Proportions of phases

For an alloy containing 30% B describe the changes that occur as it is cooled from 1600°C to 0°C. Give the proportions of phases present immediately above and immediately below each temperature at which a reaction occurs. 

As an example, result from a test sample is presented in Figure 6. A nano-crystalline thin film sample was prepared by vacuum evaporation of 100 A NiO and 100 A Al. The thicknesses were controlled by quartz thickness measurement. The proportion of phases was also checked by EDS. TEM BF and DF pictures show that the grain size of NiO is around 4 nm. 

Nanocrystalline alloys Rapid solidification (amorphization) and crystallization Exchange interaction Composition and proportion of phases... 

Figure 5. Schematic diagram showing the effect of changing the volume fraction of second phase on the apparent viscosity at a fixed rate of shear of a two-phase emulsion. The different dotted lines refer to different viscosities of the pure phases A and B, The solid line suggests the viscosity that may be displayed by a system in which both the viscosities of the pure phases and the relative proportions of phases are changing continuously, as in a pyrolysis run.

If the aim is to describe precisely the degree of incorporation of one phase into another (for example, the volume percentage or aggregates of zeolite grains in an alumina matrix), it is preferable to work on a polished section. Since a fracture path is not random (it depends on the hardness, distribution and connectivity of the phases), the proportion of phases on a fracture is not always representative of the actual proportions in the material (the dispersed phase can be bypassed). The study of the polished section can be used to obtain a representative description of the distribution of the phases in the cross section. 

As Table I also shows, the number nm n - pf of minima lying outside the primary MSB (Section II.B) is a small fraction of the total. For p = 4, the energy landscape is a perfect funnel, and although the few minima lying outside this MSB at higher values of p technically constitute secondary funnels, they represent a very small proportion of phase space. The funnellike nature of the landscapes for p = 4 and 6 is immediately visible from the... 

The relative concentrations of phases A and B can be determined by the familiar lever rule used in all phase diagrams. The fractional concentration, or relative proportion, of phase A is given by the distance between the bulk composition Y and the composition of B, divided by the distance from A to B. The fractional concentration of phase B is given by the distance between the bulk composition and the composition of A, divided by the bulk composition. Expressed in a different form ... 

Along with the progress of gelation and fusion processes, the relative proportion of phases (1) and (3) diminishes wliile phase (2) increases. When the material is completely gelled and fused, only phase (2) exists, and so just one single glass transition temperature can be observed. 

Strictly speaking, this swelling can also be observed when mixit two low-molecular liquids. The fact that there is a partition equilibrium means that phase A contains a certain proportion of phase B and thus, phase A must be swollen. If the volume of A before and after mixing was determined (not a usual procedure), it should be possible to measure this partition equilibrium. 

The relationship between the chemical structures of compounds and their chromatographic behavior has been considered by many scientists and was first reported by Martin in partition chromatography, where the partition coefficient is regarded as an additive value. The hypothesis of the additivity has raised worldwide discussion hence, additivity rales were formulated. Deviation from the / M additivity results from the complex character of the chromatographic process (change of a composition and volume proportions of phases), constitutional effects in molecules, because of reciprocal interactions of functional groups (internal hydrogen-bond effects, steric and electromeric effects) as well as ionization of substances. 

The mean-field model also allows the study of mixed-state transitions, by considering a proportion of phases (high and low magnetization) within the metastabUity region. Magnetization curves are shown in the inset of Fig. 19, for A3 = 2 Oe (emu/g) , corresponding to a critical field lOT. The mixed-phase temperature region is from 328 to... 

XRD provides identification of phases present, proportions of phases and crystalline orientation, whereas NMR provides total crystallinity. Complementing XRD and NMR measurements is necessary to develop reliable quantitative models of crystallization under shear. The possibility of conducting the Rheo-NMR work in a benchtop machine opens an affordable possibility to perform these types of studies in many laboratories. 

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