中文摘要：

以片状Fe3O4纳米颗粒为润滑油添加剂，在四球摩擦试验机中考察了其在qO机油中的摩擦化学性质和对摩擦副摩擦化学的影响。结果表明：与摩擦前的片状Fe3O4纳米颗粒相比，摩擦化学作用使得摩擦后纳米颗粒的性质（如：相组成、晶粒尺寸、比表面积、氧化转变温度、磁性能、结晶度和晶面间距）有所改变。片状Fe3O4纳米颗粒由于与摩擦副持续的高速摩擦产生了机械力化学效应，其诱发片状Fe3O4纳米颗粒在摩擦副表面发生摩擦化学反应，最终生成了一层或多层富含Fe、FeO、Fe3O4、y-FeOOH、y-Fe203和a-Fe203等物相的稳定抗摩擦自修复保护膜，从而阻止摩擦副直接接触，起到抗磨减摩作用。

英文摘要：

The tribochemical properties of Fe3O4 nanoparticles （NPs） with a hexagonal morphology as a lubricating additive in #40 engine oil, and the tribochemical effect on the formation of self-repairing film on the surface of fi＇iction pairs were investigated in a four-ball tribotester. The results show that some properties （i.e., phase composition, grain size, specific surface area, transition tem- perature of oxidation, magnetic properties, crystallinity and interplanar spacing） of Fe304 NPs are changed during friction due to the tribochemieal effect, compared to those of the original NPs. The mechanochemical reactions between Fe304 NPs and fi＇iction pairs occur during friction, resulting in the formation ofa mono- or multi-layer self-repairing film with various phases like Fe, FeO, Fe3O4, 7-FeOOH, γ-Fe2O3 and a-FezO3 on the friction pair surface. The film could prevent the direct contact between friction pairs and de- crease fi＇iction and wear as well.