Tribochemical driven interfacial energy gradient in ultralow wear PTFE composite

作者：Wei, Jiang; Sun, Wei; Liu, Kun; Liu, Xiaojun; Ye, Jiaxin^*

来源：Tribology International, 2023, 183: 108438.

DOI：10.1016/j.triboint.2023.108438

• Surface energy
• Transfer film
• Ultralow wear
• PTFE

Previous studies of certain ultralow wear PTFE composites highlighted the wear rate's extremely high sensitivity to the interfacial surface energy gradient (Delta gamma) with a scale factor of nearly 104 times per mJ/m2. This study aims to further elucidate the origin of such gradient and its relation with wear reduction by systematically studying wear and tribofilm's environmental sensitivities of a 5 wt% PPS-PTFE composite. The results found a scaling factor between wear rate and Delta gamma of about 1000 fold per mJ/m2. Results also suggest that the interfacial energy gradient is directly driven by transfer film adhesion and coverage, transfer film adhesion is dominated by PTFE tribochemistry rather than PPS enrichment, and a moderate Delta gamma minimizes bulk wear and stabilizes transfer films.