Lecture 05

Today’s objectives-Diffusion and Phase Diagrams ,[object Object],[object Object],[object Object],[object Object],[object Object]

Diffusion ,[object Object],[object Object],[object Object]

Diffusion-why it matters ,[object Object],[object Object],[object Object],[object Object],[object Object],bulk Compressive at surface - + Mg i 2+ Li Mg - O i 2- Al Mg + V O 2+ V Mg 2-

Transistors ,[object Object],[object Object],http://developer.intel.com/technology/itj/q31998/articles/art_3.htm

Si,Ge multilayers—dopant mediated diffusion Ranade et. al., Electrochemical and Solid State Letters, 5 (2), 2002, p. G5. ,[object Object],[object Object]

Binary Phase Diagram with Complete SS (Cu-Ni)

Phase diagrams: refractory: Al 2 O 3 -Cr 2 O 3 ,[object Object],[object Object],[object Object],[object Object],[object Object],Pure Cr 2 O 3 Pure Al 2 O 3 If we know temp and composition with given starting materials, then we know the phase or phases at equilibrium .

Phase diagram-interpretation: MgO-Al 2 O 3 ,[object Object],73% spinel (MgAl 2 O 4 (ss)) and 27% MgO(ss). At 72 wt% Al 2 O 3 , there is a distinct compound (spinel) up to 1400 ° C and a nonstoichiometric solid solution or liquid above that T. At 50:50 wt% and 1900 ° C, what is the equilibrium concentration? Note there is a difference between mol% and wt% . 1) Identify T and phases 10% 65% 50%

Diffusion and phase diagrams ,[object Object],[object Object],[object Object],[object Object],[object Object],Fe 3 C

[object Object],[object Object],Si and O

Si and Cu ,[object Object],[object Object],[object Object],Si Cu Cu Cu Si Cu Cu Cu η ” Si Cu Cu Cu L and Si Si Cu η η ’ η ” Cu η η ’ η ” Cu η η ’ η ”

SiO 2 -Al 2 O 3 Adding alumina leads to mullite (ss). Mullite is 3Al 2 O 3 .2SiO 2 (60 mol % Al2O3 and is an important constituent in porcelain. Clays with <60 % Al 2 O 3 convert to mullite, or porcelainite ,

Temperature/Pressure phase diagram for Silica ,[object Object],[object Object]

ZrO 2 and CaZrO 2 ,[object Object],[object Object],[object Object],[object Object],[object Object]

Yttria Stabilized Zirconia ,[object Object],[object Object],[object Object]

Si and P (common dopant) ,[object Object],[object Object]

Melting point for very small concentrations of N in Si ,[object Object]

Phase change materials ,[object Object],[object Object],[object Object],[object Object],http://www.ovonyx.com/tech_html.html

Phase change materials ,[object Object],[object Object],[object Object],[object Object]

How to read a ternary phase diagram ,[object Object],[object Object],[object Object],Pure A i Pure C Weight % C Pure B Weight % B 0% 50% 75% 25% 0% 50% 75% 25% ,[object Object],[object Object],[object Object],Weight % A ,[object Object],[object Object],[object Object]

Ternary diagrams II ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Pure A i iii ii iv Pure C Weight % C Pure B Weight % B 0% 50% 75% 25% 0% 50% 75% 25% Weight % A v

Ternary diagrams III ,[object Object],[object Object],Pure A Pure C Weight % C Pure B Weight % B 0% 50% 75% 25% 0% 50% 75% Weight % A Pure C Pure B 0% A throughout Liquid 50% A throughout Pure C Pure B Liquid

Hydroxyapatite Ca 5 (PO 4 ) 3 (OH) ,[object Object],[object Object],Individual phases are also shown: Hydroxyapatite (HA), Monetite (M), Brushite (B) also shown. Calcia Phosphorous pentoxide

SUMMARY ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Reading for next class Next class: Glass and Clay products and processing Chapter sections 13.1-3, 13.8-9

Lecture 05

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Lecture 05