Diffusion - transfer of mass either within a specific solid or from a liquid, a gas, or another solid phase.
Diffusion couple - formed by joining bars of two different metals together so that there is intimate
contact between the two faces
interdiffusion (impurity diffusion) - The process by which atoms of one metal diffuse into another
self-diffusion - atomic migration in pure metals
vacancy diffusion - one mechanism involves the interchange of an atom from a normal lattice position to
an adjacent vacant lattice site or vacancy
interstitial diffusion - A diffusion mechanism by which atomic motion is from interstitial site to
interstitial site.
-occurs more rapidly than diffusion by the vacancy mode as interstitial atoms are smaller/ more mobile
probability of interstitial diffusion > vacancy diffusion
diffusion flux - how fast the foreign mass can transfer across and area J=M/At
Fick's first law - The diffusion flux is proportional to the concentration gradient. This relationship is used
for steady-state diffusion situations.
Fick's first law equation - dM/dt = -DS (dC/dx)
M = quantity of material
D = Diffusion Coefficient
S = Area of a unit cross section
C = Drug Concentration
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller VasilyKichigin. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £10.75. You're not tied to anything after your purchase.
