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Rice husk ash (RHA), a waste product of the rice industry, is rich in SiO2. The large amount of SiO2 freely obtained from it provides an abundant and cheap alternative to metallurgical grade SiO2 for many industrial applications. The detailed analysis of the physical dimensions such as length, width and thickness of four varieties (HMT, Sonam, 1001 and JSR) was done. The FTIR analysis of the ash obtained by burning rice husk at different temperatures proves the formation of nano SiO2. The study of the isothermal thermal degradation of the RHA was done by TGA analysis .During TGA analysis it was observed that, mass trace suddenly goes backwards along the abscissa and then continues forward normally. This characteristic behavior of the TGA plot was attributed to the formation of nano SiO2 during incineration of the RHA. The minimum value of the percentage crystallinity of the SiO2 at 500°C proved the formation of amorphous SiO2.

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Metal coated reinforcements in metal matrix composites are advancing in the field of engineering to produce high quality composites by liquid metallurgy route due to improvement of wettability between reinforcement and matrix. In the present study, a comparative analysis of mechanical properties was carried out on Al based composite (with varying wt% of Mg) reinforced with uncoated and Cu coated RHA (rice husk ash) SiO 2 particles. Tensile testing results of the composites indicate that UTS and YS of the composites reinforced with Cu coated SiO 2 particles was significantly higher than uncoated particles. The Cu coated SiO 2 particles act as a protrusion over the matrix carrying the major portion of the applied tensile load and thus composites are protected from failure. When Mg reaches 1.5 wt%, wettability of matrix with reinforcement is maximum, leading to the formation of hard compounds such as CuO, CuAlO 2 and Al 2 CuMg at interface. This enhances interfacial bonding strength as well as load transfer from matrix to reinforcement, which leads to higher tensile strength along with ductility.

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