THERMAL SHOCK BEHAVIOR OF LANTHANUM ZIRCONATE-BASED THERMAL BARRIER COATINGS

Karabas M., BAL E.

Surface Review and Letters, cilt.31, sa.4, 2024 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 31 Sayı: 4
  • Basım Tarihi: 2024
  • Doi Numarası: 10.1142/s0218625x24500276
  • Dergi Adı: Surface Review and Letters
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Applied Science & Technology Source, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: failure analysis, microstructure, Thermal barrier coating, thermal shock resistance
  • Akdeniz Üniversitesi Adresli: Evet

Özet

In this study, La2Zr2O7, Yb2O3 and Gd2O3-doped La1.4(Gd, Yb)0.6Zr2O7 thermal barrier coatings have been manufactured from the crystalline and amorphous feedstock by plasma spraying. The thickness of the bond coat is 100±25 μm and the thickness of the top coat is 250±25 μm. Thermal shock tests were carried out in furnace temperature of 1200C. The thermal shock tests indicate that lifetime of the La1.4Gd0.6Zr2O7 coating has 55 cycles which is the highest thermal shock lifetime compared to other coatings in this study. The type of feedstock, amorphous or crystalline, strongly affects the thermal shock lifetime of La2Zr2O7 coatings. Coating damage after thermal shock tests was investigated using scanning electron microscope to observe the microstructure and X-ray diffraction techniques to analyze the phase composition. The failure of coatings is mainly in consequence of the accumulation of stress between bond coat-ceramic coat interface due to thermal expansion coefficient differences and thermally grown oxide layer formation during thermal shock cycling tests.