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Production of Copper-Graphene Nanocomposites Via Molecular Level Mixing, Evaluation of the Effect of Some Processing Parameters on Micro-Structure and Physical-Mechanical Properties

Fahimi, Negar | 2020

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 53005 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Abachi, Parvin
  7. Abstract:
  8. This research aimed at production of Cu-rGO via the combination of Molecular-Level-Mixing (MLM) method and powder metallurgy route (PM). First, Cu-GO composite powder was produced via MLM method. Subsequently, the resultant powder was mixed with electrolytic copper powder.Synthesis process included adjustment of the solution containing copper sulfate and 2Na.EDTA using NaOH solution. In the next step, GO suspension was added to the aforementioned solution. Finally, reduction of copper powder and formation of nanocomposite powder completed via the addition of Sodium Borohydrate. Nanocomposite powder was washed and dried in vacuum oven in 70˚C. GO reduction process took place using a tube farnace containing Ar-5H2 atmosphere in 300˚C for 4 hours. Then, Cu-rGo nanocomposite powder was cosolidated using SPS method in 600˚C, for 5 minutes under a pressure of 40 MPa.Samples produced via the the combination of both methods contained 0.25, 0.5 and 1wt.% rGO. Two other samples containing 0.5wt.% rGO were produced to examine the effect of production route on properties; one thoroughly via MLM, the other via PM method using CTAB as a surface modifier. Electrolytic copper powder was consolidate to produce a reference sample.FTIR characterization results admitted the elimination the majority of functional groups on the surface of GO, and formation of rGO. FESEM images showed that rGO powder was disperesed in copper powder. Archemedes method was employed as density measuring method. Vickers hardness measurements showed that hardness of the samples increases as the rGO increases, but decreases when the amount of rGO exceeds 0.5wt.%. Electrical resistivity was measured via four-probe method. Electrical resistivity decreased from 94% IACS in the reference sample to 70% in the sample containing 1wt.% rGO. The sample produced via PM also showed indesirable electrical resistivity in compared to other samples containing the same amount of rGO, produced through other two methods. Pin-on-Disk wear tests’ results showed that CoF decreased and then increased with the addition of rGO. Wear behaivoir of samples produced via MLM and PM was camparable to other samples produced via the combination of these two methods
  9. Keywords:
  10. Mixing ; Powder Metallurgy ; Reduced Graphene Oxide ; Copper-Graphene Oxide Nanocomposite

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