E. Altuncu, Kocaeli University, Kocaeli/ Izmit, Turkey; F. Ustel, Sakarya University, Sakarya, Turkey
Hot corrosion is one of the main destructive factors in thermal barrier coatings (TBCs) which comes as a result of molten salt effect on the coating–gas interface. Hot corrosion tests were carried out on the surface of coatings in molten salt (Na2SO4 +V2O5) at 1000 ◦C for 48 h. Spallation was observed in TBCs. The formation of monoclinic ZrO2 and YVO4 crystals as hot corrosion products caused the degradation of mentioned TBCs. Although monoclinic
ZrO2 decreased in (YSZ +Al2O3) in comparison with usual YSZ, dendritic YVO4 crystals had main role in degradation of (YSZ +Al2O3) coating. Results revealed that CSZ TBCs were better resistant to hot corrosion environment than YSZ TBCs in terms of phase stability and overall damage by the salt. From the present results, a possible microscopic degradation mechanism and effects of coating microstructures for zirconia-based TBCs under hot corrosion are discussed. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were applied to investigate structure and microstructural characterizations
Summary: Hot corrosion is one of the main destructive factors in thermal barrier coatings (TBCs) which comes as a result of molten salt effect on the coating–gas interface. Hot corrosion tests were carried out on the surface of coatings in molten salt (Na2SO4 +V2O5) at 1000 ◦C for 48 h. Spallation was observed in TBCs. The formation of monoclinic ZrO2 and YVO4 crystals as hot corrosion products caused the degradation of mentioned TBCs. Although monoclinic
ZrO2 decreased in (YSZ +Al2O3) in comparison with usual YSZ, dendritic YVO4 crystals had main role in degradation of (YSZ +Al2O3) coating. Results revealed that CSZ TBCs were better resistant to hot corrosion environment than YSZ TBCs in terms of phase stability and overall damage by the salt. From the present results, a possible microscopic degradation mechanism and effects of coating microstructures for zirconia-based TBCs under hot corrosion are discussed. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were applied to investigate structure and microstructural characterizations
