Binary Systems

(redirected from Starflight)
Also found in: Wikipedia.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Binary Systems

 

physicochemical systems consisting of two independent components. Of particular practical importance are the condensed binary systems, which do not contain gases or vapors. Phase diagrams and composition-property diagrams of such systems are represented in a plane by plotting the composition x (expressed in percentages by weight or in atom- or mole-percentages of one of the components) along the abscissa and the phase transformation temperatures T (of the beginning and end of crystallization, polymorphic transformations, and other transitions) or the numerical values of measurable properties of binary systems (density, hardness, electrical conductivity, and other properties) along the ordinate. Only the simplest isobaric (at 1 atm pressure) phase diagrams, involving only liquid phases L and solid phases S, are discussed in this article.

Figure 1

If mutual solubility of components A and B in the liquid and solid state is nonexistent, the phase diagram (Figure 1) is represented by two horizontal straight lines drawn through points TAand TB, which correspond to the melting points of A and B. Above TB the system consists of two liquid phases LA and LB; between TB and TA, of LA and crystals of B; and below TA , of a mixture of A and B crystals. If the mutual solubility of components A and B in the liquid state is not limited but mutual solubility is nonexistent in the solid state, then upon cooling, two solid phases, crystals of A and B, precipitate from a single liquid phase L (Figure 2). The liquidus curves (geometric loci of the temperatures of the beginning of crystallization) TAEE and TBEE intersect at the eutectic point E. The liquid, the composition of which corresponds to point E, solidifies at a constant temperature to give a mixture of fine crystals of A and B. From liquids having the compositions between A and E, crystals of A start to precipitate out on cooling, with the resulting increase in the content of B in the liquid. When its composition corresponds to point E, the process is terminated by the crystallization of the eutectic. In the same way, the solidification of liquids having compositions between B and E starts with the precipitation of the crystals of B and terminates by the crystallization of the eutectic. The straight line FG drawn through point E is called the solidus curve (geometric locus of the temperatures at the end of crystallization). Solidified binary systems of this type consist of two-phase mixtures of the crystals A + B. The isotherms of the properties of such mixtures approximate the straight line AR (Figure 2).

Figure 2

If the components A and B possess unlimited mutual solubility in the liquid as well as in the solid state, then on cooling, only a single crystalline phase precipitates out of a single liquid phase L, namely, the solid solution 5 (Figure 3). The phase diagram of this binary system may be without a maximum and a minimum (Figure 3, I), with a maximum (Figure 3, II), or with a minimum (Figure 3, III). The isotherms of the properties have the form of continuous curves with their convex side turned upward (Figure 3, IV) or downward (Figure 3, V).

Figure 3

If the mutual solubility of A and B is not limited in the liquid state but limited in the solid state, then any eutectic formed consists of a mixture of two solid solutions ɑ and β (Figure 4), in which case the limiting concentrations of the solid solutions correspond to points F and G at the eutectic temperature and to points M and N at room temperature. The composition-property isotherms (corresponding to temperature t) consists of three branches ∊Am1,n1,∊B and ∊Am2B the points m1, m2 and n1, n2 correspond to the limiting concentrations of the solid solutions ɑ and β temperature t.

Figure 4

When from the liquid L there crystallizes only a single chemical compound C, which melts without decomposition, and when solid solutions are nonexistent, the liquidus curve exhibits a rational maximum M or a singular point D, which corresponds to the composition of compound C, and two eutectic points E1 and E2, which correspond to the eutectics formed by C with A and B, respectively (Figure 5). The isotherms of properties have the form of two straight

Figure 5

lines intersecting at the ordinate value of compound C. More complex phase diagrams are discussed in the references listed below.

REFERENCES

Kurnakov, N. S. Izbr. trudy, vols. 1–3. Moscow, 1960–63.
Vol, A. E. Stroenie i svoistva dvoinykh metallicheskikh sistem, vols. 1–2. Moscow, 1959–62.
Hansen, M., and K. Anderko. Struktury dvoinykh splavov. Moscow, 1962. (Translated from English.)

S. A. POGODIN

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
They spent PS262,799 on private jets and helicopters with Starflight Aviation.
Kaan Air Australia, Sikorsky, a Lockheed Martin (NYSE: LMT) company, and StarFlight Australia, have signed an agreement worth up to AUD USD 63 million to bring 10 Sikorsky UH-60 Black Hawk helicopters into Australia, with options for an additional 10 aircraft, the company said.
This initiative sees Kaan Air Australia and StarFlight Australia partner to usher in a new era in Australian emergency services and disaster relief aviation.
Brisbane, Australia, May 07, 2016 --(PR.com)-- iFactory, an award-winning, full service digital agency in Brisbane, on Wednesday, April 20, 2016 was awarded the Outstanding Achievement in Website Development by the Interactive Media Awards[TM] for its work on the StarFlight Australia website.
StarFlight Australia provides turn key solutions throughout Australia and the Asia-Pacific for all operations requiring a rotary-wing platform.
The Long Journey Home is a Space Exploration RPG, combining the best of classic space adventures like Starflight and Star Control II.
"Everyone at Everton FC, ATP International, Starflight Aviation and Viking Air all worked extremely hard to try and resolve the problem, but events conspired against us."
2001) ("an agent acting ultra vires cannot bind the federal government"); see also Starflight Boats v.
Jon Roland is director of the Vanguard institute, a nonprofit research foundation, and president of the Starflight Corporation, a computer-consulting firm.
He said they used Starflight jets, a company which works with charity Cool Earth to offset emissions by protecting the rainforests.