Synthesis and properties of ceramic-based nanocomposite layer of aluminum carbide embedded with oriented carbon nanotubes

In the present work, carbon nanotubes (CNTs) were embedded in aluminum carbide coating in desired vertical/horizontal direction in order to fabricate a nanocomposite layer with unidirectional enhanced mechanical properties. A novel method based on monopolar pulsed plasma electrolysis under magnetic field was used for this purpose. Nanostructure of the obtained nanocomposite layer was examined with high precision figure analysis of SEM, AFM and TEM nanostructures. The mechanical and tribological properties of these coatings were investigated with respect to the direction of the embedded CNTs. The coefficient of friction was lowered from 0.2 to less than 0.1 in a pin-on-disc test against steel with dramatic affected coating wear rate by a decrease to near 400% with respect to raw substrate. The lower friction is attributed to more extensive creation of amorphous carbon on the counter surface and also in the coating wear track. As a conclusion, this method is appropriate for fabrication of hard coating on the surface of low-melting-point metals and light alloys.