Papers by Keyword: Stannate

Abstract: A series of Eu³⁺, Dy³⁺ actived Ca_1-xBa_xSnO₃ phosphors were synthesized by coprecipitation method. The structure, morphology and fluorescence property of phosphors were investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectroscopy. SEM results showed that the as-prepared phosphors are smooth and uniform with the cubic morphology. The incorporation of a small amount of Ba to CaBaSnO₃ improved the emission characteristics. Fluorescence spectrum showed the emission intensity is the best with the incorporation of Ba²⁺ (x = 0.3), when calcination temperature is 900°C.

Abstract: In this paper we have successfully prepared the red luminescent material of La0.01Y1.99Sn2O7: Eu3+, Dy3+ by the method of hydrothermal and sintering. The phase structure, surface morphology and fluorescence properties were investigated by the scanning electronic microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL). The EDS showed that the luminescent material is La0.01Y1.99Sn2O7: Eu3+, Dy3+. The SEM micrographs showed uniform particles with good crystallinity of luminescent material after sintering. PL spectrum showed the increasing of Eu3+ has great benefit for the increase of the luminous intensity of luminous materials. The optimal doping amount of Eu3+ ion and Dy3+ is 1:3 (nEu: nDy).

Abstract: Permanganate-based conversion coating, using nitric acid as an oxidative additive has been performed and analysis shows the reduction products of permanganate mainly MnO₂, and oxidation products of magnesium (MgO and Mg(OH)₂). Stannates-based coating has also been obtained in high basic medium using acetate- pyrophosphate additives. Isolated grains formed having a quasi-spherical form which have been identified as mixed magnesium and tin oxides. Particles very rich in tin are observed and discussed in terms of standard reduction potentials E⁰_red.

Abstract: Tin oxide (SnO ₂) ,MgSnO₃ and Mg₂SnO₄ nanocrystals have been synthesized by one-step solid-state reactions. in the first step, The powder of SnCl ₄.5H₂O was mixed with MgCl₂ and Mg(OH)₂with weight ratio of Sn to Mg (1:1), (2:1) And (1:2) in an air atmosphere at room, and annealing temperature in this work were 200°C, 400°C ,600°C , 800°C and 1000°C . XRD patterns show the SnO₂ , MgSnO₃ and Mg2SnO₄ particle size of synthesized powders by MgCl₂ were 3 nm, 4nm and 27 nm respectively. In fact the excess amount of Mg role of crystallite growth inhibitor in SnO ₂. this method is a simple ,inexpensive ,efficient and economic preparation for SnO ₂, MgSnO₃ and Mg₂SnO₄ nanoparticles with adjustable grain sizes in the range of 3-44nm in high yield. This article shows the role of mass MgCl₂ in producing of SnO₂ nanoparticles.

Abstract: The effects of Na₂SnO₃ and CuSnO₃ on the thermal decomposition and fire performance of wood were characterized by thermogravimetric (TG) analysis, differential thermogravimetry (DTG), and thermogravimetry–mass spectrometry (TG–MS) analysis. The addition of these chemicals caused a decrease in the decomposition temperature, a reduction in weight loss, and an increase in the amount of char produced. The results showed that ion current intensity and ion peak area of the typical representatives of incombustible ion such as m/z = 18 and 44 MS signals were increased by the flame retardants but the inflammable ion such as m/z =12, 26, 28 etc. MS signal was decreased at the meantime. What’s more, the maximum ion current intensity and ion peak area of m/z = 64 signals were increased obviously, which mean that the flame retardants can significantly enhances the dehydration and inhibits the deploymerisation of wood.

Abstract: A white long persistence phosphor was synthesized in a single-phase of Mg2SnO4 which was synthesized by a solid-state reaction. This phosphor crystallized in an inverse spinel structure and showed a broad-band emission from 350nm to 700nm. The afterglow was observed upon the excitation by 254nm. A Li-doped Mg2SnO4 sample showed a higher photoluminescence intensity and a longer lifetime than the non-doped one.

Abstract: The morphology and the mass change of the AZ91D alloys matrix after pretreatment, the morphology and the phase composition of chemical conversion coatings formed by phosphate and stannate were studied using scanning electron microscope, X-ray diffraction and the mass loss method. The corrosion resistance of the coatings were studied by salt spay test and damp heat test. The results show that the phase composition of matrix before and after pretreatment is almost changeless and the mass diminishes a litter, the deep micro flaw appears near between α-Mg and β phase during acidic pickling. The phosphate chemical conversion coating is mainly composed of Mg, MgO and some amorphous phase, and the stannate conversion coating is crystal structure and mainly composed of Mg, Al12Mg17 and MgSnO3•3H2O. Results from salt spay test and damp heat test indicate that the two coatings also can provide good protection for the magnesium alloy matrix, and stannate is better than phosphate.