Kaleli Hakan, Demirtaş Selman, Uysal Veli, Karnis Ioannis, Stylianakis Minas M, Anastasiadis Spiros H, Kim Dae-Eun
Faculty of Mechanical Engineering, Automotive Division, Yildiz Technical University, Besiktas, Yildiz, 34349 Istanbul, Turkey.
Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas (FORTH), GR-70013 Heraklion, Crete, Greece.
Nanomaterials (Basel). 2021 Feb 3;11(2):386. doi: 10.3390/nano11020386.
We investigated the tribological behavior of commercialized, fully synthetic engine oil upon the incorporation of reduced graphene oxide in seven different concentrations between 0.01 and 0.2 wt %. Stability of the prepared samples was assessed by turbidimetry and dynamic light scattering measurements, and their tribological properties through a reciprocating tribometer, using a steel ball on special cut steel blocks. The addition of 0.02 wt % of reduced graphene oxide led to an improvement of the tribological behavior compared to the pristine engine oil, by significantly lowering the friction coefficient by 5% in the boundary lubrication regime. Both the surfaces and the reduced graphene oxide additive were thoroughly characterized by microscopic and optical spectroscopy techniques. We also verified that a protective layer was formed between the worn surfaces, due to the presence of reduced graphene oxide. Carbon accumulation and various additive elements such as Ca, Zn, S and P were detected on the rubbing surfaces of both the ball and the block through energy-dispersive X-ray spectroscopy. Finally, it was shown that the wear scar diameter on the surface of the steel ball was lower by 3%, upon testing the engine oil sample containing reduced graphene oxide at concentration 0.02 wt %, compared to the control sample.
我们研究了在商业化的全合成发动机油中加入浓度在0.01至0.2 wt%之间的七种不同浓度还原氧化石墨烯后的摩擦学行为。通过比浊法和动态光散射测量评估制备样品的稳定性，并使用钢球在特殊切割的钢块上通过往复摩擦计测量其摩擦学性能。与原始发动机油相比，添加0.02 wt%的还原氧化石墨烯可改善摩擦学行为，在边界润滑状态下摩擦系数显著降低5%。通过显微镜和光谱技术对表面和还原氧化石墨烯添加剂进行了全面表征。我们还证实，由于还原氧化石墨烯的存在，在磨损表面之间形成了一层保护层。通过能量色散X射线光谱法在球和块的摩擦表面检测到了碳积累以及各种添加剂元素，如钙、锌、硫和磷。最后，结果表明，与对照样品相比，在测试浓度为0.02 wt%的含还原氧化石墨烯的发动机油样品时，钢球表面的磨损斑直径降低了3%。
