Preparation and tribological investigation of self-lubricating epoxy composite containing hollow mesoporous silicon nanocapsules loaded with PAO6/Cu nano-oil

The service life of self-lubricating spherical plain bearing (SLSPB) is heavily dependent on tribological property of polymeric liner between inside and outer ring. To meet urgent needs, such as ultra-long service life and harsher working conditions, enhancing SLSPB liner's tribological property is an effective option. Herein, different from conventional microcapsules, a novel nanocapsule containing nano-oil was successfully prepared mainly based on excellent tribological performance of Poly alpha olefin (PAO6, base oil) containing copper nanoparticles (Cu NPs) and pore canal and slow-release advantage of hollow mesoporous silicon nanocapsules (HMSNCs, hm -SiO 2 NCs). The results show that as-prepared PAO6/Cu@ hm -SiO 2 NCs have an average diameter of ∼150 nm and a content of 40 wt% Cu-nano-oil; when its content is 15 wt%, friction coefficient (COF) and wear rate ( W R ) of Epoxy resin (EP, as basic material of SLSPB) can be reduced by 88 % (0.74 → 0.09) and 99 % (47.312 × 10 −6  mm 3 /Nm to 0.646 × 10 −6  mm 3 /Nm), respectively. For one thing, such results have a close relationship with a synergistic effect among nano-oil, hm -SiO 2 NPs and EP resin. For another, a high-performance tribofilm with a gradient structure also plays a critical role, and this structure is closely associated with the size effect of DDP-Cu NPs, hm -SiO 2 nanoparticles, and PAO6/Cu@ hm -SiO 2 NCs. The corresponding tribological mechanism is also systematically investigated according to various surface and chemical analyses. The findings may pave a new strategy to enhance tribological property of polymer-based rubbing pairs, and contribute to designing a high-performance (such as ultra-long serve life, superior tribological performance, etc.) SLSPB liner.