Physical and mechanical properties of SiC-CNTs nano-composites produced by a rapid microwave process

In this paper, synthesis of SiC-CNTs nano-composites at low temperature by a microwave process is reported. The physical and mechanical properties of SiC based nano-composites reinforced with different amounts of carbon nanotubes (CNTs) (0, 0.5, 2, 5 and 10 vol%) were studied. The characterization of the nano-composites was carried out by means of FE-SEM, XRD, hardness, bending strength, electrical and thermal conductivity tests. The fracture toughness was tested using a Palmquist method. Results show that the hardness of nano-composite sample in 0.5 vol% of CNTs increases of about 24% compared to pure SiC sample. Also three-point bending strength and fracture toughness of the SiC-CNTs nano-composites using 0.5 vol% of CNTs increase of about 10% compared to the pure SiC sample which was produced under the same process. The electrical conductivity of the SiC-CNTs nano-composites had a tendency to decline with increasing volume fraction of the reinforcing material due to the CNT clusters and larger grain-boundary per unit volume, resulting in lower carrier mobility.