Reactive Phase Diagrams

The effects of the intramicellar confinement of polar and amphiphilic species in nanoscopic domains dispersed in an apolar solvent on their physicochemical properties (electronic structure, density, dielectric constant, phase diagram, reactivity, etc.) have received considerable attention [51,52]. hi particular, the properties of water confined in reversed micelles have been widely investigated, since it simulates water hydrating enzymes or encapsulated in biological environments [13,23,53-59]. 

Reactions Between Refractories. In Table 17, the compatibilities of various refractories are given over a range of temperatures. Dissimilar refractories can react vigorously with each other at high temperatures. Phase diagrams are an excellent source of information concerning the reactivity between refractories. 

FIG. 4 Qualitative phase diagram close to a first-order irreversible phase transition. The solid line shows the dependence of the coverage of A species ( a) on the partial pressure (Ta). Just at the critical point F2a one has a discontinuity in (dashed line) which indicates coexistence between a reactive state with no large A clusters and an A rich phase (hkely a large A cluster). The dotted fine shows a metastability loop where Fas and F s are the upper and lower spinodal points, respectively. Between F2A and Fas the reactive state is unstable and is displaced by the A rich phase. In contrast, between F s and F2A the reactive state displaces the A rich phase. 

Fig. 10 shows the phase diagram of the ZGB model with global reconstructions. For the standard ZGB model a narrow reactive regime within the range Fi. < < F2A is observed, as discussed above in the description of... 

If the desired catalyst is to consist of two or more catalytic metals after leaching or if a promoter metal is to be included, the precursor alloy becomes even more complicated with respect to phase diagrams. The approximate proportion of reactive metal (aluminum) in these ternary and higher alloys usually remains the same as for the binary metal system for the best results, although the different catalytic activities, leaching behavior and strengths of the various intermetallic phases need to be considered for each alloy system. 

Phase diagrams of alkali metal alloys. The pattern of the intermetallic reactivity of these metals is shown in Fig. 5.6, where the compound formation capability with the different elements is summarized. 

Phase diagrams of the 11th group metals. The intermetallic reactivity patterns of Cu, Ag and Au are similar, with no compound formation in the middle of the Periodic Table (groups 5-9 for Cu and Ag, about 6-9 for Au). 

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