Molecular dynamics simulation on the enhanced tribological characteristics by sulfur-based tribo-film formation of TiO₂/MoS₂ heterostructure nanocomposites

Abstract Numerical investigations of the tribological behaviors of heterostructure nanocomposites were conducted using molecular dynamics simulation techniques. The frictional characteristics, including thermal stress, were analyzed by comparing four friction models: no-nanoparticle, MoS 2 , TiO 2 , and TiO 2 /MoS 2 nanoparticle models under boundary lubrication. The no-nanoparticle model displayed high friction forces and temperature peaks owing to direct metal-to-metal contact, thus demonstrating the inherent challenges of substrate interactions without nanoparticle mediation. The addition of TiO 2 nanoparticles substantially reduced the average coefficient of friction by 56.08% compared with that of the MoS 2 model. This effect is attributable to the rolling effect induced by the nanoparticles, which minimized direct contact. The TiO 2 /MoS 2 model, which incorporated MoS 2 into the TiO 2 model, demonstrated a 24.42% reduction in the average coefficient of friction compared with the TiO 2 model. Additionally, the TiO 2 /MoS 2 composite model exhibits the lowest temperature profile during sliding, indicating its superior thermal management performance. The synergistic combination of TiO 2 and MoS 2 in the composite-nanoparticle tribological system enhanced the performance by forming tribofilms that reduced friction and wear while stabilizing the temperature. MoS 2 contributes to the formation of tribofilms that minimize wear and stabilize heat generation, while spherical TiO 2 nanoparticles prevent tribo-film degradation, further improving durability. This study highlights the synergistic efficacy of TiO 2 and MoS 2 nanoparticle additives in reducing wear and enhancing thermal management under frictional conditions, thereby providing valuable insights into advanced tribological applications.