Investigation and kinetic study of TGO growth behavior in high-entropy alloy coating systems

Odabas O., Binal G., Ozgurluk Y., Alptekin F., Karaoglanli A. C.

Surface and Coatings Technology, cilt.512, 2025 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 512
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1016/j.surfcoat.2025.132381
  • Dergi Adı: Surface and Coatings Technology
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: Composite coating systems, High-entropy alloys (HEAs), Oxidation kinetics, Thermally grown oxide (TGO)
  • Karadeniz Teknik Üniversitesi Adresli: Evet

Özet

In this study, AlCoCrFeNiTi and AlCoCrFeNiZr high-entropy alloys (HEA) developed for high temperature applications were applied as topcoats of the coating system by atmospheric plasma spraying (APS) process, while CoNiCrAlY bond coats were coated by high velocity oxygen fuel (HVOF) technique. As a result of isothermal oxidation tests performed in the range of 1000 °C–1200 °C, both HEA systems were found to be resistant to oxidation. The rate constant (Kp) and activation energy (Q) values obtained at 1200 °C were calculated as 0.1090 μm2/h/224.6 kJ/mol for AlCoCrFeNiTi and 0.1174 μm2/h/230.2 kJ/mol for AlCoCrFeNiZr, respectively. The findings reveal that the growth kinetics and microstructural evolution of the TGO layer directly affect the oxidation-induced degradation behavior of composite coating systems. The findings indicate that oxidation-induced microstructural changes and the growth behavior of the TGO layer are determinants of coating degradation.