Synthesis and sintering of 1D Al2O3@MWCNTS ceramic composite with excellent mechanical and electrical properties for advanced engineering applications

Abstract

A novel strategy was exploited to synthesize one-dimensional (1D) Al2O3 ceramic by using MWCNTs as a template. The prepared amorphous alumina [Al(OH)3] was annealed at high temperatures to convert it into corundum Al2O3. Homogeneous dispersion of MWCNTs was obtained by the deposition of Al2O3 on the MWCNTs surface. Then, the calcined 1D Al2O3@MWCNTs hybrid powder was sintered at 70 MPa and 1300 ˚C for 10 min using spark plasma sintering (SPS). The microstructure analysis confirmed the uniform distribution of MWCNTs in Al2O3 ceramic. The compressive residual stresses on MWCNTs lead to a much stronger grain boundary as well as higher interfacial shear strength between the outer wall of MWCNT and Al2O3 ceramic. As a result, by the addition of only ∼1.27 wt.% MWCNTs, the flexural strength and fracture toughness along with higher electrical conductivity (315 S/m) were simultaneously enhanced up to ∼70% and ∼73%, respectively, with respect to monolithic Al2O3.