Synthesis and characterization of Al+0.25%MWCNTs nanocomposite with reduced thermal expansion coefficient

Abstract

The present work investigates the thermodynamic and structural behaviours of an aluminium-based nanocomposite reinforced by Multi-walled Carbon Nanotubes (MWCNT). Mixture of A999 aluminium powder and MWCNTs was prepared through CVD method in a rotating reactor. 0.25% of MWCNT with average size between 10 nm and 20 nm was chosen to reinforce aluminium-based nanocomposite. Several experimental techniques, such as Calorimetry, X-ray diffraction, Thermogravimetry, Raman spectroscopy, and Dilatometry have been used in this research to explore the thermodynamic and structural behaviours. The DSC curve of Al+0.25%MWCNTs shows a high heat capacity. It is completely different from that of pure aluminium prepared in the same conditions. The thermogravimetric (TG) variation of the nanomaterial is linear compared to that of the matrix (Al). This demonstrates the stability of the material. Raman spectroscopy shows that the insertion of 0.25%MWCNTs generates few defects. X-Ray diffraction (XRD) shows that the peak intensities for Al+0.25%MWCNTs are significantly lower than those of pure aluminium. Relative dimensional variations along the two significant directions (normal to the rolling plane, Z, and within the rolling plane, X) have similar shapes but different intensities. The thermal expansion coefficients are also distinct, expansion along the Z direction is very small; the Al+0.25%MWCNTs thermal expansion is strongly anisotropic. The obtained results show that the introduction of MWCNTs in an aluminium matrix completely changed the behaviour of the studied physical quantities.

Keywords

• Nanocomposites
• MWCNT reinforcement
• Thermostructural characterization
• Thermal expansion coefficient
• Anisotropy