Frictional mechanisms of a novel base lubricant material: Optimizing tribological performance through viscosity-wear design

The advancement of aerospace and polar technologies has heightened the demand for lubricants capable of delivering stable performance under extreme temperature conditions while minimising friction and wear. However, existing lubrication systems remain inadequate for reliable operation within a broad thermal range of –50 to 350°C. In this study, we propose a wide-temperature lubricant formulation comprising chlorophenyl silicone oil (CPSO) as the base fluid, polydiethylsiloxane (PDES) as a compatibiliser, and pentaerythritol ester (PET) to enhance high-temperature anti-wear performance. At low temperatures (–50 to 25°C), the lubricant primarily functions via hydrodynamic mechanisms, maintaining fluid lubrication, although friction tends to increase with decreasing temperature. Above 200°C, a friction-induced nano-tribofilm, composed of metallic compounds and amorphous silicon oxides, forms on the surface, markedly enhancing anti-wear and friction-reducing properties. At 300°C, the hybrid lubricant reduces the wear rate of M50 steel by 86% and 61% compared with CPSO and PDES alone, respectively. Overall, this lubricant demonstrates outstanding tribological stability across a wide temperature range, offering crucial insights and support for developing advanced lubrication technologies suited for extreme environments.