Eutectic point

related topics
{acid, form, water}
{math, energy, light}
{@card@, make, design}
{line, north, south}
{island, water, area}

A eutectic system is a mixture of chemical compounds or elements that has a single chemical composition that solidifies at a lower temperature than any other composition. This composition is known as the eutectic composition and the temperature is known as the eutectic temperature. On a phase diagram the intersection of the eutectic temperature and the eutectic composition gives the eutectic point.[1] Not all binary alloys have a eutectic point; for example, in the silver-gold system the melt temperature (liquidus) and freeze temperature (solidus) both increase monotonically as the mix changes from pure silver to pure gold.[2]

Contents

Eutectic reaction

The eutectic reaction is defined as follows:[3]

This type of reaction is an invariant reaction, because it is in thermal equilibrium; another way to define this is the Gibbs free energy equals zero. Tangibly, this means the liquid and two solid solutions all coexist at the same time and are in chemical equilibrium. There is also a thermal arrest for the duration of the reaction.[3]

The resulting solid macrostructure from a eutectic reaction depends on a few factors. The most important factor is how the two solid solutions nucleate and grow. The most common structure is a lamellar structure, but other possible structures include rodlike, globular, and acicular.[4]

Non-eutectic compositions

Full article ▸

related documents
Nucleotide
Pyridine
Ribosome
Americium
Isoprene
Extractive metallurgy
Cellulose
Tartaric acid
Filtration
Primer (molecular biology)
Oxidation state
Toluene
Coenzyme Q - cytochrome c reductase
Ethylene glycol
Picric acid
Fluorite
Californium
Deoxyribose
Ununtrium
Gallium
Radionuclide
Coke (fuel)
Hydrogen cyanide
Indium
Protease
Kaolinite
Tertiary structure
Standard electrode potential (data page)
Proline
Neodymium