The melting point of a mixture of two or more solids (such as an alloy) depends on the relative proportions of its ingredients. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. An alloy is a Solid solution or Homogeneous mixture of two or more elements, at least one of which is a Metal, which itself has A eutectic or eutectic mixture is a mixture at such proportions that the melting point is as low as possible, and that furthermore all the constituents crystallize simultaneously at this temperature from molten liquid solution. Such a simultaneous crystallization of a eutectic mixture is known as a eutectic reaction, the temperature at which it takes place is the eutectic temperature, and the composition and temperature at which it takes place is called the eutectic point.

The term comes from the Greek eutektos, meaning 'easily melted. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly '

Equilibrium phase diagram for a binary system. In Physical chemistry, Mineralogy, and Materials science, a phase diagram is a type of graph used to show the equilibrium conditions The eutectic point is the point at which the liquid phase L borders directly on the solid phase α + β. Liquid is one of the principal States of matter. A liquid is a Fluid that has the particles loose and can freely form a distinct surface at the boundaries of A solid' object is in the States of matter characterized by resistance to Deformation and changes of Volume.

The equilibrium phase diagram at the right displays a simple binary system composed of two components, A and B, which has a eutectic point. In Physical chemistry, Mineralogy, and Materials science, a phase diagram is a type of graph used to show the equilibrium conditions The phase diagram plots relative concentrations of A and B along the horizontal axis, and temperature along the vertical axis. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature The eutectic point is the point at which the liquid phase L borders directly on the solid phase α + β (a homogeneous composed of both A and B), representing the minimum melting temperature of any possible alloy of A and B. Liquid is one of the principal States of matter. A liquid is a Fluid that has the particles loose and can freely form a distinct surface at the boundaries of In the Physical sciences a phase is a Set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties

Not all binary system alloys have a eutectic point: those that form a solid solution at all concentrations, such as the gold-silver system, have no eutectic. A solid solution is a Solid - state Solution of one or more solutes in a Solvent. Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Silver (ˈsɪlvɚ is a Chemical element with the symbol " Ag " (argentum from the Ancient Greek: ἀργήντος - argēntos gen An alloy system that has a eutectic is often referred to as a eutectic system, or eutectic alloy.

Solid products of a eutectic reaction can often be identified by their lamellar structure, as opposed to the dendritic structures commonly seen in non-eutectic solidification. Lamellar structures or microstructures are composed of fine alternating layers of different materials in the form of lamellae. A crystal dendrite is a crystal that develops with a typical multi-branching tree-like form The same conditions that force the material to form lamellae can instead form an amorphous solid if pushed to an extreme. An amorphous solid is a Solid in which there is no Long-range order of the positions of the Atoms (Solids in which there is long-range atomic order are

Metallic eutectics

The term is often used in metallurgy to describe the alloy of two or more component materials having the relative concentrations specified at the eutectic point. Metallurgy is a domain of Materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their An alloy is a Solid solution or Homogeneous mixture of two or more elements, at least one of which is a Metal, which itself has When a non-eutectic alloy freezes, one component of the alloy crystallizes at one temperature and the other at a different temperature. Crystallization is the (natural or artificial process of formation of solid Crystals precipitating from a homogeneous --> identical Solution With a eutectic alloy, the mixture freezes as one at a single temperature. A eutectic alloy therefore has a sharp melting point, and a non-eutectic alloy exhibits a plastic melting range. The phase transformations that occur while freezing a given alloy can be understood using the phase diagram by drawing a vertical line from the liquid phase to the solid phase on a phase diagram; each point along the line describes the composition at a given temperature.

Some uses include:

• eutectic alloys for soldering, composed of tin (Sn), lead (Pb) and sometimes silver (Ag) or gold (Au). Soldering is a process in which two or more Metal items are joined together by melting and flowing a filler metal into the joint the filler metal having a relatively low Tin is a Chemical element with the symbol Sn (stannum and Atomic number 50 Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Silver (ˈsɪlvɚ is a Chemical element with the symbol " Ag " (argentum from the Ancient Greek: ἀργήντος - argēntos gen Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79
• casting alloys, such as aluminium-silicon and cast iron (at the composition for an austenite-cementite eutectic in the iron-carbon system). WikipediaNaming Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 Cast iron usually refers to grey cast iron, but identifies a large group of Ferrous Alloys which solidify with a Eutectic. Austenite (or gamma phase iron is a metallic non-magnetic solid solution of Iron and an Alloying element Cementite or iron carbide is a Chemical compound with the formula Fe3C (or Fe2CFe and an Orthorhombic crystal structure Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6
• brazing, where diffusion can remove alloying elements from the joint, so that eutectic melting is only possible early in the brazing process. Brazing is a joining process whereby a Filler metal or Alloy is heated to melting temperature above - or by the traditional definition in the United States
• temperature response, i. e. Wood's metal and Field's metal for fire sprinklers. Wood's metal, named for American metallurgist B Wood, is also known as Lipowitz's alloy or by the commercial names cerrobend, bendalloy or Field's metal, or Field's alloy (named after Simon Quellen Field is a fusible Alloy that becomes liquid at approximately 62 °C (144 °F A fire sprinkler is the part of a Fire sprinkler system that discharges water when the effects of a fire have been detected such as when a predetermined temperature has
• non-toxic mercury replacements, such as galinstan. Mercury (ˈmɜrkjʊri also called quicksilver or hydrargyrum, is a Chemical element with the symbol Hg ( Latinized hydrargyrum Galinstan is an Eutectic Alloy of Gallium, Indium, and Tin which is liquid at room temperature typically freezing at −19 °
• experimental metallic glasses, with extremely high strength and corrosion resistance. An amorphous metal is a Metallic material with a disordered atomic-scale structure Corrosion means the breaking down of essential properties in a material due to Chemical reactions with its surroundings
• eutectic alloys of sodium and potassium (NaK) that are liquid at room temperature and used as coolant in experimental fast neutron nuclear reactors. Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 NaK (næk rhyming with "sack" is an alloy of Sodium (Na and Potassium (K and particularly one that is liquid at room temperatures A coolant is a fluid which flows through a device in order to prevent its overheating transferring the heat produced by the device to other devices that utilize or dissipate it A fast neutron reactor or simply a fast reactor is a category of Nuclear reactor in which the fission Chain reaction is sustained by Fast neutrons

Other eutectic mixtures

Sodium chloride and water form a eutectic mixture. For sodium chloride in the diet see Salt. Sodium chloride, also known as common salt, table salt, or Halite, is a Water is a common Chemical substance that is essential for the survival of all known forms of Life. It has a eutectic point of −21. 2 C^[1] and 23. 3%^[2] salt by weight. The eutectic nature of salt and water is exploited when salt is spread on roads to aid snow removal, or mixed with ice to produce low temperatures (for example, in traditional ice cream making). Snow removal is the job of removing Snow after a snowfall to make travel easier and safer Ice cream or ice-cream (originally iced cream) is a frozen dessert made from Dairy products such as Milk and Cream, combined

Lidocaine and prilocaine, both solids at room temperature, form a eutectic that is an oil with a 16°C melting point, used in EMLA (Eutectic Mixture of Local Anesthetic) preparations. Lidocaine ( INN) (ˈlaɪdoʊkeɪn or lignocaine (former BAN) (/ˈlɪgnoʊkeɪn/ is a common Local anesthetic and antiarrhythmic drug Prilocaine (ˈpraɪloʊkeɪn is a Local anesthetic of the Amino Amide type Lidocaine/prilocaine is a eutectic mixture of equal quantities (by weight of Lidocaine and Prilocaine.

Minerals may form eutectic mixtures in igneous rocks,^[3] giving rise to characteristic intergrowth textures such as that of granophyre. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock Rock microstructure includes the texture of a rock and the small scale rock structures Granophyre ( IPA: /ˈgranə(ʊˌfʌɪ(ər/ from Granite and porphyry) is an Igneous rock that contains Quartz and alkali Feldspar

Some inks are eutectic mixtures, allowing inkjet printers to operate at lower temperatures. Inkjet printers operate by propelling variably-sized droplets of liquid or molten material ( Ink) onto almost any sized page ^[4]

Other critical points

Eutectoid

When the solution above the transformation point is solid, rather than liquid, an analogous eutectoid transformation can occur. For instance, in the iron-carbon system, the austenite phase can undergo a eutectoid transformation to produce ferrite and cementite (iron carbide), often in lamellar structures such as pearlite and bainite. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Austenite (or gamma phase iron is a metallic non-magnetic solid solution of Iron and an Alloying element Cementite or iron carbide is a Chemical compound with the formula Fe3C (or Fe2CFe and an Orthorhombic crystal structure Cementite or iron carbide is a Chemical compound with the formula Fe3C (or Fe2CFe and an Orthorhombic crystal structure Lamellar structures or microstructures are composed of fine alternating layers of different materials in the form of lamellae. Pearlite is a two-phased, lamellar (or layered structure composed of alternating layers of alpha-ferrite (88 wt% and Cementite (12% that occurs Bainite is a Phase that exists in Steel Microstructures after certain Heat treatments First described by Davenport E This eutectoid point occurs at 727°C (1340. 6 ºF) and about 0. 83% carbon^[5]; alloys of nearly this composition are called high-carbon steel, while those which have less carbon are termed mild steel. The process analogous to glass formation in this system is the martensitic transformation. Steel 035 water quenchedpng|thumb|200px|035%C Steel water-quenched from 870°C]] Martensite, named after the German metallurgist Adolf Martens (1850–1914

Iron-carbon phase diagram, showing the euctectoid transformation between austenite (γ) and pearlite. In Physical chemistry, Mineralogy, and Materials science, a phase diagram is a type of graph used to show the equilibrium conditions Austenite (or gamma phase iron is a metallic non-magnetic solid solution of Iron and an Alloying element Pearlite is a two-phased, lamellar (or layered structure composed of alternating layers of alpha-ferrite (88 wt% and Cementite (12% that occurs

Peritectic

Peritectic transformations are also similar to eutectic reactions. Here, a liquid and solid phase of fixed proportions react at a fixed temperature to yield a single solid phase. Since the solid product forms at the interface between the two reactants, it can form a diffusion barrier and generally causes such reactions to proceed much more slowly than eutectic or eutectoid transformations. Because of this, when a peritectic composition solidifies it does not show the lamellar structure that you find with eutectic freezing.

Such a transformation exists in the iron-carbon system, as seen near the upper-left corner of the figure. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 It resembles an inverted eutectic, with the δ phase combining with the liquid to produce pure austenite at 1495 °C and 0. Austenite (or gamma phase iron is a metallic non-magnetic solid solution of Iron and an Alloying element 17 mass percent carbon.

References

1. ^ Muldrew, Ken; Locksley E. McGann (1997). Phase Diagrams. Cryobiology—A Short Course. University of Calgary. Retrieved on 2006-04-29. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1429 - Joan of Arc arrives to relieve the Siege of Orleans.
2. ^ Senese, Fred (1999). Does salt water expand as much as fresh water does when it freezes?. Solutions: Frequently asked questions. Department of Chemistry, Frostburg State University. Retrieved on 2006-04-29. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1429 - Joan of Arc arrives to relieve the Siege of Orleans.
3. ^ Fichter, Lynn S. (2000). Igneous Phase Diagrams. Igneous Rocks. James Madison University. Retrieved on 2006-04-29. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1429 - Joan of Arc arrives to relieve the Siege of Orleans.
4. ^ Davies, Nicholas A. ; Beatrice M. Nicholas (1992). Eutectic compositions for hot melt jet inks. US Patent & Trademark Office, Patent Full Text and Image Database. United States Patent and Trademark Office. Retrieved on 2006-04-29. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1429 - Joan of Arc arrives to relieve the Siege of Orleans.
5. ^ Iron-Iron Carbide Phase Diagram Example

• Sadoway, Donald (2004). Phase Equilibria and Phase Diagrams (pdf). 3. 091 Introduction to Solid State Chemistry, Fall 2004. MIT Open Courseware. Retrieved on 2006-04-12. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 467 - Anthemius is elevated to Emperor of the Western Roman Empire.

Bibliography

• Mortimer, Robert G. (2000). Physical Chemistry. Academic Press. ISBN 0-12-508345-9.  
• Reed-Hill, R. E. ; Reza Abbaschian (1992). Physical Metallurgy Principles. Thomson-Engineering. ISBN 0-534-92173-6.  
• Easterling, Edward (1992). Phase Transformations in Metals and Alloys. CRC. ISBN 0-7487-5741-4.  
• Askeland, Donald R. ; Pradeep P. Phule (2005). The Science and Engineering of Materials. Thomson-Engineering. ISBN 0-534-55396-6.  

See also

• Azeotrope
• Solid solution
• Phase diagram
• Freezing point depression
• Hypoeutectic alloy