Toward Highly Dense Yb-Silicate Microstructures Deposited by Air Plasma Spray for Environmental Barrier Coating Applications I: Influence of Local Deposition Rate

• DOI: 10.1007/s11666-025-01969-7
• Publication Date: 2025-04-04T14:50:22Z
• Authors: Emine Bakan; Edward J. Gilders...; Robert Vaßen
• Keywords: Deposition

Abstract Environmental barrier coatings (EBCs) are used to shield high-temperature Si-based ceramic matrix composite gas turbine components from the harsh, water vapor-rich operating environment. The success of this application is directly correlated intrinsic tightness or hermeticity EBC volatilization barrier, which typically rare-earth disilicates. For air plasma-sprayed (APS) EBCs, related processing parameters during deposition. In work, effect surface speed and feeding rate on microstructural evolution Yb 2 Si O 7 was studied. A qualitative assessment by means microstructure analysis after crystallization heat treatment influence aforementioned discussed. It found that utilizing lower rates can minimize certain types disadvantageous cracking in as-deposited coatings. Moreover, at these low (~1-5.4 g/min) regardless selected (250-1250 mm/s), highly dense microstructures could be obtained as-sprayed state. Contrastingly higher (~46.2 g/min), deleterious SiO 5 band formation observed top each spray pass, worsened microstructures, particularly (250 mm/s). monosilicate linked fine particle fraction feedstock (i.e., particles < 15 µm), sieving out eliminated when spraying rate.