Nano-particles (NPs) are extensively explored as additives (anti-friction- AF, anti-wear AW and extreme pressure- EP) in oils and greases. Combinations of NPs of graphite and hexagonal boron nitride (hBN) were tried in Group III oil keeping total amount constant (4 wt%) along with dispersant (Polyisobutylenesuccinimide-PIBSI- 1 wt%) to explore the possible synergism in AW and EP performance. Combo-oils with 2% of each NPs showed synergistic effect in AW performance with 63% improvement compared to the parent oil. The SEM and EDAX studies on ball surface worn in this oil revealed best quality film (smooth, thin and coherent) and also with lowest roughness of 56 nm as confirmed from the atomic force microscopy (AFM). In case of EP test, however, no synergism was observed. Graphite NPs (4%) proved most effective with 78% improvement. Step-wise inclusion of hBN deteriorated the performance.

中文翻译：

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石墨和六方氮化硼纳米颗粒作为抗磨添加剂和极压添加剂的组合-探讨协同作用的可能性

纳米颗粒（NPs）被广泛用作油脂中的添加剂（抗摩擦AF，抗磨AW和极压EP）。在第III组油中尝试了将石墨和六方氮化硼（hBN）的NP组合在一起以保持总量恒定（4 wt％）和分散剂（Polyisobutylenesuccinimide-PIBSI-1 wt％）的方法，以探索AW和EP性能的协同作用。每种NP含量为2％的组合油对AW性能表现出协同作用，与母体油相比，具有63％的改善。SEM和EDAX对在这种油中磨损的球表面进行的研究表明，质量最好的膜（光滑，薄且连贯），并且原子力显微镜（AFM）证实其最低粗糙度为56 nm。然而，在EP测试的情况下，未观察到协同作用。石墨纳米颗粒（4％）被证明是最有效的，改善了78％。