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Phase Stability for the Pd-Si System: First-Principles, Experiments, and Solution-Based Modeling

TitlePhase Stability for the Pd-Si System: First-Principles, Experiments, and Solution-Based Modeling
Publication TypeJournal Article
Year of Publication2016
AuthorsZhou, SH, Huo, Y, Napolitano, RE
JournalMetallurgical and Materials Transactions a-Physical Metallurgy and Materials Science
Date Published01
Type of ArticleArticle
ISBN Number1073-5623
Accession NumberWOS:000367468100021
Keywordsat-percent-si, augmented-wave method, binary-system, concentration range, metallic-glass, metastable phases, palladium-silicon system, partitionless crystallization, pt-si, silicides

The relative stabilities of the compounds in the binary Pd-Si system were assessed using first-principles calculations and experimental methods. Calculations of lattice parameters and enthalpy of formation indicate that , , , , and are the stable phases at 0 K (-273 A degrees C). X-ray diffraction analyses (XRD) and electron probe microanalysis (EPMA) of the as-solidified and heat-treated samples support the computational findings, except that the phase was not observed at low temperature. Considering both experimental data and first-principles results, the compounds , , , and are treated as stable phases down to 0 K (-273 A degrees C), while the is treated as being stable over a limited range, exhibiting a lower bound. Using these findings, a comprehensive solution-based thermodynamic model is formulated for the Pd-Si system, permitting phase diagram calculation. The liquid phase is described using a three-species association model and other phases are treated as solid solutions, where a random substitutional model is adopted for Pd-fcc and Si-dia, and a two-sublattice model is employed for , , , , and . Model parameters are fitted using available experimental data and first-principles data, and the resulting phase diagram is reported over the full range of compositions.

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Structures and Dynamics