CH 5 - Diffusion

Question 1

What is diffusion?

Answer 1

mass transport by atomic motion

Question 2

What is interdiffusion?

Answer 2

in an alloy, atoms tend to migrate from regions of high concentrations to regions of low concentrations

Question 3

What is self-diffusion?

Answer 3

atom migration in an elemental solid

Question 4

What is vacancy diffusion?

Answer 4

• atoms exchange with vacancies
• applies to substitutional impurities atoms
• rate depends on # of vacancies & activation energy to exchange

Question 5

What is interstitial diffusion?

Answer 5

• smaller atoms can diffuse between atoms

- more rapid than vacancy diffusion

Question 6

Is diffusion faster for open or close-packed crystal structures?

Answer 6

open crystal structures

Question 7

Is diffusion faster for materials with covalent bonding or secondary bonding?

Answer 7

secondary bonding

Question 8

Is diffusion faster for bigger or smaller diffusing atoms?

Answer 8

smaller

Question 9

Is diffusion faster for higher or lower density materials?

Answer 9

lower