Advanced Materials Research Vol. 1081

Abstract: Cerium vanadate nanocrystalline was prepared by cerium nitrate, vanadium (V) oxide as raw materials and sodium dodecyl sulfate as surfactant under microwave irradiation. The sample was characterized by X-ray diffraction (XRD) and scanning electron micrograph (SEM). The XRD show that the as-prepared sample calcined at 773 K is tetragonal zircon, and the SEM graph show that the as-prepared CeVO₄ nanocrystalline is layer structure formated of small particles aggregation. We studied the photocatalytic activity of the as-prepared samples by using degradation of methyl orange in visible light. It shows that the photocatalytic activity of Cerium vanadate nanocrystalline was very well. The effects of different factors such as calcination temperature and the concentration of methyl orange on the characterization of CeVO₄ are discussed. It found that when the catalyst calcined at 873 K was 0.10 g, and 0.3 mL hydrogen peroxide joined as well as, pH was 2.0, the degradation ratio of CeVO₄ for methylene orange of 100 mL 20 mg/L reached 87% in 80 min.

Abstract: In order to solve the difficulty of how nanoTiO₂ could penetrate and fixate in polypropylene fiber, the study was carried out by using supercritical CO₂ as an assistant method. According to the experiments, the stable nanoTiO₂ dispersion could be obtained by the following process. Mixed nanoTiO₂, penetrant JFC, polyethylene glycol and ethanol together under the mass ratio of 10:2:1:600, adjusted the pH value to 11, and ultrasonic dispersed for 30mins. Then the PP non-woven fabric was immersed in this solution for 10mins, followed by the treatment with the assistance of supercritical CO₂. The optimum process was achieved after three single factor experiments. The reaction time was 40mins, pressure was 30MPa and temperature was 100°C. After treatment, the content of nanoTiO₂ in 100g PP non-woven fabric could reach 4.43g, the percentage of the washed residue was 3.42g and the loss rate was 26.3%. nanoTiO₂ could penetrate and fixate very well in PP fiber.

Abstract: Mn₃B₇O₁₃Cl nanopowders were prepared by sol-gel process. X-ray diffraction (XRD) and Transmission electron microscope (TEM) were utilized to characterize the structure, shape, size of the obtained products. Mn₃B₇O₁₃Cl powder was sintered into a ceramic disk having a diameter of 20mm by Spark Plasma Sintering (SPS). The formation of Mn₃B₇O₁₃Cl nanoparticles and the dielectric properties of Mn₃B₇O₁₃Cl were discussed. The results show that Mn₃B₇O₁₃Cl nanopowders which was obtained after xerogel roasted at 550°C are uniform. The size of the average particle is about 50nm. Mn₃B₇O₁₃Cl ceramic disk has a low dielectric constant and high dielectric loss. It is believed that there is a good application prospect in the field of microwave attenuation.

Abstract: FeAu/ZnO nanoparticles were successfully synthesized by nanoemulsion process with the use of poly (ethylene glycol)-block-poly (propylene glycol)-block-poly (ethylene glycol) as the surfactant. The characterization of the FeAu/ZnO nanoparticles was performed using X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and UV-visible absorption spectroscopy, showing that the polymer-laced nanoparticles reveal high crystallinity, excellent dispersibility and well defined optical performance. The process of solvent dispersion-collection of FeAu/ZnO nanoparticles indicates that the nanoparticles possess good magnetic property for applications.

Abstract: Colloidal Antimony Pentoxide was prepared through a simple method based on reflux oxidization system. Detailed investigations about the effects of experimental parameters on the colloid stability and size distribution of the final products were carried out. The use of the combination of a brominated flame retardant 2,3-dibromo-succinic anhydride (DBrFR) as the flame-retarding agent and colloidal antimony pentoxide (APO) as the synergist to reduce the flammability of PET/cotton blend fabric was also studied. The BFR was effective in reducing the flammability of the blended fabric whereas APO enhances the effectiveness of DBrFR due to bromine–antimony synergism. The limiting oxygen index (LOI) value and the breaking strength retention of PET/ cotton fabric treated with DBrFR and APO were studied and the thermal behaviors of different treated fabrics were investigated via thermo gravimetric analysis (TGA).

Abstract: La_1-xSr_xMO₃ nanoparticles have attracted increasing interest to material sciences due to their tunable Curie temperature (Tc), superparamagnetic nature and electrical properties, which could be utilized in magnetic hyperthermia treatment. However, La_1-xSr_xMO₃ nanoparticles are toxity to biomolecules and very sensitive to oxidation because of their higher chemical reactivity. The surface modification could enhance stability, dispersibility and compatibility of La_1-xSr_xMO₃ nanoparticles. This review article will introduce the progress on the synthesis and surface modification of La_1-xSr_xMO₃ nanoparticles in recent years, and then give the perspectives of outlook.

Abstract: In this paper, we investigate the heat transfer of the power-law-fluids-based nanofluids in a rotating circular groove. The circular groove rotates with a constant speed and the temperature on the wall of the groove is different from the temperature inside in the initial time. The effects of thermophoresis and Brownian are considered. The thermal conductivity of the nanofluids is taken as a constant. We solve the model with the finite element method directly and discretize them using a continuous finite element scheme in space and a modified midpoint scheme in time. From the results we can find that the heat transfer enhancement of the nanofluids increases as the power law index of the base fluid decreases.

Abstract: Graphite-containing plasma electrolytic oxidation (PEO) composite coatings were prepared on Al alloy using periodically constant voltage, with addition of graphite in silicate electrolyte. The surface and cross-sectional morphologies of the coatings were examined using scanning electron microscope (SEM), the composition of the coatings was investigated by X-ray diffraction (XRD) and Raman spectra, the tribological properties of the coatings were evaluated on a tribometer. The results show that friction-reducing PEO composite coatings on Al alloy can be prepared in graphite-dispersed electrolyte using periodically constant voltage, the yielded coatings exhibit relatively lower and more stable friction coefficient.

Abstract: The relationship between creep rupture strength and Laves phase precipitation and growth kinetics was investigated at 650 °C for two Fe-9Cr-3Co (wt.%) alloys differing mainly in the amounts of W and Mo added. In the alloy with 3.14 wt.% W added, Laves phase precipitated heterogeneously on grain boundaries and hence had little dispersion strengthening effect. Its stress exponent for rup-ture time became lower in the lower creep stress range tested. In the alloy with 1.31 wt.% W and 3.22 Mo added, Laves phase precipitated both heterogeneously on grain boundaries and homogenously within grains and there was no reduction in stress exponent for rupture time in the whole stress range tested. The Lave phase precipitation kinetics increased with increasing the total amount of W and Mo in the alloys. The differences in stress-rupture time relationship observed between the two alloys were discussed in relation to their differences in the Lave phase precipitation behaviour.

Abstract: Wettability is interfacial phenomena by a solid interface changes from solid-gas interface to solid-liquid interface, and the contact angle is often used to characterize it. The super hydrophobic surfaces with contact angle over 150° have various excellent characteristics. In the paper, the wettability of aluminum alloy surfaces was studied. Based on the Wenzel and Cassie models, the relationship of wettability between roughnesses were investigated on body surface and coating surface. The results indicated that the hydrophobicity of surfaces could greatly enhance with high roughness on surface, and then coating process was analyzed, wettability of aluminum alloys were transformed from hydrophilicity to superhydrophilicity, when they were coated with organic materials with the low surface free energy, such as polypropylene (PP) or maleic anhydride grafted polypropylene (PP-g-MAH), so modified PP can enhanced the hydrophobicity of solid surface mostly.