Advanced Materials Research Vols. 150-151

Abstract: First-principles calculations were performed to study the electronic and optical properties of Cu3N and Cu4N. The calculated density of states show that Cu3N is a semiconductor with a 0.5ev gap while Cu4N is metallic. The dielectric functions, absorption coefficients, refractive coefficients and extinction coefficients of Cu3N and Cu4N were obtained and compared with some experiment results. It shows the calculated results agree well with the experimental values.

Abstract: Effects of silicon powder additions on the phase composition and microstructure of silicon- corundum-silicon nitride composite refractories were investigated guided by the theory of metal transient plastic phase and the Si-O-N phase diagram. On this basis, silicon-corundum-silicon nitride composites were prepared under air atmosphere. The results showed that the addition of silicon powder could reduce the width of the oxidized film and improve the densification; silicon addition could decrease the oxygen partial pressure in the specimens and contribute to the sintering of the materials. Part of silicon could remain in the materials. The industrial experiments suggested that silicon powder mostly filled in the interstices of the matrix of the sintered products with addition of less than 8 wt.% Si powder, and with increasing Si powder additions the densification of the product was improved, cold strength increased, and hot strength also increased due to the in-situ formed fibrous SIALON by silicon powder; silicon powder formed continuous phase which led to the decrease in densification and hot strength when more than 8 wt.% silicon powder was added.

Abstract: The Ionic Polymer-Metal Composites (IPMC) actuator as electro-active polymers is well known for the fast and flexible bending actuation in the electric fields. In this paper, the IPMC actuator is fabricated and designed for realization of biomimetic flapping motion of dragonflies. The resonant frequency of a wing of anisoptera(dragonfly) was calculated by using finite element method and experimental frequency response function. Flapping motion of zygoptera(dragonfly) was considered in resonant frequency of the designed wing structure. The experimental results show that the IPMC wing structure of dragonfly has a good flapping performance in resonant frequency.

Abstract: In this study, TbDy-Fe giant magnetostrictive thin films were firstly prepared by ion beam sputtering deposition (IBSD) method on water-cooled substrates, and then the films were annealed at different temperatures under vacuum condition. An Inductively Coupled Plasma Spectrometry, Scanning Electron Microscope (SEM), Scanning Probe Microscope (SPM), and Transmission Electron Microscope (TEM) were used to investigate the surface morphology and microstructure for TbDy-Fe GMFs. Besides, DWS type Ultra-precision Displacement Meter was used for measuring magnetostriction coefficient of the films by cantilever method. The results showed that TbDy-Fe GMFs of compact amorphous microstructure, smooth surface morphology, and high interfacial adhesion had been deposited under the fixed fabrication procedure. Moreover, as annealing temperature increased, microstructure of the films had been changed as following order: amorphous → amorphous + microcrystalline → nano-polycrystalline (crystallization temperature was about 400 ). It was noted that magnetostriction of TbDy-Fe GMFs could be drastically improved, particularly for low magnetic field magnetostriction sensitivity when annealed at about 400 (the value of λ was about 500ppm at 200KA•m-1).

Abstract: The shorter service life of sizing crusher tooth is a difficult technology problem. At present the coal classification used in crushing machine, due to poor working conditions, despite the use of wear resistant surfacing electrode to improve the wear resistance of broken teeth, broken teeth, but not to the average life of six months, the subject of study was significantly improve the life of the crusher tooth. To improve the service life of sizing crusher tooth, some research has been done, through system analysis and test some result can be concluded.

Abstract: Charged mosaic membrane (CMM) has high water flux, low salt retention and high organic rejection. The tri-channel hollow fiber charged-mosaic membrane (CMM) was prepared by interfacial polymerization (IP). The tri-channel polysulfone (PSF) hollow fiber ultrafiltration(UF) membrane was used as the support membrane. Polyethylenimine (PEI), 2, 5-diamino-benzenesulfonic acid (DIA) and basic fuchsin (BF) were used as aqueous phase monomer. Trimesoyl chloride (TMC) was used as organic phase monomer. ATR-IR, scanning electron microscope (SEM) and gas sorption analyzer (GSA) were applied in structural analysis of CMM. The uniform design and SPSS were applied in membrane preparation and data analysis.The polymer ATR-IR spectroscopy shows IP occurrence between aqueous phase monomer and organic phase monomer. Polymer contains both sulfonate group and quaternary ammonium group. It show that the membrane has the feature of CMM. Regression equation was gained, and it shows the CMM retention would enhance with the concentration increase of DIA, PEI and SDS and decrease with concentration decrease of FB in experimental range. The composite layer can be observed from membrane SEM after IP. The CMM retention to NaCl, polyethylene glycol(PEG), Xylenol orange and Methyl chloride is12.4%, 90%, 96%,88% and 88.2% respectively.

Abstract: A study of the effect of air corona plasma treatment on the surface of GFRP (glass-fiber reinforced polymers) has been carried out. The aim is to alter the surface in a manner and scale resulting in stronger shear strength between GFRP and wood. The specimens are exposed to air corona discharge with the irradiation time and power being variables. Goniometry is employed to determine the contact angle of GFRP surface. The results show that the plasma treatment leads to the surface contact angle decreasing significantly. The shear strength of shear test specimens using isocyanate adhesive is stronger than that of specimens using epoxy adhesive. The interface of the GFRP-wood composites is also studied by using Fourier transform infrared spectroscopic (FTIR).

Abstract: The composites of Fe/Al2O3 gradient coatings on steel substrate were prepared by spraying and sol-gel method, and the microstructure and performances of the composites were analyzed. The results show that the adhesion strength of Fe/Al2O3 gradient coatings with FeAlNi transitional layers reaches 25.3MPa when the sintering temperature is 1220°C, and the surface hardness of coatings is four times higher than that of steel substrate. The coatings are mainly composed of α-Al2O3, AlFeO3 and NiFe2O4. There is no obvious hole or macro-interface, while some organization similar to the branch appears in the coatings. The bonding of Fe/Al2O3 gradient coatings and steel substrate mainly depends on adsorption, diffusion and chemical combination.

Abstract: Synthesize a thermoplastic polyimide (TP-PI) by 4, 4’-Bisphenol A dianhydride (BPADA) and 4, 4’-diaminodiphenyl ether(ODA) to toughen thermosetting polyimide(TS-PI) of BPADA and 3-aminophenylacetylene (APA) system. Improve the toughness of matrix resin by control morphology of blends. The results show that the system has been phase separation, TP-PI as a continuous phase, blends is part miscibility or immiscibility. Compose materials anysis show that the adhesion of resin and fiber have been improved, toughness of resin-based composite materials has been improved at the same time without sacrificing original thermal properties and modulus.

Abstract: A series of polyacrylonitrile-based hollow-porous and solid carbon fibers were prepared by pyrolysis of polyacrylonitrile-based hollow-porous and solid fibers at the same condition. The microstructure, composition, surface electrical conductivity, electromagnetic parameters and reflectivity of carbon fibers were studied. The microwave absorbing properties of two kinds of carbon fibers as microwave absorbents were parallel investigated. Results show that the apparent density of the hollow-porous carbon fibers is lower than that of the solid carbon fibers due to their hollow-porous structure. The surface electrical conductivity of single solid carbon fiber is nearly 10 times that of the hollow-porous carbon fiber. The -10dB bandwidths of solid carbon fiber composites carbonized at 850 and 950°C are both 0GHz, while those of the corresponding hollow-porous carbon fiber composites are up to 3.05 and 2.62GHz, respectively. Results indicate that the microwave absorbing properties of the hollow-porous carbon fiber composites are better than those of solid carbon fiber composites.