Advanced Materials Research Vols. 554-556

Abstract: A green silicon-containing carbon black pigment was synthesized via a sol-geo combustion technique using TEOS and black ink as raw materials. The obtained black pigment was characterized by XRD, TEM and UV-vis absorption spectrophotometer. The results show that the silicon coated with carbon black pigment can be formed at pH ≥ 2 and the black pigment does not change its color after calcinations at 1300 °C in air implying the carbon black is coated completely with SiO2. When pH is 4, the properties of as-prepared sample are similar with the conventional high-temperature pigment. XRD and SEM further confirm that silicon coats with carbon black fully. The silica/ carbon black pigment may represent an opportunity for the applications in the decoration of the high-temperature ceramic.

Abstract: A novel tetra-substituted zinc phthalocyanine 4 [ZnPcNHCOCH2(PEG)5NH2] was synthesized from 4-nitrophthalonitrile by using a four-step procedure. The compound has been characterized by UV–Visible, fluorescence, IR, 1H NMR spectra and MALDI-TOF MS, and the satisfactory result has been obtained. Most importantly, this compound is soluble in many solvents including CHCl3, CH2Cl2, DMF, DMSO, THF and water.

Abstract: Al-doped ZnO nanomaterials were synthesized by microwave-induced combustion method using urea as main fuel, aluminum nitrate provide doping ions and zinc nitrate as oxidant. The effects of microwave power, amount of urea and ratio aluminum nitrate to zinc nitrate on the properties of synthesized sampler were investigated .X-ray, diffraction(XRD), scanning electron microscope(SEM), and photoluminescence(PL) were used to characterize the properties of the sample respectively. The experimental results show that ZnO nanomaterials with cubic ZnO crystal phase of best optical property are obtained at 340W when molar ratio of the zinc nitrate to aluminum nitrate is 40% and fuel just completely reaction. The average primary granularity of the synopsized sample is about 56rnm estimated according to Scherrer Equation. PL test results indicate that the Ultraviolet(UV) emission peak in 360nm can be attributed to the recombination of free excitations through an excitation-excitation collision process, and the green emission peak in 470nm is commonly referred to a deep-level or trap-state.

Abstract: In this paper, the effect of the adjustable permanent magnetic field with the maximum magnetic flux density as 4100mT on the calcium carbonate(CaCO₃) precipitation process was investigated from hard water in the absence and in the presence of foreign ions Al³⁺、Fe²⁺、Mg²⁺、SO₄²⁺. By changing the strength of the magnetic field, the fouling resistance efficiency, the total CaCO₃ precipitation and precipitation in the bulk solution were determined by measurement of the mass of CaCO₃ precipitation, and the polymorph composition of CaCO₃ precipitated in bulk solution and particle size fouling on the loading slice was determined by XRD and electron microscope. The effect of MF on the precipitation process of CaCO₃ was tested by degassifying dissolved CO₂ in calcocarbonic pure water containing foreign ions. The results showed that magnetic water treatment increased the total precipitation and favored the precipitation in bulk solution instead of precipitating on the walls regardless the presence of foreign ions. The effect is intensifying with the strengthening of the magnetic flux indendity. The Magnetic field (MF) did not affect the polymorph composition of CaCO₃ in the absence of foreign ions. While in the presence of foreign ions, the precipitation and structure of precipitated CaCO₃ were significantly affected. The MF favored the precipitation of aragonite and inhibited the formation of calcitein the presence of Mg²⁺ and SO₄^2-. In the case of Al³⁺ and Fe²⁺, the precipitation of aragonite is favored, calcite and vaterite is inhibited. The MF influenced CaCO₃ precipitation process by influencing the hydration process of the ions in the solution and changing the dehydration process of hydrated CaCO₃ as the precursor of crystal nuclei for the magnetic field change the structure of water cluster. The reason that foreign ions can change the polymorph composition of CaCO₃ is probably owing to its hydration and dehydration.

Abstract: The capability for the adsorption of Cu (II) ion with mesoporous material SBA-15, amino-functionalized SBA-15 and mercaptopropyl-functionalized SBA-15 was investigated. XRD, FT-IR and FESEM were used for characterizing the structure and surface properties of adsorbent prepared. Effects of initial concentrations and pH on adsorption process were studied. Amino-functionalized SBA-15 was found to show the highest percentage removal of Cu (II) ion from aqueous solution compared to mercaptopropyl-functionalized SBA-15. Adsorption isothermal model was also examined. Langmuir isothermal model was found to be better fitted with adsorption process compared to Freundlich isotherm model.

Abstract: The nanocomposite of polyaniline (PAni)-coated Carbon nanotubes (CNT) for NH₃ gas sensing application are presented in this paper. The nanorods of PAni/CNT nanocomposite was synthesized by chemical oxidative polymerization of aniline using ammonium persulfate in acidic medium. The aniline was adsorbed in CNT by vacuum absorption method. The morphologies and properties of the nanocomposite have been characterized by SEM, XRD and FTIR respectively. Thin sensor of PAni/CNT nanorods was prepared by spin coating method. Finally, the response of these composite films for NH₃ gas was evaluated by monitoring the change in electrical resistance at room temperature. With compared to the pure PAni and CNT, t_{Subscript text}he nanorods of PAni/CNT composite films show a higher sensitivity.

Abstract: Hexagonal sodium yttrium fluoride has been successfully synthesized via a facile solvothermal route, using yttrium nitrate, sodium fluoride and polyethanediol as raw materials to react in propanetriol solvent. The as-prepared product was characterized by powder X-ray diffraction, scanning electron microscopy, thermogravimetric and differential thermal analysis, Fourier transform infrared spectrum and energy dispersive X-ray spectrum. The characterization results revealed that the products are hexagonal and denoted as NaYF₄. The as-synthesized hexagonal sodium yttrium fluoride composed of hollow-structured nanotubes self-assembled and arrayed orientedly to take on bamboo raft morphology. Hexagonal NaYF4 nanotube arrays exhibited high heat stability. This study provides a simple method to prepare bamboo raft-shaped NaYF₄ in large scale, which broads their practical applications.

Abstract: Mechanical properties and microstructural evolution of an Al-Cu-Mg-Ag alloy during thermal exposure at elevated temperature were characterized by means of tensile tests, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The tensile test results suggested that tensile strength ( ) and yield strength ( ) reduced with both increasing exposure time and temperature. Correspondingly elongation of samples increased steadily with increasing exposure time and temperature, which resulted in ductile fracture. TEM results suggested the reduction of mechanical property of samples was attributed to coarsening and reduction in amount of dominant strengthening phase-Ω phase during thermal exposure.

Abstract: Titanium dioxide is an important inorganic chemical product, and low iron and rich titanium slag can be made into titanium dioxide. In this paper, process parameters for preparing titanium dioxide were investigated. The results show that with the increase of sulfuric acid concentration, curing time and curing temperature, the rate of sulfuric acid hydrolysis rate will be improved, as well as charging temperature. According to the orthogonal test, the optimum process parameters condition of sulfuric acid is 95% sulfuric acid, 180°C reaction temperature, and 120min curing time.

Abstract: Based on the Pauling’s nature of chemical bond, the valence electron structures of diamond and c-BN crystals have been constructed. Then the relationship between covalent bond and glide plane system is analyzed. The results show that the hardness of diamond and c-BN is correlated to the covalent electron structure and the slip system of crystals. The hardness for diamond and c-BN so large is explained satisfactory form valence electron structures.