Microstructures ternary phase diagram

Fig. 15.4 Schematic ternary-phase diagram of an oU-water-surfactant microemulsion system consisting of various associated microstructures. A, normal miceUes or O/W microemulsions B, reverse micelles or W/O microemulsions C, concentrated microemulsion domain D, liquid-crystal or gel phase. Shaded areas represent multiphase regions.

Figure 17 Illustration of the fact that microemulsion structure is not simply a function of composition. Shown are partial ternary phase diagrams with nonionic and cationic surfactants at room temperature. For a similar composition (approximately 15% surfactant, 65 wt% water, and 20 wt% oil), the microstructures of the two systems are widely different, as shown by the ratio of the water and oil diffusion coefficients, Dn /Dhc where he here denotes oil (hydrocarbon). The nonionic system has an oil-in-water structure (D //)hc = 200), while the cationic system has a water-in-oil structure (D,/Z)h. = 1/200).

Finally, from all obtained results the ranges of the discussed structures could be drawn in the ternary phase diagram (Figure 10.9). It is necessary to stress that the crossing between two microstructures could not be regarded as a sharp border but more or less as a transitional region, which is obviously detected differently by various techniques. 

Fig. 1.44. Simplified ternary phase diagram of alkali aluminosilicate glass compositions that were tested to obtain glasses suitable for microstructuring with thermal expansion coefficients a that match those of Si, GaAs, Ni or Cu [128], Point A symbolises (not quantitatively) the composition of FS 21-glass. Prom A to R1 and R2 a decreases, from A to R4, R5, R6 and R7 a increases, from A to R3 a does not change remarkably...

The effect of adding a surfactant, (NaDDS), was also investigated. One such case only is shown in Fig. 6 where BE is replaced by a 5 1 mixture of BE-NaDDS. The main effect of NaDDS is to increase the miscibility range of the oil in water. Various ratios of BE-NaDDS were used and, as a first approximation, the change in the phase diagram is directly proportional to the concentration of NaDDS. The addition of a surfactant probably stabilizes the microstructures which were already present in the ternary system BE-DEC-H O and decreases the quantity of BE needed to solubilize DEC. Therefore the presence of a surfactant is useful but not essential to the stability of microemulsions. 

From an economic viewpoint, the classical determination of alloy phase diagrams is a laborious process, involving alloy preparation and heat treatment, compositional, structural, and microstructural analysis (and, even then, not yielding reliable phase boundary information at low temperatures due to kinetic limitations). While this investment is justified for alloys of major technical importance, the need for better economics has driven an effort to use alternative methods of phase discovery such as multiple source, gradient vapor deposition or sputter deposition followed by automated analysis alternatively, multicomponent diffusion couples are used to map binary or ternary alloy systems structurally and by properties (see Section 6). These techniques have been known for decades, but they have been reintroduced more recently as high-efficiency methodologies to create compositional libraries by a combinatorial approach, inspired perhaps by the recent, general introduction of combinatorial methods in chemistry. 

Figure 9 A schematic phase diagram of a cut at constant surfactant concentration through the temperature-composition phase prism of a ternary system with nonionic surfactant showing the characteristic X-like extension of the isotropic liquid phase L. (O is the volume fraction of oil in the solvent mixture.) Schematic drawings of the various microstructures are also shown. (Courtesy of Ulf Olsson.)...

Phase diagrams of several ternary surfactant-solute-solvent systems predicted using lattice MC simulations and quasichemical theory have been compared and shown to lead to qualitatively similar results. The two diagrams for h t with C solvent are in excellent agreement [25], as this surfactant does not aggregate to form any microstructures. However, similar comparisons for A2/4 [25] and A4/4 [25,36] are not as good, because quasichemical theory cannot account for the formation of micelles. 

Imal] Imai, Y, Masumoto, T., Maeda, K., Microstructures and Nitrides of Fe-Cr-N Ternary System , Set Repts. Res. Inst Tohoku Univ., 19A, 21-34 (1967), translated fsova. Nippon Kin-zoku Gakkai Shi 29(9), 860-866 (1965) (Experimental, Phase Relations, Morphology, 13) [1967Ima2] Imai, Y, Masumoto, T., Maeda, K., Stmctural Diagrams and Phase Reactions of Fe-Cr-N Ternary System , Set Repts. Res. Inst Tohoku Univ, 19A, 35-49 (1967) (Phase Diagram, Phase Relations, Experimental, 3)... 

Hor] Hombogen, E., Schmidt, I., Microstructures of Glassy and Metastable Crystalline Phases Formed from Fe-C- Ternary Alloys , Rapidly Solidified Amorphous Crystalline Alloys, 199-204 (1982) (Morphology, Phase Diagram, Phase Relations, Thermodyn., Experimental, 7)... 

However, intriguingly all the aforementioned studies, except the one reported by Atkin and Warr [29], were performed at room temperature so that detailed knowledge about the phase diagram and the structure were not explored. To fill this gap, we carried out a thorough study of water-[bmim][PF ]-TX-100 microemulsions as a function of temperature, T, and surfactant mass fraction at different IL mass fractions. The results are described later where we illustrate the formation of 1, 2, and 3 phases and present the fishtail phase diagram as well as the location of the point of optimal efficiency, called X point. The coordinates of the X point are y and r, the fraction of surfactant and temperature, respectively. The reported construction is carried out by inspection of the samples with optical and polarizing microscopy, and the microstructure is studied by SANS. For the sake of completeness, the experimental evidences are compared with data on the phase behavior of water-[bmim] [PFJ ternary systems with two CiEj surfactants. 

Since C and Si are the alloying elements which dominate the solidification behavior and the resulting microstructures of cast irons, their phase equilibria need to be taken into account. Figure 3.1-120 shows a section through the metastable ternary Fe—C—Si diagram at 2wt%Si which approximates the Si content of many cast irons. Compared to the binary Fe—C system, the addition of Si decreases the stability of FesC and increases the stability of ferrite, as indicated by the expansion of the a-phase field. With increasing Si concentration, the C concentrations of the eutectic and the eutectoid equilibria decrease while their temperatures increase. 

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