Advanced Materials Research Vols. 197-198

Abstract: Materials, include polymer modified asphalt, coarse aggregate, fine aggregate, packing and lignin fiber, of SMA-13 Warm Mix Asphalt used in maintenance engineering of Jing-Shen expressway (K17-K22), were tested in quality. Based on different grading Marshall tests of stone matrix asphalt of HMA (no additive) and WMA (with additives), materials proportion, asphalt aggregate ratio and target densities of SMA-13 WMA were designed, which will be applied in expressway surface maintenance. Through rutting test, water immersion Marshall test, tensile strength ratio test, seepage test and other proportioning examinations, it shows that the designed asphalt can meet code requirements and guarantee good high temperature stability and water stability.

Abstract: A nanometer coupled oxide ZnO-SnO₂ was prepared by the fractional homogeneous co-precipitation route using urea as the latent precipitant under boiling reflux condition. The samples prepared from different initial concentrations of urea or at different calcination temperatures were characterized by X-ray diffration (XRD) or transmission electron microscopy (TEM). It was found that the coupled oxides ZnO-SnO₂ mainly consist of nanosized ZnO and SnO₂, the calcination temperature had obvious effect on the phase composition and the crystal size of the samples obtained, and the precipitant concentration also had obvious effect on the oxide particles size and the production rate of ZnO. Moreover, their photocatalytic activity was investigated for the liquids-phase photocatalytic degradation of methyl orange (MO) in water under UV light irradiation.The coupled oxides showed better photocatalytic activity for the degradation of MO than the pure ZnO or SnO₂.

Abstract: A modified ZSM-5 molecular sieve was prepared by the combination of recrystallization and carbon template methods. The samples were characterized by X-ray diffraction, N2 adsorption-desorption, NH3-TPD, TEM and SEM. The results show that the modified ZSM-5 molecular sieve has double pore distribution. The diameters of the two kinds of channels are 0.51~0.56 nm and 1.4~1.6 nm, respectively. In addition, the modified HZSM-5 (H-type ZSM-5) sample mainly has moderate strength of acid sites. Finally, the alkylation of benzene with 1-dodecene olefin was used to evaluate the catalytic performance of the as-synthesized modified ZSM-5 on macromolecules. The conversions of 1-dodecene on the modified ZSM-5, ZSM-5 prepared by conventional process and aluminum-containing SBA-15 mesoporous molecular sieve are 96%, 39% and 83%, respectively. And the selectivities of long chain alkyl benzene on those are 97%, 68% and 91%, respectively. The catalytic properties of the modified ZSM-5 on macromolecules are superior to those of ZSM-5 prepared by conventional process and aluminum-containing SBA-15 mesoporous molecular sieve.

Abstract: The olivine-type LiFePO₄ powder was prepared by a chemical method using the synthesized FePO₄ 1.78H₂O, LiOH, citric acid and PEG as raw materials. The synthesized FePO₄ 1.78H₂O precursor powder was obtained by co-precipitation method. LiFePO₄ powder was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermo-gravimetric analysis (TGA)/differential scanning calorimetry (DSC). The results showed that the calcined LiFePO₄ was in a single phase when fabricated by using the synthesized FePO₄ 1.78H₂O powder at pH of 3.5 in argon atmosphere.

Abstract: Two types of supercapacitor electrode materials have been synthesized: AC/PANI, activated carbon composites polyaniline by in-situ polymerization of aniline on the surface of activated carbon, and Ni-AC/PANI, the AC/PANI composite dopes with nickel. The microstructure of composites has been examined by scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FI-IR) has been used to determine the molecular structure and chemical bond of the composites. The nickel content has been measured by atomic absorption spectrometry (AAS). The electrochemical performance of the composite has been characterized by cyclic voltammery and galvanostatic charge-discharge in 6mol•L-1 KOH solution using Hg/HgO as reference electrode. Due to the doping of nickel salt, Ni-AC/PANI shows desired microstructure, good high-current charge-discharge performance and good electrochemical behavior with an capacitance of 535F•g^-1, 38.2% higher than that of AC/PANI.

Abstract: A novel porous CaO microsphere catalyst was synthesized by calcining spherical CaCO₃ precursor which was prepared easily by mixing CaCl₂ with Na₂CO₃. After characterized by scanning electron microscope and X-ray diffraction analysis, the synthesized CaO was studied on Studies on the catalyzing transesterification of soybean oil with methanol for biodiesel. The effects of calcining temperature, reaction time and temperature, amounts of catalyst and methanol on the catalytic activity of CaO microsphere had been evaluated by catalyzing transesterification of soybean oil with methanol for biodiesel. It expressed excellent catalytic activity with a transesterification yield of more than 98% at 65 °C in one hour with 3 wt% of CaO microsphere calcined at 800 °C.

Abstract: In this paper, various kinds of high-temperature phase change thermal storage Al-Si-Cu-Mg-Zn alloys were prepared, and the thermal properties were studied through integrated thermal analysis. Then the corrosion kinetics of Cr20Ni80 alloy in Al-7% Si alloy and Al-Cu-Mg-Zn alloy at 700°C in thermal cycles were obtained. The microstructures, element concentration and phases in the interface were analyzed by means of metallographic microscope, EPMA and XRD. The results show that all materials phase transition temperatures are during 450°C ~650°C . The total thermal energies of the materials are higher than 900J/cm³. Quaternary alloys and quinary alloys show much more advantages when applying for solar thermal power generation systems. The latent heat depends strongly upon the composition and percentage of elements and the phase composition. Besides, experimental results show that the corrosion rate of Cr20Ni80 alloy in Al-7%Si alloy at 700°C is 0.167mm/h. Under thermal cycling conditions, the corrosion rate of Cr20Ni80 alloy in Al-Cu-Mg-Zn alloy is a little lower and the reaction interface layer does not significantly affect the rate of further corrosion. The corrosion of Al-Si-Cu-Mg-Zn phase change thermal storage materials depends on the content of aluminum element, and nickel-based alloys are not suitable for use as packaging materials.

Abstract: Novel Ag/TiO₂-NTs composites have been synthesized using titanium dioxide nanotubes (TiO₂-NTs) modified by (3-aminopropyl)trimethoxysilane (APS) as supports. The composites have been characterized by TEM and XRD. The better dispersion of Ag on TiO₂-NTs modified by APS can be observed than that of TiO₂-NTs without being modified by APS, which implies that APS is helpful for uniform nanoparticles. The electrocatalytic properties of Ag/TiO₂-NTs for hydrazine oxidation were investigated in details. Excellent electrocatalytic activity was observed. The results showed that TiO₂-NTs have a very good application potential as supporting materials for noble catalysts.

Abstract: The effects of modification by antimony on Al－Si cast alloys have been extensively used, but the modification mechanism has not been well accepted. 0.2wt%Sb has perfect modification effects at the existence of of Mg, while much enough Sb for example 1wt % has effects on modification as well without Mg. The cooling process of alloys and the existence manner of elements in cast Al-Si alloy of different content of Sb is studied in this paper. Viewed from the results of DSC thermal analysis, crystallization supercooling increases, nucleation supercooling reduces and eutectic latent heat increases when the content of Sb reaches 0.2wt %. HCombiningH the existence manner of elements in cast Al-Si alloy analyzed by energy - dispersive spectrometry, it is found that the actual modification agent is the clustered Sb in free state. Mg can intensify the modification effects of Sb because Mg added to alloy decreases the solubility of Sb, which allow enough Sb left over to effect modification of alloy.

Abstract: The Cr5Mo alloy steel is the most commonly used high pressure vessel and heat pipe using the material. This article on external forcing Cr5Mo alloy steel of high-temperature oxide layer for microscopic analysis of oxide layers of micro-cracks and exfoliation, oxidation layer portion of the oxide layer break, the oxide layer fold, multilayer structure oxide, oxidation and give the structure of the matrix and the proliferation of microstructure of the oxide layer. To compare Cr5Mo alloy steel for high temperature oxidation layer in a load-time and there is no loading time variation of topography.