Question

What is the diffusion constant (Do) when copper is dissolved in copper?

(a) 0.2 * 10^-4

(b) 0.15 * 10^-4

(c) 1.98 * 10^-4

(d) 5400 * 10^-4

I have been asked this question in final exam.

My doubt is from Fick’s Law, Carbon Steels topic in portion Diffusion in Solids & Ferrous Materials of Engineering Material & Metallurgy

Answer 1

The correct option is (a) 0.2 * 10^-4

Explanation: Diffusion of Cu in Cu has a Do value of 0.2 * 10^-4 m^2 s^-1. The diffusion constants of Zn in Zn, Al in Al, and Si in Si are 0.15 * 10^-4, 1.98 * 10^-4, and 5400 * 10^-4 in that order.