Current Issue : July - September Volume : 2019 Issue Number : 3 Articles : 5 Articles
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The effects of laser heat treatment on the microstructure and properties of alloy 800H\nwere investigated. The fracture morphology, elemental changes, and phase composition of the\nspecimens were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy\n(EDS), and X-ray diffractometry (XRD). The results show that the long-lasting life of the specimen\nafter laser heat treatment increased by 28.6%, and the elongation after fracture increased by 20.7%.\nThe macroscopic morphology of the fracture specimen exhibited obvious ductile fracture morphology,\nand the changes in the elemental content and grain size significantly affected the ductility and\ntoughness of the alloy. This study has certain guiding significance for the optimization of the heat\ntreatment process of this type of alloy....
In this study, films of graphene oxide and chemically or thermally reduced graphene oxide were produced by a simple vacuum\nfiltration method and submitted to a thorough characterization by X-ray diffraction (XRD), Raman and infrared spectroscopies,\nfield-emission scanning electron microscopy, transmission electron microscopy, atomic force microscopy, confocal microscopy,\nand contact angle measurements. Graphene oxide (GO) was produced from graphite by the modified Hummers method and\nthereafter reduced with NaBH4 or by heating under argon in a tubular furnace. The films were produced from aqueous\nsolutions by vacuum filtration on a cellulose membrane. Graphite presents two characteristic XRD peaks corresponding to d =\n0 34 nm and d = 0 17 nm. After oxidation, only a peak at d = 0 84nm is found for powder GO, confirming the insertion of\noxygen groups with an increase in the interplanar distance of graphene nanoplatelets. However, for GO films, other unexpected\npeaks are observed at d = 0 63nm, d = 0 52nm, and d = 0 48nm. After reduction, both chemical and thermal, the peak at\n0.84 nm disappears, while those corresponding to interplanar distances of 0.63 nm, 0.52 nm, and 0.48nm are still present. The\nother characterizations confirm the production and chemical composition of GO and reduced GO films. The results indicate the\ncombination of crystalline regions with different interplanar distances, suggesting the ordering of graphene/graphene oxide\nintercalated sheets....
TiAlSiN coatings were deposited on YT 15 cemented carbide substrate by reactive direct\ncurrent magnetron sputtering (DCMS) in a Plasma Immersion Ion Implantation and Deposition\n(PIII&D) system. The pre-implantation step and the coating deposition were carried out in the same\nexperimental facility. In this article the effects of pre-implantation of several different elements (N, C,\nand O) were investigated. The adhesion strength, hardness, micro-structure, element concentration,\ndepth profile, and the formation of coatings after the PIII experiments were characterized by a wide\nvariety of techniques such as Rockwell indentation, scratch test, nano-indentation measurement, X-ray\ndiffraction, energy dispersive spectroscopy, and Auger electron spectroscopy. The results showed that\nthe adhesive strength of TiAlSiN coatings was significantly improved on samples pre-implanted with\nN and O whereas only slightly improved with pre-implantation of C. Additionally, the microstructure\nand mechanical properties of the TiAlSiN coatings were also altered through pre-implantation.\nThe improved adhesion could be explained by the grain refinement and surface energy enhancement\nof the substrate by pre-implantation....
A new MoS2/TiSi2 complex catalyst was designed and synthesized by a simple one-step\nin situ photo-assisted reduction procedure. The structural and morphological properties of the\ncomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM),\nscanning electron microscopy (SEM), and ultraviolet-visible diffused reflectance spectroscopy\n(UV-vis DRS), which proved the formation of MoS2/TiSi2. MoS2/TiSi2 with optimized composition\nshowed obviously enhanced photocatalytic activity and superior durability for water reduction to\nproduce H2. The H2 generation rate over the MoS2/TiSi2 photocatalyst containing 3 wt %MoS2\nreached 214.1 micromole.h^-1.g^-1 under visible light irradiation, which was ca. 5.6 times that of the\npristine TiSi2. The improved photocatalytic activity of MoS2/TiSi2 could be related to the broad\nresponse spectrum, large visible light absorption, and synergies among MoS2 and TiSi2 that enhance\nphotoexcited charge transfer and separation....
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