Peritectic


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Related to Peritectic: Peritectoid, peritectic point

peritectic

[¦per·ə¦tek·tik]
(physical chemistry)
An isothermal reversible reaction in which a liquid phase reacts with a solid phase during cooling to produce a second solid phase.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Peritectic

 

a liquid that is in equilibrium at constant pressure with crystal phases of chemical compounds or solid solutions; the number of crystal phases equals the number of components in the system and reduces to unity upon a change in temperature. The number of crystal phases serves to distinguish a peritectic from a eutectic, which is a liquid in equilibrium with crystal phases whose number does not change upon a decrease in temperature (a eutectic is completely converted into a solution or melt upon an increase in temperature). For example, in a binary system that consists of water and sodium sulfate (Na2SO4 at 32.4° C, the solution (which contains 33.2 percent Na2SO4 by weight) is in equilibrium with two crystal phases: anhydrous Na2SO4 and the decahydrate Na2SO4• 10H2O. Only Na2SO4• 10H2O crystals are in equilibrium with the solution at temperatures below 32.4°C, whereas only Na2SO4 crystals are in equilibrium with the solution above this temperature.

The term “peritectic,” or “peritectic point,” is often used to designate the point of intersection between the temperature lines on a phase diagram at the onset of crystallization of two solid phases in equilibrium with a peritectic liquid.

REFERENCES

See references under BINARY SYSTEMS.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
[11], which presents cell interdendritic microstructures that Hunziker and Kurz [5] defined as peritectic structures.
The extrapolation of isotherms in the [H.sub.2]O-NaCl-LiCl diagram from the more known [H.sub.2]O-NaCl-Ca[Cl.sub.2] diagram can be justified by the fact that these two thermodynamic systems have very similar invariant points (i.e., eutectic, peritectic; see [44]).
But, the decagonal phase is directly peritectic reaction with the liquid phase and the amount of aluminum present.
have analyzed L + [beta] [right arrow] [alpha] peritectic reaction of Ti-46Al-5Nb and Ti-45Al-6Nb-0.3B alloys and prepared single lamellar grain with lamellar boundaries parallel to the ingot growth direction by double directional solidification [13]; Oering et al.
The elements of higher concentration of the cobalt and niobium with small amounts of oxygen present peritectic reaction and allow the formation of oxides.
Above 1565K (1292C), the phase diagram shows that carbon-saturated alloy melts could yield graphite upon cooling, followed by Mn7C3 through a ternary peritectic reaction.
Among the topics are producing magnesium metal with the least carbon dioxide emission, the operational cost analysis of a typical South African high pressure die-casting business, investigating the high-temperature oxidation behavior of titanium/aluminum-based alloys with nickel and ruthenium additions, the influence of initial grain size and strain sequence of slab hot rolling on the austenite evolution of peritectic microalloyed plate steels, and the time-dependent solvent extraction of tantalum and niobium.
It is detected that refractory carbides of MC type precipitate in steel R6M5 (EBCHR) during solidification at the stage of peritectic transformation and don't form eutectic.
Sn-5Sb and Sn-10Sb are hypoperitectic and approximately peritectic system alloys, respectively.
The 80 papers cover the effect of microgravity, modeling solidification, grain refinement, microstructure and phase evaluation, continuous casting, in situ observations of solidification processes, eutectic and peritectic solidification, forced conversion and melt flow, cast iron, and rapid solidification.
On the Crystallography of Peritectic Austenite and the Role of Primary Ferrite in High Manganese and Aluminum Steels (12-052)