氧化铈纳米添加剂与商用添加剂的共吸附行为及其协同润滑机制研究

纳米添加剂因其高效的减摩抗磨效应在节能内燃机油中具有广阔的应用前景，与内燃机油中商用添加剂的协效机制是开发纳米添加剂内燃机油配方的关键问题. 本文中利用石英晶体微天平(QCM-D)研究油胺修饰CeO2纳米微粒与商用内燃机油添加剂在金属表面的协同吸附行为，及其对CeO2纳米添加剂减摩抗磨性能的影响机制. 发现清净剂(DE)、减摩剂(FM)、抗氧剂(AO)和黏指剂(VII)都可以同CeO2纳米微粒共同形成摩擦膜，使抗磨性能优于单一添加剂，表现出了协同效应. CeO2纳米微粒与有机分子添加剂复配的抗磨性能与其吸附层的吸附质量成正比. 对于趋近于单层刚性吸附的添加剂，随分子中烷基链长度的增大，CeO2纳米微粒参与共吸附的程度逐渐降低. 分散剂中的长烷基链PIB (聚异丁烯)部分阻碍了CeO2纳米微粒的吸附，使其无法在摩擦副表面沉积成膜，导致了显著的拮抗效应.

Nanoparticle additives hold great application prospects in energy-saving internal combustion engine oils due to their efficient friction-reduction and anti-wear effects. The synergistic mechanism with commercial additives in internal combustion engine oils is a key issue for developing nanoparticle additive-containing internal combustion engine oil formulations. In this study, quartz crystal microbalance with dissipation monitoring (QCM-D) was used to investigate the synergistic adsorption behavior of oleylamine-modified CeO2 nanoparticles and commercial internal combustion engine oil additives on metal surfaces, as well as the mechanism underlying their effects on the friction-reduction and anti-wear performance of CeO2 nanoparticle additives. It was found that detergent (DE), friction modifier (FM), antioxidant (AO) and viscosity index improver (VII) can jointly form tribofilms with CeO2 nanoparticles, endowing better anti-wear performance than single additives, thus exhibiting synergistic effects. The anti-wear performance of the composite system of CeO2 nanoparticles and organic molecular additives is proportional to the adsorbed mass of their adsorption layer. For additives that approach rigid monolayer adsorption, the degree of CeO2 nanoparticles participating in co-adsorption gradually decreases with the increase of alkyl chain length in their molecules. The long alkyl chain polyisobutylene (PIB) in dispersants partially hinders the adsorption of CeO2 nanoparticles, preventing them from depositing and forming films on friction pair surfaces, resulting in significant antagonistic effects.