Rice husk-extracted silica reinforced graphite/aluminium matrix hybrid composite

Abstract

Silica plays an important role in aluminium-based materials. However, role of silica in aluminium matrix composite is not clear so far. In the present study, pure silica was successfully extracted from rice husk by thermal and chemical treatments. The extracted silica had undergone FESEM, FTIR, and XRD for characterizing the purity of silica particles. The results showed that the obtained silica particles were highly pure. The rice husk-extracted pure silica was used as reinforcement in graphite/aluminium matrix hybrid composites. Composites were made using powder metallurgy process followed by sintering. Reinforcements of silica and graphite in aluminium matrix composites were done at different compositions to control the hardness in order to improve machinability. The aluminium matrix hybrid composites had shown excellent physical, mechanical, and thermal properties in terms of surface strength along with light mass as well as controlled thermal conductivity. The hardness of the hybrid composites had increased significantly compared to the single phase aluminium and also was controlled by the combined effect of added silica nanoparticle and graphite flake as reinforcements. Beside mechanical properties, these hybrid composites showed significantly desired thermal properties, particularly lower thermal expansion than that of pristine aluminium. Hence, the newly developed rice husk-extracted pure silica reinforced graphite/aluminium matrix hybrid composites can be used as potential materials for various advanced applications including microelectronic devices, engine piston, and automobile components.