This works investigates the in-situ formation of MoS₂ and WS₂ tribofilms by the synergy between transition metal oxide nanoparticles and conventional sulphur-containing anti-wear and extreme pressure additives. The formation of these low friction tribofilms can be obtained under reciprocating sliding contact and under extreme pressure conditions, as evidenced using X-ray photoelectron spectroscopy. Under reciprocating sliding conditions, the synergy between transition metal oxide nanoparticles and the ZDDP leads to coefficients of friction around 0.06 before they rise as consequence of oxidation. The synergy is more outstanding in extreme pressure conditions, particularly for MoO₃ nanotubes combined with extreme pressure additive. This combination outperforms base oil mixtures containing EP additive or MoS₂ nanotubes. While MoS₂ nanotubes build superb extreme pressure tribofilms containing iron and molybdenum oxides and sulphides, MoO₃ nanotubes are able to build similar tribofilms that can continuously re-sulphurize in the presence of the extreme pressure additive. Despite having a similar chemistry, MoO₃ nanotubes are observed to sulphurize more easily when compared to WO₃ nanoparticles. The work highlights the tribological potential of these nanoparticles otherwise typically used as precursors for the synthesis of transition metal dichalcogenide nanoparticles.

中文翻译：

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过渡金属氧化物纳米粒子与含硫油添加剂的协同作用原位形成MoS 2和WS 2摩擦膜

这项工作研究了MoS ₂和WS ₂摩擦膜的原位形成，该过渡膜是通过过渡金属氧化物纳米粒子与常规含硫抗磨和极压添加剂之间的协同作用而形成的。这些低摩擦的摩擦膜的形成可以在往复滑动接触和极端压力条件下获得，如使用X射线光电子能谱所证明的。在往复滑动条件下，过渡金属氧化物纳米粒子与ZDDP之间的协同作用会导致摩擦系数在0.06之前变大，然后由于氧化而升高。在极端压力条件下，尤其是对于MoO _3而言，协同作用更为出色纳米管结合极压添加剂。这种组合优于包含EP添加剂或MoS ₂纳米管的基础油混合物。尽管MoS ₂纳米管可形成包含铁，钼的氧化物和硫化物的极佳的超压摩擦膜，但MoO ₃纳米管却能够构建类似的摩擦膜，在存在极压添加剂的情况下，这些摩擦膜可连续地重新硫化。尽管化学性质相似，但与WO ₃纳米颗粒相比，观察到MoO ₃纳米管更容易硫化。这项工作突出了这些纳米颗粒的摩擦学潜力，这些纳米颗粒通常用作合成过渡金属二硫化碳纳米颗粒的前体。