- Gibbs-Thomson effect
The Gibbs-Thomson effect (also called the Gibbs-Kelvin effect or Kelvin effect) relates surface
curvature tovapor pressure andchemical potential . It is named afterJosiah Willard Gibbs andWilliam Thomson, 1st Baron Kelvin . (It is not to be confused with the thermoelectricThomson effect .)It leads to the fact that small liquid droplets (i.e. particles with a high surface curvature) exhibit a higher effective
vapor pressure , since the surface is larger in comparison to the volume. The Gibbs-Thomson effect can cause strong depression of the freezing point of liquids dispersed within fine porous materials.Another notable example of the Gibbs-Thomson effect is
Ostwald ripening , in which concentrationgradients cause smallprecipitates to dissolve and larger ones to grow.The Gibbs-Thomson equation for a precipitate with radius is:
: : Atomic volume: :
Boltzmann constant : :Surface tension (J m): : Equilibrium partial pressure (or chemical potential or concentration): : Partial pressure (or chemical potential or concentration): :Absolute temperature Ostwald ripening is thought to occur in the formation of
orthoclase megacrysts in granites as a consequence ofsubsolidus growth. Seerock microstructure for more.
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