Chapter4_lecture

Chapter4_lecture - Chapter 4 Point Defects and Diffusion...

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
Introduction Point Defects Impurities Solid State Diffusion Chapter 4 Point Defects and Diffusion
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Introduction- Defects and Impurities Considering that the number of atoms in a cm 3 of crystalline material ( 8.5X10 22 ) it should not be surprising that some atoms will be missing from the lattice. The presence of the missing atoms aid in the atomic transport process in the solid state. Trace elements, impurities, can have a dramatic effect on the properties of a material.
Background image of page 2
Point Defects Vacancies and interstitials in a crystalline material
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Point Defects
Background image of page 4
Point Defects Vacant lattice site G = H - T S
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The Effect of Temperature on the Vacancy Concentration of Nickel -40 -35 -30 -25 -20 -15 -10 -5 0 0 0.001 0.002 0.003 0.004 1/T, 1/K ln(Vc) Room Temperature, 25 C Melting Temperature, 1083 C fr Q slope R = - ( 29 exp exp 1 ln fr v t fr v fr v Q N N RT Q C RT Q C R T   = -       = -       = -    
Background image of page 6
1E-15 1E-13 1E-11 1E-09 1E-07 1E-05 0.001 0.1 0 0.001 0.002 0.003 0.004 1/T Cv The Effect of Temperature on the Vacancy Concentration of Nickel T RT T m
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Point Defects Schottky defect 2V Cl and 1V Mg - 2+ Schottky defect 1V Cl and 1V Na - + Cation-anion pair Schottky defect , , exp 2 fvc v cat v an Q C C RT - = =
Background image of page 8
Point Defects The defect involves a cation The defect involves an anion The cation defect is more common because of the size of the cation compared to the size of the anion. Vacancy-Interstitial Pair Frenkel defect in AgCl exp 2 fvi v i Q C C RT - = =
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Impurities Interstitial Solid Solution Solvent Solute
Background image of page 10
Impurities Substitutional Solid Solution Solvent Solute
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 40

Chapter4_lecture - Chapter 4 Point Defects and Diffusion...

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online