Testing and Evaluation of Inorganic Materials I

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Authors: Jian Peng Wu, Chun Yan Yao, Li Yun Cao, Jian Feng Huang, Hai Yan He, Hui Zhu
Abstract: In order to make quantitative analysis by internal standard method, 24 standard curves of inorganic compounds including quartz, corundum, TiO2, BaTiO3, etc. were obtained and the corresponding quantitative analyses were accomplished based on the quantitative analysis software attached in Rigaku D/Max-2200 X-Ray diffractometer. Results show that the coefficient of association R of the as-prepared curves are at the range of 0.928-0.980. By validating the samples with due content, it reveals that the analytical results are consistent with the actual values well, which indicate that the prepared standard curves are suitable for high-precision XRD phase quantitative analysis. Uniformity of samples is an important factor in the quantitative analysis by internal standard method.
Authors: Cai Xia Li, Hai Fang Xu, Tao Feng, Na Zhang, Qiang Li
Abstract: The layered sodium cobalt oxide Na0.6CoO2 phase has been synthesized from Na2O2 and Co3O4 by solid-state reaction at 550°C for 12h with the heating rate about 2°C /min. The colloidal suspension of exfoliated, layered cobalt oxide nanosheets was prepared through the intercalation of tetrabutyl ammonium hydroxide ions (TBA) into protonated sodium cobalt oxide. The as-obtained composites were analyzed by powder X-ray diffraction (XRD). They were also cross-confirmed by a range of methods including UV/Vis spectroscopy, and Transmission Electron Microscopy (TEM). The Zeta-potential measurements clearly demonstrated the negative surface charge of cobalt oxide nanosheets.
Authors: Jie Song, Bing Xu, De Xin Huang, Cai Xia Li, Qiang Li
Abstract: In this paper, super fine LiMn2O4 powder was synthesized by mechanochemical method starting from Li2CO3 and Mn2O3. The structure, size and morphology of LiMn2O4 were explored with X-ray diffraction and scanning electron microscopy (SEM). The electrochemical properties of LiMn2O4 were studied in 2 mol/L (NH4)2SO4 solution. The result showed that pure spinel LiMn204 powder was prepared after 8h grinding with 3.0KW of power and the particle size was about 1µm. Cyclic vohammetry curve indicate LiMn2O4 electrode material has better capacitive performances.
Authors: Bao Rang Li, Xing Tao Liu, Yang Sheng Zheng, Hui Bin Chang
Abstract: In this paper SrBi2Nb2O9 was prepared by molten salt synthesis method and KCl chosen as molten medium. In order to disclose possible formation mechanism of SrBi2Nb2O9, a simple route was established for comparison by dividing the starting precursors into four groups. With the help of XRD, possible synthesis route was analyzed. The results showed that pure SrBi2Nb2O9 powders could be obtained at temperature higher than 700oC by molten salt synthesis. Intense synthesis reaction happened in the temperature range from 500 to 700oC. The reaction mechanisms of SrBi2Nb2O9 included four steps, namely the formation of 1) SrBi2O4 at close to 600oC,2) BiNbO4 from the reaction of at 600-700 oC, 3) SrBi2Nb2O9 from the reaction of SrBi2O4 and Nb2O5 and 4)SrBi2Nb2O9 from the reaction of BiNbO4 and SrCO3. The molten salt could improve distribution and reactivity of the precursors and significant formation of SrBi2Nb2O9.
Authors: Jing Song, Tao Cheng
Abstract: For the adoption of the EU directive “Restriction on use of certain Hazardous Substances” (RoHS) using X-ray fluorescence (XRF) analysis suitable materials are required. This paper aims at the determination of heavy metals in inorganic materials by XRF, and briefly introduces the theory, test method, characteristics. The application of quantitative analysis of XRF is discussed in detail.
Authors: Zheng Min Li, Min Tan, Bing Jiang, Zhi Wei Chen, Wei Jiang Si
Abstract: The shape of inorganic powder particles, prepared by spray-drying process, is close to sphere, and the dry conditions have greater effect on the sphericity. The particle shape is normally described by words or shown by micrographs — these are qualitative and imprecise. In order to characterize the particle shape quantitatively, three shape factors, i.e. aspect ratio (M), roundness (R) and concavity (C), are proposed to describe the particle shape of the inorganic powders in different aspects. An image process method, that “holes” were filled and then particle clusters were separated, was developed and applied in scanning electron microscope (SEM) image in which some particles with “shadow” contact with each other. Mean shape factors, based on about 500 particles in 10 micrographs, are proposed to characterize the particle shape of the inorganic powders. The determination results of four inorganic powders show that cracking catalyst powders without silicon additive and produced after rebuilding of the spray-drying device are closer to spheres.
Authors: Zheng Min Li, Zhi Wei Chen, Min Tan, Ke Jing Xu, Bing Jiang
Abstract: Nano-TiO2 coating film is one of the efficient photocatalysts. The particle size distribution of TiO2 has important influence on photocatalytic activity. A new method to determine the particle size distribution of TiO2 nano-film coated on ceramic was developed, by which the images of film acquired by Atom force microscope (AFM) were processed, and TiO2 particles contacted with others were separated and detected. The particle size distributions of two TiO2 nano-films were determined.
Authors: Bao Rang Li, Bin Cao, Cong Lu
Abstract: Bismuth titanate nano-crystals were prepared successfully by sol-gel method and the critical particle size for phase transition was analyzed by Raman techniques. The results revealed the new Raman peaks at the wave number about 87, 227, 442, 467, 577 and 617cm-1 discerned gradually with increasing the particle size and abrupt increase in integrated intensity ratios of these modes, companied with strong decrease of half-widths happened at the particle size ranging from 18 to 33nm, which suggested an obvious size driven tetragonal-to-orthorhombic phase transition in Bismuth titanate nano-crystals.
Authors: Hao Wu, Cheng Chen, Dan Yu Jiang, Tao Feng, Qiang Li
Abstract: This paper presents a novel mechanochemical synthesis technique for making nano-structured Pb(Mg1/3Nb2/3)O3 (PMN) ferroelectric material without annealing treatment in a much shorter time and at much lower temperature than those reported in the literature, by using the starting precursors MgO, PbO, and Nb2O5. Specimens of various milling time (3-6h) are characterized from XRD patterns to track and analyze the synthesizing procedure of this mechanochemical processing route. The time used to make the desired PMN powders varies with different milling power. When the constituent oxides were mechanically activated at 1.8KW milling power for 6h, the perovskite phase PMN powder was obtained; while it was formed when milling at 3KW for only 3h. Typical SEM images of the as-received PMN powders show that the powders are aggregated of nano-particles of about 100nm in size.

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