Papers by Keyword: Crystalline Size

Abstract: In this manuscript, the effect of substituting strontium with barium on the structural properties of Tl_0.8Ni_0.2Sr_2-xBr_xCa₂Cu₃O_9-δ compound with x= 0, 0.2, 0.4, have been studied. Samples were prepared using solid state reaction technique, suitable oxides alternatives of Pb₂O₃, CaO, BaO and CuO with 99.99% purity as raw materials and then mixed. They were prepared in the form of discs with a diameter of 1.5 cm and a thickness of (0.2-0.3) cm under pressures 7 tons / cm², and the samples were sintered at a constant temperature of 860 ° C. The structural properties were studied using X-ray diffraction for all samples, and the results showed that the samples have tetragonal structure and the change of the parameters structure with the change of the barium concentration. Full Width Half Maximum (FWHM) was calculated by Orange Pro using X-RAY data. The crystal size was calculated using Scherrer and Willeamson-Heall methods, where the results showed that the crystal size, compliance and degree of crystallinity changed with the change of barium concentration, and the highest average for the crystal size was 70.0271nm at x=0, and crystallization at 61.46% at x=0.6, and the strain decreased to 0.0037 when barium concentration equals 0.4.

Abstract: Calcium phosphates ceramics such as a hydroxyapatite have composition and structure similar to be mineral component of bone. Hydroxyapatite could be production from natural and chemical source with various techniques. In this study, Calcium phosphates was prepared and characterized for future applications on the utilization of bioactivity and resorbability of Hydroxyapatite. Hydroxyapatite was synthesized by precipitation method using cuttlefish bone as the calcium (Ca) source in the form of calcium nitrate and ammonium phosphate as the phosphate (P) source. The property, crystal structure and crystalline size of samples were investigated by X-ray diffraction (XRD) and Fourier transforms infrared spectroscopy (FTIR). The results showed that the raw cuttlefish bone was calcite and aragonite phase and completely transformed to calcium oxide at 1000 °C. Hydroxyapatite from cuttlefish bone was hexagonal phase. The crystalline size of hydroxyapatite increases with increasing temperature from 200-1300 °C. This experiment indicated that the hydroxyapatite could be synthetized from cuttlefish bone.