Thermodynamics of reactions and phase transformations at interfaces and surfaces

Abstract

Recent advances in the thermodynamic description of reactions and phase transformations at interfaces between metals, semiconductors, oxides and the ambient have been reviewed. Unanticipated nanostructures, characterized by the presence of phases at interfaces and surfaces which are unstable as bulk phases, can be thermodynamically stabilized due to the dominance of energy contributions of interfaces and surfaces in the total Gibbs energy of the system. The basic principles and practical guidelines to construct realistic, practically and generally applicable thermodynamic model descriptions of microstructural evolutions at interfaces and surfaces have been outlined. To this end, expressions for the estimation of the involved interface and surface energies have been dealt with extensively as a function of, e. g., the film composition and the growth temperature. Model predictions on transformations at interfaces (surfaces) in nanosized systems have been compared with corresponding experimental observations for, in particular, ultrathin (< 5 nm) oxide overgrowths on metal surfaces, as well as the metal-induced crystallization of semi-conductors in contact with various metals.

First-principles study of an interfacial phase diagram in the V-doped WC-Co system

“…It has been well established that the appearance of certain interfacial "phases" different from those of the adjoining bulk phases (e.g., segregation structures, amorphous wetting films, etc.) can be understood from thermodynamic considerations; [1][2][3][4][5][6] the disparate interfacial phases are equilibrium states stabilized by the interface. The term "complexion" has been suggested to separate these interfacial phases from ordinary bulk phases.…”

“SURFACE and INTERFACE ENGINEERING”

“…Amorphous oxides and intermediate (long range) ordered oxide structures can develop, which can be investigated successfully by application of dedicated high resolution electron microscopical methods (paper by Jeurgens et al, [1]) and surface X-ray diffraction techniques employing synchrotron radiation; the power of the application of the latter technique is demonstrated in a second overview paper (Stierle,[2]). …”

“…However, work on "interface thermodynamics" in the last decade has made it crystal clear that the field of thermodynamics is not "dead", in fact is "hot": new, unusual phenomena occur at surfaces and interfaces which can be given a thermodynamic explanation or, if not observed yet, can be thermodynamically predicted, as pertaining to equilibrium situations much different from those corresponding to "bulk" material, "Classically" such anomalous observations were and still are, mostly erroneously, interpreted as kinetic "artefacts". Against this background the first in the series of papers in this issue devoted to "Surface and Interface Engineering" reviews the current possibilities of assessing, in particular for practical situations, the interface and surface energies involved, recognizing that most of these energy terms have not been or cannot be measured experimentally (Jeurgens et al, [1]) On that basis equilibrium states strived for during reactions and phase transformations at surfaces and interfaces can be determined.…”

Interdiffusion in amorphous AlxZr1-x alloys

“…Several factors determine the glass forming ability, such as the enthalpy of mixing, size difference of the elemental components, energies of the interfaces between the amorphous and crystalline phases as well as long range diffusivity. 7,[19][20][21] Therefore, in order, to understand and control the high glass forming ability and resistance against crystallisation of these metallic glasses, as well as the oxidation and corrosion resistance, 3,22 knowledge about interdiffusion is essential, also for the design of new (bulk) metallic glasses with even higher glass forming ability.…”