Phase relationships, solid

Phase Relationship between the Solid and Liquid. A phase relationship may involve a number of crystalline forms from which materials can be separated. When a solid material is precipitated as a result of the solution becoming supersaturated, crystallization occurs. Crystallization may be achieved by... 

Oxysalt bonded cements are formed by acid-base reactions between a metal oxide in powdered solid form and aqueous solutions of metal chloride or sulphate. These reactions typically give rise to non-homo-geneous materials containing a number of phases, some of which are crystalline and have been well-characterized by the technique of X-ray diffraction. The structures of the components of these cements and the phase relationships which exist between them are complex. However, as will be described in the succeeding parts of this chapter, in many cases there is enough knowledge about these cements to enable their properties and limitations to be generally understood. 

Two situations are found in leaching. In the first, the solvent available is more than sufficient to solubilize all the solute, and, at equilibrium, all the solute is in solution. There are, then, two phases, the solid and the solution. The number of components is 3, and F = 3. The variables are temperature, pressure, and concentration of the solution. All are independently variable. In the second case, the solvent available is insufficient to solubilize all the solute, and the excess solute remains as a solid phase at equilibrium. Then the number of phases is 3, and F = 2. The variables are pressure, temperature and concentration of the saturated solution. If the pressure is fixed, the concentration depends on the temperature. This relationship is the ordinary solubility curve. 

The best-known examples of phase transition are the liquid-vapour transition (evaporation), the solid-liquid transition (melting) and the solid-vapour transition (sublimation). The relationships between the phases, expressed as a function of P, V and T consitute an equation of state that may be represented graphically in the form of a phase diagram. An idealized example, shown in figure 1, is based on the phase relationships of argon [126]. 

Another example of pressure-induced polymorphism is seen in the case of amiloride hydrochloride, where ball-milling Form-B causes a solid-state phase transformation into Form-A [43]. These workers deduced the phase relationship between two different pressure-induced polymorphs of the dihydrate, as well as the alternative route to one of those dihydrate forms that used the anhydrous form as the source material and effected the phase transformation through storage at high degrees of relative humidity storage. 

The purpose of laboratory testing to obtain contaminant-solid phase relationships is not only to obtain some insight into the accumulation and transmission characteristics of the solid materials with specific regard to the contaminants) of interest, but also to obtain physical input for transport modeling and chemodynamic purposes. It is also most important to conduct tests with the actual contaminant leachate or chemical species and also with the solid particle samples representative of the field matrix. 

The mass flow continuity relationship between the gas phase and solid is % = -p ,/pg (3.66)... 

Foster, P.K. Welch, A.J.F. (1956) Metal-oxide solid solutions. Part 1. Lattice constant and phase relationships in ferrous oxide (wiistite) and in solid solutions of ferrous oxide and manganous oxide. Trans. Faraday Soc. 52 1626-1635... 

Fig. 2. Schematic diagram of the relationship between the three limiting phases (double outline) and the six mesophases. The top five phases are solid. The bottom four phases show increasing mobility...

Considering all the facts discussed above, we are able to draw a diagram which shows the temperature-stable phase relationship of a binary system in which no solid solution forms. The completed equilibrium diagram or phase diagram may look like the following figure ... 

Figure 7.7 Phase relationships in the system Al2Si05-Mn2Si05 in pressure-temperature-composition space projected onto the P,Tplane (from Abs-Wurmbach et al., 1983 Langer, 1988). Note the large increase of the andalusite stability field (And) with increasing Mn3+ contents plotted as mole per cent theoretical MnjSiO end-member. Insets (a) and (b) show how the triple point at 500 °C and 3.8 kb for pure Al2Si05 increases with rising Mn3 content of andalusite. [Legend to Mn-Al solid-solutions (ss) Ky = kyanite Sill = sillimanite Bm=braunite Cor=corundum Vir=viridine Qu=quartz.]...

Figure 13 Experimental, estimated, and calculated phase relationships for chlorite stability. Thin solid lines experimentally determined reactions chi = fo -h prp -h spl -h H2O and chi = fo -h en -h sp -h H2O as summarized by Ulmer and Trommsdorff (1999). Short dashed line for chi + en = fo -h prp -h H2O as estimated by Ulmer and Trommsdorff (1999). Solid line for chi -h en = fo -h prp -h H2O from Pawley (2003). Long dashed lines calculated position of the same three reaction boundaries. Calculated with version 3.21 of THERMOCALC (source Holland and Powell, 1998).

Li, S., and Lin, Z., Phase relationship and ionic conductivity of Li,+xTi2 xInxP30,2 system. Solid State Ionics, 9, 835, 1983. 

Summarizing one can conclude that due to the empirical linear relationship between H and Tg in a rather broad range of Tg (-50 up to 250°C) which covers most commonly used polymers of the polyolefin-type and also polyesters and polyamides, it is possible to calculate the microhardness value of any amorphous polymer provided its Tg is known H =. 91Tg - 571). Furthermore, one can account for the contribution of soft liquid-like components and/or phases (characterized by a negligibly small microhardness) to the microhardness of the entire system. As we shall see in Chapter 5 the plastic deformation mechanism of such systems is different from that when all the components and/or phases are solid, i.e. have Tg above room temperature. 

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