﻿

# phase diagram

a graph, usually using temperature, pressure, and composition as coordinates, indicating the regions of stability of the various phases of a system.
[1910-15]

* * *

graph showing the limiting conditions for solid, liquid, and gaseous phases of a single substance or of a mixture of substances while undergoing changes in pressure and temperature or in some other combination of variables, such as solubility and temperature. The Figure—> shows a typical phase diagram for a one-component system (i.e., one consisting of a single pure substance), the curves having been obtained from measurements made at various pressures and temperatures. At any point in the areas separated by the curves, the pressure and temperature allow only one phase (solid, liquid, or gas) to exist, and changes in temperature and pressure, up to the points on the curves, will not alter this phase. At any point on the curves, the temperature and pressure allow two phases to exist in equilibrium: solid and liquid, solid and vapour, or liquid and vapour. For example, the line drawn for the variation with temperature of vapour pressure for the liquid is the boundary between liquid and vapour; only vapour can exist on the low-pressure, high-temperature side of the line, while the substance must be liquid on the high-pressure, low-temperature side; liquid and vapour exist together at temperatures and pressures corresponding to points on the line; at the place where this line vanishes, called the critical point, the liquid and its vapour become indistinguishable. Along the line between liquid and solid, the melting temperatures for different pressures can be found. The junction of the three curves, called the triple point, represents the unique conditions under which all three phases exist in equilibrium together. A phase diagram for two components usually shows melting curves on a temperature-composition diagram.

Phase diagrams are specific for each substance and mixture. Complex mixtures may require three-dimensional phase diagrams, which can be represented in two dimensions through use of perspective. Phase diagrams are widely used in studies of mineral equilibriums in connection with the conditions of formation of rocks and minerals within the Earth. They also are invaluable when designing industrial equipment and seeking optimum conditions for manufacturing processes, and in determining the purity of substances.

* * *

Universalium. 2010.

### Look at other dictionaries:

• Phase diagram — Phase diagram. См. Фазовая диаграмма. (Источник: «Металлы и сплавы. Справочник.» Под редакцией Ю.П. Солнцева; НПО Профессионал , НПО Мир и семья ; Санкт Петербург, 2003 г.) …   Словарь металлургических терминов

• phase diagram —  Phase Diagram  Фазовая диаграмма (диаграмма состояния)   Графическое изображение соотношения между параметрами состояния термодинамически равновесной системы (температурой, давлением, составом и др.). Фазовая диаграмма позволяет определить,… …   Толковый англо-русский словарь по нанотехнологии. - М.

• Phase diagram — In physical chemistry, mineralogy, and materials science, a phase diagram is a type of graph used to show the equilibrium conditions between the thermodynamically distinct phases. In mathematics and physics, a phase diagram also has an… …   Wikipedia

• phase diagram — būsenos diagrama statusas T sritis chemija apibrėžtis Pusiausvirųjų fazių savybes apibūdinančių termodinaminių parametrų tarpusavio priklausomybės grafinis vaizdas. atitikmenys: angl. constitution diagram; constitutional diagram; equilibrium… …   Chemijos terminų aiškinamasis žodynas

• phase diagram — fazių diagrama statusas T sritis chemija apibrėžtis Fizikocheminės sistemos pusiausvyros grafinis vaizdas. atitikmenys: angl. constitution(al) diagram; equilibrium diagram; phase diagram rus. диаграмма состояния; диаграмма фазового равновесия;… …   Chemijos terminų aiškinamasis žodynas

• phase diagram — noun : a diagram composed of equilibrium curves between different phases of the same substance the phase diagram of the gold uranium system Journal of Research …   Useful english dictionary

• phase diagram — fazių diagrama statusas T sritis fizika atitikmenys: angl. phase diagram vok. Phasendiagramm, n rus. фазовая диаграмма, f pranc. diagramme de phase, m; diagramme des phases, m …   Fizikos terminų žodynas

• phase diagram — fazių diagrama statusas T sritis Standartizacija ir metrologija apibrėžtis Daugiafazės termodinaminės sistemos būsenų diagrama. atitikmenys: angl. phase diagram vok. Gleichgewichtsdiagramm, n; Phasendiagramm, n; Zustandsdiagramm, n;… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

• phase diagram — noun a) A graph, with axes representing temperature and pressure, showing the equilibrium conditions for a given substance to be a solid, liquid or gas. b) a similar diagram for a binary …   Wiktionary

• phase diagram method — fazių diagramos metodas statusas T sritis fizika atitikmenys: angl. phase diagram method vok. Phasendiagrammethode, f rus. метод фазовой диаграммы, m pranc. méthode du diagramme de phase, f …   Fizikos terminų žodynas