Phase decomposition in nanoporous Au-Pt
نویسندگان
چکیده
This study explores microstructure and phase decomposition in nanoporous Au-Pt made by dealloying. The starting alloy, Ag75Au12.5Pt12.5, forms a uniform solid solution. Removing the Ag dealloying at room temperature equimolar with ligament size as small 4 nm. That alloy’s composition is diagram’s regime of spinodal instability. Surprisingly, view instability substantial atomic rearrangements accompanying dealloying, X-ray diffraction transmission electron microscopy reveal homogeneous single-phase state bulk material. can be traced back to enrichment Pt surface, which depletes Pt. Pt-depleted metastable region alloy diagram, between binodal spinodal. Annealing prompts curvature-driven coarsening diffusion, diminishing number sites for surface segregation. ensuing accompanied formation first crystallographically coherent, Pt-rich regions later semi-coherent phase. morphology coherent compatible decomposition. Yet, evolution pathway nonstandard, since here concurs rapid porous microstructure. Among prospect are its high kinetic stability opportunity tune through annealing temperature.
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ژورنال
عنوان ژورنال: Acta Materialia
سال: 2022
ISSN: ['1873-2453', '1359-6454']
DOI: https://doi.org/10.1016/j.actamat.2022.118419