Hot corrosion behaviour of atmospheric and solution precursor plasma sprayed (La0.9Gd0.1)2Ce2O7 coatings in sulfate and vanadate environments

• Published in: Journal of the European Ceramic Society 2019-11, Vol.39 (14), p.4233-4244
• Main Authors: Praveen, K., Sravani, Nalla, Alroy, Rahul Jude, Shanmugavelayutham, G., Sivakumar, G.
• Format: Article
• Language: English
• Subjects: Gadolinium oxide doped lanthanum cerate; Hot corrosion; m-ZrO2; Solution precursor plasma spraying; YVO4
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2019.05.061

Conventional and solution precursor plasma spraying (SPPS) techniques were employed for developing gadolinium oxide doped lanthanum cerate ((La0.9Gd0.1)2Ce2O7, Gd-LC) based double-layered thermal barrier coatings (TBCs). Hot corrosion studies of the above coatings were carried out in molten Na2SO4 + V2O5 (1:1) environment at 900 °C. The state-of-the-art yttria-stabilized-zirconia (YSZ) coating was found to be completely delaminated after 120 h by forming yttrium vanadate (YVO4) and m-ZrO2. The accelerated delamination of YSZ can be attributed to the undesired phase transformation during exposure to corrosive species. Double-layered APS coatings were found to last for more than 300 h without densification of underlying YSZ layer and also, show better adherence with bond coat. SPPS Gd-LC coatings were found to be completely delaminated on densifying the underlying YSZ within 300 h. Lanthanum vanadate (LaVO4) was found to be the main corrosive product along with minor amounts of gadolinium vanadate (GdVO4) in Gd-LC double-layer coatings.