Superlubricity in CoCrFeNiMn high entropy alloys: Tackling friction and wear challenges for advanced engineering applications

High entropy alloys (HEAs) are known for their excellent mechanical properties but suffer from poor wear resistance. This study introduces a novel method to enhance wear resistance by combining boriding surface treatment with glycerol-based lubrication to achieve superlubricity on CoCrFeNiMn HEA. Boriding treatment produced a dual-layer structure, increasing hardness to 24 GPa. When lubricated with glycerol, a near-zero friction coefficient (0.003) and ultra-low wear rate (10⁻⁷ mm³/Nm) were achieved after a brief running-in period (∼ 700 s). Stribeck curve analysis confirmed stable superlubricity across varying loads and velocities. The performance enhancement is attributed to a boron ester tribofilm (∼6 nm) formed during tribochemical reactions. This approach provides a promising solution for durable, low-friction materials in engineering applications.