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

摘要：作为温室气体排放的一部分，航空航天工业已经设定了明确的目标，即到2050年将净碳排放量在2005年的基础上减少50%。要实现这一雄心勃勃的目标，需要对当前燃气涡轮发动机的发展进行阶段性的改变，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部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航空涂料，这种涂料既能承受飞行过程中的振动，又能在恶劣环境中有效运行数十亿次。随着热喷涂工艺的最新进展，低温沉积技术，如高速空气燃料（HVAF）、冷喷涂（CS）和液体加速冷喷涂（LACS）方法，最近成为在极端环境下制造复杂摩擦学涂层的潜在候选方法。然而，航空航天工业对该技术的研究有限，特别是对自润滑摩擦学涂层的研究。因此，在新型高性能航空航天部件的工程中提供创新将需要系统研究1)涂层合成过程中的所有步骤，2)对滑动接触界面现象的基本理解，3)涂层成分的优化以及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态沉积工艺（例如LACS）为极端环境开发下一代耐磨涂层，并严格检查其界面现象，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优化碳化物基摩擦学涂层的沉积工艺。涂层将由LACS和HVAF在Concordia大学的热喷涂设施以及多伦多大学的表面工程实验室进行开发。这里提出的工作将包括开发、验证和校准多尺度处理和性能建模，以优化喷射条件，获得最理想的微观结构。随后，将使用高温亚组分摩擦计对涂层的摩擦学性能进行严格评估，以充分捕捉其在相关条件下的性能。这项工作对航空航天和能源生产社区的主要好处将是展示这些表面工程策略的概念证明，以及极端条件下界面过程的识别。最初用于燃气涡轮发动机的沉积工艺和材料也将用于石油、天然气和汽车工业，这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.