High purity amorphous silica (SiO₂) is extracted from agriculture waste (rice husk) that supplied from Al-Najaf province, Iraq. Silica is the major inorganic constituent of the rice husk. It is prepared with using acid pretreatment of (3N HCl), then burned it at (700°C) for 4 hrs, and followed with leaching process by 1.5, 2, 2.5, and 3N NaOH. The extracted results are high-surface area of amorphous silica particles. Extracted results are silica particles were high surface area of amorphous silica particles. These particles were characterized by X-Ray diffraction (XRD), and X-Ray Fluorescence (XRF) and Atomic force microscopy (AFM) techniques. High pure amorphous silica observed from rice husk ash was confirmed by XRD diffraction. The silica purity results measured by X-Ray fluorescence was 99.714% for leaching at 3N NaOH. Results from (AFM) of silica with nanoscale sizes and microparticles with diameters ranging from (87-114) nm.

The specifications of lubricating oil are fundamentally the final product of materials that have been added for producing the desired properties. In this research, spherical nanoparticles copper oxide (CuO) and titanium oxides (TiO2) are added to SAE 15W40 engine oil to study the thermal conductivity, stability, viscosity of nano-lubricants, which are prepared at different concentrations of 0.1%, 0.2%, 0.5%, and 1% by weight, and also their pour point, and flash point as five quality parameters. The obtained results show that CuO nanoparticles in all cases, give the best functionality and effect on engine oil with respect to TiO2. With 0.1 wt. % concentration, the thermal conductivity of CuO/oil and TiO2/oil increased by 7.27% and 4.54%, respectively. In the same time, the flash point of them increased by 12.62% and 9.3%, respectively in comparison with parent oil.