Polyimide/DLC double-layered coatings achieving ultralow friction at elevated temperatures

To solve the severe friction and wear problem of bearings in aircraft engine low-pressure compressors, polyimide (PI)/layered double hydroxide (LDH)/diamond-like carbon (DLC) double-layered coatings were fabricated, and their tribological performance were investigated in a high temperature range. Results showed that the PI/1.0LDH/DLC double-layered coating exhibited an ultralow friction coefficient of 0.06 at 300 °C, demonstrating a reduction of over 60 % compared to both single-layer PI and DLC coatings under high-temperature conditions. A uniform carbon-based tribofilm was formed from the double-layered coating, endowing the sliding interface with exceptional lubrication performance. The findings of this study offer novel strategies for the development of solid lubricant coatings intended for high-temperature applications.