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Tunable thermal properties in yttrium silicates switched by anharmonicity of low-frequency phonons
Luo, YX; Sun, LC; Wang, JM; Tian, ZL; Nian, HQ; Wang, JY; Wang, JY (reprint author), Chinese Acad Sci, Inst Met Res, High Performance Ceram Div, Shenyang Natl Lab Mat Sci, Shenyang 110016, Liaoning, Peoples R China.
2018-04-01
Source PublicationJOURNAL OF THE EUROPEAN CERAMIC SOCIETY
ISSN0955-2219
Volume38Issue:4Pages:2043-2052
AbstractCoordinated modulation of thermal resistance and thermal expansion compatibility has become a chief concern in designing reliable environmental/thermal barrier coating candidates for Si-based ceramics. This study reports phonon behaviors and thermal properties of prototypical silicates X-2-Y2SiO5 and gamma-Y2Si2O7. The nature of an-harmonicity for low-frequency phonons is analyzed, and the finding is discussed with respect to specific crystal structures and interatomic force constants. Low lattice thermal conductivities (KJ basically derive from the giant phonon anharmonicity enhanced by interactions between low-frequency optic and acoustic phonons. gamma-Y2Si2O7 is predicted with considerably lower thermal expansion coefficient (av) than Y2SiO5. The mechanism is disclosed as an effect of the extensive number of low-frequency phonons with negative Griineisen constants (contributing to negative thermal expansion) in gamma-Y2Si2O7, together with its higher elastic stiffness against internal thermal pressure at elevated temperature. A guideline for simultaneously approaching low CL and low av is proposed for searching promising E/TBC candidates.; Coordinated modulation of thermal resistance and thermal expansion compatibility has become a chief concern in designing reliable environmental/thermal barrier coating candidates for Si-based ceramics. This study reports phonon behaviors and thermal properties of prototypical silicates X-2-Y2SiO5 and gamma-Y2Si2O7. The nature of an-harmonicity for low-frequency phonons is analyzed, and the finding is discussed with respect to specific crystal structures and interatomic force constants. Low lattice thermal conductivities (KJ basically derive from the giant phonon anharmonicity enhanced by interactions between low-frequency optic and acoustic phonons. gamma-Y2Si2O7 is predicted with considerably lower thermal expansion coefficient (av) than Y2SiO5. The mechanism is disclosed as an effect of the extensive number of low-frequency phonons with negative Griineisen constants (contributing to negative thermal expansion) in gamma-Y2Si2O7, together with its higher elastic stiffness against internal thermal pressure at elevated temperature. A guideline for simultaneously approaching low CL and low av is proposed for searching promising E/TBC candidates.
description.department[luo, yixiu ; sun, luchao ; wang, jiemin ; wang, jingyang] chinese acad sci, inst met res, high performance ceram div, shenyang natl lab mat sci, shenyang 110016, liaoning, peoples r china ; [luo, yixiu] univ sci & technol china, sch mat sci & engn, hefei, anhui, peoples r china ; [tian, zhilin] chinese univ hong kong, dept elect engn, hong kong, hong kong, peoples r china ; [nian, hongqiang] chinese acad sci, shanghai inst ceram, shanghai, peoples r china
KeywordEnvironmental Barrier Coatings Molten-salt Corrosion Functional Perturbation-theory Silicon-nitride Si3n4 Ceramics Expansion Conductivity Y2sio5 Gamma-y2si2o7 Composites
Subject AreaMaterials Science, Ceramics
Funding OrganizationNational Key R&D Program of China [2017YFB0703201]; Natural Science Foundation of China [51372252, 51772302]
Indexed BySCI
Language英语
Document Type期刊论文
Identifierhttp://ir.imr.ac.cn/handle/321006/79416
Collection中国科学院金属研究所
Corresponding AuthorWang, JY (reprint author), Chinese Acad Sci, Inst Met Res, High Performance Ceram Div, Shenyang Natl Lab Mat Sci, Shenyang 110016, Liaoning, Peoples R China.
Recommended Citation
GB/T 7714
Luo, YX,Sun, LC,Wang, JM,et al. Tunable thermal properties in yttrium silicates switched by anharmonicity of low-frequency phonons[J]. JOURNAL OF THE EUROPEAN CERAMIC SOCIETY,2018,38(4):2043-2052.
APA Luo, YX.,Sun, LC.,Wang, JM.,Tian, ZL.,Nian, HQ.,...&Wang, JY .(2018).Tunable thermal properties in yttrium silicates switched by anharmonicity of low-frequency phonons.JOURNAL OF THE EUROPEAN CERAMIC SOCIETY,38(4),2043-2052.
MLA Luo, YX,et al."Tunable thermal properties in yttrium silicates switched by anharmonicity of low-frequency phonons".JOURNAL OF THE EUROPEAN CERAMIC SOCIETY 38.4(2018):2043-2052.
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