Advanced Materials Research Vol. 1051

Abstract: Base on the thermodynamic calculation, CsI _(s) does not decompose to Cs _(s) and I _(s) at 600°C, either does not from I_2(g), CsO_(g), CsO_2(g), Cs₂O_(g), and Cs₂O_3(g). However during the experiment when CsI_(s) is heated above to 200 °C at 1 atm the purple vapor can clearly be obviated. The vapor should be I_2(g). It is because the incomplete boing of I^- which in the CsI compound is evaporation. In this paper, we are interesting in CsI properties during heating and calculation the Cs-I-O thermodynamic characterizations by the thermodynamic data books.

Abstract: The effect of surfactant on improving the leaching rate of uranium was studied under both batch and column experiments. Batch experiments show that surfactant DMSS can improve the leaching rate and the the surface tension is decreased about 55.29%. 70 mg/l DMSS has the highest leaching rate of uranium , which close to the micellar concentration of DMSS. In the column study, with the addition of DMSS, the leaching rate of uranium is improved 8.3%. Thus the surfactant DMSS can accelerate leaching of uranium.

Abstract: In order to assess the safety and reliability of lap joint structures with dissimilar materials in aircraft, the mixed structure of CFRP and 2A12 was taken as an example, and a calculation model that based on the boundary element method was provided to simulate the galvanic corrosion. Depend on this, the research in the influence of the electrolyte concentration and the film thickness on the corrosion current density and potential distribution on the surface of simulation structures was developed. Meanwhile, the measured data was also used to verify the accuracy of the output result of the model. The comparsion result shows that outputs of the model are in good agreement with experiment datas. This model can be used to predict the galvanic corrosion in the lap joint structure in aircraft, thus minimizing the potential threats caused by corrosion to the flight safety.

Abstract: This thesis is focused on the catalyst of ionic liquids. Firstly, chloroaluminate ionic liquid consisting of triethylaminia hydrochloride and anhydrous A1C1₃ was prepared, and its catalytic performance on the alkylation of benzene with 1-bromobutane was studied experimentally. The composition of the system was analyzed using gas chromatogram. The effect of such influencing factors were investigated as the constitute of ionic liquid,the dosage of catalyst, the mole ratio of benzene to 1-bromobutane, temperature,reaction time,the regeneration approach of the used ionic liquid catalyst. The results suggested that it helps to increase the conversion of propylene and the selectivity of 1-butylbenzene by increasing the mole fraction of AlCl3 in the ionic liquid, the amount of catalyst, the mole ratio of benzene to 1-butylbenzene, reaction time and by reducing reaction temperature. At optimal conditions of 66.7% of mole fraction of AlCl₃ in the ionic liquid, l0wt% of catalyst with respect to benzene, 10:1 of mole ratio of benzene to 1-bromobutane and 313 .15K, both conversion of 1-bromobutane and selectivity of butylbenzene can reach 96.6% in 20 minutes. The activity of the catalyst can be basically remained after eight times reused. For the used ionic liquid, its catalytic activity can be partially recovered via adding some extra AlCl₃ notwithstanding less satisfactory. The catalyst performance of ionic liquids on the esterification of ethanol with ethanonic acid was studied.

Abstract: A novel synthesis method of bromoalkanol at high selectivity from the monobromination of diol with aqueous HBr (48%) in toluene under microwave irradiation was reported in this paper. Based on orthogonal tests results, 10-bromo-1-decanol was synthesized in 53.5% yield and at 95.2% selectivity. Other six bromoalkanols were synthesized according to the above method in 40.9%-78.7% yield and at 90.5%-96.6% selectivity, which were as follows: 8-bromo-1-octanol, 9-bromo-1-nonanol, 11-bromo-1-undecanol, 12-bromo-1-dodecanol, 13-bromo-1-tridecanol and 14-bromo-1-tetradecanol.

Abstract: Doped carbon materials have been recognized as a promising non-Pt cathode catalyst for oxygen reduction reaction (ORR). We prepared a new Fe-N codoped carbon meterial by the carbonization of Polyaniline-Prussian blue composite (PANI-PB). PANI-PB was first prepared by doping polyaniline with ferrous ion and ferricyanide ion in turn. The composite was then carbonized in a nitrogen atmosphere at a heating rate of 10°C min⁻¹ up to a maximum temperature of 800°C, forming a Fe-N doped carbon meterial (Fe-N/C). The product demonstrates a unique graphitized structure and has a relatively high Fe-N doping amount. The cyclic voltammetry curves (CV) show that the composite can catalyze the ORR much more efficiently than either of the single materials containing only carbonized PANI or carbonized PB in alkaline media.

Abstract: Degradation of cathode induced by sodium chloride in air has been investigated for (La_0.8Sr_0.2)_0.98MnO₃ (LSM). Cell performance was measured by volatilizing NaCl into the air supplied to the cathode at a constant current density of 200 mA cm^-2 up to 100 h. At 800 °C, an exposure to 30 ppm NaCl caused negligible degradation of LSM cathode at least for 100 h, yet degradation became obvious with increasing NaCl concentration. Slight change in the composition of the cathode materials was observed which may lead to the gradual degradation of cell performance. In addition, cell performance degradation was compared between 700 °C to 900 °C, being poisoned by 30 ppm NaCl. Degradation was negligible for the LSM cathode, while it showed slightly poor tolerance at 700 °C due to the decomposition of the cathode material. Further study should be done to clarify the long-term influence of NaCl on cathode performance.

Abstract: The Al-5wt.%Cu based alloy with different levels of Al5Ti1B master alloy additions have been prepared by conventional casting method. The effect of Al5Ti1B contents on microstructure of Al-Cu based alloy was studied by means of XRD, OM and SEM. The results show that when the addition level of Al5Ti1B master alloy is less than 0.6wt.%, the average grain size of the alloys decreases with the increase of Al5Ti1B content. But the grain size increases somewhat with further addition of Al5Ti1B. It is considered that TiB₂ particles can serve as the heterogeneous nucleation sites of α-Al during solidification, and heterogeneous nucleation is the main reason of the grain refinement of Al-Cu based alloy. The superior comprehensive mechanical properties of tensile strength of 435 MPa and elongation of 11% of the refined Al-5wt.%Cu based alloy with 0.6% Al5Ti1B were obtained after solution and aging treatment.

Abstract: In this study, Ti-45Al-7Nb-4V alloy protective coating which base on γ-TiAl phase was deposited on the surface of 5803 aluminum alloy by supersonic particles deposition technology. Researchers observed the micro-structure of the TiAl alloy casting and coating by SEM, and researched the electrochemical characteristics and the galvanic corrosion between TA2 titanium alloy and 5083 aluminum alloy or TiAl alloy casting and coating by electrochemical work station. The results show that,the galvanic corrosion current between 5083 aluminium alloy and TA2 titanium alloy declines from 16.2μA to 0.27μA after TiAl protecting coatings are prepared on the substrates, besides, the corrosion susceptibility drops from E degree to A degree. It also manifests that the 5083 aluminium alloy with Ti-45Al-7Nb-4V coatings can be contacted and utilized with TA2 titanium alloy directly, which tackles the issues of gavanic corrosion prevention between aluminium alloys and titanium alloys.

Abstract: This article proposes a frictional resistance description approach in sheet metal forming and the objective is to characterize the friction coefficient value under a wide range of friction conditions without performing time-consuming experiments. To describe the friction condition in sheet metal forming simulations, the friction coefficient should be quantified using friction models. Realistic friction models must account for the influence of surface roughness and surface topography on the lubricant flow and dry friction conditions. Due to considerable amount of factors that affect the friction coefficient value, building the analytical friction model for specified process conditions is too demanding. Thus, mathematical models that describe the friction behaviour using multiple regression analysis (MRA) and artificial neural networks (ANN) are utilized. The regression analysis was performed using the user subroutine in the MATLAB, while the ANN model was built in STATISTICA Neural Networks. As input variables for regression model and training of multilayer perceptron (MLP) the results of strip drawing friction test were utilized.