Advanced Materials Research Vols. 194-196

Abstract: ITO (indium tin oxide) film of a high transmittance and high conductivity has been extensively studied because of its applications in optoelectronics. In this study, ITO nano-powder was prepared by constant pH chemical coprecipitation method. The experimental results show the precursor of the powders play a key role. The optimum was selected with orthogonal experiments. The optimum showed pH 8.5, temperature 60 °C, solution of indium and tin adding speed 100 mL/min, stirring rate 500rpm, additives 25 mg/L. the primary particle size is less than 10 nm with narrow distribution and good decentralization. SEM shows that particles are sphere-like and XRD shows that precursor consist of indium hydroxide and amorphous body. Zeta potential showed the powder is in nanoscale with uniformly dispersiveness. ITO nanocrystalline powder was formed after sintering at 600°C.

Abstract: This article presents a research on friction and wear properties of titanium composite lubricating grease containing ultrafine PTFE particles by using scanning electron microscopy to observe surface morphology of the worn steel balls and EDS to analysis the main elements in the worn surface of steel ball. The results show that the compound titanium grease with 3% ultrafine PTFE has the best wear and friction reduction properties. Its friction coefficient decrease about 25.5%, the diameter of wear scar decrease about 23.2%. The appropriate amount of PTFE particles go into the frictional surface with the grease, form the PTFE particle layer on the frictional surface, which reduces the direct contact of metal to metal, effectively reduces the friction and wear.

Abstract: The nanocrystalline TiC_1-xN_x powders were synthesized by high energy milling from the mixture of Ti and carbon black in nitrogen milling atmosphere. The phase transformation and powder morphology characteristics were studied by using XRD and SEM. The results show that nanocrystalline TiC_1-xN_x powders were fabricated successfully by milling for 24 h at a rotational speed of 450 rpm in planetary ball-mill. The formation mechanism was mechanically induced self-propagating reactive synthesis (MSR). According to changing the mole ratio of C to Ti, serial TiC_1-xN_x powders can be produced, including TiC₇N₃, TiC₅N₅, and TiC₃N₇.

Abstract: Because of their unique properties, gold nanoparticles(NPs) show a wide range of applications such as surface-enhanced raman characteristics, biological sensing, biomedical and other fields. Different initial concentrations of Bull Serum Albumin(BSA) and egg white lysozyme respectively react with different size of gold nanoparticles. The condition of adsorption is determined by spectrometry method, then the area of protein with different molecular mass on the surface of a gold nanoparticle is calculated. The results show that the larger particle size of a gold nanoparticle is, the more protein the surface a gold nanoparticle adsorbs; the smaller the molecular mass of protein is, the more protein is adsorbed by gold nanoparticles surface.

Abstract: The electroless deposition is an excellent method for the preparation of the CNTs with Ni-P layers. Pristine CNTs were first oxygen-functionalized by treating them with a mixture of concentrated (HNO₃ :H₂SO₄=1:3) acids. The SWNTs were obtained in the suspension of purification solution, In this work, the heat-treatment at 400°С transformed the amorphous Ni-P layer into the nanocrystalline Ni-P (crystalline Ni and Ni₃P intermetallic compound) layer. The Ni-P-SWNTs before and after heat-treatment were studied using XRD and SAED. It is observed that the lattice parameters of Ni-P layers has difference from the bulk’s, indicting that the lattice change has taken place.

Abstract: The acoustic insulation and hydrophobic properties of a new non-woven material were analyzed and discussed in this paper. The new non-woven material absorbs sound energy to transfer into heat energy by friction between viscosity of air near fiber and fiber. The acoustic insulation properties of the new non-woven material, polyurethane foam and felt were measured. With the same thickness and half weight of felt, the sound absorption coefficient of non-woven was 20~30% higher than felt. Further more, with the same weight of felt, the sound absorption coefficient of non-woven was50~60% higher than felt. However, the sound absorption coefficients of non-woven materials with different thickness and weight were also discussed. The amount of the sound absorption coefficient gradient increased with the increase of thickness and frequency. Comparing the existing sound absorption materials, the new non-woven material has high sound absorption, light weight, hydrophobic property, workability, and flame resistance property. The non-woven material can improved thermal insulation and sound absorption by combining conventional non-woven with aluminum evaporated film.So the new nonwoven material has been widely applied in industries to reduce noises, especially in the car.

Abstract: The nano-NiO powder was prepared by sol-gel method combining heat treatment technology and its structure and morphology were explored. In addition, the NiO powder electrochemical properties were tested by constant current charging and discharging. The results show that the stable performance sol can be composed by nickel acetate as source of nickel and PAA as chelating agent. Nano-NiO powder of crystal structure integrity, particle uniformity can be prepared by the sol. The gel decomposes completely and gradually forms nanocrystal at 430^οC. Its grain size is gradually increasing when the annealing temperature rise. The nano-NiO powder sintered at 600°C exhibits uniform particle, integrity crystal structure, low aggregation and superior electrochemistry performance and may be used in Li-ion battery as the anode material.

Abstract: A jet electrodeposition device was carried out to prepare Cu-Al₂O₃ nanocomposite coatings. The influence of the concentration of Al₂O₃ in the electrolyte and parameters on the content of the Al₂O₃ in the deposite were investigated. The coatings ingredient and microstructure was measured by the scanning electron microscope, the microhardness tests were conducted on an microhardness tester. The results show that the copper deposited layers have nanocrystalline microstructure with grain size of about 50nm . The amount of Al₂O₃ in composites first increased and then decreased with an increase in the concentration of Al₂O₃, current density, temperature and jet velocity. The composite with optimum atomic percent of Al₂O₃ (14.4 at%) can be obtained at the concentration of 30 g/l , cathodic current densities 300 A/dm², temperature 30°С , and jet velocity 8 m/s . The addition of Al2O3 in copper increases the microhardness of the electrodeposited coatings.

Abstract: Biopolymer cassava starch(ST)-chitosan(CS)/montmorillonite(MMT) nanocomposites were prepared in which MMT was used as nanofiller and diluted acetic acid was used as solvent for dissolving and dispersing cassava starch, chitosan and MMT. XRD and TEM results indicated the formation of an exfoliated nanostructure of ST-CS/MMT nanocomposites. Mechanical properties testing revealed that at the range of the MMT content from 1wt% to 5wt%, tensile strength of the composites increased from 30MPa to 37.5MPa. But the elongation at break fall from 28% to 22% with the increasing of MMT. Obviously, MMT had an enforced effect to the composites. TGA results showed that the nano-dispersed MMT improved the thermal stability of the matrix systematically with the increasing of MMT.

Abstract: Polyaniline/attapulgite (PANI/ATP) nanocomposites doped by hydrochloric acid (HCl) were prepared by in-situ polymerization method. The structure and absorption mechanism for eriochrome blue black of nanocomposite were investigated. Amount of absorbent and influence of pH for absorbent effect were also studied. The results reveal that the nanocomposites have not only the structure of ATP but also the property of the PANI. The nanocomposites hold an excellent adsorption for eriochrome blue black when the pH value is 5. The adsorption thermodynamics of the nanocomposites follows the Langmuir isothermal adsorption equation. The maximum adsorption capacity can reach 192.67mg/g. The calculate results show that the adsorption enthalpy is 4.15kJ/mol, the Gibbs free energy is (–22.98 to –19.26) kJ/mol, and the entropy of 81J/(mol·K), which imply that the adsorption is an endothermal and spontaneous process.