Authors: S Wang C S Ni F Gesmundo Y Niu
Publish Date: 2009/12/18
Volume: 73, Issue: 3-4, Pages: 419-453
Abstract
An example of an isothermal thermodynamic phase diagram of a quaternary system composed of a binary alloy and two oxidants has been calculated under appropriate values of the stability of the corresponding compounds assuming that each metal forms only one compound with each oxidant Initially twodimensional sections of the complete threedimensional diagram made along planes corresponding to constant values of one of the variables involved were examined in detail The actual structure of this type of threedimensional diagram was then discussed by analyzing the shape and the boundaries of the various regions corresponding to the conditions of stability of each phase taken separately or in combination with other phasesOther important parameters involved in the construction of the complete 3D phase diagram are PCl2E1 and PO2E2 already defined earlier The first of them is calculated by setting x = xE1 in Eq 4 and solving for PCl2 Similarly PO2E2 is calculated by setting x = xE2 in Eq 2 and solving for PO2 With the present choice of the various equilibrium constants the combination of PO2E1 and PCl2E1 corresponds to a condition of equilibrium between an alloy with x = xE1 and a mixture of AO ACl2 and BO point η1 of the 3D phase diagram while the combination of PO2E2 and PCl2E2 corresponds to a condition of equilibrium between an alloy with x = xE2 and a mixture of ACl2 BO and BCl2 point η2 of the 3D phase diagram
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