Some topological relationships in multisystems of n+3 phases; [Part] 1, General theory; unary and binary systems

Abstract

An n-component (n+3) phase multisystem has n+3 invariant points and (n+3) (n+2) /2 univariant lines. In the absence of thermochemical data for all phases, chemographic relations and topologic considerations permit limited predictions about the nature of a p-T grid. An internally consistent grid of invariant points and univariant lines constitutes a net. Nets may be closed, partially open, or open. Closed nets may or may not be realistic, but can be used to generate congruent sequences of partially open and open nets. For each n-component multisystem of n+3 phases, there are C(n+3,n)=(n+3)(n+2)(n+1) /6 different divariant assemblages. There are as many possible closed nets as there are divariant fields. To transform these nets from one another, the concept of representation polyhedron is introduced, which is an artificial construction that summarizes the possible topological relations of all p-T nets