纳米颗粒影响润滑膜摩擦特性的分子动力学

Molecular Dynamics Simulation of the Effect of Nanoparticles on the Tribological Properties of Lubricant Film

向润滑油中添加纳米颗粒可以降低摩擦系数,提高承载能力,但其中的物理机制并不完全清晰.采用分子动力学方法研究了理想摩擦副间纳米流体和基础流体摩擦特性的不同,着重探明纳米颗粒与基础流体的相互作用机制.研究发现在较高的载荷下纳米流体和基础流体均由液态转化成类固体,但纳米流体的相变压力明显高于基础流体;在相变点后,纳米流体表现出了良好的摩擦特性.纳米颗粒增强了润滑膜的承载能力,且在相变点后强化效果更好.最后对纳米颗粒改善润滑摩擦的物理机制做了详细的解释.

The lubricant film has excellent load-carrying capacity,anti wear and friction-reducing properties with the addition of nanoparticles,but the physical mechanism is still unclear. Using molecular dynamics simulation,the difference of tribological properties between nanofluid and base fluid was studied when the lubricant film was confined to idealized atomistic surfaces. The interaction between nanoparticles and base fluid was studied. The results indicate that： under high load,liquid-solid transition takes place for both base fluid and nanofluid; the critical pressure of nanofluid phase transition is higher than that of the base fluid. After phase transition,nanofluid shows excellent friction-reducing properties. Nanoparticles can also increase the load-carrying capacity effectively and the enhancement effect is better after phase transition. The mechanisms responsible for the nanofluids friction properties are explained in detail.