Enhanced tribological properties of MWCNT/Ni bulk composites - Influence of processing on friction and wear behaviour

The friction and wear behaviour of MWCNT-reinforced Ni matrix bulk composites is investigated and compared to the response of a pure bulk reference sample. Several effects are observed in the composites such as microstructural refinement, leading to improved hardness, coefficient of friction and wear resistance. Said refinement might also be responsible for a non-trivial behaviour of hot-pressed composites under a 300 mN load, due to higher oxidation rates. The worn volume is analysed and discussed from a microstructural and morphological point of view. In this context, a direct correlation is shown between two relevant wear parameters, namely, the wear constant K and the cutting efficiency fAB. In addition, the tribochemistry is investigated by Raman spectroscopy and linked to the friction and wear behaviour. Finally, the wear volume reduction peaked at 94.1% in HUP samples. This clearly indicates the high potential of these composites for tribological applications.