Suspension plasma sprayed ytterbium disilicate coatings: Phase stability and microstructural evolution in extreme environments

• Published in: Journal of the European Ceramic Society Vol. 44; no. 15; p. 116779
• Main Authors: Owusu, Ebenezer B., Rincón Romero, Acacio, Lynam, Alex, Zhang, Buhao, Gavalda-Diaz, Oriol, Hussain, Tanvir
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2024
• Subjects: Calcium-magnesium-aluminium-silicate (CMAS); Environmental barrier coatings (EBCs); Steam recession; Ytterbium disilicate (YbDS); Ytterbium monosilicate (YbMS); Steam recession; Calcium-magnesium-aluminium-silicate (CMAS); Environmental barrier coatings (EBCs); Ytterbium disilicate (YbDS); Ytterbium monosilicate (YbMS)
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2024.116779

Suspension plasma spray (SPS) is a promising technique to deposit coatings with controlled microstructure. In this work, we explored this capability to produce ytterbium disilicate environmental barrier coatings with enhanced performance against steam and molten calcium-magnesium-aluminium-silicate (CMAS) corrosion. Steam exposure tests on the samples using steams with velocities of 1 m/s and 5 m/s at 1350 ᵒC for 96 h revealed that low-velocity steam caused silica volatilisation whereas the high-velocity steam caused both silica volatilisation and material erosion, yet no new cracks formed in the coating. CMAS degradation test for 5 and 240 mins at 1300 ᵒC on the coatings showed that the large aspect ratio of the splats facilitated reaction between CMAS and ytterbium monosilicate to form a dense layer that slowed further CMAS infiltration. These outcomes suggest that SPS has the proclivity to manufacture EBCs with improved resistance to steam and CMAS degradation.