within a crystal when all atoms are of the same type. In this process, atoms move from one lattice site to an adjacent site, and the motion is due to vacancies or interstitial sites. This process is generally slower than interdiffusion.
  • Interdiffusion is the diffusion of atoms of one metal into another metal. This process involves the diffusional exchange of atoms across two materials that are in contact. Interdiffusion is typically faster than self-diffusion.

In summary:

  • Self-diffusion involves the movement of atoms within a single crystal lattice.
  • Interdiffusion involves the movement of atoms between two different materials in contact.

Comparative Table: Self Diffusion vs Interdiffusion

The main difference between self-diffusion and interdiffusion lies in the types of materials involved and the process of atomic exchange. Here is a table comparing the two processes:

Process Description Materials Atomic Exchange
Self-diffusion Describes the change in the position of atoms within a single-component material One-component material Atoms of the same type exchange positions
Interdiffusion Refers to the diffusional exchange of atoms across two materials in contact Two materials in contact Atoms of different types exchange positions across the materials

In summary, self-diffusion occurs within a single-component material, while interdiffusion involves the exchange of atoms between two different materials that are in contact with each other. Interdiffusion is generally faster than self-diffusion because the atomic exchange process is more complex and requires overcoming energy barriers.