The ability to lubricate and resist wear at temperatures above 600 °C in an oxidative environment remains a significant challenge for metals due to their high-temperature softening, oxidation, and rapid degradation of traditional solid lubricants. Herein, we demonstrate that high-temperature lubricity can be achieved with coefficients of friction (COF) as low as 0.10-0.32 at 600-900 °C by tailoring surface oxidation in additively-manufactured Inconel superalloy. By integrating high-temperature tribological testing, advanced materials characterization, and computations, we show that the formation of spinel-based oxide layers on superalloy promotes sustained self-lubrication due to their lower shear strength and more negative formation and cohesive energy compared to other surface oxides. A reversible phase transformation between the cubic and tetragonal/monoclinic spinel was driven by stress and temperature during high temperature wear. To span Ni- and Cr-based ternary oxide compositional spaces for which little high-temperature COF data exist, we develop a computational design method to predict the lubricity of oxides, incorporating thermodynamics and density functional theory computations. Our finding demonstrates that spinel oxide can exhibit low COF values at temperatures much higher than conventional solid lubricants with 2D layered or Magnéli structures, suggesting a promising design strategy for self-lubricating high-temperature alloys.

由于传统固体润滑剂的高温软化、氧化和快速降解，在氧化环境中润滑和抗磨损的能力对金属来说仍然是一个重大挑战。在此，我们证明，通过在增材制造 Inconel 高温合金中定制表面氧化，可以在 600-900 °C 时以低至 0.10-0.32 的摩擦系数 （COF） 实现高温润滑性。通过整合高温摩擦学测试、先进材料表征和计算，我们表明，与其他表面氧化物相比，尖晶石基氧化物层的剪切强度较低，负形成和内聚能更多，因此在高温合金上形成尖晶石基氧化物层促进了持续的自润滑。立方晶石和四方晶系/单斜晶尖晶石之间的可逆相变是由高温磨损过程中的应力和温度驱动的。为了跨越高温 COF 数据很少的 Ni 和 Cr 基三元氧化物组成空间，我们开发了一种计算设计方法来预测氧化物的润滑性，结合了热力学和密度泛函理论计算。我们的研究结果表明，尖晶石氧化物在远高于具有 2D 层状或 Magnéli 结构的传统固体润滑剂的温度下可以表现出低 COF 值，这表明自润滑高温合金的设计策略很有前途。