Advanced tribological coating solutions for extreme environments developed by solid state thermal spray processes

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Title: Advanced tribological coating solutions for extreme environments developed by solid state thermal spray processes Abstract: As part of the GHG emissions, the aerospace industry has set a clear target to reduce net carbon emissions by 50 percent by 2050 compared to 2005. The achievement of this ambitious goal will require a step change in the development of current gas turbine engines, including significant improvement in the thermal efficiency as well as implementation of hydrogen fuel propulsion. However, such advanced technologies will create a more challenging environment within the engines, which can degrade the physical properties of the employed materials. Therefore, there is a strong desire in developing novel aerospace coatings that, while being capable of surviving the vibrations during a flight, can operate effectively over billions of cycles in harsh environments. With the recent advances in thermal spray processes, lower temperature deposition techniques, such as the high velocity air fuel (HVAF), cold-spray (CS) and liquid-accelerated cold spray (LACS) methods, have recently become potential candidates for manufacturing of complex tribological coatings in extreme environments. However, limited research has been performed on this technology in the aerospace industry, in particular on self-lubricating tribological coatings. Thus, providing innovation in the engineering of new high-performance aerospace components will require systematic studies of 1) all steps during the coating synthesis processes, 2) the fundamental understanding of interfacial phenomena in sliding contacts, 3) optimization of the coating composition and 4) the deformation mechanisms and phase transformations of the self-lubricating materials.The main objective of this work is to develop next generation wear resistant coatings for extreme environments by solid-state deposition processes (e.g. LACS) as well as critically examine their interfacial phenomena in order to optimize tribological performance and consequently improve component durability. The early stage of the program will focus on the optimization of the deposition process for carbide-based tribological coatings. The coatings will be developed in the thermal spray facility at Concordia University by LACS and HVAF as well as in the surface engineering lab at the University of Toronto. The work proposed here will include the development, validation and calibration of multi-scale processing and performance modeling in order to optimize the spraying conditions for the most desirable microstructure. Subsequently, the tribological behavior of the coatings will be critically evaluated using high temperature, sub-component tribometers in order to fully capture their capability in relevant conditions. The major benefits of this work to the aerospace and energy generation community will be demonstrating proof of concept for these surface engineering strategies as well as the identification of interfacial processes in extreme conditions. The deposition process and the materials made initially for gas turbine engines will also be utilized by the oil & gas and automotive industries, which are important sectors to the Canadian economy.