Physico-Chemical, Mechanical and Thermal Behaviour of Agro-waste RHA-Reinforced Green Emerging Composite Material

Ceramic particles such as SiC, ${\text{Al}}_2{\text{O}}_3$ and ${\text{B}}_4$C are most commonly used as reinforcement particles while developing composite materials. The industries producing these particles emit huge amount of greenhouse gases such as ${\text{N}}_2{\text{O}}_{3,}{\text{CH}}_4$ and ${\text{CO}}_2$. Emission of these gases poses serious threats to the neighbouring environment. Adding to environmental concerns, the costs of production for ceramic particles are very high. The present study has used rice husk ash (RHA) as a partial replacement of ceramic particles. Microstructural examinations have shown evidence of RHA particles in the aluminium-based metal matrix composite samples. It was also revealed that tensile strength and hardness increased about 48% and 48.33% with respect to base metal (AA6063), after mixing the carbonized RHA into matrix material. Presence of ${\text{SiO}}_2$, CaO, ${\text{Fe}}_2{\text{O}}_3$ compositions in carbonized RHA improves the tensile strength and hardness of composites. Porosity of Al/7.5 wt% carbonized RHA metal matrix composite was found to be 6.33%, which is acceptable. Maximum specific strength and minimum corrosion loss were found to be 65.57 kN m/Kg (for 8.75 wt% of carbonized reinforced RHA) and 0.17 mg (for 5 wt% of carbonized reinforced RHA), respectively. Density and cost of RHA-reinforced composite continuously decrease with the increase in percentage of reinforcement. Minimum thermal expansion (50.98 mm${}^3$) was observed for 6.25 wt% of carbonized RHA-reinforced composite. It was also observed from the analysis that carbonized RHA-reinforced composite provides better result as compared to uncarbonized RHA-reinforced composite.