Abstract

GONZALEZ H, Andrés G et al. Evaluation of hot corrosion behavior of yttria-stabilized-zirconia coating elaborated by atmospheric plasma spraying. Rev. LatinAm. Metal. Mater. [online]. 2017, vol.37, n.1, pp.2-10. ISSN 0255-6952.

In this study, hot corrosion behavior in molten salts of 7 wt. % Yttria-Stabilized-Zirconia (YSZ) coatings manufactured by atmospheric plasma spraying was evaluated. YSZ coating was studied with two kind of thickness of NiCrAlCo-Y₂O₃ bond coat, which was elaborated on the Inconel 718 superalloy. The morphology of the raw material, the microstructure and fracture of the cross section of the coatings were evaluated by Microscopy Scanning Electron (SEM). The phases of the raw material and YSZ coating were analyzed from spectra of X-Ray Diffraction (XRD). Hot corrosion tests was performed in the presence of a mixture V₂O₅ and Na₂SO₄ powders at a temperature of 1050 °C for 40 h. The surface morphology and the phases of the coating after the hot corrosion test were evaluated by SEM and XRD respectively. Hot corrosion tests showed mainly the formation of yttrium vanadate crystals (YVO₄) and monoclinic zirconia (m-ZrO₂) in the top coating surface. These phases showed the destabilization of YSZ coating and therefore the decrease in its mechanical and thermal properties by the presence of a large amount of m-ZrO₂ resulting from XRD analysis after hot corrosion test. The two thicknesses of the bond coat resisted the thermal stresses generated during the hot corrosion test without generating appreciable cracks or delamination in the thermal barrier coating.

Keywords : YSZ; plasma spraying; hot corrosion; molten salts; thermal barrier coating.

        · abstract in Spanish     · text in Spanish     · Spanish ( pdf )