Graphene-incorporated aluminum with enhanced thermal and mechanical properties for solar heat collectors

A simple yet innovative approach has been made through a powder metallurgy route for the synthesis of aluminum–graphene (Al–Gr) composite materials for commercially viable solar thermal collectors. The Al–Gr composite (with 1 wt. % of graphene filler content) recorded an enhanced thermal conductivity of ∼280 W/mK, which is higher than that of pristine Al (∼124 W/mK), at room temperature. It has also been found that the prepared composite has a lower coefficient of thermal expansion. The structures and morphologies of the composites have been investigated in detail with the help of X-ray diffraction technique, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Raman spectroscopy, etc. Furthermore, the density measurements showed that the composites retain ∼97.5% of the density of pristine aluminum even after the sintering treatment. X-ray micro-computed tomography revealed the structural integrity and non-porous nature of the samples, free from any defects and deformations. The thermal fusing of Al-based composite materials at 630 °C is found to be satisfactory with the required strength, and the composites showed at least ∼125% increase in the thermal conductivity than that of pristine Al. These results suggest that the Al–Gr composites can be deployed as solar thermal collectors and heat sink materials for thermal dissipation.