Silicon nanoparticles stuck graphene from graphite: Simulations of formation, deformation and lubrication

Abstract

The study first simulates formation of the graphene-stuck silicon nanoparticles from the silicon nanoparticle embedded into the annealed graphite. Covering graphene on nanoparticle can be more conveniently by using graphite instead of graphene. Graphene and silicon of the obtained nanoparticles show the tightly bonding situation to each other. In the annealing cases of 500, 1000 and 1500 K, the annealing at the higher temperature provides the stronger bond. The study then investigates their deformation and lubrication. The nanoparticles show the high stability under experiencing the pressure up to 3 GPa. As used as solid lubricants in contact with the diamond slab at 0.5–3 GPa, they provide the friction coefficients of 0.00022–0.00649, which strongly depend on the nanoparticle size. The nanoparticles provide the better mechanical and lubrication properties than the corresponding bare silicon nanoparticles. Thus, the study provides the method to cover graphene on nanoparticle from graphite and the obtained nanoparticles well experience the pressure and have the high lubricity. In order to avoid the damage to the silicon nanoparticle and graphite and increase the bond between them, the hole on graphite should have its radius larger than (or close to) the silicon nanoparticle radius plus the stable adsorption distance. The stability and lubricity are more advanced with increasing the nanoparticle size; therefore, experimental methods may be used to design such particles of large sizes for these behaviors. Friction dependent on the roughness is also investigated.