First-principles study of Zr–N crystalline phases: phase stability, electronic and mechanical properties

Using a variable-composition ab initio evolutionary algorithm, we investigate stability of various Zr–N compounds. Besides the known ZrN and Zr 3 N 4 , new candidate structures with Zr : N ratios of 2 : 1, 4 : 3, 6 : 5, 8 : 7, 15 : 16, 7 : 8 and 4 : 5 are found to be ground-state configurations, whi...

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Bibliographic Details
Published in:RSC advances Vol. 7; no. 8; pp. 4697 - 4703
Main Authors: Yu, Shuyin, Zeng, Qingfeng, Oganov, Artem R., Frapper, Gilles, Huang, Bowen, Niu, Haiyang, Zhang, Litong
Format: Journal Article
Language:English
Published: Royal Society of Chemistry 01.01.2017
Subjects:
algorithms
Catalysis
chemical bonding
Chemical Sciences
energy
mechanical properties
modulus of elasticity
nitrides
nitrogen
zirconium
ISSN:2046-2069, 2046-2069
Online Access:Get full text
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Summary:Using a variable-composition ab initio evolutionary algorithm, we investigate stability of various Zr–N compounds. Besides the known ZrN and Zr 3 N 4 , new candidate structures with Zr : N ratios of 2 : 1, 4 : 3, 6 : 5, 8 : 7, 15 : 16, 7 : 8 and 4 : 5 are found to be ground-state configurations, while Zr 3 N 2 has a very slightly higher energy. Besides Zr 2 N, the newly discovered Zr x N y compounds adopt rocksalt structures with ordered nitrogen or zirconium vacancies. The electronic and mechanical properties of the zirconium nitrides are further studied in order to understand their composition–structure–property relationships. Our results show that bulk and shear moduli monotonically increase with decreasing vacancy content. The mechanical enhancement can be attributed to the occurrence of more Zr–N covalent bonds and weakening of the ductile Zr–Zr metallic bonds. These simulations could provide additional insight into the vacancy-ordered rocksalt phases that are not readily apparent from experiments.
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ISSN:2046-2069
2046-2069
DOI:10.1039/C6RA27233A