Papers by Author: Bai Ling Jiang

Abstract: LiFePO4/C is synthesized via sol-gel method using Fe3+ as iron sources and complexing agents, followed by sintering at high temperature for crystallization. The amount of carbon in these composites is less than 6.8 wt.% and the XRD experiment confirms that all samples are pure single phase indexed with orthorhombic Pnma space group. The particle size of the LiFePO4/C synthesized by acetic acid as complexing agent is drastically fine with 200nm. The electrochemical performance of this material, including reversible capacity, cycle number and charge-discharge characteristics, exhibits better.

Abstract: The addition of metal atoms within the matrix of the graphite-like carbon films lead to the improvement of their mechanical properties. In this paper, metal (Cr, Al, Zr, W) doped graphite-like carbon(GLC) films were deposited on silicon substrates by closed field unbalanced magnetron sputtering from pure metal target and pure graphite target. Chemical composition and chemical states of films were measured by X-ray photoelectron spectroscopy (XPS) and show that mainly sp2 bond existing in all the metal doped films, and sp2/sp3 ratios are not depend on the doped metal. Cross-section micrographs were observed by high resolution transmission electron microscopy (HRTEM) and revealed a structure of composite that metal or metal carbides embedded in amorphous carbon matrix. The relationship between microstructure and chemical composition was discussed.

Abstract: In this experiment UDP450 was used to prepare the CrAlTiN films with different Y contents deposited on Si(100) substrates. The thickness and structure of CrAlTiN films were characterized by scanning electron microscopy (SEM). The results show that the thickness of CrAlTiN films increases with the increasing of Y contents in Al targets. Meanwhile, the structures of these films are column structures with the least changes. XPS and EDS results indicate that Al contents in the films also increased with the increasing of Y contents in Al targets. Voltages of Al targets were changed with the variation of Y contents in Al targets when CrAlTiN layers were formed. The current of Al targets was a constant during producing CrAlTiN layer. The original voltages of Al targets during forming CrAlTiN layers increased greatly with the increase of Y contents in Al targets. The results show that the collision probability between the neutral particles and positive ions increased in the vacuum chamber. This indicates that the sputtering yield of Al targets is increased at a higher voltage. Consequently, the growing speed of CrAlTiN film and the sputtering yield of Al targets are all improved with the addition of Y element.

Abstract: Magnesium alloy slurry was prepared using Strain-Induced Melt Activation(SIMA) technique. The samples were quenched into water so as to fix the high temperature instantaneous microstructures. The microstructure evolution of compressed deformation Mg alloy is studied in the process of continuous heating and iso-temperature of semi-solid state. The results indicate that deformed Mg alloy (AZ91) has first occurred to have the conversion of dendrite crystal-oriented isometric crystals in the continuous heating process. When the temperature rises to the range of semisolid state, the region with high energy at the pressed stripes begins to melt, showing that the cellular structures emerge in the crystal boundary and melting micro-pool phenomena appear within the crystals. With the iso-temperature time in semisolid state prolongs, the isometric crystals can be gradually converted into spherical crystal grains.