Composites consisting of 8 mol.% yttria-stabilized zirconia (8YSZ) and 1 wt.%, 5 wt.% and 10 wt.% multiwall carbon nanotubes (MWCNTs) have been prepared by attrition milling and spark plasma sintering (SPS). The effect of sintering temperature and MWCNT content on the microstructural features including apparent density, phase transition, crystal size and mechanical properties were investigated. The phase transformation during the sintering process was observed with X-ray diffraction. The MWCNT stability was investigated by Raman spectroscopy. Vickers hardness and indentation fracture toughness of 8YSZ/MWCNTs composites were evaluated and compared with reference 8YSZ composite. The crack propagation mechanisms of composites were determined. MWCNT pull-out, crack bridging and crack deflections were found and constituted a key factor of fracture toughness enhancement in the composites with MWCNT addition.

In this work multiwall carbon nanotubes (MWCNTs) reinforced 8 mol.% yttria-stabilized zirconia (8YSZ) composites were prepared using attrition milling and spark plasma sintering (SPS, at 1400 °C) in different compositions (0, 1, 5, 10 wt.% MWCNTs). The effect of sliding speed at low (V1= 0.036 m/s) and high (V2= 0.11 m/s) values has been investigated. Outstanding wear improvement at both low/high sliding speed has been reported with the addition of 1 wt.% of MWCNTs. This was most likely attributed to two main factors: 1) the formation of a perfectly continuous and uniform tribo-film. 2) the improved flexural strength, fracture toughness and density.