Phase Rule and Phase Diagramms

A portion of matter macroscopically uniform throughout chemical and physical composition.

F=C-P+2

P=number of phases (as in number of physical states)

C=number of components(Number of species at eq.-1)

F=C-P+1

P=number of phases (as in number of physical states)

C=number of components(Number of species at eq.-1)

for Δcp=0

The lever rule gives you the composition of a point in a phase diagramm.

The fraction of the liquid is Fl

By introducing a reference state, which introduces a joined enthalphy level, which the (melting) enthalphies can be related to.

Reference level delta G(a,a) or (L,L) mix

Very slow temperature change, so at all time equilibrium conditions are maintained in the system.

omega describes the heat of mixing

When the bonding energy between the two components is higher than the average of both pure phases bonding energy.

A compound that exist at a specific stoichiometry.

A compound that undergoes a phase transition at a certain temperature with no change in composition. (=doesnt pass through other phases than liquid)

A compound that undergoes phase transitions with changes in composition. (eg. Eutecticum)(goes through multiple phases)

Eutectic: Liquid to solid+solid

Eutectoid: Solid to solid + solid

Peritectic: melt + solid to solid

Peritectoid: solid +solid to solid