Advanced Materials Research Vols. 284-286

Abstract: In order to improve the corrosion resistance of Nd-Fe-B, the new technological process is done which involves electroplating Ni–P alloys with ultrasonic. The influence of ultrasonic on electroplating Ni–P alloy on Nd-Fe-B was studied by using microscope, adhesion test and NaCl solution immersion test. The results showed that the Ni–P alloy deposit on Nd-Fe-B is rough and has poor adhesion without ultrasonic agitation; however, the Ni–P alloy deposit on Nd-Fe-B with ultrasonic agitation has more compact and uniform microstructure, smoother morphology. At the same time, the adhesion and corrosion resistance are greatly enhanced.

Abstract: The study aims to research the effect of the particle size of fly ash on the compressive strength and fracture toughness of high performance concrete (HPC). In all HPC mixtures, the water-to-binder ratio selected is 0.35; the cement replacement ratios includes 0%, 10% and 20%; the particle sizes of fly ash have three types of passing through sieves No. 175, No. 250 and No. 325. Three-point-bending test was adopted to measure the load-deflection relations and the maximum loads to determine the fracture energy (G_F) and the critical stress intensity factor (K^S_IC). Test results show that adding fly ash in HPC apparently enhances the late age strengths of HPC either for replacement ratio of 10% or 20%, in which the concrete with 10% fly ash shows the higher effect. In addition, the smaller the particle size is the better the late age concrete strength will be. The HPC with the finer fly ash can have higher strength development and the values of G_F and K^S_IC due to the facts of better filling effect and pozzolanic reaction. At late age, the G_F and K^S_IC values of concrete with 10% fly ash are all higher than those with 20% fly ash.

Abstract: The CoQ10-NLC aqueous dispersion has been produced and its antioxidative properties have been explored. Several employed methods such as scavenging effect on DPPH radical and inhibition of hydroxyl radical and superoxide anion generation exhibited CoQ10-NLC aqueous dispersion potent antioxidative property. Antioxidative activity analysis demonstrated that CoQ10- NLC aqueous dispersion formulation expressed antioxidative property.

Abstract: Usually the heat treatment in the cyclic ARB passes is indispensable to reduce work-hardening effects and improve interface bonding quality. The possibility of accelerating grain refinement of aluminum sheets with a dimension of 300 mm×50 mm×1 mm is investigated during the ARB process at room temperature, in which the samples are rotated by 180 degree around normal plane axis perpendicular to the rolling plane between the adjacent cycles. By means of optical microscopy and transmission electron microscopy, it shows that the bonding interfaces can not obviously observed after five cycles, and grains are refined to be ~0.5 μm. Tensile tests show the ARB samples exhibit strain hardening behavior after yielding without a sudden fracture even up to seven cycles of ARB. The softening behavior and enhanced ductility was explained by dynamic recovery, the recrystallization process and even abnormal large grains.

Abstract: In order to analyze the impact of anchor length, ends anchorage measures, strength of concrete, shear-span ratio, reinforcement ratio and the amount of carbon fiber plate on the bearing capacity of strengthened bridge structures with carbon fiber plate, 11 pieces of rectangle beams are fabricated for flexural experimental study. The experimental results show that the ultimate bearing capacity of the specimens increase different degree as different strengthened schemes: the bearing capacity of rectangle beams with plate end anchorage has increased remarkably; The beams have greater bearing capacity with more anchorage length in contrast to those without any anchorage measure; The ultimate bearing capacity enhanced more prominent for those specimens with low shear-span ratio and low reinforcement ratio.

Abstract: This paper adopts wet method to prepare serpentine particles on the planetary ball mill, executes lipophilic degree tests and friction and wear tests of these particles. The results showed that: 1) as the modification agent, the optimum dosage of oleic acid is when the volume ratio of oleic acid and serpentine particles is 2, and the optimum time of milling (modification) is 24h. 2) 4012 maritime lubricating oil with serpentine particles has obvious anti-wear and friction effect, and the optimum dosage range of serpentine particles is 0.9%-1.0%. According to the outcomes of metallurgical microscope observation and electron microprobe analysis, a conclusion can be drawn: during the process of friction and wear, serpentine particles brought on physical or chemical reactions with the surface of test samples, create a layer of protective film, thus this kind of lubricating oil has filling function to the furrow of friction pair surface, so as to decrease the surface roughness, decrease the degree of friction and wear.

Abstract: In(OH)₃ and InOOH were prepared through a simple hydrothermal method at different volume ratios of En and H₂O. C-In₂O₃ and H-In₂O₃ were obtained by annealing these two precursors at 400°C in air, respectively. One-step In₂O₃ was also synthesized via solvothermal process using DEG as solvents. The effects of reaction conditions on phase structures and morphologies were studied. The gas sensing properties of the obtained materials toward ethanol were measured and X-ray diffraction, field-emission scanning electron microscope and PL were used to characterize the as-obtained products.

Abstract: Polyaniline–C₆₀ nanoshuttle composites have been successfully synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in the presence of C₆₀ using an interfacial reaction at room temperature, in which the molar ratio of oxidant to monomer was kept at 0.25:1. The influence of initial C₆₀/aniline molar ratio on the supramolecular structure of the composites was studied. It was found that at low molar ratio (0.01:1) amorphous powders could be synthesized, while the as-synthesized products at the higher molar ratio (0.04:1) were shuttle-like superstructures. FTIR and UV-vis spectroscopy confirmed the presence of C₆₀ in the resultant nanocomposite and suggested significant interaction of polyaniline with C₆₀. The evolution of supramolecular structure of polyaniline nanoshuttle–C₆₀ nanocomposites was discussed.

Abstract: Indium tin oxide (ITO) nanopowders with high crystalline were synthesized by a simple solvothermal method with isopropanol as the selected solvent. X-ray diffraction was employed to characterize the crystal structure and crystalline size while the effect of the reaction time on morphologies was studied by FE-SEM. The results revealed that, with the increase of solvothermal time, the morphologies were evolved gradually from porous plates with high specific surface area to rods with narrow diameter distribution. The solvothermal time has little effect on crystalline size, which is 18nm approximately for all the samples. With the increase of solvothermal time, the electric conductivity decreases slightly first and then increases greatly. The possible mechanisms for the effect of solvothermal time on ITO powder morphologies and electric conductivity are proposed.

Abstract: The influence of residual magnesium on compact graphite rate and characteristic of thermal analysis curve was studied by fading of magnesium treated molten iron. The results indicate that with fading time, the residual magnesium decreases and the rate of compact graphite increases. The content of magnesium can remarkably change the characteristics of thermal analysis curve, such as the lowest eutectic temperature (T_EU) and the recalescence degree △Tr.