Advanced Materials Research Vols. 239-242

Abstract: The effect of equal channel angular pressing (ECAP) process on the electrochemical behavior of chromium bronze in NaCl solution was investigated by three-electrode cell setup. The result shows the difference of electrochemical behavior between X plane and Y plane is still exist, and even in the unodd number passes for “route C” of ECAP process. ECAP process don’t change the corrosion nature of chromiun bronze, but the corrosion potential of 12 passes ultra-fine grain (UFG) chromium bronze is a little more positive than that of 0 pass chromium bronze. For better understanding the effect of ECAP on the electrochemical behavior of chromium bronze, we chose the cold-rolled materials with the same composition as reference materials. The result shows that ECAP process is more benefical to electrochemical behavior of chromium bronze than cold-rolled process. On the other hand, the result of EIS also shows that ECAP process is more benefical to form compacted corrosion layers on the surface of specimens.

Abstract: During the wet PU, PVC synthetic production, MCC could be served as a good micropore and thickening agents, and could obviously enhance the feel and elasticity of synthetic leather, but cotton pulp and wood pulp resources, which were used as raw material commonly to produce MCC for synthetic leather, was limited. In this paper, MCC was prepared with wheat straw pulp through the dilute acid hydrolysis, alkali treatment, enzyme treatment, drying and crushing. This paper focused on the effect of conditions of acid hydrolysis on performance of MCC, and the optimization of process parameters. The morphology, size, crystallinity and thermostability of MCC were characterized by scanning electron microscopy, X-ray diffraction, TGA spectrograph. Wheat Straw MCC could meet the requirements of synthetic leather industry standards for MCC.

Abstract: Nanocrystalline nickel ferrite has been successfully synthesized through carbon-adsorb auto combustion method from Ni and Fe nitrate salts. The powders were characterized by X-raydiffraction(XRD) techniques,scanning electron microscopy(SEM),transmission electron microscopy(TEM) and vibrating sample magnetometry(VSM). XRD indicated that the products were spinel NiFe₂O₄. SEM and TEM indicated that the particles were spherical with particle size in the range 10-80nm. VSM showed that the sample exhibited typical ferromagnetic behavior at room temperature,while the coercivity of the sample was 150.45Oe and the residual magnetization of the sample was 5.1emu/g.The saturation magnetization of the sample(25.3emu/g)was lower than that for the reported bulk particles(55emu/g), and it has the ultrafine nature.

Abstract: This paper reports the current development of technologies to analyse the conveying performance of bypass low velocity dense phase pneumatic conveying system for transporting powder bulk materials and slug flow low velocity dense phase pneumatic conveying system for transporting granular sized bulk materials. It reveals that the bypass system can be operated at a lowered air velocity than conventional pipe line and slug flow system can be also controlled to operate at a lower velocity zone. Hence these technologies have the potential to extend the conveying capability of a pneumatic conveying system to a broader range of materials, also provide better performance in reduction in pipe wear and product degradation.

Abstract: SiC_p/Gr/ZL101 aluminum-based composites is prepared by semi-solid stirring and gravity pouring method. The effects of SiC_p/Gr with different volume fractions on the microstructure and property of aluminum-based composites are studied by means of microstructure observation, tensile test, fracture scanning and analysis and damping capacity test and analysis. The results show that the primary phase α-Al of ZL101 alloy prepared by semi-solid stirring and gravity pouring method is fragmented dentrite，along with the rising SiC_p volume fractions, the tensile strength of the composites first increases and then decreases while its elongation gradually decreases, the maximum tensile strength of the material can reach to 168MPa, up to 16% than that of ZL101 alloy, the fracture morphology is obvious brittle fracture. They also show that the addition of SiC_p and Gr improves the damping capacity of ZL101alloy, the internal dissipation Q^-1 of the composites is obviously higher than that of matrix alloy and gradually increases along with the rising SiC_p volume fractions. The damping mechanism of the composites is mainly the combined effects of both dislocation damping and interfacial damping.

Abstract: The effects of Gd and Er on ignition-proof behavior of magnesium alloys were investigated. The XRD, SEM and EDS were used to study the ignition-proof performance, oxide products and oxide layer morphology of these alloys. The results indicate that the proper addition of Gd and Er can increase the ignition point of the magnesium alloy. The better ignition-proof property can be obtained after the addition of Er in the Mg-Gd alloy. The mechanism of ignition-proof of magnesium alloy containing Gd and Er are also discussed in this work.

Abstract: The co-doping effect of Be and Mn have been studied in the ferromagnetic semiconductor (Ga,Mn)As thin films. The measurement of magnetic properties shows that the Be doping decreases the Curie temperatures of the ferromagnetic sample due to defects formation. The transport studies show that the Be incorporation decreases the resistivity of the (Ga,Mn)As thin films. It is found that Be incorporation decreases the planar Hall resistance but increases the resistance transitions in the magnetic samples.

Abstract: In the present study, effect of sintering temperature and atmosphere on corrosion behavior of 316L stainless steel specimens manufactured by metal injection molding (MIM) process were investigated. Sintering experiments were carried out at 1320°C, 1370°C and 1375°C under various sintering atmospheres, i.e. Ar+H₂, Ar, N₂+H₂ or N₂. The corrosion behavior of as-sintered specimens was studied by weight loss immersion test in 5%HCl solution. The results indicated that a better corrosion resistance was accompanied higher density, finer and rounder surface pores. The specimens sintered under Ar+H₂ atmosphere at 1370°C had little susceptibility to intergranular corrosion.

Abstract: Seven types of electrodes have been selected. DC resistances, AC impedances and voltage difference of the electrode pairs have been studied, according to the requirement of low and extra low frequencies electric fields detection in sea water. The feasibilities of these electrodes used for detecting these signals have been studied and explained on theories. The results show that the all-solid-state Ag/AgCl electrode is the most sensitive electrode with its very low DC resistances, AC impedances and the voltage difference controlled within 20μV, which makes it detecting low frequency electric field accurately.

Abstract: In this study, carbon fibers (CF) were braided with polypropylene (PP) fibers on a 16-spindle braid machine, forming the PP/ CF composite braids. The composite braids with different levels of strength could be obtained by changing the speed of the yarn turntable and volume gauze. The composite braids with optimum tensile strength then received the thermal treatment, which melted the PP fibers to wrap the CF more tightly, stabilizing the structure of the composite braids. According to CNS 11623 (Tensile Properties of Geogrids by the Single), the composite braids were thermal-treated at 170 °C, 180 °C and 190 °C for1 min, 2 min and 3 min, determing the influence of thermal temperature and duration on the tensile strength of PP/ CF composite braids.