Non-equilibrium phases

Low-temperature solid-state synthesis is preferred in most cases, where appropriate, for obvious reasons such as energy and cost economy and process safety or for critical concerns regarding the accessibility of compounds that are stable only at low temperatures or non-equilibrium phases, i.e., compounds thermodynamically unstable with respect to the obtained phase (e.g., a ternary instead of binary phase). The use of low-temperature eutectics as solvents for the reactants, hydrothermal growth... 

Rasmussen D., Luyet B. Complementary study of some non equilibrium phase transitions in frozen solutions of glycerol, ethylene, glycol, glucose and sucrose. Biodynamica. Vol 10, No 220, Dec. 1969... 

Chvoj, Z., Sestak, J. andTriska, A. (ed.) (1991) Kinetic Phase Diagrams. Non Equilibrium Phase Transitions (Elsevier Science, Amsterdam). 

Y. Chen, J. S. Williams, High-Energy Ball-Milling-Induced Non-Equilibrium Phase Transformations, Mater. Sci. 

Figure 73. Non-equilibrium phase transition (insulator-conductor transition) in Au-doped silicon as a result of voltage variation in the nonlinear range.271 272...

Solomatov V. S. and Stevenson D. J. (1994) Can sharp seismic discontinuity be caused by non-equilibrium phase transformation Earth Planet. Sci. Lett. 125, 267-279. 

F. Schlogl, Chemical reaction models for non-equilibrium phase transition. Z. Physik. 253, 147-161 (1972)... 

At temperatures of about 1300 °C and higher, only mullite and the melt are equilibrium phases. In fact, however, porcelain usually contains the non-equilibrium phase Si02 in the form of quartz. This is due to the very high melt viscosity and the low diffusion coefficient for S1O2 dissolution of quartz particles, which is controlled by diffusion, is therefore very slow, even though, according to the equilibria, all the Si02 should dissolve. 

Quartz is also seen to be a non-equilibrium phase in another respect. At the firing temperature of porcelain it should transform to a more stable modification, which is cristobalite or tridymite under these conditions. However, the transformation is similarly very slow and cannot be completed during the firing cycle. Only in cases when the melt is saturated with quartz and its dissolution stops (or when the rate of dissolution is particularly low), distinct formation of a cristobalite layer occurs on the surface of quartz grains. 

Langmuir and Whittemore (33) point out that oxyhydroxide precipitates formed in the laboratory at low temperatures are usually mixtures of colloidal-sized amorphous material and crystalline phases, with individual crystal dimensions ranging from 50 to 2000 A. In such mixtures, the most soluble phase, usually amorphous, determines the pQ, the value calculated for pKj, for non-equilibrium phases. Although the crystalline phases grow at the expense of the amorphous material and each other, colloidal-sized crystalline phases can persist indefinitely in dilute waters low in dissolved Fe(II) or Fe(III). 

Gliding Arc Stability Analysis and Transitional and Non-Equilibrium Phases of the Discharge... 

For the calculations, different EoS have been used the lattice fluid (LF) model developed by Sanchez and Lacombet , as well as two recently developed equations of state - the statistical-associating-fluid theory (SAFT)f l and the perturbed-hard-spheres-chain (PHSC) theoryt ° . Such models have been considered due to their solid physical background and to their ability to represent the equilibrium properties of pure substances and fluid mixfures. As will be shown, fhey are also able to describe, if not to predict completely, the solubility isotherms of gases and vapors in polymeric phases, by using their original equilibrium version for rubbery mixtures, and their respective extensions to non-equilibrium phases (NELF, NE-SAFT, NE-PHSC) for glassy polymers. 

Non-equilibrium phase diagrams. All were determined using LEED with the exception of Na/Cu(100)... 

Figure 6, Non equilibrium phase diagram of the pH responsive gels coupled to the CT reaction, o swollen state x trigger waves A volume oscillations collapsed state A transition of the CSTR into the T state. The parameter d is the inner diameter of the mold.

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