Samarium-Substitution Effects in Sol-Gel Derived Yttrium Aluminium Garnet

In this study, yttrium aluminium garnet (YAG) powders substituted by samarium were prepared by simple an aqueous sol-gel method using aluminium nitrate nonahydrate, yttrium oxide, samarium oxide as the starting materials and etane-1,2-diol as complexing agent. The powders annealed at 1000 degrees Celsius in air were characterized by X-ray diffraction (XRD) analysis, infrared spectroscopy (IR) and scanning electron microscopy (SEM). It was demonstrated, however, that the total substitution of yttrium by samarium does not proceed in the YAG. Pure cubic garnet phase was formed only at low concentration of samarium. With further substitution, the main part of garnet phase transformed in to the perovskite samarium aluminate phase. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3483

Wet Polymeric Precipitation Synthesis for Monophasic Tricalcium Phosphate

Tricalcium phosphate (β-Ca3(PO4)2, β-TCP) powders were synthesized using wet polymeric precipitation method for the first time to our best knowledge. The results of X-ray diffraction analysis showed the formation of almost single a Ca-deficient hydroxyapatite (CDHA) phase of a poor crystallinity already at room temperature. With continuously increasing the calcination temperature up to 800 °C, the crystalline β-TCP was obtained as the main phase. It was demonstrated that infrared spectroscopy is very effective method to characterize the formation of β-TCP. The SEM results showed that β-TCP solids were homogeneous having a small particle size distribution. The β-TCP powders consisted of spherical particles varying in size from 100 to 300 nm. Fabricated β-TCP specimens were placed to the bones of the rats and maintained for 1-2 months

Approaching Highly Leaching-Resistant Fire-Retardant Wood by in Situ Polymerization with Melamine Formaldehyde Resin

The objective of the work was to improve the leaching resistance of fire-retardant (FR) modified wood by the incorporation of a thermoset resin. Here, Scots pine (Pinus sylvestris L.) sapwood was impregnated with melamine formaldehyde (MF) resin and hydrophilic FRs guanyl-urea phosphate/boric acid by a vacuum-pressure treatment. Resistance to leaching of FR-modified wood was evaluated, after conducting an accelerated aging test according to European standard EN 84. Inductively coupled plasma analysis showed that the incorporation of MF resin significantly reduced the leachability of FRs. Scanning electron microscopy/energy-dispersive X-ray spectrometry revealed that the mechanism of water resistance was by doping the FRs into MF resin microspheres. Fourier transform infrared spectra showed the chemical functionality changes of FR-modified wood such as the formation of methylene bridges by drying the modified wood specimens. An increase in the thermal stability of FR-modified wood was confirmed by thermal gravimetric analysis. Excellent fire performance of FR-modified wood after leaching was affirmed by the limiting oxygen index and cone calorimeter tests.