Tribological properties of graphene nanosheets as an additive in calcium grease |
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| Authors: | Bahaa M Kamel Alaa Mohamed M El Sherbiny K A Abed M Abd-Rabou |
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| Institution: | 1. Mechanical Engineering Department, National Research Centre, Giza, Egyptbahaa2004eg@yahoo.com bmehany@kku.edu.sa;3. Production Engineering and Printing Technology Department, Akhbar El Yom Academy, Giza, Egypt;4. Mechanical Design and Production Engineering Department, Cairo University, Giza, Egypt;5. Mechanical Engineering Department, National Research Centre, Giza, Egypt |
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| Abstract: | The addition of graphene nanosheets (GNSs) in lubricating grease could significantly reduce the interfacial friction and improve the load-bearing capacity of the parts. Therefore, it has been considered as having great potential as lubricant additives. In this study, we synthesized GNSs that are prepared by a modified Hummer method, and investigated the effect of GNS with different concentration (0.5%, 1%, 2%, 3%, and 4?wt%) on the tribological properties of the calcium grease. The friction and wear experiments were performed using a four-ball tribometer. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to examine the GNS and the friction mechanisms. Results indicate that the friction reduction ability and anti-wear property of the base grease can be improved with the addition of GNS. It was also found that the friction reduction decreases by 61%, and the wear scar diameter (WSD) decreases by 45%, and the extreme-pressure (EP) properties increased 60% at 3?wt% GNS. It is clear that the GNS in grease easily forms protective deposited films to prevent the rubbing surfaces from coming into direct contact, thereby improving the entire tribological behavior of the grease. |
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| Keywords: | Calcium grease four-ball tribometer friction coefficients graphene nanosheets wear |
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