In this study, Inconel 718 coatings were fabricated by high pressure cold spray deposition and the microstructure and tribological properties of the coatings were systematically investigated at both room and elevated temperatures. At the first place, the investigation on the effect of thermal exposure on the surface oxidation of the coatings was conducted in the absence of sliding. It was found that oxides started to form on the coating surface when the ambient temperature was above 500 °C. At 600 °C, a NiFe₂O₄ spinel oxide layer spread over the coating surface. Under sliding against an Al₂O₃ counter ball, oxides started to form on the coating surfaces in contact with the ball when the ambient temperature was above 200 °C due to the fact that the frictional and external heat had facilitated the formation of the oxides. Thus, the friction coefficients of the Inconel 718 coatings decreased with the increase of ambient temperatures. However, the wear rates of the coatings increased at 100 °C and 200 °C compared to those of the coatings tested at room temperature, which was due to the decrease of hardness and severe abrasive wear. When the ambient temperature was further increased to 300 °C, a transition in wear mechanism occurred and the wear rates decreased due to the formation and breakage of the surface oxides that could act as lubricants between the counter ball and coating. With further increase of ambient temperature, a ‘glaze’ layer was formed and grew on the wear tracks, which could act as a protective layer and showed a load-bearing effect that prevented further removal of the coating materials, resulting in an improved wear resistance of the Inconel 718 coatings at elevated temperatures. Therefore, cold sprayed Inconel 718 coatings could be potentially used under wear conditions at elevated temperatures.

在这项研究中，Inconel 718涂层是通过高压冷喷涂沉积法制造的，并且在室温和高温下都系统地研究了该涂层的微观结构和摩擦学性能。首先，在没有滑动的情况下研究了热暴露对涂层表面氧化的影响。发现当环境温度高于500℃时，氧化物开始在涂层表面上形成。在600°C时，NiFe ₂ O ₄尖晶石氧化物层遍布涂层表面。在对Al ₂ O _3的滑动下相反，当环境温度高于200°C时，与球接触的涂层表面开始形成氧化物，原因是摩擦和外部热量促进了氧化物的形成。因此，Inconel 718涂层的摩擦系数随环境温度的升高而降低。但是，与在室温下测试的涂层相比，在100°C和200°C下的涂层磨损率增加，这是由于硬度降低和严重的磨料磨损所致。当环境温度进一步升高到300°C时，磨损机理发生了转变，并且由于表面氧化物的形成和破裂而导致磨损率降低，而表面氧化物可能会在副球和涂层之间起润滑剂的作用。随着环境温度的进一步升高，形成了一层“釉”层，并在磨损轨道上生长，该釉层可以充当保护层，并显示出承重效果，阻止了涂层材料的进一步去除，从而提高了Inconel 718涂层在高温下的耐磨性温度。因此，在高温下的磨损条件下，可能会使用冷喷涂的Inconel 718涂层。