Advanced Materials Research Vols. 690-693

Abstract: Copper/LDPE composites are novel materials for intrauterine devices and they are the dispersion-type composites with high resistances. When the electrochemical impedance spectroscopy was used to evaluate the properties of materials with high resistances, in order to reduce the fluctuations in the measured data, the AC perturbation should be optimized. In this paper, the effects of the AC perturbations on the electrochemical impedance spectroscopy of copper/LDPE were discussed and the optimal AC perturbation was confirmed. The results have shown that the optimal perturbation of the electrochemical impedance spectroscopy of copper/LDPE composite, in the earlier period was 50mV, after achieving the saturation point the perturbation would change to 5mV.

Abstract: Based on the elliptic element model, the new sorting method on the same pattern compound materials was given in this paper according to the pictures obtained by electronic microscopy systems on the surfaces. Here, the block design combined with variance analysis was introduced to sort the compound materials that contained that the copper-base mingled with graphite, silica and other non-pronounced components. Here, the five kinds of the same pattern compound materials were proposed for sorting, only the graphite distribution was considered and their mixture ratios of components were separately 10%, 15%, 20%, 25%, 30%. At last, through experiment data and statistical analysis, the result of sorting was basically corresponding to the above mixture ratios of components.

Abstract: The starch xanthate/natural rubber (SX/NR) composite was prepared by directly mixing and co-coagulating NR latex and the modified starch paste with carbon bisulfide. The vulcanization kinetics of NR and SX/NR composite were investigated by using a rubber process analysis (RPA). The mechanism of SX/NR composite vulcanization was similar to that of pure NR. The values t₀ and t_dis of XS/NR composite were shorter than that of NR, and the activation energy E₁ for the induction period was smaller. The activation energies E₂ and E₃ for the curing period were smaller than that of NR.

Abstract: Quality of metal-matrix composite castings, similarly as quality of conventional metal castings is defined by the collection of data concerning chemical constitution, properties (e.g. strength) and structure of final products. During study aimed at determining these parameters, the priority is to maintain the highest possible repeatability and automation of measurement. In case of chemical constitution or mechanical properties analysis it is considerably easy to achieve thanks to application of appropriate research procedure. Analysis of structure of studied materials is however a much bigger problem. To improve it, different tools of digital image analysis are being used, but because of only slight differences (e.g. in color) between different elements of structure, conducting such analysis without performing additional study may result in obtaining false results. In such case, identification of an object is very important: unequivocal conclusion whether a given object is a reinforcement or maybe an impurity or an inclusion foreign matter, or is it a structure of improper, unintentional chemical constitution. It is particularly important concerning composites for which on the images obtained using both optical and scanning microscopy individual phases (reinforcement, matrix and impurities) are difficult to distinguish. In such case identification of particular phases is aimed at avoiding mistakes, for example while analyzing the quantity or uniformity of spacing of reinforcement phase in given space. X-ray diffraction may be a solution for this problem. An example of identification (quantitative and qualitative description) of reinforcement phase in suspension composites is presented further in the paper. The authors present also a chemical constitution of selected elements of structure of metal-matrix composites from ex-situ group.

Abstract: In a certain reaction time, CO2 concentration and flow rate, the carbonation experiment was carried out about green pellets prepared by the ferrous dust and active lime with 15%, 20%, 25%, 30% CaO content ratio respectively. The conversion ratio, porosity and compressive strength of carbonation pellets were analyzed at 200°C, 400°C, 600°C, 800°C.The results show that, with the reaction temperature increasing, CaO conversion ratio of carbonation reaction and the compressive strength increased, and the porosity decreased significantly; when the reaction temperature is 800°C, the CaO conversion ratio of reaction with 25% CaO content pellet can reach 47.26%, these can make the carbonation pellet to achieve a better carbonation degree and quality.

Abstract: The present authors have utilized, for the first time, H₃BO₃ as an additive in pilot scale experiments of Mg production using Pidgeon process. The results from the experiments revealed positive effects of H₃BO₃ on both quantity and quality of the Mg metal crowns. Besides acting as a catalyzer for MgO reduction, H₃BO₃ stabilized also β-Ca₂SiO₄ in the Mg slag. Based on these results, H₃BO₃ may be adopted as an innovative additive replacing fluorite in the Mg production, to enhance sustainability and environmental soundness for the Pidgeon process in China.

Abstract: Two-liquid bimetal composite casting technology by double induction furnace fusion was utilized for preparing bimetal product in tradition. Single induction furnace fusion has been investigated between the high carbon steel and the low carbon steel, and varying casting thickness has an obvious effect on the bimetal bonding layer. The results have shown that the bimetal bonding layer can not been generated under over thinness or thickness. In the condition of the thicker low carbon steel, two kinds of metal liquid were easy to rush mixture without the distinct interface, whereas the thinner low carbon steel can also effectively form metallurgical bonding. While the low carbon steel owned the proper thickness, metallurgical bonding can been observed distinctly, confirming the feasibility of the single induction fusion for preparing the bimetal.

Abstract: Organified attapulgites (AT) were modified withγ-Amino propyl triethoxysilane ( KH550 ). Then, the modified AT (AT-KH550) and untreated AT particles were compounded with polypropylene (PP) to prepare PP/AT-KH550 and PP/AT composites respectively. The micro-structrue, chemical structure and properties of the composites were also investigated with scanning electron microscopy (SEM), Fourier-transform infrared spectra (FTIR), Differential scanning calorimetry (DSC) and mechanical testing. The FTIR results showed that the KH550 is grafted on the AT particles. The izod impact strength of PP/AT-KH550 composites were improved obviously than those of PP/AT composites. The melting and crystallization temperatures of PP/AT and PP/AT-KH550 composites were increased with the loading of pristine AT and KH550 modified AT particles.

Abstract: Recently the steel wire reinforced thermoplastics composite pipelines are increasingly used in many different fields. In this paper, a parametric finite element model (FEM) of Steel Wire Reinforced Thermoplastics Composite Pipe (SRTP) was established by using ANSYS parametric design language (APDL). The purpose of optimization was to reduce the cost, so the minimum of pipelines total weight was chosen as the optimization objective. The wall thickness of SRTP and the diameter and axial pitch of braided steel wire were chosen as the main optimize parameters. The whole optimization process must ensure that the bearing capacity of SRTP was not weakened, so the yield strength was chosen as the optimization constraints. The optimization results were reasonable and correct.

Abstract: The HAP whiskers were prepared by hydrothermal homogeneous precipitation method at the constant temperature. Diammonium hydrogen phosphate, calcium nitrate tetrahydrate, urea and nitric acid were used as the main raw materials. Sorbitol was selected as the template agent and the hydroxyapatite whiskers seeds were served as the inducers. SEM, TEM, XRD and EDS were applied in characterization. The results show that the reaction products are the HAP whiskers with high crystallinity, smooth appearance and no agglomeration; the obtained HAP whiskers are monocrystal and the length-diameter ratio distribution of the HAP whiskers is concentrated at about 30.