Phase Equilibrium Phase Rule Phase Diagram

C. Binary Peritectic SystemsAs T lowered Xliq follows pathto c: the eutecticAt 1543oC, enstatite forms: dNow f = 3 and F = 2 - 3 + 1 = 0invariantDiscontinuous reaction:liq = En + CrstcolinearStay at this T until liq isconsumedThen have En + Crstphi = 2F = 2 - 2 + 1 = 1univariantAt 1470oC get polymorphictransition Crst -> TridAnother invariantdiscontinuous rxnFigure 6-12. 6Isobaric T-X T X phase diagram of thesystem Fo-Silica at 0.1 MPa. After Bowen andAnderson (1914) and Grieg (1927). Amer. J. Sci.