Prof. Stephen A. Nelson Ternary Phase Diagrams Crystallization
in Ternary Systems I. Equilibrium Crystallization Where all 2
Component Systems are Binary Eutectic Systems. |Figure 1 shows a
three dimensional representation of the three component
(ternary) system ABC. Note that composition is measured along
the sides of the basal triangle and temperature (or pressure) is
measured vertically. The top of the figure shows a surface with
contour's representing lines of constant temperature. These
contours are called isotherms. Note that the eutectic points in
each of the binary systems project into the ternary systems as
curves. These curves are called boundary curves, and any
composition on one of these curves will crystallize the two
phases on either side of the curve.| |Figure 2 shows the same
figure in two dimensions as seen from above. The boundary curves
and isotherms are also shown projected onto the basal triangle.
Note how the temperature decreases toward the center of the
diagram In Figure 3 we trace the