Tribological Anisotropy and Wear Mechanisms in Pre‐Compressed PTFE /Nomex Fabric/Phenolic Composites

ABSTRACT The tribological anisotropy behavior and underlying wear mechanisms of woven polytetrafluoroethylene (PTFE)/Nomex fabric/phenolic composites under pre‐compression were systematically investigated. Four pre‐compression levels (0%–8.9%) were established based on finite element simulations to achieve a uniform strain distribution. Ball‐on‐disk friction tests revealed that pre‐compression dramatically altered directional wear behavior, with moderate compression (4.3%–6.5%) reducing wear anisotropy from 81% to merely 1.1% between warp and weft directions. Comprehensive microscopic analysis revealed that this remarkable reduction in anisotropy resulted from pre‐compression‐induced optimization of fiber arrangement and resin redistribution, which fundamentally changed the wear mechanism from irregular fiber pull‐out to uniform friction film formation. Elemental mapping confirmed that appropriate pre‐compression facilitated continuous PTFE‐rich friction films, while excessive compression (8.9%) triggered transition to abrasive wear with patchy film distribution. These findings provide new insights into the tribological anisotropy mechanisms of fabric composites and demonstrate how controlled microstructural modification can achieve unprecedented directional wear uniformity.