Materials Science Forum Vol. 724

Abstract: Effect of solution treated temperature at 5001100°C on ferrite/austenite ratio and σ phase precipitation has been studied in this paper, and the tensile properties after solution treatment at 950°C and 1050°C is compared. The results shows that the ferrite/austenite ratio treated 1050~1100°C is about 1:1; and the formation of σ phase occurs in the ferrite or at ferrite - austenite boundary. The quantity of the σ phase precipitation increases firstly and then decreases with increase of the solution treatment temperature, reaching the maximum at 900°C, and disperse at above 1050°C. Tensile tests show that the fracture is brittle divided and stretched by ductile belt at 950°C, and ductile at 1050°C.

Abstract: Nowadays, rapidly growing mobile machines such as tablet PC and smart phone equipped with touch screen panel using a sturdy material for products surface protection. Therefore, surge of chemical strengthening glass was increased. Through large areas of chemical strengthening glass, the surface scratch will cause a major failure. Most of these failures will be discarded because it is difficult to reuse. Thus, discarded chemical strengthening glass is expected to increase as with the demand. Accordingly, the importance of environmental pollution, waste landfill has been proposed. Recently, touch screen of chemical strengthened glass all-in-one type was commercialized. Therefore reuse is possible, due to surface of discarded chemical strengthening glass is washed and wipe off the electrode. In this study, we carried out the MLCA(Material Life Cycle Assessment; MLCA) on a chemical strengthening glass by landfill scenario, reuse scenario and identified the key issues.

Abstract: Recently, touch screen is one of the most popular pieces of electrical and electronic equipment in our society, such as laptops, cellular phones, and digital cameras. Indium tin oxide (ITO) is mainly used to make transparent conductive coatings for touch and flat screen. Therefore, there is an increasing demand accordingly. Although accounted for 1% of the touch screen, indium is rare metals. Consequently, it is important to Recycling ITO for National Strategies about Resource Conservation, and reduce Environmental burden. The case which disuses ITO like landfill or incineration, it cloud be harmful to the human health in the long-term. This study intended to identify the environmental aspects with the ITO recycling. The potential environmental impacts were evaluated by using Material Life Cycle assessment method (MLCA). As the result of this study, MLCA would provide more information for environmental issues of ITO. So that it is possible to improve the environmental issues by the monitoring that could be useful and effective for ITO. The study includes two scenarios, the basic scenario is recycling of ITO (10, 20 and 30%) and the other scenario is landfill of ITO.

Abstract: Experimental program and preparation technology of highly densified reaction bonded silicon carbide resistance materials with different resistivity were investigated by using alumina or silicon nitride as aids for improving of the volume resistivity. The microstructure of the materials was observed by scanning electron microscope. According to the experimental results, the resistivity of the material could be controlled by the particle size and the content of the aids. Besides, alumina could reduce silicon penetration and increase resistivity greatly, and 10wt.% of alumina could satisfy the requirement of resistance. In addition, different particle size of matrix materials had a great impact on the resistivity. Compared with the coarse silicon carbide, the room temperature resistivity value by using the fine silicon carbide could increases for six times.

Abstract: The PVP+Ti (OC₄H₉)₄+SnCl₄·5H₂O/sesame oil composite fibers were successfully prepared by a sol-gel method combined with a coaxial electrospinning technique. The Sn⁴⁺/TiO₂ nanotubes were obtained by calcining the above-mentioned composite fibers and characterized by XRD and TEM. XRD results show that increasing reaction temperature facilitates to form a stable phase. TEM results show that the Sn⁴⁺/TiO₂ nanotubes have smooth surface with wall thickness of ~120 nm and are composed of small particles of ~5 nm. The photocatalytic activity of Sn⁴⁺/TiO₂ nanotubes was investigated. The photodegradation efficiency of Sn⁴⁺/TiO₂ nanotubes decreases in UV region but increases in visible light region. The photocatalytic properties of three 0.52at% Sn⁴⁺/TiO₂ nanomaterials with different morphologies were also evaluated. The photodegradation efficiencies of Sn⁴⁺/TiO₂ nanopowers, Sn⁴⁺/TiO₂ nanofibers and Sn⁴⁺/TiO₂ nanotubes increase in visible light region in sequence. In summary, chemical modification by doping Sn⁴⁺ and morphology changing for TiO₂ can improve its photocatalytic activity in visible light region significantly.

Abstract: This study was conducted to investigate the effect of operational parameters in anodized photocatalytic metal membrane reactor (PMMR) for the removal of Isopropyl alcohol in electric wastewater. The effect of UV light type, the strength of UV light, the injection of TiO2 powder and air flowrate was investigated. About 70% of removal of IPA under the condition of UV irradiation (UV-C, 64W) in combination with an anodized TiO₂ metal membrane was achieved within 180 minutes treatment, indicating that the UV/anodized photocatalytic TiO₂ metal membrane process is a promising treatment technology for treating IPA in electric wastewater.

Abstract: This study aims to show the catalyst effect for the removal of low molecular weight organics in semiconductor wastewater. To investigate and compare the removal efficiency, experiments were conducted to change in mixing ratio of catalyst with activated carbon. As a result, optimal condition for the removal of acetone and IPA of the catalyst ratio was (Cu+Fe) = 8:2 and (Fe+Al)=9:1 with activated carbon at pH 3. Acetone was removed above 70% and isopropyl alcohol (IPA) was almost removed 100% in the pH 3, pH 4 except for pH 7 condition, the remaining acetone concentration was 51.4 ppb in IPA solution, these results is attributed that IPA transformed to acetone after the reaction. Solid-advanced oxidation processes was believed to be an effective method to treat the low adsorbability of organics contained in electric wastewater.

Abstract: We evaluated the treatment efficiency of humic acid using Ti and anodized TiO₂ metal plate with/without Fe-doping. Variation of humic acid concentration after 60 minutes of UV irradiation in the case of Ti only, Fe-Ti, TiO₂ only and Fe-TiO₂ was about 3.0%, 5.5%, 9.8% and 9.2%, respectively. . It is found that hypochromic effect was revealed in all cases with respect to doping time. Fe doping method is considered to be effective for humic acid degradation in spite of relatively low surface area of Ti and anodized TiO₂ metal plate.

Abstract: Hierarchical AlOOH microspheres assembled from nanosheets were successfully synthesized via a microwave hydrothermal method, by using AlCl₃·6H₂O and NaOH as raw materials and cetyltrimethyl ammonium bromide (CTAB) as a surfactant. Thermal decomposition of the AlOOH precursor at 500°C for 2h produced γ-Al₂O₃ that maintained the precursors morphology. The products were well characterized by SEM, TEM and XRD. Finally, both hierarchical AlOOH and γ-Al₂O₃ microspheres were used to adsorb Congo red from a water solution. The experimental results show that hierarchical AlOOH microspheres with the diameter about 1μm are assembled from nanosheets with average thickness of about 20nm. The morphology of the obtained γ-Al₂O₃ microspheres is well preserved, and nanometer-size holes appear on the surface of the nanosheets. Both AlOOH and γ-Al₂O₃ microspheres are very effective in the removal of Congo red pollutant from waste water which may be attributed to their textured microstructure and high specific surface area.