Performance of single YSZ, Gd2Zr2O7 and double-layered YSZ/Gd2Zr2O7 thermal barrier coatings in isothermal oxidation test conditions

Döleker K. M., KARAOĞLANLI A. C., ÖZGÜRLÜK Y., Kobayashi A.

VACUUM, cilt.177, 2020 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 177
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1016/j.vacuum.2020.109401
  • Dergi Adı: VACUUM
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Applied Science & Technology Source, Chemical Abstracts Core, Chimica, Compendex, Computer & Applied Sciences, INSPEC, Metadex
  • Anahtar Kelimeler: Double-layered thermal barrier coating, Cold gas dynamic spray (CGDS), Isothermal oxidation, Thermally grown oxide (TGO), Gadolinium zirconate (Gd2Zr2O7), EB-PVD TBCS, MECHANICAL-PROPERTIES, BEHAVIOR, MICROSTRUCTURE, GD, TEMPERATURE, RESISTANCE, LIFETIME, DY
  • Ondokuz Mayıs Üniversitesi Adresli: Evet

Özet

Oxidation is an inevitable failure mechanism under the operating temperature in gas turbines. To avoid negative effects of oxidation, ceramic-based materials having low thermal conductivity and high stability should be used to hot section components. In accordance with this purpose, thermal barrier coatings (TBCs) are used in order to increase the lifetime of gas turbine engine components that have not reached to desired levels yet. Yttria stabilized zirconia (YSZ) has been used as a conventional top coat material in TBCs. Increased the turbine inlet temperatures (TIT) promote to researchers to try higher stable material such as rare earth zirconates. In this study, CoNiCrAlY metallic powders were sprayed using a new emerging technique as called cold gas dynamic spray (CGDS) on Inconel 718 substrates. Single layer YSZ, Gd2Zr2O7 and double-layered YSZ/Gd2Zr2O7 were deposited by electron beam physical vapor deposition (EB-PVD) technique as top coat materials. In high temperature furnace, both TBC samples were isothermally oxidized at 1000 degrees C under different time periods. TBCs were examined as microstructural before and after oxidation tests. Thermally grown oxide (TGO) layer forming at the interface during oxidation were investigated and compared for each TBC systems. Oxidation and TGO growth behaviors were discussed.