Stable phase diagram

Pandat software package and applications (Chen et al. 1993). Pandat is a software package for multi-component phase diagram calculations. Given a set of thermodynamic parameters for all phases in a system and a set of user constraints, Pandat automatically calculates the stable phase diagram without... 

It has long been appreciated that phase equilibria of complex salt systems measured under laboratory conditions may have limited industrial use. It was first noted by van t Hoff (1903), when crystallizing salts from seawater, that certain thermodynamically expected stable salts never crystallized. Even exceedingly slow crystallization together with deliberate seeding by the salts themselves did not help. Yet the salts in question all occupied clearly defined zones on the appropriate stable phase diagrams. 

Fig. 6. C-Cu-Fe. (7Fe) projection with lines of double saturation in the C-Cu-Fe stable phase diagram...

Sal] Saltykov, S.A., Stable Phase Diagram Iron-Carbon Alloys with Silicon (in Russian), Litey-noe Delo, 10-11, 15-16 (1939) (Review, Phase Diagram, Phase Relations, 4)... 

Che] Chen, S-L., Daniel, S., Zhang, F., Chang, Y.A., Oates, W.A., Schmid-Fetzer, R., On the Calculation of Multicomponent Stable Phase Diagrams , J. Phase Equilib., 22(4), 373-378 (2001) (Phase Relations, Calculation, Theory, 26)... 

A stable phase diagram is a constitution diagram where all existing phases at any point (x, T) have the lowest G x, T). The kinetic characteristics of this diagram are that x and T change at an infinitely slow rate, or the time of phase transformation is subject to the condition of r — . 

The research method for the stable phase equilibria of salt-water system is isothermal dissolution method. It is worthy of pointing out that the status of the stable phase equilibrium of salt-water system is the in a sealed condition under stirring sufficiently, and the speed of dissolution and crystallization of equilibrium solid phase is completely equal with the marker of no change for the liquid phase composition. As to the thermodynamic stable equilibrium studies aiming at sea water system (Na - K - Mg - Cl - SO4 - H2O), J.H. Vant hollf (1912) was in the earliest to report the stable phase diagram at 293.15 K with isothermal dissolution method. 

Fig. 5. Stable phase diagram of the quaternary system (NaCl - KCl - Na2B4C>7 - K2B4O7 - H2O) at 298.15 K. (a), dry-salt phase diagram (b), water-phase diagram.

Gor] Gorev, K.V., Gurinovich, V.I., The Stable Phase Diagram of Fe-C-Al Alloys in die Iron-Rich Region (in Russian), in Stable and Metastable Phase Equilibria in Metallic Systems , Nauka, Moscow, 119-124 (1985) (Phase Relations, Phase Diagram, Experimental,, 6)... 

Figure A2.5.1. Schematic phase diagram (pressure p versus temperature 7) for a typical one-component substance. The full lines mark the transitions from one phase to another (g, gas liquid s, solid). The liquid-gas line (the vapour pressure curve) ends at a critical point (c). The dotted line is a constant pressure line. The dashed lines represent metastable extensions of the stable phases.

Figure A3.3.2 A schematic phase diagram for a typical binary mixture showmg stable, unstable and metastable regions according to a van der Waals mean field description. The coexistence curve (outer curve) and the spinodal curve (iimer curve) meet at the (upper) critical pomt. A critical quench corresponds to a sudden decrease in temperature along a constant order parameter (concentration) path passing through the critical point. Other constant order parameter paths ending within tire coexistence curve are called off-critical quenches.

These data underline the phase diagrams for tire pairs of elements which are in contact in microchips, where Pd-Si and Pt-Si form stable inter-metallic compounds, and An-Si forms a eutectic system. 

Take the silica-alumina system as an example. It is convenient to treat the components as the two pure oxides SiOj and AI2O3 (instead of the three elements Si, A1 and O). Then the phase diagram is particularly simple, as shown in Fig. 16.6. There is a compound, mullite, with the composition (Si02)2 (Al203)3, which is slightly more stable than the simple solid solution, so the alloys break up into mixtures of mullite and alumina, or mullite and silica. The phase diagram has two eutectics, but is otherwise straightforward. 

Figure 9.2. Constitutional supercooling in alloy solidification (a) phase diagram (b) solute-enriched layer ahead of the solid/liquid interface (c) condition for a stable interface (d) condition...

The lowest value of Qeff corresponds to different structures for different along the bifurcation line. The sequence of phases is always the same for various strengths of surfactant (with 7 > 27/4) and for increasing p it is L—>G—>D—>P—>C. For 7 = 50 (strong surfactant, like C10E5) the portion of the phase diagram corresponding to the stable cubic phases is shown in Fig. 14(b). For surfactants weaker than in the case shown in Fig. 14 the cubic phases occur for a lower surfactant volume fraction for example, for 7=16 cubic phases appear for p 0.45. 

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