G REEN chemistry was used to prepare yttrium oxide (Y 2 O 3), barium carbonate (BaCO 3), and copper oxide (CuO) nano-particles (NPs) using aqueous Neem fruit extract Azadirachta indica as a capping agent. The resulted metal complexs were calcined at temperature of 750 o C. The produced NPs were characterized using X-ray Powder Diffraction (XRD), Scanning and Transmission Electron Microscope (STEM), Fourier transform infrared spectroscopy (FTIR), UV-Vis Spectroscopy and Thermal Gravimetric Analysis (TGA). XRD analysis confirmed the monoclinic structure for CuO NPs, orthorhombic structure for BaCO 3 NPs and cubic structures for Y 2 O 3 NPs. XRD data for the three metal oxides were matched with the ICDD standards. The crystallite size for the CuO, BaCO 3 and Y 2 O 3 NPs were 29.9, 49.0 and 10.3 nm, respectively. UV-vis spectroscopy showed that for the scanned suspended oxides were in the UV range which is an indication of the formation of nano-sized materials. STEM results showed agglomerated NPs with an average particle size of < 50 nm for all oxide samples. FTIR results confirmed that the metal-oxide bond existed and represented by bands in the range 500-700 nm-1 .

In this research, some physical properties such as the density, specific heat capacity, and micro-hardness of galena ore lumps purchased from the public market were determined. The microscopic study, using the scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), confirmed that the as-received galena ore was mostly lead sulfide (PbS). The XRD pattern of the galena powder also elucidated that all the peaks were assigned to PbS. In addition, the as-received galena was roughly crushed, and fine-milled using a high-vibration milling machine with tungsten carbide rings. Nanoscale particles of about 90 nm were produced in a very short milling time of around 15 min. The obtained nanoscale powder was well investigated in the SEM at low and high magnifications to assess the exact range of particle size. Meanwhile, the SEM was employed to investigate the microstructure of sintered samples, where a part of the milled galena powder was compacted and sintered at 700 °C for 2 h. Again, the result of this investigation proved the formation of PbS with even smaller grain size compared with the grain size of the starting galena ore. A high relative sinter density of approximately 97% for galena powder was achieved by sintering under vacuum.

No abstract

No abstract

No abstract