ABSTRACT Sliding bearings serve critical functions in various machinery systems, particularly in automobile engines. Their operational reliability necessitates regular lubricant inspection to prevent premature failure, posing a challenge to the development of high‐accuracy and low‐cost online monitoring sensors for oil. This study developed a smart triboelectric metal‐polymer sliding bearing (T‐MPSB) based on diamond‐like carbon (DLC) coating for the real‐time monitoring of the lubricating oil. Fluorine and nitrogen codoped diamond‐like carbon (FN‐DLC) coatings were systematically investigated as promising electronegative materials with enhanced triboelectric output and extraordinary tribological robustness. Integration of the FN‐DLC coating to the sliding bearing system reduced the friction under boundary lubrication and enabled self‐sensing ability for intelligent monitoring of moisture, wear debris, and oxidation in the base lubricating oil. Additionally, commercial engine oil with full additive packages was used to demonstrate the ability of the T‐MPSB in monitoring the consumption of additives, which has never been reported before. Furthermore, an intelligent monitoring system for the consumption of lubricant additives was realized by combining the T‐MPSB with AIoT technology, thereby achieving online visualization of the oil condition and early warning of additive depletion. This study provides a feasible pathway for the intelligent monitoring of lubricant conditions toward future smart machinery.
Yang et al. (2026) studied this question.