Exploring tribo-electro-chemistry mechanisms of h-BNO@PDA as lubricant additives under electrified conditions for electrical vehicles powertrain

Abstract

The study explores the use of polydopamine-functionalized hexagonal boron nitride (h-BNO@PDA) as a lubricant/insulator additive in polyalphaolefin (PAO6) oil. This article's novelty lies in the formulation of an innovative lubricant that is free from sulfated ash, phosphorus, and sulfur (SAPS), exhibiting super-lubrication and desirable dielectric properties under electrified conditions. The h-BNO@PDA nanolubricant is specifically designed to mitigate the negative effects of shaft currents and enhance powertrain lubrication for electric vehicles (EVs). Herein, the physicochemical, dielectric strength, and tribological properties of h-BNO@PDA nanolubricant are compared to commercial fully synthetic oil (ATF-6S) used in EVs. The SRV-IV tribometer was used to assess tribological performance under various currents (0–10 A). Subsequently, characterization techniques were utilized to illustrate wear mechanisms and explore tribochemical reactions. The h-BNO@PDA nanolubricant presented superior physicochemical and dielectric properties. The h-BNO@PDA nanolubricant reduced the friction coefficient by 18–20 % and the wear rate by 4–72 % compared to ATF-6S oil under electrified conditions at temperatures of 27 °C and 100 °C. These findings can be attributed to the positive effects of oxidational wear (Fe3O4) and h-BNO@PDA on tribolayer formation under electrification conditions. Eventually, our findings will offer promising insights to enhance the durability of EVs powertrain.