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Article
Phase Stability for the Pd-Si System: First-Principles, Experiments, and Solution-Based Modeling
Metallurgical and Materials Transactions A
  • S. H. Zhou, Ames Laboratory
  • Y. Huo, Iowa State University
  • Ralph E. Napolitano, Iowa State University and Ames Laboratory
Document Type
Article
Publication Version
Accepted Manuscript
Publication Date
1-1-2016
DOI
10.1007/s11661-015-3206-8
Abstract

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 Pd5Si-μPd5Si-μ, Pd9Si2-αPd9Si2-α, Pd3Si-βPd3Si-β, Pd2Si-γPd2Si-γ, and PdSi-δPdSi-δ are the stable phases at 0 K (–273 °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 PdSi-δPdSi-δ phase was not observed at low temperature. Considering both experimental data and first-principles results, the compounds Pd5Si-μPd5Si-μ, Pd9Si2-αPd9Si2-α, Pd3Si-βPd3Si-β, and Pd2Si-γPd2Si-γ are treated as stable phases down to 0 K (−273 °C), while the PdSi-δPdSi-δ 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 Pd5Si-μPd5Si-μ, Pd9Si2-αPd9Si2-α, Pd3Si-βPd3Si-β, Pd2Si-γPd2Si-γ, and PdSi-δPdSi-δ. 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.

Comments

This is a manuscript of an article published as Zhou, S. H., Y. Huo, and Ralph E. Napolitano. "Phase Stability for the Pd-Si System: First-Principles, Experiments, and Solution-Based Modeling." Metallurgical and Materials Transactions A 47, no. 1 (2016): 194-208. DOI: 10.1007/s11661-015-3206-8. Posted with permission.

Creative Commons License
Creative Commons Attribution-Noncommercial-No Derivative Works 4.0
Copyright Owner
The Minerals, Metals & Materials Society and ASM International
Language
en
File Format
application/pdf
Citation Information
S. H. Zhou, Y. Huo and Ralph E. Napolitano. "Phase Stability for the Pd-Si System: First-Principles, Experiments, and Solution-Based Modeling" Metallurgical and Materials Transactions A Vol. 47 Iss. 1 (2016) p. 194 - 208
Available at: http://works.bepress.com/ralph_napolitano/27/