Effect of Polydopamine‐Modified Boron Nitride on the Tribological Behavior and Interfacial Evolution of Carbon Fiber‐Reinforced PEEK Composites Under Dry Sliding and Starved Lubrication

ABSTRACT Polyetheretherketone (PEEK)‐based composites are promising materials for high‐load sliding components. However, their tribological reliability under severe conditions is often limited by interfacial instability and insufficient transfer‐film formation. In this work, dopamine‐modified boron nitride (BN@PDA) was prepared and incorporated into neat PEEK and carbon fiber‐reinforced PEEK (P/CF) composites. The role of BN@PDA in regulating filler dispersion, interfacial structure, mechanical properties, and tribological behavior was investigated under dry‐sliding and starved‐lubrication conditions. Compared with unmodified BN, BN@PDA provided more evident improvements in filler dispersion and high‐PV interfacial stability, particularly in the CF‐reinforced system. Under dry sliding, both P/CF/BN and P/CF/BN@PDA maintained stable low‐friction behavior at 4 MPa and 2 m/s, with average friction coefficients of approximately 0.049. P/CF/BN@PDA showed a slightly lower wear rate of 0.49 × 10 −6 mm 3 /N m and fewer friction fluctuations. Under starved lubrication, P/CF/BN@PDA remained stable for more than 10 h at 6 MPa and 2 m/s, whereas P/CF/BN failed under the same condition. Morphological and elemental analyses suggested that BN@PDA promoted the development of protective layers on both the polymer wear surface and the steel counterpart. These findings indicate that BN@PDA is an effective functional filler for improving the tribological reliability of P/CF composites under severe operating conditions.