Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Concept
Spinodal decomposition
Summary
Spinodal decomposition is a mechanism by which a single thermodynamic phase spontaneously separates into two phases (without nucleation). Decomposition occurs when there is no thermodynamic barrier to phase separation. As a result, phase separation via decomposition does not require the nucleation events resulting from thermodynamic fluctuations, which normally trigger phase separation.
Spinodal decomposition is observed when mixtures of metals or polymers separate into two co-existing phases, each rich in one species and poor in the other. When the two phases emerge in approximately equal proportion (each occupying about the same volume or area), characteristic intertwined structures are formed that gradually coarsen (see animation). The dynamics of spinodal decomposition is commonly modeled using the Cahn–Hilliard equation.
Spinodal decomposition is fundamentally different from nucleation and growth. When there is a nucleation barrier to the formation of a second phase, time is taken by the system to overcome that barrier. As there is no barrier (by definition) to spinodal decomposition, some fluctuations (in the order parameter that characterizes the phase) start growing instantly. Furthermore, in spinodal decomposition, the two distinct phases start growing in any location uniformly throughout the volume, whereas a nucleated phase change begins at a discrete number of points.
Spinodal decomposition occurs when a homogenous phase becomes thermodynamically unstable. An unstable phase lies at a maximum in free energy. In contrast, nucleation and growth occur when a homogenous phase becomes metastable. That is, another biphasic system becomes lower in free energy, but the homogenous phase remains at a local minimum in free energy, and so is resistant to small fluctuations. J. Willard Gibbs described two criteria for a metastable phase: that it must remain stable against a small change over a large area.
In the early 1940s, Bradley reported the observation of sidebands around the Bragg peaks in the X-ray diffraction pattern of a Cu-Ni-Fe alloy that had been quenched and then annealed inside the miscibility gap.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Related courses (4)
MSE-302: Phase transformations
Ce cours est une introduction aux transformations de phases liquide-solide et solide-solide. Il aborde les aspects thermodynamiques et cristallographiques. Il traite principalement des matériaux métal
MSE-322: Building materials + Laboratory work
Science des matériaux de construction non métalliques les plus utilisés et plus particulièrement des matériaux cimentaires (béton). Composition chimique, fabrication et comportement sur la durée.
MSE-431: Physical chemistry of polymeric materials
The student has a basic understanding of the physical and physicochemical principles which result from the chainlike structure of synthetic macromolecules. The student can predict major characteristic
Related lectures (10)
Polymer Phase Behavior
Explores the physical chemistry of polymeric materials, emphasizing concentrated solutions and phase separation behavior.
Phase Transitions: Metastable States
Explores phase transitions, metastable states, nucleation, and practical applications like cloud seeding and superconductivity.
Cavity method and Approximate Message Passing
Explores the cavity method, Approximate Message Passing, and phase transitions in probabilistic models.
Related publications (18)
Related concepts (1)
Critical point (thermodynamics)
In thermodynamics, a critical point (or critical state) is the end point of a phase equilibrium curve. One example is the liquid–vapor critical point, the end point of the pressure–temperature curve that designates conditions under which a liquid and its vapor can coexist. At higher temperatures, the gas cannot be liquefied by pressure alone. At the critical point, defined by a critical temperature Tc and a critical pressure pc, phase boundaries vanish.