Influence of the concentrate of rare-earth elements on the stabilization of high-temperature phases and properties of ceramics based on ZrO2–7Y2O3

Using chemical co-precipitation from inorganic precursors, powders based on ZrO2–7wt.%Y2O3 were obtained. Oxides of rareearth elements (REE) – La, Nd, Pr – were introduced into them in concentrated form from 5 to 15 wt.%. Using differential thermal analysis, it was found that an increase in the proportion of concentrate leads to a shift of the temperature maxima of thermal effects to high temperatures from 450 to 505 °C. The influence of the annealing temperature in the range of 600–1200 °C on the phase transformations of the synthesized powders of the ZrO2–7%Y2O3–REE system was studied through Raman spectroscopy. The results showed that their phase composition consists of tetragonal zirconium dioxide ZrO2 regardless of the concentrate content. The effect of sintering temperature on compaction of synthesized powders, phase composition and microstructure of ceramics was examined. It was found that ceramics with 10 % REE concentrate has the highest compaction speed during sintering, and an increase in the concentrate content to 15 % leads to inhibition of compaction during sintering.  Ceramics with 15 % REE had the highest open porosity at all sintering temperatures. It was noted that for samples with 10 and 15 % REE concentrate, with increasing sintering temperature, a decrease in the intensity of the Raman spectra peaks and their broadening is observed. It is associated with the formation of a different type of tetragonal modification. The results of atomic force microscopy showed that after sintering at a temperature of 1350 °C in the structure of ceramics containing 15 % REE concentrate, in contrast to other compositions, a new phase with a faceting and a layered structure was detected.

zirconium dioxide, stabilization, REE concentrate, yttrium oxide, phase transformations, synthesis, sintering, microstructure

1. David R. Clarke, Matthias Oechsner, Nitin P. Padture. Thermal-barrier coatings for more efficient gas-turbine engines. MRS Bull. 2012. Vol. 37. No. 10. Р. 891—898. DOI: 10.1557/mrs.2012.232.

2. Moskal G. Thermal barrier coatings: characteristics of microstructure and properties, generation and directions of development of bond. J. Ach. Mater. Manuf. Eng. 2009. Vol. 37. No. 2. P. 323—331.

3. Kumar V., Kandasubramanian B. Processing and design methodologies for advanced and novel thermalbarrier coatings for engineering applications. Particuology. 2016. Vol. 27. P. 1—28. DOI: 10.1016/j.partic.2016.01.007.

4. Kablov E.N., Muboyadzhyan S.A. Heat-resistant coatings for the high-pressure turbine blades of promising GTES. Russ. Metall. (Metally). 2012. Vol. 2012. No. 1. P. 1—7. DOI: 10.1134/S0036029512010089.

5. Chubarov D.A., Budinovskii S.A. Selection of ceramic material for heat-shielding coatings of aircraft turbine blades for operating temperatures up to 1400 °С. Trudy VIAM. 2015. URL: http://viam-works.ru/plugins / content/journal/uploads /articles/pdf/802.pdf (accessed: 28.01.2018) (In Russ.).

6. Pan We., Phillpot Simon R., Wan Chunle, Chernatynskiy A., Qu Zhixue. Low thermal conductivity oxides. MRS Bull. 2012. Vol. 37. No. 10. Р. 917—922. DOI: 10.1557/ mrs.2012.234.

7. Clarke David R., Phillpot Simon R. Thermal barrier coating materials. Mater. Today. 2005. Vol. 8. No. 6. P. 22—29.

8. Cao X. Application of rare earths in thermal barrier coating materials. J. Mater. Sci. Technol. 2007. Vol. 23. No. 1. P. 15—35.

9. Vaßen R., Jarligo M.O., Steinke T., Mack D.E., Stöver D. Overview on advanced thermal barrier coatings. Surf. Coat. Technol. 2010. Vol. 205. Iss. 4. P. 938—942. DOI: 10.1016/j.surfcoat.2010.08.151.

10. Cao X.Q., Vassen R., Stoever D. Ceramic materials for thermal barrier coatings. J. Eur. Ceram. Soc. 2004. Vol. 24. P. 1—10. DOI: 10.1016/S0955-2219(03)00129-8.

11. Jing Zhang, Xingye Guo, Yeon-Gil Jung, Li Li, James Knapp. Lanthanum zirconate based thermal barrier coatings: A review. Surf. Coat. Technol. 2016. Vol. 323. P. 18—29. DOI: 10.1016/j.surfcoat.2016.10.019.

12. Yang Wang, Rishi Kumar, Justin Rollerand, Radenka Maric. Synthesis and characterization of nano-crystalline La2Zr2O7 film by reactive spray deposition technology for application in thermal barrier coatings. MRS Adv. 2017. Vol. 2. Iss. 28. P. 1519—1525. DOI: 10.1557/adv. 2017.154.

13. Dowon Song, Ungyu Paik, Xingye Guo, Jing Zhang, TaKwanWoo, Zhe Lu, Sung-Hoon Jung, Je-Hyun Lee, YeonGil Jung. Microstructure design for blended feedstock and its thermal durability in lanthanum zirconate based thermal barrier coatings. Surf. Coat. Technol. 2016. Vol. 308. P. 40—49. DOI: org/10.1016/j.surfcoat.2016.07.112.

14. Zhou Hongming, Yi Danqing. Effect of rare earth doping on thermo-physical properties of lanthanum zirconate ceramic for thermal barrier coatings. J. Rare Earths. 2008. Vol. 26. Iss. 6. P. 770—774. DOI: org/10.1016/S10020721(09)60002-8.

15. Chubarov D.A., Matveev P.V. New ceramic materials for heat-shielding coatings of GTE blades. Aviatsionnye materialy i tekhnologii. 2013. No. 4 (29). P. 43—46 (In Russ.).

16. Tsipas S.A. Effect of dopants on the phase stability of zirconia-based plasma sprayed thermal barrier coatings. J. Eur. Ceram. Soc. 2010. Vol. 30. P. 61—72. DOI: 10.1016/j. jeurceramsoc.2009.08.008.

17. Byung-Koog Jang, Seongwon Kim, Yoon-Suk Oh, HyungTae Kim, Yoshio Sakka, Hideyuki Murakami. Effect of Gd2O3 on the thermal conductivity of ZrO2—4mol.%Y2O3 ceramics fabricated by spark plasma sintering. Scr. Mater. 2013. Vol. 69(2). P. 165—170. DOI: 10.1016/j. scriptamat.2013.01.037.

18. Jamali H., Loghman-Estarki M.R., Shoja Razavi R., Mozafarinia R., Edris H., Bakhshi S.R. Comparison of thermal shock behavior of nano-7YSZ, 15YSZ and 5.5SYSZ thermal barrier coatings produced by APS method. Ceram.-Silik. 2016. Vol. 60 (3). P. 210—219. DOI: 10.13168/cs.2016.0032.

19. Daniel Soares de Almeida, Carlos Alberto Alves Cairo, Cosme Roberto M. Silva, Maria do Carmo A. Nono. Thermal barrier coating by electron beam-physical vapor deposition of zirconia co-doped with yttria and niobia. J. Aerosp. Technol. Manag. 2010. Vol. 2. No. 2. Р. 195—202. DOI: 10.5028/jatm.2010.02026910.

20. Smirnov A.A., Budinovskii S.A., Matveev P.V., Chubarov D.A. Development of heat-shielding coatings for TVD blades from nickel single-crystal alloys VZhM4, VZhM5U. Trudy VIAM. 2016. No. 1. URL: http://viam-works.ru/ plugins/content/journal/uploads/articles/pdf/907.pdf (accessed: 28.01.2018) (In Russ.).

21. Budinovskii S.A., Smirnov A.A., Matveev P.V., Chubarov D.A. Development of heat-shielding coatings for working and nozzle blades of the turbine from heat-resistant and intermetallic alloys. Trudy VIAM. 2015. No. 4. URL: http://viam-works.ru/plugins/content/journal/ uploads/articles/pdf/800.pdf (accessed: 28.01.2018) (In Russ.).

22. Mazilin I.V., Baldaev L.Kh., Zaitsev N.G., Drobot D.V., Marchukov E.Yu. Phase composition and thermal conductivity of zirconia-based thermal barrier coating. Inorg. Mater. 2016. Vol. 52. No. 8. Р. 802—810. DOI: 10.1134/ S0020168516080124.

23. Tang X., Zheng X. Raman scattering and t-phase lattice vibration of 3 % (mole fraction) Y2O3—ZrO2. J. Mater. Sci. Technol. 2004. Vol. 20. No. 5. Р. 485—489.

24. Torres D.I., Llopis J. Infrared photoluminescence and Raman spectra in the Y2O3—ZrO2 system. Superlatt. Microstruct. 2009. Vol. 45. P. 482—488. DOI: 10.1016/j. spmi.2008.11.020.

25. Basahel S.N., Ali T.T., Mokhtar M., Narasimharao K. Influence of crystal structure of nanosized ZrO2 on photocatalytic degradation of methyl orange. Nanoscale Res. Lett. 2015. Vol. 10. P. 73. DOI: 10.1186/s11671-0150780-z.

26. Yashima M., Ohtake K., Arashi H., Kakihana M., Yoshimura M. Determination of cubic-tetragonal phase boundary in Zr1–x YxO2–x/2 solid solutions by Raman spectroscopy. J. Appl. Phys. 1993. Vol. 74. Iss. 12. P. 7603—7605. DOI: 10.1063/1.354989.

27. Céline Viazzi, Jean-Pierre Bonino, Florence Ansart, Antoine Barnabé. Structural study of metastable tetragonal YSZ powders produced via a sol-gel route. J. Alloys Compd. 2008. Vol. 452. No. 2. P. 377—383. DOI: 10.1016/j. jallcom.2006.10.155.

28. Guo L., Zhang Y., Ye F. Phase structure evolution and thermo-physical properties of nonstoichiometry Nd2–xZr2+xO7+x/2 pyrochlore ceramics. J. Am. Ceram. Soc. 2015. Vol. 98 [3]. P. 1013—1018. DOI: 10.1111/jace. 13374.

29. Xu Z., He L., Zhong X., Zhang J., Chen X., Ma H., Cao X. Effects of Y2O3 addition on the phase evolution and thermophysical properties of lanthanum zirconate. J. Alloys Compd. 2009. Vol. 480. No. 2. P. 220—224. DOI: 10.1016/j.jallcom.2009.02.048.