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Vacancy-driven extended stability of cubic metastable Ta-Al-N and Nb-Al-N phases
- Source :
- Surface and Coatings Technology Volume 326, 2017, Pages 37-44
- Publication Year :
- 2017
-
Abstract
- Quantum mechanical calculations had been previously applied to predict phase stability in many ternary and multinary nitride systems. While the predictions were very accurate for the Ti-Al-N system, some discrepancies between theory and experiment were obtained in the case of other systems. Namely, in the case of Ta-Al-N, the calculations tend to overestimate the minimum Al content necessary to obtain a metastable solid solution with a cubic structure. In this work, we present a comprehensive study of the impact of vacancies on the phase fields in quasi-binary TaN-AlN and NbN-AlN systems. Our calculations clearly show that presence of point defects strongly enlarges the cubic phase field in the TaN-AlN system, while the effect is less pronounced in the NbN-AlN case. The present phase stability predictions agree better with experimental observations of physical vapour deposited thin films reported in the literature than that based on perfect, non-defected structures. This study shows that a representative structural model is crucial for a meaningful comparison with experimental data.<br />Comment: 15 pages, 7 figures, submitted to S&CT
- Subjects :
- Condensed Matter - Materials Science
Subjects
Details
- Database :
- arXiv
- Journal :
- Surface and Coatings Technology Volume 326, 2017, Pages 37-44
- Publication Type :
- Report
- Accession number :
- edsarx.1706.09959
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1016/j.surfcoat.2017.07.012