Effect of Nano-BN on the Tribological Properties of Aramid Fiber Composites

Abstract

Aramid fibers, with their excellent mechanical properties and thermal stability, face limitations in tribological applications due to surface inertness. In this study, aramid fibers were modified with the silane coupling agent KH550. Subsequently, composites containing different amounts of nano-BN (ranging from 0 to 2.5%) were prepared using an epoxy resin matrix and an aramid fiber via the vacuum infusion process. FTIR confirmed successful fiber modification, showing new peaks at 2925, 2852, and 3310 cm^–1 from methylene, methoxy, and amino groups, respectively. The incorporation of nano-BN was confirmed by SEM-EDS through the detection of B and N elements. Tribological tests on an MFT-3000 tester under 100 N load, 10 Hz frequency, 1 mm wear distance, and 15 min duration revealed optimal performance at 0.5 wt.% nano-BN. SEM results showed the COF of ~0.4 and wear rate of 6.2∙10^–10 m³∙(N∙m)^–1, attributed to a stable transfer film reducing direct contact. However, as the BN content increased, the agglomeration of nano-BN became more severe. This agglomeration led to an elevation in both the wear rate and the COF. Besides, the load and friction speed had a significant impact on the friction and wear performance of the composites, with higher speeds increasing the rate of wear and the volatility of the coefficient. The primary wear mechanism was identified as adhesive wear. Nano-BN played a crucial role in facilitating the formation of a transfer film by enhancing the wear resistance of the composites and effectively decreasing the COF.