Phase binary mechanical mixture

Figure 7,1 Relationships between chemical potential and composition in binary phases with different miscibility behavior a = complete miscibility ]8 = partial miscibility y = lack of miscibility or mechanical mixture. ...

Figure 7.2 G-X and T-X plots for a binary system with a molten phase with complete miscibility of components at all T conditions and a solid phase in which components are totally immiscible at all proportions (mechanical mixture, 7 = 7 + V )-...

Figure 7.3 depicts phase stability relations in the pseudobinary system CaMgSi206-CaAl2Si208 (diopside-anorthite). The original study of Bowen (1915) described crystallization behavior identical to the previously discussed case a mechanical mixture (Di-An) in equilibrium with a completely miscible melt. A later investigation (Osborn, 1942) showed that the system is not strictly binary... 

No binary phases could be detected by X-ray analysis, and the fact that the best catalyst resulted from a mechanical mixture of rutile and Mo03... 

In binary alloy systems, a eutectoid alloy is a mechanical mixture of two phases which form simultaneously from a solid solution when it cools through Ihe eutectoid temperature. Alloys leaner or richer in one of the metals undergo transformation from the solid solution phase over a range of temperatures beginning above and ending al the eutectoid temperature. The structure of such alloys will consist of primary particles of one of the stable phases in addition to ihe eutectoid. lor example ferrite and pearlite in low-carbon steel. See also Iron Metals, Alloys, and Steels. 

With respect to late stages of phase separation in the bulk, rather convincing and broad evidence for scaling in the late stages, Eq. 20, has been obtained [2, 6,7,17]. For off-critical quenches in binary fluid mixtures, one normally finds a growth law (t) oc in the last stages, compatible with the droplet diffusion-coalescence mechanism [2, 9], For critical quenches, a slow... 

Such phase-separated polymer mixtures serve as an excellent model system where molecular-level interactions between components are small. The system studied here is a film made of an immiscible binary mixture of atactic polystyrene and low-density polyethylene [2], The dynamic IR measurement was carried out as before by mechanically stimulating the system at room temperature with a 23-Hz dynamic tensile strain with an amplitude of 0.r/>. The time-dependent fluctuations of IR absorbance induced by the strain were recorded at a spectral resolution of 4 cm. ... 

Figure 1(A) shows a phase diagram of a typical eutectic mixture system, which has a minimum melting temperature, i.e. a eutectic point. The eutectic pwint of a binary condensed mixture is defined as the temperature at which a solid mixture phase is in equilibrium with the liquid phase and a eutectic is generally considered to be a simple mechanical mixture of the solid and liquid (Rastogi and Bassi, 1964).

How fast is a phase transition If you cool a binary liquid mixture, what limits the rate of phase separation How fast do crystals form in a liquid How fast do micelles form in a surfactant solution For such processes, there are two different mechanisms. First, if you supercool a single-phase solution into the always-unstable part of the two-phase region (see Figure 25.9), the process is spontaneous. It is called spinodal decomposition. But a different mechanism applies if you supercool a single-phase solution into the metastable region... 

CH2 Chalykh, A.E., Sapozhnikova, I.N., and Medvedeva, L.I., Mechanism of formation of a phase stmcture of binary polymeric mixtures from polymer-polymer-solvent ternary systems (Russ.), Dokl. Akad. NaukSSSR, Fiz. Khim., 288, 939, 1986. 

As we have seen, binary polymer mixtures can vary in structure with temperature, forming either a homogeneous phase or in a miscibility gap a two-phase structure. We now have to discuss the processes which are effective during a change, i.e. the mechanisms of phase transition. 

Two mechanisms of the phase separation of binary mixtures of any substances (including polymeric) are known nucleation and spinodal decomposition. Our task does not involve detailed examination of the phase separation mechanisms. When interphase phenomena in pol5Tneric composites are considered, however, these mechanisms are essential from two standpoints they govern the microphase structure of a polymer-pol5aner composite and the filler influence on the microphase structure and they also determine the mechanism of the formation of the interphase. 

In the macroscopic heat-transfer term of equation 9, the first group in brackets represents the usual Dittus-Boelter equation for heat-transfer coefficients. The second bracket is the ratio of frictional pressure drop per unit length for two-phase flow to that for Hquid phase alone. The Prandd-number function is an empirical correction term. The final bracket is the ratio of the binary macroscopic heat-transfer coefficient to the heat-transfer coefficient that would be calculated for a pure fluid with properties identical to those of the fluid mixture. This term is built on the postulate that mass transfer does not affect the boiling mechanism itself but does affect the driving force. 

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