Advanced Materials Research Vol. 662

Abstract: Double-walled carbon nanotubes (DWCNTs) have been synthesized by a floating catalytic chemical vapor deposition method (FC-CVD) in diameter-varied reactor with xylene as carbon sources, ferrocene as catalyst precursor, and sulfur as additive. The as-grown products were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), and Raman spectrometer. The results show that DWCNTs with a high graphite degree is centimeter-scale in length, and the inner diameter varies in the range of 1.5-1.7 nm. The effect of reactor diameter on the structure and morphology of the products was also investigated and compared. It is believed that the diameter-varied reactor may become a feasible route to the mass and continuous production of DWCNTs.

Abstract: The purpose of this paper is to study the feasibility of nano-material (1~100nm) level powder preparation by wet ball milling. The powder was used to prepare the ceramic and the performance of the ceramic was analyzed. The experimental results show that the average particle size of the powder is close to nano-material level (around 120nm) and the ceramic possess high compactness, high dielectric constant and low dielectric loss.

Abstract: Nonaligned and curly β-SiC nanowires (nw-SiC) were grown on porous silicon array (PSA) by a chemical vapor deposition method with nickel as the catalyst. The morphology, structure and the composition of the nw-SiC/PSA and the SiC-SiO₂ core-shell fibers which is the semi-product were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Based on the experimental results a possible growth mechanism of nw-SiC was explained. Two broad photoluminescence peaks located around ~409 and ~494 nm were observed in nw-SiC/PSA in the PL measurement when utilizing 300 nm ultraviolet fluorescent light excited at room temperature. The excellent luminescent performances are ascribed to the quantum confinement effects in nw-SiC. The optical merits of nw-SiC/PSA made it a promising material in the fields of ultraviolet-blue emitting devices.

Abstract: The porous anode alumina (PAA) films on silicon substrate with good physicochemical properties have hopeful for the nano-scale devices. The various factors which influence the preparation of high performance PAA film based on silicon were systematically studied, the DC magnetron sputtering technology was used to deposit aluminum and the two-step anodic oxidation method to growth PAA membrane. The results demonstrated that about 2 μm aluminum film deposited on the p-type silicon substrate, in advance deposited 50 nm Ti film on the Si substrate, can get high quality Si-based PAA membrane with good adhesivity, stable structure and consistent pore shape and diameter.

Abstract: Novel K2Ti6O13 nanowires were successfully synthesized by a new method， that is sol-gel/ hydrothermal combined method. The crystal structure and morphology of the products were characterized by a series of methods including XRD, SEM, EDX and TEM. The results indicate that the products synthesized are K2Ti6O13 nanowires. The diameter is about 5nm, and its length is in the range of from a few micrometers to hundreds of micrometers. The TiO2 nanoparticles synthesized via a sol-gel method, as hydrothermal reaction precursors, play an important decisive role on the diameter of K2Ti6O13 nanowires and the hydrothermal reaction rate. Photocatalytic degradation of MB in presence of the K2Ti6O13 nanowires was compared with that in presence of the TiO2 nanoparticles. The results show that the nanowires have better photocatalytic activity.

Abstract: Single crystalline Y(OH)3 nanorods were synthesized from Y2O3 powder by a simple hydrothermal synthesis method under alkaline conditions. SEM images displayed that the nanorods have average diameters of about 400nm and lengths up to several micrometers. In this paper, it is used nano-inorganic particles yttrium hydroxide to modified MC nylon. The different mass fraction of yttrium hydroxide has affected mechanical and thermal properties of the MC nylon composites. The results show that with increasing of the mass fraction of yttrium hydroxide, the impact strength is the highest value when yttrium hydroxide mass fraction of 0.25wt%, however the tensile strength decrease 20%. And there is a little change in thermal stability when Yttrium Hydroxide added.

Abstract: The OA protected, Eu doped CdSe nanocrystals (NCs), which optical property could be control by temperature and reactant molar ratio, were prepared by non-injection one-pot synthesized method. And after modifying TTA, the Eu doped NCs showed energy transfer from NCs to Eu. The size, crystal structure, composition and the optical property of product were further studied in detail by TEM, PL, UV, XRD and EDS. The Eu doped NCs with excellent lanthanide characteristic fluorescence were possessed many potential applications in various fields, such as biological labeling, immunoassays, optical sensing, and so on.

Abstract: Hydroxyapatite (HA)-zirconia nanocomposite is synthesised by mixing as-synthesised HA with commercially available yttria-stabilised zirconia nanopowder using wet ball milling. The sample is consolidated using uniaxial pressing followed by cold isostatic pressing. The composites containing 0 wt%, 0.05 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, and 5 wt% zirconia are prepared and sintered at 1100, 1200, and 1300 °C. Results from the X-ray diffraction (XRD) and density analyses show that the proposed approach produced a highly dense sample (>98.8%) with minimum amount of impurity, which is suitable for dental applications.

Abstract: In this article, MC nylon/carbon nano tubes (CNTs) composites were prepared by in-situ polymerization method. The friction and wear properties were determined. The sample wear surface morphology carried out by scanning electron microscope (SEM) and the wear mechanism was investigated. It was found that the friction coefficient of composites has decreased with the amount of CNTs increasing in the composites. Addition amount of CNTs is up to 0.3% (weight percent), abrasion index decreased to minimum. The abrasion index of the sample of wearing a long time is smaller than that of the sample of wearing a short time. The sample with wearing less time mainly take place adhesive wear, however, mainly happen abrasive wear and adhesive wear for wearing time is longer. Further more, carbon nano tubes (CNTs) are not only improve the wear resistance of composites but also improve the mechanics performance.