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

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. Highlights PDA modification improves BN dispersion in PEEK composites. BN@PDA enhances the mechanical properties of CF-reinforced PEEK composites. P/CF/BN@PDA maintains stable sliding for over 10 h under high-PV starved lubrication. BN@PDA promotes tribofilm formation on polymer and steel surfaces.