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

由固态热喷涂技术开发的用于极端环境的高级摩擦学涂层解决方案摘要：作为温室气体排放的一部分，航空航天工业制定了一个明确的目标，到2050年将净碳排放量比2005年减少50%。要实现这一雄心勃勃的目标，将需要对目前燃气轮机发动机的发展进行阶段性改变，包括显著提高热效率以及实施氢燃料推进。然而，这种先进的技术将在发动机内创造一个更具挑战性的环境，这可能会降低所用材料的物理性能。因此，人们强烈希望开发新型的航空涂层，这种涂层能够在飞行过程中经受住振动，并能够在恶劣的环境中有效地运行数十亿次。随着热喷涂工艺的发展，高速空气燃料(HVAF)、冷喷涂(CS)和液体加速冷喷涂(LACS)等低温沉积技术已成为在极端环境下制备复杂摩擦学涂层的潜在候选者。然而，在航空航天工业中，对这项技术的研究有限，特别是在自润滑摩擦学涂层方面。因此，要创新高性能航空新部件的设计，需要系统地研究1)涂层合成过程中的所有步骤，2)对滑动接触中界面现象的基本了解，3)涂层成分的优化，4)自润滑材料的变形机制和相变。这项工作的主要目标是通过固相沉积工艺(如LACS)开发适用于极端环境的下一代耐磨涂层，并严格检查它们的界面现象，以优化摩擦学性能，从而提高部件的耐久性。该计划的早期阶段将侧重于碳化物基摩擦涂层沉积工艺的优化。这些涂层将由LACS和HVAF在康科迪亚大学的热喷涂设施以及多伦多大学的表面工程实验室开发。本文提出的工作将包括多尺度工艺和性能建模的开发、验证和校准，以优化喷涂条件以获得最理想的微观结构。随后，将使用高温亚组分摩擦仪对涂层的摩擦学行为进行严格评估，以充分了解它们在相关条件下的性能。这项工作对航空航天和能源发电界的主要好处将是展示这些表面工程战略的概念证明，以及在极端条件下识别界面过程。沉积过程和最初用于燃气轮机发动机的材料也将被石油天然气和汽车行业使用，这些行业是加拿大经济的重要部门。

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.