Why to study phase diagram?
A phase equilibrium diagram is a graphical presentation of data that gives considerable information about
a single compound (such as SiO2, Al2O3. or MgO) or the nature of interactions between more than one
compound (1-3). The following list indicates some of the information that can be read directly from the
diagram:
1- Melting temperature of each pure compound
2- The interaction of two compounds (such as SiO2 plus Al2O3) to form a third compound (3Al2O3.2 SiO2,
mullite)
3- The presence and degree of solid solution
4- The effect of temperature on the degree of solid solution
5- The temperature at which a compound goes from one crystal structure to another (polymorphic phase
transformation)
6- The amount and composition of liquid and solid phases at a specific temperature and bulk composition
7- The presence at high temperature of immiscible liquids (liquids that are not soluble in each other).
What is the phase equilibrium diagrams ?
