Pohl, Johan ; Stahl, Christian ; Albe, Karsten (2012)
Size-dependent phase diagrams of metallic alloys: A Monte Carlo simulation study on order-disorder transitions in Pt-Rh nanoparticles.
In: Beilstein Journal of Nanotechnology, 3
doi: 10.3762/bjnano.3.1
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Nanoparticles of Pt–Rh were studied by means of lattice-based Monte Carlo simulations with respect to the stability of ordered D022- and 40-phases as a function of particle size and composition. By thermodynamic integration in the semi-grand canonical ensemble, phase diagrams for particles with a diameter of 7.8 nm, 4.3 nm and 3.1 nm were obtained. Size-dependent trends such as the lowering of the critical ordering temperature, the broadening of the compositional stability range of the ordered phases, and the narrowing of the two-phase regions were observed and discussed in the context of complete size-dependent nanoparticle phase diagrams. In addition, an ordered surface phase emerges at low temperatures and low platinum concentration. A decrease of platinum surface segregation with increasing global platinum concentration was observed, when a second, ordered phase is formed inside the core of the particle. The order–disorder transitions were analyzed in terms of the Warren–Cowley short-range order parameters. Concentration-averaged short-range order parameters were used to remove the surface segregation bias of the conventional short-range order parameters. Using this procedure, it was shown that the short-range order in the particles at high temperatures is bulk-like.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2012 |
| Autor(en): | Pohl, Johan ; Stahl, Christian ; Albe, Karsten |
| Art des Eintrags: | Bibliographie |
| Titel: | Size-dependent phase diagrams of metallic alloys: A Monte Carlo simulation study on order-disorder transitions in Pt-Rh nanoparticles |
| Sprache: | Englisch |
| Publikationsjahr: | 2 Januar 2012 |
| Verlag: | Beilstein Institut |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Beilstein Journal of Nanotechnology |
| Jahrgang/Volume einer Zeitschrift: | 3 |
| DOI: | 10.3762/bjnano.3.1 |
| URL / URN: | http://www.beilstein-journals.org/bjnano/single/articleFullT... |
| Kurzbeschreibung (Abstract): | Nanoparticles of Pt–Rh were studied by means of lattice-based Monte Carlo simulations with respect to the stability of ordered D022- and 40-phases as a function of particle size and composition. By thermodynamic integration in the semi-grand canonical ensemble, phase diagrams for particles with a diameter of 7.8 nm, 4.3 nm and 3.1 nm were obtained. Size-dependent trends such as the lowering of the critical ordering temperature, the broadening of the compositional stability range of the ordered phases, and the narrowing of the two-phase regions were observed and discussed in the context of complete size-dependent nanoparticle phase diagrams. In addition, an ordered surface phase emerges at low temperatures and low platinum concentration. A decrease of platinum surface segregation with increasing global platinum concentration was observed, when a second, ordered phase is formed inside the core of the particle. The order–disorder transitions were analyzed in terms of the Warren–Cowley short-range order parameters. Concentration-averaged short-range order parameters were used to remove the surface segregation bias of the conventional short-range order parameters. Using this procedure, it was shown that the short-range order in the particles at high temperatures is bulk-like. |
| Freie Schlagworte: | Monte Carlo simulation; nanoparticles; nanothermodynamics; phase diagram; Pt-Rh; thermodynamics |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Materialmodellierung 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften |
| Hinterlegungsdatum: | 21 Mär 2012 09:40 |
| Letzte Änderung: | 05 Mär 2013 09:59 |
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