Electro-mechanical and thermal properties of multiwalled carbon nanotube reinforced alumina composites

Multi-walled carbon nanotube (MWNT) reinforced alumina composites with different MWNT contents (5 and 10 vol %) were fabricated by spark plasma sintering. The room temperature dc electrical conductivity, thermal conductivity, and mechanical properties were investigated. Results showed that the electrical conductivity has improved around twelve orders of magnitude by addition of 5 vol% of MWNT. The fracture toughness changed from 3.2 to 4.4 MPa m(1/2) with 39% improvement over monolithic Al2O3. The thermal conductivity decreased with increase of MWNT contents. The low values of thermal conductivity suggest that interfacial thermal barrier play an important role in determining these properties. MWNT can be used to improve concurrently electrical, mechanical properties of Al2O3 but with lower values of thermal properties.