Papers by Keyword: XRD

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Authors: B. Anandan, S. Gopalakannan
Abstract: A high density nanoscale clusters of Y–Ti–O exhibit superior creep strength and potential for high resistance to radiation damage. X-Ray Diffraction is used to determine the formation of the complex nanoclusters (NCs). The formation of Y2TiO5 NCs takes place during heat treatment of mechanically milled (MM) titanium and Yttria, and also it forms the mixture of Y2Ti2O5 and Y2Ti2O7 NCs during the high temperature soaking of MM iron, MM titanium and yttria. The microstructure of the hot consolidated mixture of MM iron, MM titanium and yttria were obtained through scanning electron microscopy (SEM). The back scattered electron mode is used to show the contrast between different elements in the microstructure. The increase in soaking temperature increases the size of the nanocluster, which decrease the volume fraction and number densities. A large population of nanoclusters precipitates during the heat treatment at high soaking temperature.
Authors: Yu Wang, Hong Li, Ying Guo Yang, Geng Wu Ji, Kong Chao Shen, Hao Liang Sun, Jiong Li, Zheng Jiang, Fei Song
Abstract: The beta-phase of Zn4Sb3 has been regarded as a very promising thermoelectric material since middle nineties, owing to its unique merit: intermediate temperature region (200-400 °C), made of cheap, non-toxic and abundant elements and high thermoelectric property. However, the thermal stability of Zn4Sb3 seems to be an inherent obstacle for the practical application during the working temperatures. Herein, magnesium doped Zn-Sb semiconductor (Mg0.04Zn3.96Sb3) was investigated thoroughly in-situ during thermal annealing up to 600 K, whilst both microstructure and electronic structures were recorded via the combination of synchrotron-based two dimensional X-ray diffraction techniques and the X-ray photoemission spectroscopy. While the time-resolved grazing incidence XRD reveals the preserved crystal structures during thermal annealing to 600 K, XPS measurement demonstrate the robustness of electronic structures. On basis of these findings, it was concluded in the end that the doping of magnesium significantly improves the thermal stability of zinc-antimonite compounds and introduces minor influence on the electronic structure of Zn-Sb alloy. Our study may propose an effective approach towards the wild application of Zn4Sb3 related thermoelectric materials.
Authors: Ahmad Huzaifah Mohd Yusoff, Midhat Nabil Ahmad Salimi, Mohd Faizal Jamlos
Abstract: Magnetite’s abilities rely on the quantitative phases present in the sample. Magnetite quality can strongly influence several physical properties, such as magnetism, catalytic performance, and Verwey transition. However, differentiation of magnetite and maghemite through the conventional X-ray diffractogram comparison are not relevant for the intermediate phases. In this study, the deviation from the ideal stoichiometric magnetite and the relative quantification of both phases were mathematically achievable through a new XRD technique. Various synthesis conditions were applied to obtain different crystallite sizes, in the range of 9 to 30 nm. Generally, the stoichiometric deviation and maghemite content would be significantly influenced by the final size, whereas system conditions (temperature of solution, agitation rate, and pH of solution) would only have minor significance. In this study, iron oxide nanoparticles prepared using the co-precipitation method was calculated to contain 100% magnetite for particles of 30.26 nm in size, while 100% maghemite was calculated for particles at 9.64 nm.
Authors: Kai Li, Hai Jian Li, Ping Wu
Abstract: This paper studied the problems met in the quantitative analysis of synthetic Mullite phase,which was based on the analysis of various typical Mullite composite scheme. A method of quantitative analysis of Mullite phase (excluding amorphous phase SiO2) by use X-ray diffraction was discussed. The error of the analysis can be verified by chemical analysis of Al2O3 content. The method can effectively improve the accuracy of quantitative analysis of the Mullite phase, the error analysis is less than 3%. The error range can meet the accuracy requirement of Mullite content in the production.Studies show that this method is preliminarily solved how to quantitative the content of mullite phase by X-ray diffraction method .
Authors: Anna Danuta Dobrzańska-Danikiewicz, Mirosława Pawlyta, Dariusz Łukowiec
Abstract: A structure of nanocomposite materials consisting of carbon nanotubes with a varying fraction of platinum nanoparticles (5, 10 and 20 wt %) is compared in the paper. High-quality CNTs obtained in the CVD process, 100-200 mm long with a standard deviation of below 20% and with a diameter of 10-20 nm, with a standard deviation of below 30%, were used in the research. Raw CNTs did not contain metallic impurities or amorphous carbon deposits. An indirect method of bonding the earlier produced platinum nanoparticles to the surface of functionalised carbon nanotubes was employed to deposit platinum nanoparticles onto the surface of carbon nanotubes. A full array of changes in the loading of carbon nanotubes’ surface with platinum nanoparticles was achieved as a result of the experiments performed, starting with homogenous deposition to the clearly developed large agglomerations of platinum nanoparticles. The studies carried out using scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy and X-ray structural analysis have confirmed differences in the morphology, homogeneity and density of coating the carbon nanotubes’ surface with variedly concentrated platinum nanoparticles. Differences were also revealed in the structure of the newly formed nanocomposites. A nanocomposite with a 5% fraction of platinum nanoparticles demonstrates the best structure-related properties for the materials obtained.
Authors: N.G. Siddeshkumar, G.S. Shiva Shankar, S. Basavarajappa
Abstract: An attempt has been made to study the dry sliding wear behaviour of Aluminium based hybrid composites in room temperature.Al 2219 is used as base material with B4C and MoS2 as reinforcements. The hybrid composite were prepared by conventional stir casting technique. The dry sliding wear test were carried out for various parameters like sliding distance, applied load and sliding speed. The Optical Microscope and SEM results showed the presence of B4C and MoS2, which are fairly uniform and randomly dispersed on matrix material.XRD analysis, shown the presence of B4C and MoS2 phases in the prepared composites.The incorporation of reinforcement particles B4C and MoS2 reduces the specific wear rate of composites. The addition of MoS2 as a secondary reinforcement has significant effect on reducing specific wear rate of prepared composites. By using SEM worn surface of hybrid composites were studied.
Authors: Andra Predescu, Ecaterina Matei, Andrei Predescu, Cristian Predescu, Cristina Covaliu, Roxana Trusca
Abstract: The paper had as purpose the fabrication and characterization of magnetic nanoparticles covered with TiO2 for applications in environmental field. The research consisted in investigating the properties of magnetic iron nanooxides, synthesized from ferric and ferrous chloride and then covered with TiO2, with minimum costs and high efficiency in industrial wastewater treatment. The iron nanoparticles were obtained by co-precipitation method and the titan dioxide was obtained by sol-gel method. After covering the nanoparticles with TiO2, the samples were characterized by X-Ray diffraction (XRD) and scanning electron microscopy (SEM).
Authors: Hasani Chauke, Mordecai Mashamaite, Rosinah Modiba, Phuti Ngoepe
Abstract: In this study, we investigate the effect of ternary addition on the structural, mechanical properties and temperature dependence of Ti-based as potential shape memory alloys using molecular dynamics approach. We found that binary Ti-Pt alloys exhibit shape memory properties and display possible martensitic transformation from B2 to B19 phases. Partial addition with Zr, Co, Pd, Ir showed preferential ternary high temperature shape memory alloys formation of 6.25 at. % X composition (Ti-Pt-X). We found that the equilibrium lattice constants are in better agreement with the available experimental values. The heats of formation and elastic properties reveal possible composition and phases at temperature above 900 K with good shape memory properties. Their structures were confirmed using the X-ray diffraction patterns at different temperatures.
Authors: Zulhelmi Alif Abdul Halim, Muhamad Azizi Mat Yajid, Zulkifli Mohd Rosli, Riyaz Ahmad M. Ali
Abstract: In this work, the effects of room temperature deposition on the structural properties of Al-Cu bilayers thin films were investigated. The bilayers were sputter deposited by RF magnetron sputtering on Si {100} wafers without substrate heating. The thickness of each layer is approximately 500 nm thick. Characterization were performed with grazing incidence X-ray diffraction (XRD) cross-sectional field emission scanning electron microscope (FE-SEM) with chemical analysis by energy dispersive X-ray (EDX) and atomic force microscope (AFM). It was found polycrystalline Al and Cu thin films have been grown with {111} preferred growth orientation with very fine crystallites size (less than 20 nm). The bilayers were in non-strained condition, but each layer shows different morphologies between the columnar and non columnar structure. AFM analysis revealed that the bilayers top surface appears to have higher surface roughness (Ra = 20 nm) due to low adatoms surface mobility during room temperature deposition.
Authors: Chu Pong Pakpum
Abstract: This paper reports the analysis of the composition, structure and phase of the re-deposition material that was generated from the reaction from CF4 plasma etching on the Al2O3-TiC substrate. The re-deposition was sputtered from the etching area and deposited on a silicon coupon for analysis. The morphology of the re-deposition was investigated by scanning electron microscope (SEM) and the composite element of the re-deposition was detected by using energy dispersive x-ray spectroscopy (SEM-EDX). X-ray diffraction (XRD) was used to analyse the structure and phase of the re-deposition. The results show that the prepared re-deposition was composed of F and Al atoms, with 51.24 At% and 27.67 At%, respectively. XRD revealed that this was owing to the chemical formula AlF3, which has a rhombohedral crystal structure in the most stable alpha phase (α-AlF3).
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