Abstract A high quality three dimensional graphene nanosheets (3D GNS) with few layers’ thickness was prepared by the arc-discharge method. The 3D GNS is used as oil additive to explore its tribological performance under different working conditions. The results demonstrate that with the help of 3D GNS, the anti-wear and friction-reduction capabilities of base oil are improved in a wide range of speed and load. Especially under low speed and heavy load condition (4.2 mm/s and 1.0 GPa contact pressure), the reduction in coefficient of friction and wear volume loss can be as high as 29.1% and 55%, respectively. Raman spectrum and its mapping together confirmed the existence of protective film consisted by 3D GNS on rubbing surface, which avoids the direct contact of tribo-pairs and thus enhances the tribological performance of oil. In the case of heavier load condition, the lubricating performance of 3D GNS was reduced owing to the deteriorated 3D structure of the GNS. For higher speed, the thicker oil film brings better tribological properties to oil and minute 3D GNS is needed to participate in the friction process. The results are in good agreement with the Stribeck curve prediction. In brief, 3D GNS is helpful for improving the tribological properties of base oil under low speed and heavy load; thus providing a new insight for practical application as lubricant additive.

中文翻译：

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通过电弧放电方法制备的 3D 石墨烯作为油添加剂在可变负载和速度下减少摩擦和磨损

摘要 采用电弧放电法制备了高质量的三层石墨烯纳米片（3D GNS）。3D GNS 用作油添加剂，以探索其在不同工作条件下的摩擦学性能。结果表明，在3D GNS的帮助下，基础​​油的抗磨减摩能力在较宽的速度和负载范围内都有所提高。特别是在低速重载条件下（4.2 mm/s和1.0 GPa接触压力），摩擦系数和磨损体积损失的降低分别高达29.1%和55%。拉曼光谱及其映射共同证实了摩擦表面存在由3D GNS组成的保护膜，避免了摩擦对的直接接触，从而提高了油的摩擦学性能。在较重负载条件下，由于 GNS 的 3D 结构恶化，3D GNS 的润滑性能降低。对于更高的速度，更厚的油膜为油带来更好的摩擦学性能，并且需要微小的 3D GNS 参与摩擦过程。结果与 Stribeck 曲线预测非常吻合。总之，3D GNS有助于改善基础油在低速重载下的摩擦学性能；从而为作为润滑剂添加剂的实际应用提供了新的见解。结果与 Stribeck 曲线预测非常吻合。总之，3D GNS有助于改善基础油在低速重载下的摩擦学性能；从而为作为润滑剂添加剂的实际应用提供了新的见解。结果与 Stribeck 曲线预测非常吻合。总之，3D GNS有助于改善基础油在低速重载下的摩擦学性能；从而为作为润滑剂添加剂的实际应用提供了新的见解。