What is the Difference Between Self Diffusion and Interdiffusion

The自扩散和扩散之间的关键区别is that self diffusion refers to the atomic migration in pure metals when all the atoms in the crystal structure that exchange positions are of the same type, whereas interdiffusion refers to thediffusionof atoms of one metal into another metal.

自扩散描述了原子在晶体中的位置的变化。另一方面，扩散可以描述为原子在两种接触的材料中的扩散交换。通常，自扩散过程比互扩散过程要慢，而互嵌段的速度比许多其他可能发生的扩散过程更快crystal lattice.

1.Overview and Key Difference
2.What is Self Diffusion
3.What is Interdiffusion
4.Self Diffusion vs Interdiffusion in Tabular Form
5.Summary – Self Diffusion vs Interdiffusion

What is Self Diffusion?

自扩散描述了原子在晶体中的位置的变化。Typically, self diffusion occurs by a vacancy mechanism. We can use a parameter called the diffusion coefficient, which measures the mobility of diffusing species. The presence of native point defects is useful in this type of diffusion process. This means self diffusion in semiconductors is usually mediated by native point defects. These defects include vacancies and self-interstitials.

自扩散系数是扩散系数D_i* of the species i when the chemical potential gradient is equal to zero. The equation that links these parameters is as follows:

D_i* = D_i(∂lnc_i/∂lna_i)

In the above equation, a_irefers to the activity of the species i in the solution, while c_iis the concentration of i. Commonly, we assume that this term is equal to the tracer diffusion that is determined by observing the movement of an isotope in the material of interest.

What is Interdiffusion?

Interdiffusion can be described as the process of the diffusional exchange of atoms across two materials that are in contact. This type of diffusion is conducted by the chemical potential gradient across the boundaries. In simple words, interdiffusion is the diffusion of atoms of one metal into another metal.

Interdiffusion usually occurs through a retentive interface that is created within dentine by the penetration of an adhesive restorative resin. This interface lies between the applied resin composite material and the deep resin-free dentine. Generally, interdiffusion is faster than self-diffusion and vacancy diffusion. This is because the bonding of interstitials to the surrounding atoms is typically weaker, and there are many moreinterstitial sitesin the interface of the interdiffusion process compared to a vacancy site to jump to.

What is the Difference Between Self Diffusion and Interdiffusion?

自扩散描述了原子在晶体中的位置的变化。同时，扩散是在两种接触的材料中扩散原子的传播过程。自扩散和扩散之间的关键区别在于，当晶体结构中的所有原子交换位置相同时，自我扩散是指纯金属中的原子迁移金属。

The below infographic presents the differences between self diffusion and interdiffusion in tabular form for side by side comparison.

Summary – Self Diffusion vs Interdiffusion

There are different types of diffusions that can take place in crystal lattices, such as self diffusion and interdiffusion. The key difference between self diffusion and interdiffusion is that self diffusion refers to the atomic migration in pure metals when all the atoms in the crystal structure that exchange positions are of the same type, whereas interdiffusion refers to the diffusion of atoms of one metal into another metal.