What is kirkendall effect?

The Kirkendall effect is a phenomenon in materials science where there is a diffusion-driven atomic migration leading to the formation of voids or pores in a material. This effect was first observed by researchers John W. Cahn and John E. Hilliard in the 1950s.

The Kirkendall effect occurs when two different materials with different diffusion rates are in contact and undergo a diffusion process. This results in the faster diffusing material moving ahead of the slower diffusing material, creating a vacancy behind it. As a result, voids or pores are formed in the material as the vacancy continues to grow.

The Kirkendall effect is commonly observed in metal alloys during processes such as solid-state diffusion bonding, sintering, and high-temperature annealing. It can also occur in other materials such as ceramics and polymers.

Understanding the Kirkendall effect is important for material scientists and engineers as it can affect the mechanical properties and integrity of materials. It can also be utilized in various applications such as in the controlled diffusion of materials and in the fabrication of nanomaterials.