= = =

If one has to deal with binary or ternary alloys in a single-oxidant system, the thermodynamic description of the condensed phase equilibria will be more complicated due to the presence of a second or third element as a variable. In such a situation, it will be more convenient to consider a stability diagram of the alloy-oxidant system at a constant temperature [3]. Such an isothermal phase diagram for the Fe-Cr-0 system at 1573 K is presented in Fig. 5.5. Here, mole fraction of Cr in binary Fe-Cr alloy has been plotted against logarithm of oxygen partial pressure. This figure depicts the stability regions of different solid solutions and mixed oxides with variation in Cr content and oxygen potential.