Emergency‐Ready Functional Coatings: Sustaining Friction Performance Through Oil Lubrication Failure

ABSTRACT

To mitigate risks from abrupt transition to oil‐free lubrication, we prepared a functional solid lubricant coating demonstrating superior stability across diverse lubrication conditions. The coating is an epoxy resin as the matrix, reinforced with graphite and molybdenum disulfide (MoS₂) as the functional fillers. Through a systematic spraying‐sintering process, the formulated slurry yields a composite coating characterized by exceptional antifriction and wear‐resistant properties. The tribological behavior of the coating is obviously influenced by both graphite and MoS₂. Under low loads, graphite dominates lubrication due to its lower shear resistance while MoS₂ excels under high loads by its higher load‐bearing capacity. After filler proportion is optimized, synergistic interactions between the fillers promote the formation of a continuous transfer film, effectively isolating friction surfaces and mitigating adhesive wear. Specifically, the optimal coating, comprising 14 wt% MoS₂ and 8 wt% graphite, exhibits outstanding performance. Under a load of 200 N, it exhibits an average friction coefficient of 0.041 and a specific wear rate of 4.25 × 10⁻⁶ mm³/(N·m) under oil lubrication. Under oil‐free conditions, these values increase to a friction coefficient of 0.049 and a wear rate of 1.25 × 10⁻⁵ mm³/(N·m). This work supports the safety of mechanical systems during abrupt transition from oil lubrication to oil‐free conditions.