Phase stability and thermal insulation of YSZ and erbia-yttria co-doped zirconia EB-PVD thermal barrier coating systems

• Published in: Surface & coatings technology Vol. 389; p. 125566
• Main Authors: Boissonnet, G., Chalk, C., Nicholls, J.R., Bonnet, G., Pedraza, F.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.05.2020; Elsevier BV; Elsevier
• Subjects: Annealing; Chemical Sciences; Coatings; Conduction heating; Conductive heat transfer; Electron beams; Electron-beam physical vapour deposition (EB-PVD); Erbia-yttria co-stabilized zirconia (ErYSZ); Erbium oxide; Gas turbines; Insulation; Material chemistry; Operating temperature; Phase stability; Phase transitions; Physical vapor deposition; Room temperature; Thermal barrier coatings; Thermal barrier coatings (TBCs); Thermal diffusivity; Thermal insulation; Transport properties; Yttria stabilized zirconia (YSZ); Yttria-stabilized zirconia; Yttrium oxide; Zirconium dioxide; Thermal diffusivity; Erbia-yttria co-stabilized zirconia (ErYSZ); Thermal barrier coatings (TBCs); Yttria stabilized zirconia (YSZ); Electron-beam physical vapour deposition (EB-PVD); thermal diffusivity
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2020.125566

In order to cope with the ever-increasing operating temperature of aero gas turbines, new thermal barrier coatings are being investigated. Among the different solutions, erbia-yttria co-doped zirconia coatings made by electron-beam physical vapour deposition (EB-PVD) show promising results in terms of thermal insulation enhancement. Annealing of these coatings was performed at 1100 °C in air in order to investigate their stability in comparison with that of standard 8 wt% yttria-stabilized zirconia (8YSZ). Their thermal transport properties were measured using the laser-flash technique. The results show that the as-deposited co-doped coatings offered lower heat conduction than the standard ones in the studied temperature range (from room temperature to 1100 °C). However, the microstructural and phase transformations of the co-doped coatings after annealing were significantly greater than those of the standard coatings, hence strongly modifying their thermal insulation potential. •Erbia-yttria co-stabilized coatings showed better thermal insulation than the standard yttria-stabilized zirconia coatings,•The erbia-yttria co-stabilized coating systems were more affected by the annealing at high temperature,•Erbia addition led to a faster degradation of the thermal barrier coating system via the rapid oxidation of the bond coating.