Phase Rule as applied to Binary Diagrams

Binary diagrams are drawn for atmospheric pressures, thus P is no longer a variable and the Phase Rule becomes:

P + F = C + 1 (Condensed Phase Rule)

With reference to the hypothetical binary diagram:

  1. At X
    Point X lies within the liquid field,
  2. At Y
    Point Y lies on the boundary curve between the fields of Liquid and A + Liq.
  3. At E
    Point E is the eutectic, the point where the liquidus and solidus intersect.