Congruent composition

Figure 1. Solid-liquid phase diagrams for water — (n-C4H9)i+N00CR systems.The number attached to each curve stands for the same salt as the one listed in TABLE I. The congruent composition corresponds to the hydrate with hydration number 30.

Turner RC, Fuierer PA, Newnham RE, Shrout TR (1994) Materials for high temperature acoustic and vibration sensors A review. Applied Acoustics 41 299-324 Uda S, Komatsu R, Takayama K (1997) Congruent composition and solid solution range of Li2B407 crystal. J Cryst Growth 171 458-462... 

Figure 8.5 shows the phase diagram for the hthium niobate system. There is a wide range of lithium deficiency in lithium niobate. Since electro-optic applications of this material require large crystals having a very uniform composition, it is essential that the congruent composition be known very accurately in order to grow... 

Although arc melting the elements together will result in a pure carbide, composition homogeneity and reproducibility are difficult to obtain. This is due to a combination of rapid evaporation which moves the surface to the congruent composition (ZrCdensity difference between... 

The exact congruent composition has not been measured, but Lyon (1962) has shown that it does lie somewhat below TaCo.5. 

Because of the very high temperatures and the low pressures involved, no Knudsen studies have been undertaken. Even the Langmuir technique should only be used at the congruent composition. In view of this, the metal pressure over TaC + C is best calculated from thermochemical data. This was done using the following information A/f (298.15 ) = — 34.0 kcal/mole (Huber et al, 1963) a heat of vaporization for the metal of 186.5 kcal/mole (Edwards et al, 1951b) the thermal values in Table 37, the JANAF (1963) tables for and Stull and Sinke (1956) for TU(g). The resulting equation... 

A number of vapor pressure measurements have been made at several isolated compositions, i.e., over UC2 -I- C and over compositions near the congruent composition. Storms (1966a) has studied this system as a function of composition and has shown how the previous measurements relate to the general behavior. The following discussion will be based primarily on his work, starting at UC2 -I- C. As can be seen in Fig. 66, the collection study of Leitnaker and Witteman (1962) and the mass... 

Congruency for free evaporation occurs when these two quantities are equal. It is clear that above 2300 K the congruent composition lies near... 

The equations describe the partial pressures as a function of x in Th. N and, in particular, define the congruent composition when the vapors have the same composition as the solid, i.e., when pN/pjh = x/2(1-x). 

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