Roozeboom phase types

Figure 7.4 Gibbs free energy curves and phase stability relations for two binary mixtures with complete miscibility of components (types I, II, and III of Roozeboom, 1899).

Figure 7,6 Phase stability relations in pseudobinary system NaAlSi30g-KAlSi30g, after Waldbaum and Thompson (1969). (A) High-T relations loop of metastable persistency of sanidine like a Roozeboom type III. (B) Expanded T-range with decreasing T, a solvus held opens downward.

Figure 7.12 shows the liquidus surface of a ternary system with complete miscibility at solid state between components 1-2 and complete immiscibility at solid state between components 1-3 and 2-3. Note also that components 1 and 2 form a lens-shaped two-phase field, indicating ideality in the various aggregation states (Roozeboom type I). 

Whenever one looks into modern textbooks of thermodynamics or physical chemistry in order to get information on the phase behaviour of fluid mixtures one might think that most of the inspiring work of van der Waals, Kohnstamm, Roozeboom, Timmermans, Kuenen, and the other pioneers in this field had been completely forgotten and that practically nothing had happened since that time. Only the most simple types of gas-liquid and liquid-liquid equilibria are discussed very rarely are the so-called gas-gas equilibria that were discovered some thirty years ago additionally treated. 

An alternative method of representing ternary solid solution systems graphically is to plot the concentration of one component in the solid phase against its composition in the liquid phase. On this basis, Roozeboom in 1891 showed that five different types of system were possible. Only two of these will be mentioned here, however, but a good account of all five types of behaviour is given by Blasdale (1927). 

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