CHAP. 7: PHASE EQUILIBRIA [CONTENTS] 186
Obr.7.3:Triangular diagram.7.4.4 Phase diagrams of three-component (ternary) mixtures
Phase diagrams of three-component mixtures delimit the homogeneous and heterogeneous re-
gions at a different composition of the mixture at a constant pressure and temperature.
- For three-component systems,triangular diagrams[see Figure7.3] are used to illus-
trate phase equilibria. The vertices represent pure substances A, B, C. The sides of
the triangle represent the composition of two-component mixtures (point L indicates a
mixture of substances A + B in a 2/8 ratio). On the line segments parallel to any of
the sides there is a constant relative amount of that substance which is indicated by the
opposite vertex. - The region denoted (γ) in Figure 7.4 is a homogeneous region with two degrees of
freedom [see7.3]. - The regions (α) + (γ) and (β) + (γ) are heterogeneous. In these regions the system
splits into two phases: a pure substance and a mixture of the composition given by the
intersection of the conode (tie line) with the binodal line [see7.4.1].