Advanced Materials Research Vols. 306-307

Abstract: Crystallization behavior of melt aluminum on the surfaces of SiC whisker (SiCw) was analyzed based on the consideration to obtain the SiC-Al interfaces with the lowest energy in SiCw/Al composite. The interfacial structure was investigated to determine whether a specific orientation relationship exists between SiC and Al. Analysis results indicate that four kinds of orientation relationships possibly exist between SiC and Al when only the <110> crystal direction of the aluminum is considered as the firstly formed crystal direction along the concave joint line of <110> of the SiC whisker. Interfacial atom match bonding models were set up in theory and one kind of crystal orientation relationship has been proved by our previous experimental result.

Abstract: A kind of low-heat Portland cement clinker was prepared with coal gangue, limestone and gypsum through optimizing the mix proportion of raw materials, and its properties and hydration characteristics were studied. The results showed that the cement clinker meeting the demands of mid (low)-heat Portland cement standard could be prepared with 35% (by weight, the same below) coal gangue, 57-60% limestone and 6-8% gypsum. The raw materials were burned at 1380°C for 40 minutes. The main hydrates were calcium silicate hydrate (C-S-H) gel, ettringite (AFt), monosulfate (AFm) and Ca(OH)₂.

Abstract: Organic modified sol-gel glass with tetraethylorthosilicate (TEOS), methyl triethoxysilane (MTEOS) and vinyltriethoxysilane (VTEOS) as raw material, ethanol as solvent and nitric acid as catalytic agent have been prepared. The influence caused by the amount of catalytic agent, water and the ratio of TEOS/MTEOS or TEOS/VTEOS on properties of porosity has been investigated. The optimal ration of M_HNO3/M_TEOS and M_water/M_TEOS were obtained. The modification of sol-gel glass using organic groups results in some decrease of porosity.

Abstract: The influences of the types of chemical blowing agent (CBA) namely endothermic, exothermic and their mixture, on the properties of the foamed poly(vinyl chloride) (PVC) and rice hull wood plastic composites (WPC) were investigated in the current research. Specifically, azodicarbonamide and sodium bicarbonate were selected to represent the exothermic the endothermic CBA respectively. Particles of sodium bicarbonate and azodicarbonamide were modified with 25 wt% citric acid and 20 wt% ZnO respectively, and they were used at 0 to 3.0 wt%. Maximum reduction of density by 45% was achieved when the exothermic CBA was applied at 2.0% by weight. Overall, the flexural properties decreased as the level of the CBA was increased from 0-2.0 wt%, but there was an upturn when the CBA reached 3.0 wt%. The mixture of exo/endothermic CBA illustrated the mechanical properties averaged between their parents.

Abstract: In this work, the Fe-based amorphous powder/S-glass fiber reinforced epoxy composite panels of different amorphous powder and gradient layer structure were prepared by mould pressing method. The waveguide method and arch form method can be used to measure the electromagnetic parameters and the reflectivity of the samples respectively in the frequency range from 2GHz to 18GHz. The results showed that the amorphous powders distributed evenly during the S-glass fiber reinforced epoxy layers and the main absorbing mechanism of composite panels is magnetic loss. The absorbing properties of samples improve with the increase of the Fe-based amorphous powder contents and the thickness of panels. The model of gradient layer structure has a significantly effect to improve the impedance matching between the samples and the air. Thus, the absorbing properties of the composite panels can be increased effectively. When the thickness of the gradient layer structure composite panels is designed at 4.8mm excepting the Al plate thickness with 0.6~1.3mm thickness of Fe-based amorphous powder/S-glass fiber reinforced epoxy, the absolute value of the reflection coefficient of the multi-composite panels is above 4dB in the frequency ranged from 2GHz to 8GHz and above 10dB during 8GHz ~18GHz.

Abstract: E-glass fiber woven roving reinforced polyurethane composites were manufactured by three different processes: hand lay-up, compression molding and vacuum infusion to assess the feasibility of all the processes. The results showed that all composites led to significant improvements in both flexural and tensile properties except elongation at break in comparison with the neat PU. Among the three processes, the best bending strength was exhibited by the hand lay-up process. This is attributed to higher PU mass fraction leads to a better fiber–matrix interfacial adhesion. Mechanical properties of the composite molded by vacuum infusion were superior to that produced by compression molding process. The SEM morphology revealed that vacuum infusion composite had more homogeneous micro- structure.

Abstract: This paper mainly investigates the effect of embedded optical fibers on the tensile prosperities of carbon fiber reinforced polymer-matrix composites (CFRPs). Different optical fibers are considered. The results show all the specimens are declining. And Optical Fiber (OF) with 245μm exhibit about 23.5% reduction.

Abstract: The research on the conductive asphalt concrete(CAC) is to melt snow and ice on the pavement and improve the property of skid resistance. However, research at present mainly focuses on the electrical property not on the fatigue behavior which is also important to the application of CAC in the future. The specific rheological model is developed and the relation between creep and fatigue is investigated in this paper. By the single axial static creep test, the existed rheological model (Burgers model) and method of regression, the creep deformation of asphalt concrete is measured with time and parameters of the model are obtained. The results indicate that strain increases quickly with increasing time at initial loading phase, and then the change of strain tend to a stable value in a constant load. At unloading phase, strain decreases immediately and then keep another stable value which was greater than zero. The addition of conductive fillers improves the elastic properties and has no significant influence to the viscosity of asphalt concrete. In addition, the fatigue life can be predicted by the parameters of the Burgers model. The addition of conductive fillers improves energy dissipated, which leads to shorter fatigue life of conductive asphalt concrete compared to the control at levels of longer fatigue life.

Abstract: A novel natural rubber/silk fibroin (NR/SF) antibacterial composite was prepared firstly by using bombyx mori silk fibroin as the antimicrobial filler through latex compounding techniques. The results from scanning electron microscopy and universal tensile machine proved that the compatibility between SF and NR matrix is excellent, and the tensile strength of composite sheets is enhanced to some extent. NR/SF antibacterial composite sheets have a good antimicrobial effect on Escherichia coli and Staphylococcus aureus. Moreover, the suitable loading of SF is 0.5~1 wt% according to the results above.

Abstract: The Ni-P-W/nano-Al₂O₃ composite coatings were deposited on the surface of sintered NdFeB permanent magnet by electroless plating method. The morphology and the phases of Ni-P-W/nano-Al₂O₃ composite coatings were investigated using scanning electron microscopy and X-ray diffraction respectively. The hardness and the corrosion resistance of the composite coatings were also tested. The results indicated that the composite coatings morphology appears closely nodules morphology, and the microhardness increases with increasing incorporation of Al₂O₃ ratio. Compared with NdFeB magnet and Ni-P-W alloy coatings, the corrosion resistance of the composite coatings was superior to that of the NdFeB magnet and the alloy coating obviously.