Question

The mechanism of diffusion of small atomic radius compared to the parent material would be described by __________________

(a) Substitutional diffusion

(b) Interstitial diffusion

(c) Vacancy diffusion

(d) Drift

This question was posed to me in an interview.

My question is from Uses and Limitations of Phase Rule topic in portion Phase Rule of Engineering Chemistry I

Answer 1

Correct option is (b) Interstitial diffusion

To elaborate: During equilibrium process, metastable curve appears and due to variation in equilibrium composition, the curve disappears. To fix this equilibrium back to form, there takes place diffusion between interstitial atoms called interstitial diffusion.