Grant: Alliance Grants

New generations of gas turbine engines are striving to increase their operating temperature to yield greater efficiency in the engine cycle. Consequently, improved thermal barrier coatings (TBCs) must be used to protect metallic components exposed to these high temperatures. These coatings consist of a thermally insulating ceramic layer deposited on a metal bond layer (bondcoat). The bondcoat has two essential roles: it increases the adhesion between the insulating ceramic layer and the parts to be protected while providing protection against oxidation occurring at high temperature. This project aims to develop an improved bondcoat layer to increase the performance and durability of TBCs while reducing the manufacturing costs. In this project, the HVAF deposition process will be used to optimize the structure and roughness of the bondcoat layers while optimizing their resistance to oxidation. The HVAF (High-Velocity Air-Fuel) process is a thermal spray process for metallic powders which enables efficient deposition of dense and weakly oxidized coatings without the need for expensive vacuum systems. One of the important challenges of the project is to establish whether it is possible to produce dense layers while sufficiently limiting the reaction of the powders in air to avoid the formation of detrimental phases in the deposits. The proposed research strategy is structured into three stages. The first combines computer fluid dynamics (CFD) modeling with improved diagnostic methods to optimize and control of the HVAF process. The second step deals with the ultrafine microstructure characterization of the deposited bondcoat layers using a complete set of advanced electron microscopy techniques. In a third step, the oxidation resistance and the durability of the deposited coatings are optimized by varying the deposition parameters of the HVAF process and the properties and composition of the starting metal powders. Optimized coatings have the potential to improve engine fuel efficiency, reduce greenhouse gas emissions, and reduce engine manufacturing and maintenance costs. _x000d_Pour augmenter l'efficacité énergétique des nouvelles générations de moteurs d'aéronefs, on vise à augmenter leur température de fonctionnement. En conséquence, on doit faire appel à des revêtements barrières thermiques (TBC)de haute performance pour pr