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Abstract: This work reports on the impact of surface modification on the optical absorption and luminescence response of vacuum deposited tris(8-hydroxyquinoline) gallium (Gaq3) films. This surface modification was achieved by means of thermal treatment under nitrogen gas in the temperature range from 85 oC to 255 oC. The results of field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD) technique ascertained the formation of amorphous nano-rods along the surface of Gaq3 films. Considerable improvement in the absorption and luminescence characteristics of Gaq3 films was observed upon surface modification, which has been resulted from this treatment process. Keywords: Gaq3, thermal treatment, FESEM, XRD, morphology. |
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Abstract: We report the difference in electronic bond structure and surface chemical property of amorphous carbon nitride (a-CNx) film as a function of N/C which has been deposited by high power impulse magnetron sputtering (HiPIMS) and DC magnetron (dc-MS) plasma. The spectroscopic analyses suggest that the presence of oxide layer is the major cause for the surface charging in the core level peak. The core electron peaks (C1s, N1s and O1s) in x-ray photoelectron spectroscopy (XPS) show higher surface charging in HiPIMS compare to the film deposited by dc-MS plasma. The core peaks are moved gradually toward its virgin position as the etching duration is increased from 1 min to 80 mins. The films deposited by HiPIMS retain a higher N/C ratio following ion etching as compared to those deposited by DC magnetron sputtering suggesting denser films with a higher degree of cross-linking. Keywords: Carbon nitride, HiPIMS, dc-MS, a-CNx disintegration by Ar-sputter clean, Surface charging, X-ray photoelectron spectroscopy. |
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| Abstract: Iron aluminides (Fe3Al and FeAl3) coatings were fabricated on a steel substrate by self-propagating high temperature synthesis (SHS) method. Raw materials, Fe and Al powders, were mixed at two different stoichiometry ratios (3:1 and 1:3). The mixtures and the substrate were placed in a furnace at 950 °C to ignite the SHS process. Coating phases were investigated using X-ray diffraction (XRD) and Energy Dispersive Spectroscopy (EDS). The microstructure of the coatings was analyzed with optical microscopy (OM) and scanning electron microscopy (SEM). The results confirmed that it is possible to produce Fe3Al and FeAl3 coatings on steel substrate using SHS method. In addition, the results show that the coatings were composed of two different phases and their microstructures were non-porous and dense. Wear resistance of the coatings were higher than that of the substrate.
Keywords: Iron Aluminide Coating, Fe3Al, FeAl3, Low carbon steel, Self-propagating high-temperature synthesis (SHS), SEM, XRD, Wear test. |
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Abstract: Organic (PLA) inorganic (OMMT nano clay) hybrid nanocomposite films were fabricated using poly lactic acid (PLA) with various weight percentages (1-3wt%) of organically modified montmorillonite (OMMT) nano clay by means of one step solvent casting method. The thermal, mechanical and water absorption properties were determined as per standard testing methods to determine the optimum percentage of OMMT nano clay within the nanocomposite was investigated. The surface morphology of the organic-inorganic hybrid nanocomposite films was analyzed through XRD, SEM, and TEM surface analytical techniques. The incorporation ofOMMT clay in to PLA matrix is found to have enhanced the thermo-mechanical properties. The water absorption and solubility test resultsalso support the data from thermo-mechanical tests. The 2 wt % OMMT clay loaded PLA films showed the best results among all. The obtained results showed that the thermal, mechanical and water absorption properties could be increased significantly with the optimum incorporation of OMMT nano clay in a PLA matrix, in comparision wih the neat PLA. Keywords: PLA, OMMT nano clay, Mechanical properties, Thermal stability, Surface morphology, Water absorption. |
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Abstract: Focused Electron Beam Induced Processing allows to generate nanocrystalline materials with metallic conductivity and also nanogranular materials with metal crystals embedded in a fullerene matrix, which shows at room temperature 1000 times better conductivity than superconductors at 40 K due to a Bose Einstein Condensate. Resistors and field emitters carry > 50 MA/cm² current density and deliver up to 1 mA current by field emission, when having an enlarged foot point contact to normal metal like Gold. An explanation for the different characteristics is given. The reason for the generation of the Bose Einstein Condensate is explained, and applications are described. Keywords: Field emission, Focused electron beam induced processing,GDSII-layout exposure control, x,-y,-t,-nested loop exposure control, 3-d e-beam printing, Super conductivity, Cooper pairs, Bose Einstein Condensate, Koops-Pairs, Applications. |