Effect of multi-walled carbon nanotube on mechanical properties and electrical conductivity of alumina

Alumina and multi-walled carbon nanotube (MWNT) composites with different multi-walled carbon nanotube contents were fabricated by spark plasma sintering technique (SPS). The direct current electrical conductivity and mechanical properties were investigated. Results have shown that an improvement of electrical conductivity of around twelve orders of magnitude is observed when 5% of MWNTs were used and fracture toughness was changed from 3.2 MPa m(1/2) to 4.44 MPa m(1/2) with an improvement of about 39% from the monolithic alumina. Low volume fraction of MWNT can be used to concurrently improve electrical conductivity and mechanical properties of alumina without deteriorating other intrinsic properties.