Mechanical property enhancement of kinetic sprayed Al coatings reinforced by multi-walled carbon nanotubes

Significant mechanical property enhancement was observed when kinetic sprayed (KS) Al coatings were reinforced by the addition of multi-walled carbon nanotubes (MWCNTs). Embedding the MWCNTs in a ductile Al matrix through mechanical milling to fractions of 0.5 and 1.0 wt.% led to significant improvements in elastic modulus, micro-hardness, and wear resistance. Reinforcement of the Al matrix with MWCNTs is based on the mechanical interaction of MWCNTs with the Al, i.e. elastic wave reflection and dispersion hardening and toughening. These effects were able to overcome the innate ductility of the Al, thereby widening the potential applications of Al coatings. This study provides insight into the strengthening mechanisms of KS MWCNT reinforced Al composite coatings with respect to the spray process, microstructure and mechanical properties.