Tribological properties of PEEK-based composite coatings modified with black phosphorus

High-performance coating polyether-ether-ketone (PEEK) has been widely used in fields such as aerospace, mechanical and chemical industry, but industrial development has put forward higher requirements for PEEK's self-lubricating performance. In this work, an emerging two-dimensional black phosphorus (BP) modified PEEK self-lubricating composite coating was prepared by slurry printing techniques, and the microstructure, microhardness and tribological properties of coatings with different BP content were investigated. The results show that the introduction of BP results in the roughening of the coating surface and the reduction of the compactness. The microhardness was first improved, reaching a maximum value of 27.2 HV at 1wt% BP, but subsequently decreased. BP exhibited excellent anti-friction ability, which reduced the friction coefficient of the coating from 0.21 to the lowest value of 0.06. The wear rate was strongly dependent on the microhardness and reached the lowest value of 5.35×10⁻⁶ mm³·N⁻¹·m⁻¹ at 1wt% BP, which was 17.1% lower than that of pure PEEK. Pure PEEK suffered primarily from abrasive wear. BP weakened the grooves on the worn surface and transformed the friction mechanism into fatigue wear. The lubricating effect was attributed to the synergistic promotion of the tribo-transfer film formation by phosphorus oxides and BP.