The Basics of

1
The Basics of Binary Solid Solution Diagrams
2
3 General Types
Continuous solid solution -Labeling
Regions Partial solid solution -Labeling
Regions -Maximum Solubility Limits Complex
solid solution -Labeling Regions
-Polymorphic Phase Transitions -Invariant
Points - Stabilization Region The
Cubic Phase of Zirconia
3
Continuous Solid Solution

Liquid
Characteristics
Liquid ssAB
Single Phase Solid Solution -Varies from A to
B -Same Crystal Structure
ssAB
A
4
Partial Solid Solution
Characteristics

Liquid
Forms two phase region ssA ssB
Liq ssA
Liq ssB
Maximum Solubility -Extent that A is soluble in B
or B into A with only one phase present
ssB
ssA
ssA ssB
-mol1 maximum limit of B into A mol2 maximum
limit of A into B
mol1
mol2
Eutectic Point ssA ssB ? Liquid
5
Complex Solid Solution I
Characteristics
Liquid
Two Phase Regions -a-ssA b-ssB and b-ssA
b-ssB
Liq a-ssA
Liq a-ssB
a-ssB b-ssB
a-ssA b-ssA
a-ssB
a-ssA
Polymorphism of Components -Represents a change
in crystal structure within the end members
a-ssA b-ssB
b-ssA
b-ssB
b-ssA b-ssB
Two Phase Mixture of an End Member -Represents a
Mixture of polymorphs for an end member
A
B
6
Complex Solid Solution II
Characteristics (cont.)
Liquid
High Temperature Phase Stabilization
Region -region normally associated with higher
temperatures stable at a lower temperature
Liq a-ssA
Liq a-ssB
a-ssB
a-ssA
T1
a-ssB b-ssB
-original polymorph stable to T1 ?
a-ssA b-ssB
-stable to a lower temperature T2
T2
a-ssA b-ssA
Eutectic Point a-ssA b-ssB ? Liquid
b-ssA
b-ssB
b-ssA b-ssB
Eutectoid Point b-ssA b-ssB ? a-ssA
Peritectoid Point b-ssB ? a-ssB Liquid
A
B
7
Stablization of Cubic Zirconia
3000 2500 2000 1500 1000 500
0
Fully Stabilized Region -Cubic polymorph of ZrO2
becomes more stable with addition of CeO2
Cubic ss
Two Phase Region -Represents a region of
partial stability of the cubic phase
Tetragonal ss
Tetragonal ss Cubic ss
Monoclinic ss
ZrO2
CeO2
-18
Mol.
8
Summary
Topics or Ideas Covered -Labeling Phase
Regions -Eutectic, Peritectic, Eutectoid and
Peritectoid Points -Solubility Limits
-Polymorphic Phase Transitions -Phase
Stabilization Regions