| Popis: |
Copper-graphene composite is prepared with 0.25,0.50,0.75,1.00,1.25 and 1.50 wt.% graphene. Powder metallurgy technique is used for the preparation process. In which copper powder is mechanically milled with graphene nanosheets (GNSs) by 10: 1 ball to powder ratio, and 400 rpm for 12 hr milling time. The mixtures are compacted by a uniaxial press under 700 Mpa pressure. The compacted samples are sintered under a controlled atmosphere at 950 oC for 1.5 hrs. A comparison between methanol & hexane as a process control agent is established. The effect of both on the microstructure, electrical and thermal conductivities of the prepared Cu /graphene nanocomposites is studied. All results indicated that hexane samples have a more homogeneous microstructure with low porosity. For the two groups (Hexane and Methanol group samples), the density was decreased gradually by increasing the graphene percentage. The results indicated that both the electrical and thermal conductivities decrease by increasing graphene content. 1wt. % graphene sample has the most homogenous microstructure, while, 0.25 wt. % graphene is the most one for the methanol group samples. Generally, all results indicated that hexane is the better PCA than methanol. |
