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A phase-change material (PCM) is a substance which releases/absorbs sufficient energy at phase transition to provide useful heat or cooling. Generally the transition will be from one of the first two fundamental states of matter - solid and liquid - to the other.
A phase diagram in physical chemistry, engineering, mineralogy, and materials science is a type of chart used to show conditions (pressure, temperature, etc.) at which thermodynamically distinct phases (such as solid, liquid or gaseous states) occur and coexist at equilibrium.
Furthermore, there is no change in G at phase transitions between substances in their standard states. Hence, the main functional application of Gibbs energy from a thermodynamic database is its change in value during the formation of a compound from the standard-state elements, or for any standard chemical reaction (Δ G ° form or Δ G ° rx ).
In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of matter : solid , liquid , and gas , and in rare cases, plasma .
In the physical sciences, a phase is a region of material that is chemically uniform, physically distinct, and (often) mechanically separable. In a system consisting of ice and water in a glass jar, the ice cubes are one phase, the water is a second phase, and the humid air is a third phase over the ice and water.
The classical Stefan problem deals with stationary materials with constant thermophysical properties (usually irrespective of phase), a constant phase change temperature and, in the example above, an instantaneous switch from the initial temperature to a distinct value at the boundary.
In addition to the use of AlSi alloys as a structural material, in which the mechanical properties are paramount, another area of application is latent heat storage. In the phase change of the alloy at 577 °C, thermal energy can be stored in the form of the enthalpy of fusion. AlSi can therefore also be used as a metallic phase change material ...
Metallic and insulating states of materials can be considered as different quantum phases of matter connected by a metal-insulator transition. Materials can be classified by the structure of their Fermi surface and zero-temperature dc conductivity as follows: [4] Metal: Fermi liquid: a metal with well-defined quasiparticle states at the Fermi ...