Advanced Materials Research Vols. 197-198

Abstract: In order to develop porous ceramics with high strength and corrosion resistance as the support for the preparation of asymmetric ceramic membranes, porous ZrO₂-Al₂O₃ composite is designed and fabricated by adding Zr(OH)₄.as sintering aid. The content of Zr(OH)₄, the sintering temperature and the bending strength before and after corrosion of the composite are discussed. The results shows that 10wt% ZrO₂-10wt% Zr(OH)₄ -80wt%Al₂O₃ composite bar fabricated by cold press with the porosity of 32% can be fabricated in 1550°C for 4 h. The bending strength of the composite is 111.2MPa. After corrosion, the quality lose and the bending strength lose is no more than 1%. The tubular composite is suit for the preparation of micro-filtration membrane.

Abstract: The stress corrosion cracking (SCC) susceptibility of X80 pipeline steel, which was used in the Second West-East Gas Pipeline, was investigated in simulated soil solution of Xinzhou in Hubei province of China. The SCC susceptibility was studied using the slow strain rate tensile (SSRT) tests in which different potentials were applied. The fracture surfaces were observed using SEM. X80 steel was susceptible to SCC in simulated solution. The SCC was not serious with the anodic potentials applied. The fracture mechanism was anodic dissolution. But the SCC was affected obviously with different cathodic potentials because of the different influence of the hydrogen.

Abstract: Effect of intermediate annealing and final annealing on microstructures and properties of Al3003+Zn sheets is studied. The microstructure of aluminum sheets is observed by Optical Microscope and Transmission Electron Microscope，and the sagging resistance of aluminum sheets is tested by sagging test rig. The results indicate that complete recrystallization can be obtained after intermediate annealing at 380°C，and the recrystallization grain size of aluminum sheets reduces appreciably when annealing temperature rise. The sagging distance of aluminum sheets decreases proportionally with the grain size. Final annealing after final cold rolling eliminates subgrain structure of aluminum sheet, and improves sagging resistance of aluminum sheets observably.

Abstract: To obtain the critical quantity of Cl^- content when magnesite products absorb the moisture and effloresce, some experiments were done about the effects of certain elements (the density of brine, the active content of magnesia, maintaining time and modifiers, etc.) on the moisture regain and bittern accumulation of magnesite products. By analyzing the content of water-soluble Cl^- in magnesite products, the criterion was arrived at and thus the newest examining method, quantitative analysis method, was found out.

Abstract: Analysis of mechanical behaviors near crack tip for linear elastic anisotropic composite plate under bending loadings and twisting loadings was done. By introducing proper deflection function, the mechanical problem reduced to the boundary value problem of partial differential equation. The mixed mode stress intensity factor at the crack tip were presented under bending loadings and twisting loadings at infinity. By solving boundary value problem of partial differential equation and using a complex variable function method, the expressions for bending moments, strains and displacements near crack tip are derived. The obtained results are used to the theoretical research and experimental analysis of the fracture problems of composite plate.

Abstract: By using a low frequency inverted torsion pendulum, the high temperature internal friction spectra of Al-0.013wt%Ce alloy subjected to deformation at different tensile rates was measured, and three peaks, the conventional grain boundary peak (P1), the bamboo peak (P2) and the soild solution peak (P3) were found. Increases of annealing temperature and deformation rate make P1 and P2 lower with P1 shifting to higher temperature and P2 to lower temperature. P3 was only found in the as-received samples. The dependence of P1 and P2 on grain size indicates that the two peaks are originated from the grain boundary sliding, and P3 may be associated with the diffusion of Ce atoms or other impurities at grain boundaries.

Abstract: Poly (N-vinyl-2-pyrrolidone) (PVP) - stabilized ruthenium (0) nanorods have been successfully synthesized by refluxing ruthenium (Ⅲ) chloride (RuCl₃) in low boiling point alcohols (including ethanol, n-propanol, and n-butanol) using microwave heating for the first time. The effects of low boiling point alcohols on the preparation and catalytic property of ruthenium nanorods were discussed. UV-Vis absorption spectra indicated ruthenium nanorods could be synthesized in n-butanol after 2 h refluxing, far below the refluxing time in ethanol and n-propanol. The activation energy of the hydrolysis of NaBH₄ catalyzed by Ruthenium (0) nanorods obtained in ethanol, n-propanol, and n-butanol were determined to be 41.1, 33.3, and 27.9 kJ / mol, respectively.

Abstract: The research aimed to provide scientific basis for developing Proanthocyanidins from peanut skin. In this study, the antioxidant activity of Proanthocyanidins form peanut skin was studied at different system (O₂-•, •OH and DPPH•) in vitro, with Vc. For O₂-•, •OH and DPPH•, the IC₅₀ of Proanthocyanidins form peanut skin was 0.143mg/mL, 0.097mg/mL and 0.274mg/mL; the IC₅₀ of Vc was 0.163mg/mL, 0.097mg/mL and 0.306mg/mL. The result showed that proanthocyanidins from peanut skin had stronger antioxidant activity than Vc, and that Proanthocyanidins would be a effective natural free radical scavenger.

Abstract: MCM-22 zeolite of high crystallinity was synthesized with varying-temperature hydrothermal method. Zeolite was characterized by means of XRD, SEM, TEM and TG-DTA. XRD pattern showed that the sample was MCM-22 zeolite. SEM analysis indicated that the MCM-22 sample is in the form of thin platelet-like crystals, and no amorphous material. TEM analysis exhibited regular shaped aggregate assembled by the independent growth of many small flaky crystals. N2-adsorption/desorption analysis showed that the pore size and BET surface area of MCM-22 were 3.5 nm and 387.8 m2/g, respectively. By means of the varying-temperature hydrothermal method, synthesis time can be effectively reduced, and energy consumption also decreases.

Abstract: This paper deals with the finite frictional contact of a functionally graded coating with considering the effect of Poisson’s ratio. We assume that a functionally graded coated half-space is indented by a rigid spherical punch and that the shear modulus of FGMs varies as exponential function. The whole contact region is divided into the central adhesion zone and the slip annulus. Within the slip annulus, the shear stress is limited by friction. By using the Hankel integral transform technique, the problem is reduced to a set of Cauchy singular integral equations. A numerical method is used to get the contact pressure and tangential tractions in the contact region for different Poisson’s ratio. The results show that the variation of Poisson’s ratio has obvious effect on both normal and tangential tractions. With the increase of ν, the peak value of the normal traction increases and that of the tangential traction decreases.