Advanced Materials Research Vols. 239-242

Abstract: In this paper, a practical micromachining technology was applied for the fabrication of a micro drill using electrochemical etching process. Sodium chloride solution was used as electrolyte, a tungsten carbide rods can be dissolved to some micrometers from original dimension by electrochemical etching with supersonic agitation. High-aspect-ratio of micro tungsten carbide rod was easily obtained by this process. Processing performance was investigated according to applied voltage, etching time, and electrolyte concentration. A micro drill of diameter 60 μm was processed by proposed supersonic aided electrochemical etching process.

Abstract: The cracking mechanism of pressure vessel because of stress corrosion is analyzed, which under the high temperature and high pressure aqueous solution medium with chloride, sulfide, hot concentrated caustic, and the protection methods for corrosion under different situation are described.

Abstract: To reduce the cost and improve concrete performance, massive admixtures were needed to be added to the concrete. With the research going, the high quality mixture is increasingly becoming the indispensable concrete component. The steel slag powder is the steel-slag comprehensive utilization technical commanding point compared with the level of the steel slag application nowadays in the world. In order to develop the application of the steel slag fine powder in cement concrete domain, this article analyzes autoclaved soundness of the Baosteel steel-slag fine powder as well as the compatibility of it with the cement and the concrete admixtures.

Abstract: In this research, the nonwoven fabrics were made of 50 % high-tenacity polyester fiber and 50 % low melting polyester fiber, after which the nonwoven fabrics were thermal-treated at 110 °C, 120 °C, 130 °C, 140 °C and 150 °C for 1 min, 2 min, 3 min, 4 min and 5 min. Next, two layers of nonwoven fabrics were laminated with a layer glass (GF) fiber plain fabric or a layer of Nylon 66 grid, forming the sandwich structure. The nonwoven/ GF composite fabrics and the nonwoven/ Nylon 66 grid composite fabrics were also reinforced by needle-punching and thermal treatment, after which the two composite fabrics were measured with tensile strength and stab-resistant strength. Meanwhile, two layers of nonwoven fabrics needle-punched served as the control group. According to the results, Nylon 66 grid and glass fibers plain fabrics were both good at strengthening, the former reinforced the tensile strength of the composite fabrics and the later heightened the stab-resistant strength of the composite fabrics.

Abstract: Layered SmBaCo₂O_5+δ with the cation-ordered double perovskite structure were synthesized by the solid-state reaction route and characterized by thermal analysis, X-ray diffraction, infrared spectrum, electrical conductivity and infrared emissivity. The Sm_1-xBa_xCoO₃ (SBCO) system shows the different crystal structures with the variation of barium content, which results in the different electrical behavior. The electrical conductivity reaches maximum when x is 0.5 with SmBaCo₂O_5.54 phase. The infrared absorption occurs at about 600 cm^-1 for all the samples which were attributed to Co-O stretching modes. The peak shifted to a lower frequency with the increase of doping level. In addition, the comparison of electrical and emissivity measurements suggested that variation of infrared emissivity is in agreement with the electrical properties.

Abstract: Microstructure of Cr-rich phase in undercooled hypereutectic Cu₉₅Cr₅ alloys was studied by using arc melting, electromagntic levitation melting and splat quenching. The results showed that the alloys generally have a microstructure consisting of a fine Cr-rich dendrites in a Cu-rich matrix. Even there existed strong electromagnetic stirring during solidification process, the nonhomogeneous Cr-rich dendrites were observed in electromagnetic levitation melted alloys. However, fine homogenous primary Cr-rich particles or equiaxed Cr-rich grains distributed in the Cu-rich matrix in splat quenched alloys.

Abstract: Phase selection of undercooled Cu₈₅Cr₁₅ composites was analyzed by using different solidification conditions. The results revealed that the arc melted composites generally have non-uniform Cr-rich dendrites distributes on Cu-rich matrix. Due to strong electromagnetic stirring, uniform Cr-rich dendrites distributes on Cu-rich matrix for electromagnetic levitation melted composites. Both fine Cr-rich dendrites and Cr-rich particles coexisted in Cu-rich matrix for splat quenched composites, which means liquid phase separation occurred for the high cooling rate.

Abstract: Activated carbons with good spherical shape were prepared from polystyrene-derived ion exchange resin D001 having various divalent cations of Mg²⁺, Mn²⁺, and Fe²⁺ by CO₂ activation at 800 °C for 1.0 h. The resins having univalent cation such as Na⁺ became fragmentized after activation, which can be attributed to their poorer thermostability than that having divalent cation. The resultant spherical activated carbon SACMg has the largest specific surface area (S_BET) of 1025 m² g^-1, total pore volume (V_t) of 0.781 cm³ g^-1 and mesopore volume (V_me) of 0.510 cm³ g^-1. SACMg, SACMn, and SACFe all have high mesopore fraction of 65.3%, 61.0, and 59.8%, respectively.

Abstract: The properties of UHMW-PE film produced by hot compression molding and films modified by acid and anti-static agent were characterized. The results showed that: a) the thickness distributing of the film which processing by calendar rolling with conventional design roller is inhomogeneity; the tensile strength was 37.22 MPa, the elongation at break was 368.00%; the transmittance increases with wavelength redshift shows short-wave absorption and long-wave transmission; initial temperature of dissociation is 320°C; the surface resistance 10¹⁰ Ω and maximum is higher than 10¹⁶ Ω. b) Acid modification the surface of UHMW-PE film moderates the surface antistatic performance. C) After modified the film with external anti-static agent, the surface resistance was around 10⁷Ω, but anti-static properties loss rapidly after friction. If modified the film with internal anti-static agent, the surface resistance was around 10¹⁰ Ω and have a long-lasting anti-static effect.

Abstract: The synergistic scale inhibition effect of rare-earth permanent magnetic material and polyaspartic acid is studied. The performance of synergistic scale inhibition is studied in different magnetic field intensity, water hardness and rate of concentration. Static and dynamic scale inhibition tests show that the two water treatment ways have good synergistic scale inhibition effect. The scale inhibition performance of polyaspartic acid can be increased greatly by the magnetization of water.