Advanced Materials Research Vols. 239-242

Abstract: Fe₃O₄ modified Pt/C electro-catalyst was synthesized and studied. Fe₃O₄ and Fe₃O₄ with carbon coating (designated as Fe₃O₄/C) were prepared by co-precipitation method and ethyl acetate pretreatment. Fe₃O₄ and Fe₃O₄/C were sprayed onto the Pt/C cathode surface. X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) results show that Fe₃O₄ and Fe₃O₄ with carbon coating nano-particles (Fe₃O₄/C) are distributed evenly and c.a. 11.2 nm and 14.3 nm, respectively. TEM images show that electrode surfaces with Fe₃O4 and Fe₃O₄/C are of little difference from that with Pt/C only; Fe₃O₄/C is much more evenly distributed on the electrode surface than Fe₃O₄ because of the adaptability of carbon coating. Cathodic curves of Rotating Disk Electrode (RDE) tests shows that the adding of Fe₃O₄ (7 wt %) improves oxygen reduction reaction (ORR) activity about 30 mV in both cases. The adding of Fe₃O₄/C (Fe₃O₄: 7 wt %) to the Pt/C catalysts demonstrates the highest peak current of about 13.8 mA•cm^-2 in all cases. The promotion of Fe₃O₄ in O₂ enrichment and dispersion of Pt particles are confirmed in the study. The paramagnetism of Fe₃O₄ and its promotion in 4-electron oxygen reduction reaction (ORR) are the possible reasons for the promotion.his template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

Abstract: A facile and inexpensive environmental-friendly method was developed to prepare a biomimetic superhydrophobic CuO surface with hierarchical micro- and nanostructures by the combination of a simple solid state reaction and a convenient dipping-coating method. The biomimetic CuO surface showed superhydrophobicity even for some corrosive liquids including salt solutions and acidic and basic solutions at a wide pH range from 2 to 13. Moreover, the superhydrophobic CuO surface showed high stability in ambient environment even exposed to ultraviolet light for 10 h.

Abstract: The corrosion behavior of reinforcing bars in concrete was studied by simulating the 4×4 wire-beam electrode array. Different inhibitors were added to reinforced concrete. By measuring the open-circuit potential of an iron wire, the impact of different inhibitors on the corrosion of rebar in the concretes was studied after immersion in NaCl solution. The result showed that best protection was achieved by adding NaNO₂ and aniline as inhibitors jointly to the concrete, as this combination maintained the open-circuit potential within the passivation range at all times, so ensuring the integrity of the passive membrane. By addition of this combination of the inhibitors, the compactibility of the cement concrete structure can be increased, thereby protecting the reinforcing bar against the external corrosive media.

Abstract: With stearic acid/lauric acid binary of fatty acids as phase change material, polyacrylonitrile (PAN) as framework material, PAN/ binary of fatty acids phase change fibers is prepared by wet spinning process. Morphology and latent heat storage capacity of phase change fibers are investigated using microscope, scanning electron microscope (SEM) and differential scanning calorimetry (DSC), respectively. Influences of the ratio of PAN/ binary of fatty acids, concentration of the coagulation and spinning liquid on breaking strength have been studied by yarn strength tester. The results show that breaking strength of phase change fiber dried at 110°C hot air is higher than that of dried at room temperature, the breaking strength of PAN/ binary of fatty acids fiber increases with the increment of the ratio of PAN/ binary of fatty acids, concentration of the coagulation and spinning liquid. The latent heat storage capacity of phase change fiber has reached 18J/g, the phase transition temperature is about 28.6°C.

Abstract: Fe-Cr-V-C hardfacing alloys of three different Cr contents were produced by GTAW. The microstructure and hard phases morphology were investigated by means of OP, SEM and XRD. The results showed that the microstructure of hardfacing alloys consists of lamellar martensite, retained austenite, ferrite, VC particles and (Fe,Cr,V)₇C₃ complex carbides. The VC particles with exploded, globular shape and (Fe,Cr,V)₇C₃ complex carbides with interrupted netted, hexagonal shape are observed in the alloys.The amount of Cr affect the microstructure and wear resistance of the hardfacing coating. The volume fraction of (Fe,Cr,V)₇C₃ complex carbides increase as the Cr content increase. When the Cr content reached 22%, a multitude of hexagonal (Fe,Cr,V)₇C₃ complex carbides and a small amount globular VC particles are distributed in the softer ferrite and austenite matrix which ensure the high wear resistance.

Abstract: The two component filament/staple fiber core-spun yarn is spun on FA506 ring spinning frame with PTT filament as interlaced yarn and Tencel staple fiber as outer sheath. The spinning process and process parameters were analyzed. The morphology, mechanical property and wear-resisting property of two component core-spun yarn were tested. Results indicate that elastic recovery rate of core-spun is up to 90.6%; broken strength is up to 20 cN/tex after boiling water treatment. The core-spun yarn can be used as a new kind of knitting yarn for sweater.

Abstract: The preparation and properties of indium tin oxide (ITO) coated transparent polyimide substrates were reported in the paper. The transparent polyimide films were prepared through thermal imidization of poly(amic acid) films. Transparent conducting ITO films were prepared on polyimide substrates by magnetron-sputtering technique at room temperature. The optical and electrical properties of the obtained films have been investigated. Polycrystalline ITO films were deposited with resistivity as low as 10^-4 Ω.cm on polyimide substrates. The average transmittance exceeded 78% in the visible spectrum for 200nm thick films deposited on polyimide.

Abstract: Zn-25Al and Zn-50Al coatings were prepared by arc spray in mild carbon steel Q235. The corrosion behaviors of these coatings were studied by potentiodynamic polarization test in natural seawater, corrosion potentials and electrochemical impedance spectrum. The results show that the E_corr of Zn-25Alcoating is -1.025V (SCE) and the E_corr of Zn-50Al coating is -0.997V (SCE) at the beginning of the immersion. The E_corr of the Zn-50Al coating is not stable as the Zn-25Al coating. Self-corrosion potential of Zn-25Al coating is lower than Zn-50Al coating. Zn-25Al can provide lower protection potential and promising current to protect the substrate from corrosion than Zn-50Al. The EIS of these two coatings reveal single capacitive loop. The anti-corrosion properties of Zn-25Al coatings are better than that of Zn-50Al coatings.

Abstract: The principle and characteristic of Stray Current (SC) resulting from rail transit system were introduced. Measurement methods and corrosion evaluation of SC were also discussed. For an underground gas pipeline located in the neighboring area and parallel to the rail transit in Shanghai, a virtual instrument-based SC monitoring system was developed to measure pipe-to-soil potential, current within pipeline. Results obtained from Fourier transformation reveal that pipe-to-soil potential fluctuation of the tested gas pipeline is 200mV and the current is 150 mA, which is closely related to operation of subway. Serious corrosion of the buried gas pipeline might happen.

Abstract: On the basis of laminated plate theory and piezoelectric theory, the nonlinear free vibration governing equations for symmetric cross-ply moderately thick laminated piezoelectric plates are established. The Galerkin procedure furnishes an infinite system of equations for time functions which are solved by the method of harmonic balance. In the numerical results, the influences of piezoelectric effect and various location of piezoelectric layer on the nonlinear vibrating frequency of the laminated piezoelectric plates are discussed.