Solid State Phenomena Vols. 121-123

Abstract: This study uses molecular dynamics simulations to investigate the crystalline process of Co-Cu nanoparticles of high and low Co concentrations (5 and 25 %) during the annealing process. The modified many-body tight binding potential is adopted to accurately model the Cu-Cu, Co-Co, and Co-Cu pair inter-atomic interactions. The structural transformations at the upper and lower melting points are observed by the radial distribution function (RDF) and the angle correction function (ACF).

Abstract: High yield synthesis of bamboo-like multi-walled carbon nanotubes (BCNTs) over a novel zeolite catalyst has been achieved using acetonitrile as a carbon source. The synergism of nickel (Ni) and rare earth oxides (REO) in the zeolites is considered very important for the high activity of the catalysts for the rapid decomposition of acetonitrile and diffusion of carbon. The yield of BCNTs increases with the Ni content and the growth time. The as-grown BCNTs are arranged in the form of flower-like clusters surrounding each zeolite. This CNT-zeolite composite may be regarded as a complex zeolite which will be very useful for the selective absorption, filtration and storage of gas.

Abstract: The monodispersed zinc oxide nanowires with lateral dimensions as thin as 20 nm and lengths up to 2 μm have been synthesized in a simple organic solution by using hydrothermal method. Particularly, these zinc oxide nanostructures has been prepared into single-crystalline prisms or belts with uniform diameters along the entire length. The structure and characteristic of the as-obtained ZnO nanostructures were confirmed by XRD, TEM, HRTEM, and EDX. UV measurements and photoluminescence had been used to characterize the optical properties and confirm the crystal perfection of these ZnO nanomaterials.

Abstract: Nearly monodispersed SiO2 nanospheres, with different size and size standard deviation smaller than 5%, have been prepared by using batch/semibatch process. The SiO2 colloids were used as building blocks to self-assemble into the colloidal crystals, which photonic band gaps are close to the theoretical values, and can be modified by changing the size SiO2 nanospheres. With the increase of the size of SiO2 spheres, the photonic band gap red shift.

Abstract: Polyaniline(PANI) microwires and microspheres containing Au nanoparticles were prepared using different organic acid as dopant by an in-situ polymerization method. When L-CSA was used to synthesize PANI/Au composite, microwires were obtained. While by introducing hydrogen bonding and/or electrostatic interactions between mercaptocarboxylic acid capped Au nanoparticles and aniline molecules, microspheres were synthesized. SEM and TEM indicated that the diameter of the microwires was about 200 nm and the diameter of the microspheres was between 1 μm and 3 μm. FTIR and XRD characterized the structure of the PANI/Au composite microwires and microspheres.

Abstract: Hollow microspheres of nickel hydroxide and nickel oxide were prepared with as-synthesized PS/Ni(OH)2 composite particles by sacrificing core method, respectively. The composite particles were synthesized by deposition of the Ni(OH)2 nanoflakelets formed by the hydrolysis of nickel nitrate onto the surfaces of polystyrene (PS) particles. The effects of different concentrations of nickel salt and urea on the deposition of the nanoflakelets of nickel hydroxide were studied. It was found that the uniform nanoflakelets were deposited on the polystyrene particles under the conditions of the 4╳10-3 M nickel salt and 0.667M urea. Compared with the directly calcinating of composite particles, Integral hollow microspheres of nickel hydroxide were attained by removal of cores of polystyrene in composite particles with toluene and NiO hollow microspheres by calcinating of these Ni(OH)2 hollow spheres in oven at 600°C for 2h.

Abstract: An Al-5vol%Ti3SiC2 nanocomposite has been prepared by ball milling technique. Steel ball, agate ball and zirconia ball were selected during the ball milling process and then the microstructure evolution of the powder mixture was investigated. The homogenous fine mixed powder can be obtained with zirconia ball, whereas the conglomeration will be formed in the case of steel ball and agate ball. The bulk Al/Ti3SiC2 nanocomposite was fabricated by hot pressing technique. The effects of the particle size and agglomerate state of Ti3SiC2, as well as the microstructure of Al/Ti3SiC2 nanocomposite were studied by SEM and TEM. It was found that the nanosized Ti3SiC2 particle could be obtained during the ball milling process and distributed in aluminium homogenously.

Abstract: In this work, PZT (Zr/Ti=52/48) thin films have been prepared using aqueous organic gel method. The desired metal cations are chelated in a solution using citric acid and ethylenediaminetertraacetic acid (EDTA) as the chelating agents. The thermal decompostion of the metal carboxylate precursors gels have been studied by TG/DTA and the products derived from calcinations of the gels at different temperatures have been characterized by XRD and SEM. By heat-treatment at 650°C for 2h, PZT thin films with smooth and crack-free surface could be achieved. The thickness of each layer was 50nm. Electric properties measurement indicated that the PZT films demonstrated a ferroelectric hysteresis loop. The remanent polarization(Pr) and coercive field (Ec) were 20.7μC/cm2 and 75.5kV/cm, respectively. The dielectric constant and the dielectric loss at 100 kHz of the films were 930 and 0.045, respectively.

Abstract: The preparation method of CdO-SnO2-WO3 series (Cd-Sn-W for short), CdO-Sb2O3-WO3 series (Cd-Sb-W for short) and double-base three-phase (Cd2Sb2O7、CdSnO3、 CdWO4) structure linear NTC(Negative Temperature Coefficient)ceramics made of these two combined materials were studied. Six equations were independently designed, according to which NTC Sensitive Ceramic micro powders were prepared through chemical coprecipitation. The part that polyethylene glycol (PEG) and anhydrous ethanol played to prevent granules agglomeration when making nano-powders was deeply analyzed. As large formula weight polyethylene glycol (PEG) is not poisonous and does no harm to people’s health, it is worth popularizing widely