Synthesis of yttria by aqueous sol-gel route to develop anti-CMAS coatings for the protection of EBPVD thermal barriers

Design of a new yttrium silicate Environmental Barrier Coating (EBC) based on the relationship between microstructure, transport properties and protection efficiency

“…This method has been selected in the aim of obtaining a pure compound with the expected polymorph. The sol-gel method consists in synthesizing a solid powder by means of solution precursors [46][47]. The principle is based on the succession of hydrolysis-condensation reactions to form networks of oxides which are then heat-treated.…”

“…For instance, lutetium disilicate (ionic radius of Lu = 86 pm) is less sensitive to volatilization phenomena than yttrium disilicate (ionic radius of Y = 90 pm). According to literature data [46][47][48][49], the formation of a monosilicate layer above a disilicate coating allows contributing to limit surface recession, by changing the chemical composition and the microstructure of the surface [50].…”

Preparation of Dense Al₂O₃ Film on 8YSZ Coating by Sol-Gel Method

“…Some researches focused on preparing a ceramic film with sol-gel method on the surface of YSZ TBCs. For example, Y 2 O 3 coatings were prepared by sol-gel dip-coating routes on the EB-PVD 6-10% YSZ coatings, and had proven efficiency against the infiltration of CMAS at hightemperature for a limited time [10]. Al 2 O 3 films were prepared by sol-gel method on the APS 7YSZ coatings after the coating was laser remelted, and the TGO growth rate was found to be decreased [9].Some other researches focused on preparing a ceramic coating with sol-gel method instead of ASP or EB-PVD method just on the surface of bond-alloy substrate.…”