Journal Home > Volume 11 , Issue 6

The high-entropy rare-earth zirconate ((La0.2Nd0.2Sm0.2Gd0.2Yb0.2)2Zr2O7, 5RE2Zr2O7 HE- REZs) ceramics were successfully prepared by a new high-speed positive grinding strategy combined with solid-state reaction method. The microstructure, crystal structure, phase composition, and thermophysical and mechanical properties of the samples were systematically investigated through various methods. Results indicate that the samples have a single-phase defect fluorite-type crystal structure with excellent high-temperature thermal stability. The as-prepared samples also demonstrate low thermal conductivity (0.9-1.72 W·m-1·K-1 at 273-1273 K) and high coefficient of thermal expansion (CTE, 10.9 × 10-6 K-1 at 1273 K), as well as outstanding mechanical properties including large Young’s modulus (E = 186-257 GPa) and high fracture toughness (KIC). Furthermore, the formation possibility of the as-prepared samples was verified through the first-principles calculations, which suggested the feasibility to form the 5RE2Zr2O7 HE-REZs in the thermodynamic direction. Therefore, in view of the excellent multifunctional properties exhibited by the as-prepared 5RE2Zr2O7 HE-REZs, they have great potential applications in next-generation thermal-barrier coatings (TBCs).


menu
Abstract
Full text
Outline
About this article

High-entropy rare-earth zirconate ceramics with low thermal conductivity for advanced thermal-barrier coatings

Show Author's information Debao LIUaBaolu SHIaLiyan GENGbYiguang WANGaBaosheng XUa( )Yanfei CHENa
Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
Shanghai Space Propulsion Technology Research Institute, Shanghai 201109, China

Abstract

The high-entropy rare-earth zirconate ((La0.2Nd0.2Sm0.2Gd0.2Yb0.2)2Zr2O7, 5RE2Zr2O7 HE- REZs) ceramics were successfully prepared by a new high-speed positive grinding strategy combined with solid-state reaction method. The microstructure, crystal structure, phase composition, and thermophysical and mechanical properties of the samples were systematically investigated through various methods. Results indicate that the samples have a single-phase defect fluorite-type crystal structure with excellent high-temperature thermal stability. The as-prepared samples also demonstrate low thermal conductivity (0.9-1.72 W·m-1·K-1 at 273-1273 K) and high coefficient of thermal expansion (CTE, 10.9 × 10-6 K-1 at 1273 K), as well as outstanding mechanical properties including large Young’s modulus (E = 186-257 GPa) and high fracture toughness (KIC). Furthermore, the formation possibility of the as-prepared samples was verified through the first-principles calculations, which suggested the feasibility to form the 5RE2Zr2O7 HE-REZs in the thermodynamic direction. Therefore, in view of the excellent multifunctional properties exhibited by the as-prepared 5RE2Zr2O7 HE-REZs, they have great potential applications in next-generation thermal-barrier coatings (TBCs).

Keywords: thermal conductivity, first-principles calculations, thermal stability, high-entropy rare-earth zirconates (HE-REZs), Young’s modulus, thermal-barrier coatings (TBCs)

References(59)

[1]
Vassen R, Cao XQ, Tietz F, et al. Zirconates as new materials for thermal barrier coatings. J Am Ceram Soc 2000, 83: 2023-2028.
[2]
Wu J, Wei XZ, Padture NP, et al. Low-thermal- conductivity rare-earth zirconates for potential thermal- barrier-coating applications. J Am Ceram Soc 2002, 85: 3031-3035.
[3]
Zhao ZF, Chen H, Xiang HM, et al. High entropy defective fluorite structured rare-earth niobates and tantalates for thermal barrier applications. J Adv Ceram 2020, 9: 303-311.
[4]
Padture NP, Gell M, Jordan EH. Thermal barrier coatings for gas-turbine engine applications. Science 2002, 296: 280-284.
[5]
Clarke DR, Phillpot SR. Thermal barrier coating materials. Mater Today 2005, 8: 22-29.
[6]
Vaßen R, Jarligo MO, Steinke T, et al. Overview on advanced thermal barrier coatings. Surf Coat Technol 2010, 205: 938-942.
[7]
Liu B, Liu YC, Zhu CH, et al. Advances on strategies for searching for next generation thermal barrier coating materials. J Mater Sci Technol 2019, 35: 833-851.
[8]
Clarke DR, Oechsner M, Padture NP. Thermal-barrier coatings for more efficient gas-turbine engines. MRS Bull 2012, 37: 891-898.
[9]
Zhou YC, Xiang HM, Feng ZH. Theoretical investigation on mechanical and thermal properties of a promising thermal barrier material: Yb3Al5O12. J Mater Sci Technol 2014, 30: 631-638.
[10]
Curran JA, Kalkancı H, Magurova Y, et al. Mullite-rich plasma electrolytic oxide coatings for thermal barrier applications. Surf Coat Technol 2007, 201: 8683-8687.
[11]
Joulia A, Vardelle M, Rossignol S. Synthesis and thermal stability of Re2Zr2O7 (Re = La, Gd) and La2(Zr1-xCex)2O7-δ compounds under reducing and oxidant atmospheres for thermal barrier coatings. J Eur Ceram Soc 2013, 33: 2633-2644.
[12]
Du AB, Wan CL, Qu ZX, et al. Thermal conductivity of monazite-type REPO4 (RE = La, Ce, Nd, Sm, Eu, Gd). J Am Ceram Soc 2009, 92: 2687-2692.
[13]
Ren K, Wang QK, Shao G, et al. Multicomponent high- entropy zirconates with comprehensive properties for advanced thermal barrier coating. Scripta Mater 2020, 178: 382-386.
[14]
Wright AJ, Wang QY, Ko ST, et al. Size disorder as a descriptor for predicting reduced thermal conductivity in medium- and high-entropy pyrochlore oxides. Scripta Mater 2020, 181: 76-81.
[15]
Subramanian MA, Aravamudan G, Subba Rao GV. Oxide pyrochlores—A review. Prog Solid State Chem 1983, 15: 55-143.
[16]
Strange P, Svane A, Temmerman WM, et al. Understanding the valency of rare earths from first-principles theory. Nature 1999, 399: 756-758.
[17]
Cao XQ, Vassen R, Tietz F, et al. New double-ceramic- layer thermal barrier coatings based on zirconia-rare earth composite oxides. J Eur Ceram Soc 2006, 26: 247-251.
[18]
Xu ZH, He LM, Mu RD, et al. Double-ceramic-layer thermal barrier coatings of La2Zr2O7/YSZ deposited by electron beam-physical vapor deposition. J Alloys Compd 2009, 473: 509-515.
[19]
Cao XQ, Li JY, Zhong XH, et al. La2(Zr0.7Ce0.3)2O7—A new oxide ceramic material with high sintering-resistance. Mater Lett 2008, 62: 2667-2669.
[20]
Xiang HM, Xing Y, Dai FZ, et al. High-entropy ceramics: Present status, challenges, and a look forward. J Adv Ceram 2021, 10: 385-441.
[21]
Zhang RZ, Reece MJ. Review of high entropy ceramics: Design, synthesis, structure and properties. J Mater Chem A 2019, 7: 22148-22162.
[22]
Zhu JT, Meng XY, Xu J, et al. Ultra-low thermal conductivity and enhanced mechanical properties of high-entropy rare earth niobates (RE3NbO7, RE = Dy, Y, Ho, Er, Yb). J Eur Ceram Soc 2021, 41: 1052-1057.
[23]
Zhao ZF, Xiang HM, Dai FZ, et al. (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2O7: A novel high-entropy ceramic with low thermal conductivity and sluggish grain growth rate. J Mater Sci Technol 2019, 35: 2647-2651.
[24]
Zhou L, Li F, Liu JX, et al. High-entropy thermal barrier coating of rare-earth zirconate: A case study on (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)2Zr2O7 prepared by atmospheric plasma spraying. J Eur Ceram Soc 2020, 40: 5731-5739.
[25]
Li F, Zhou L, Liu JX, et al. High-entropy pyrochlores with low thermal conductivity for thermal barrier coating materials. J Adv Ceram 2019, 8: 576-582.
[26]
Segall MD, Lindan PJD, Probert MJ, et al. First-principles simulation: Ideas, illustrations and the CASTEP code. J Phys Condens Matter 2002, 14: 2717-2744.
[27]
Perdew JP, Burke K, Ernzerhof M. Generalized gradient approximation made simple. Phys Rev Lett 1996, 77: 3865-3868.
[28]
Miracle DB, Senkov ON. A critical review of high entropy alloys and related concepts. Acta Mater 2017, 122: 448-511.
[29]
Wang J, Wu FS, Zou RA, et al. High-entropy ferroelastic rare-earth tantalite ceramic: (Y0.2Ce0.2Sm0.2Gd0.2Dy0.2)TaO4. J Am Ceram Soc 2021, 104: 5873-5882.
[30]
Leitner J, Voňka P, Sedmidubský D, et al. Application of Neumann-Kopp rule for the estimation of heat capacity of mixed oxides. Thermochimica Acta 2010, 497: 7-13.
[31]
He JJ, He G, Liu J, et al. New class of high-entropy defect fluorite oxides RE2(Ce0.2Zr0.2Hf0.2Sn0.2Ti0.2)2O7 (RE = Y, Ho, Er, or Yb) as promising thermal barrier coatings. J Eur Ceram Soc 2021, 41: 6080-6086.
[32]
Burggraaf AJ, van Dijk T, Verkerk MJ. Structure and conductivity of pyrochlore and fluorite type solid solutions. Solid State Ionics 1981, 5: 519-522.
[33]
Vayer F, Decorse C, Bérardan D, et al. New entropy- stabilized oxide with pyrochlore structure: Dy2(Ti0.2Zr0.2 Hf0.2Ge0.2Sn0.2)2O7. J Alloys Compd 2021, 883: 160773.
[34]
Liu Y, Withers RL, Norén L. The pyrochlore to ‘defect fluorite’ transition in the Y2(ZryTi1-y)2O7 system and its underlying crystal chemistry. J Solid State Chem 2004, 177: 4404-4412.
[35]
Zhu JT, Meng XY, Zhang P, et al. Dual-phase rare-earth- zirconate high-entropy ceramics with glass-like thermal conductivity. J Eur Ceram Soc 2021, 41: 2861-2869.
[36]
Feng J, Xiao B, Wan CL, et al. Electronic structure, mechanical properties and thermal conductivity of Ln2Zr2O7 (Ln = La, Pr, Nd, Sm, Eu and Gd) pyrochlore. Acta Mater 2011, 59: 1742-1760.
[37]
Teng Z, Zhu LN, Tan YQ, et al. Synthesis and structures of high-entropy pyrochlore oxides. J Eur Ceram Soc 2020, 40: 1639-1643.
[38]
Wan CL, Qu ZX, Du AB, et al. Order-disorder transition and unconventional thermal conductivities of the (Sm1-xYbx)2Zr2O7 series. J Am Ceram Soc 2011, 94: 592-596.
[39]
Glerup M, Nielsen OF, Poulsen FW. The structural transformation from the pyrochlore structure, A2B2O7, to the fluorite structure, AO2, studied by Raman spectroscopy and defect chemistry modeling. J Solid State Chem 2001, 160: 25-32.
[40]
Díaz M, Pecharromán C, del Monte F, et al. Synthesis, thermal evolution, and luminescence properties of yttrium disilicate host matrix. Chem Mater 2005, 17: 1774-1782.
[41]
Zhou L, Huang ZY, Qi JQ, et al. Thermal-driven fluorite- pyrochlore-fluorite phase transitions of Gd2Zr2O7 ceramics probed in large range of sintering temperature. Metall Mater Trans A 2016, 47: 623-630.
[42]
Kong LG, Karatchevtseva I, Gregg DJ, et al. Gd2Zr2O7 and Nd2Zr2O7 pyrochlore prepared by aqueous chemical synthesis. J Eur Ceram Soc 2013, 33: 3273-3285.
[43]
Pan W, Phillpot SR, Wan CL, et al. Low thermal conductivity oxides. MRS Bull 2012, 37: 917-922.
[44]
Zhao M, Ren XR, Yang J, et al. Low thermal conductivity of rare-earth zirconate-stannate solid solutions (Yb2Zr2O7)1-x(Ln2Sn2O7)x (Ln = Nd, Sm). J Am Ceram Soc 2016, 99: 293-299.
[45]
Sood A, Cheaito R, Bai TY, et al. Direct visualization of thermal conductivity suppression due to enhanced phonon scattering near individual grain boundaries. Nano Lett 2018, 18: 3466-3472.
[46]
Zhou FF, Wang Y, Cui ZY, et al. Thermal cycling behavior of nanostructured 8YSZ, SZ/8YSZ and 8CSZ/8YSZ thermal barrier coatings fabricated by atmospheric plasma spraying. Ceram Int 2017, 43: 4102-4111.
[47]
Sun ZQ, Li MS, Zhou YC. Thermal properties of single- phase Y2SiO5. J Eur Ceram Soc 2009, 29: 551-557.
[48]
Braun JL, Rost CM, Lim M, et al. Charge-induced disorder controls the thermal conductivity of entropy-stabilized oxides. Adv Mater 2018, 30: 1805004.
[49]
Callaway J, von Baeyer HC. Effect of point imperfections on lattice thermal conductivity. Phys Rev 1960, 120: 1149-1154.
[50]
Wan CL, Pan W, Xu Q, et al. Effect of point defects on the thermal transport properties of(LaxGd1-x)2Zr2O7: Experiment and theoretical model. Phys Rev B 2006, 74: 144109.
[51]
Tian ZL, Zheng LY, Li ZJ, et al. Exploration of the low thermal conductivities of γ-Y2Si2O7, β-Y2Si2O7, β- Yb2Si2O7, and β-Lu2Si2O7 as novel environmental barrier coating candidates. J Eur Ceram Soc 2016, 36: 2813-2823.
[52]
Qu ZX, Wan CL, Pan W. Thermophysical properties of rare-earth stannates: Effect of pyrochlore structure. Acta Mater 2012, 60: 2939-2949.
[53]
Chen L, Hu MY, Wu P, et al. Thermal expansion performance and intrinsic lattice thermal conductivity of ferroelastic RETaO4 ceramics. J Am Ceram Soc 2019, 102: 4809-4821.
[54]
Xu L, Wang HJ, Su L, et al. A new class of high-entropy fluorite oxides with tunable expansion coefficients, low thermal conductivity and exceptional sintering resistance. J Eur Ceram Soc 2021, 41: 6670-6676.
[55]
Yang KL, Chen L, Wu FS, et al. Thermophysical properties of Yb(TaxNb1-x)O4 ceramics with different crystal structures. Ceram Int 2020, 46: 28451-28458.
[56]
Zong RF, Wu FS, Song P, et al. Influence of zirconia alloying on the thermophysical and mechanical properties of YTaO4 ceramics. Ceram Int 2019, 45: 24894-24899.
[57]
Kibsey M, Romualdez J, Huang X, et al. Mechanical properties of titania-doped yttria stabilized zirconia (TiYSZ) for use as thermal barrier coating (TBC). J Eng Gas Turbines Power 2011, 133: 122101.
[58]
Boccaccini AR. Machinability and brittleness of glass- ceramics. J Mater Process Technol 1997, 65: 302-304.
[59]
NIST Material Properties Database in web of the American Ceramics Society. Available at https://www.nist.gov/srd/online-scientific-databases.
Publication history
Copyright
Acknowledgements
Rights and permissions

Publication history

Received: 21 November 2021
Revised: 16 March 2022
Accepted: 19 March 2022
Published: 11 May 2022
Issue date: June 2022

Copyright

© The Author(s) 2022.

Acknowledgements

This work is supported by the National Science and Technology Major Project (2017-VI-0020-0093) and the National Natural Science Foundation of China (12090031). By the way, the authors would like to thank Jinghua XU from Shiyanjia Lab (www.shiyanjia.com) for the TG/DSC analysis. The authors would like to thank the Analysis and Testing Center of Beijing Institute of Technology.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.

The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Return