Kmu479 tutorial Flashcards
(15 cards)
What is Hacettepe University known for?
Hacettepe University is known for its Department of Chemical Engineering.
Who is Öznur Çakmak?
Öznur Çakmak is a PhD at Hacettepe University.
Contact: oznurcakmak@hacettepe.edu.tr
What is diffusion?
Diffusion is the phenomenon of material transport by atomic motion.
How is diffusion demonstrated?
Diffusion can be demonstrated using a diffusion couple formed by joining bars of two different metals.
What happens to a copper-nickel diffusion couple when heated?
When heated, a copper-nickel diffusion couple reveals pure copper and nickel at the extremities, separated by an alloyed region.
What is interdiffusion?
Interdiffusion is the process whereby atoms of one metal diffuse into another.
What is self-diffusion?
Self-diffusion occurs when atoms exchange positions within the same type of atoms.
What are the two conditions for atomic migration in diffusion?
- There must be an empty adjacent site.
- The atom must have sufficient energy to break bonds and cause lattice distortion.
What is vacancy diffusion?
Vacancy diffusion involves the interchange of an atom from a normal lattice position to an adjacent vacant lattice site.
What is interstitial diffusion?
Interstitial diffusion involves atoms migrating from an interstitial position to a neighboring empty position.
Which type of diffusion occurs more rapidly in metal alloys?
Interstitial diffusion occurs more rapidly than vacancy diffusion due to smaller interstitial atoms.
What is diffusion flux?
Diffusion flux (J) is defined as the mass or number of atoms diffusing through a unit cross-sectional area per unit of time.
What is steady-state diffusion?
Steady-state diffusion occurs when the diffusion flux does not change with time.
What is Fick’s first law?
Fick’s first law states that the diffusion flux is proportional to the concentration gradient.
What is nonsteady-state diffusion?
Nonsteady-state diffusion occurs when the diffusion flux and concentration gradient vary with time.
