SiC formation on carbon nanotube surface for improving wettability with aluminum

High interfacial strength between the host matrix and reinforcing material is the key factor in developing mechanically robust composite materials. Strengthening the interface between aluminum and carbon nanotubes (CNTs) is very crucial to achieve desirable mechanical properties of Al-CNT composites. Silicon carbide that highly wets Al was coated on the CNT surface in order to promote interfacial strength while preventing CNT disintegration during reinforcement. The SiC interface layer on the CNT surface was successfully formed by a three-step process: (i) mechanical crushing of a Si powder by a CNT promoter, (ii) coating of crushed Si nanoparticles onto CNT surfaces, and (iii) formation of a SiC layer by high temperature annealing. The wettability of CNTs during Al melting was significantly improved by this method, which is critical for improving mechanical properties of Al-CNT composites. Improvements of 15% in tensile strength and 79% in Young’s modulus were achieved by adding 0.84 wt% Si powder and 1 wt% CNTs.