Advanced Materials Research Vols. 418-420

Abstract: The Mg-Ca-Ce ignition-proof Mg-alloy with high ignition temperature was developed based on the synergy of flame retardant role of Ca element and Re element ,and the flame retardant mechanism were investigated. The interfacial tension of Mg-Ca-Ce alloy melt was measured with the maximum bubble method. The interfacial tension is found to be remarkably lowered with the increase of Ce element that is a kind of surface active element to Mg-Ca alloy. The results also showed that the compact composite film composed of Ce2O3,CaO and MgO could be formed and reduce the flammability significantly when the Ca content and Re content were 1.2wt.% and 1.5 wt.% respectively, which prevented alloys from oxidation further and raised the ignition point nearly 150°C.

Abstract: NaOH solution was utilized in the molten salt reaction of titanium slag for investigating desiliconization effects. The thermodynamic behaviors of Si in the reaction system was examined to explore the impacts of molten salt reaction conditions on the conversion rates of the foreign substance Si and the target element Ti. On this basis, the influences of NaOH concentration, liquid-solid ratio, cleaning temperature and cleaning time on Si removing rate were discussed. The experimental results showed that, Si reacted with NaOH to produce sodium silicate was feasible in terms of thermodynamics within the temperature interval 400-1000K. 3Na₂O•2SiO₂, 2Na₂O•SiO₂ could stably exist under high reaction temperature. As the reaction time extended and temperature rose, the conversion rate of Si was increasing. In the process of Si removing by NaOH cleaning of molten salt reaction products, as NaOH concentration, liquid-solid ratio, cleaning temperature and cleaning time increased, Si removing rate became larger. The optimum alkali cleaning conditions were: NaOH concentration 150g/l, liquid-solid ratio 3:1, cleaning temperature 50°C and cleaning time 60min, then the desiliconization rate reached 61.16%.

Abstract: The influence of surface oxidizing using a Q-sw laser on the wear loss of titanium-4Al-6V (Ti64) alloy during rolling contact fatigue is investigated. Titanium components are widely appreciated for their superb biocompatibility, high strength to weight ratio and corrosion resistance. Due to the above mentioned advantages titanium bearings are a popular choice in applications requiring high strength, light weight, and minimum maintenance (for example, aerospace and defence industries). In these rolling contact applications however issues such as fretting and wear related problems are a common occurrence as the tribological properties of titanium alloys are inferior to those of other metal alloys, such as steel. In an attempt to tackle this problem, a Q-sw laser was used in this work to coat Ti64 bearings with complex titanium oxide layers in a closed chamber without any protective gas. Non-coated and coated samples were tested under water by using a thrust-type rolling contact fatigue machine. The morphology and crystallographic texture of the layers were observed by laser confocal microscope, scanning electron microscope and X-ray diffraction. The wear loss of the coated samples was at least fifty-fold lower than that of the non-coated bearings and a 3-fold increase in the maximum load capacity compared with TiN layers was achieved.

Abstract: Cubic layer-structured calcite and spherical vaterite were successfully prepared in the present of PS-b-PAA at room temperature. The products were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and flourier transform infrared spectrum (FI-IR). The characterized results revealed that the PS-b-PAA concentration had a considerable influence on the morphologies and crystal phase transformation. With the PS-b-PAA concentration increasing, the crystal phase of CaCO₃particles would have a significant transition from calcite to vaterite, and the morphologies also showed remarkable changes from cubic layer-superstructure to spherical shape. Furthermore, cubic structured CaCO₃ particles with a larger size of ca. 100 μm in side length could be prepared by gas diffusion method, indicating that the “crew-cut” micelles are able to result in long-live crystal active sites so that novel large-scale inorganic materials might be prepared.

Abstract: The objective of this work was to study the comparison of the adsorption performances of phenol in aqueous solution onto H103 resin and XAD-4 resin. Experimental results showed that the molecular form of phenol is favorable for the adsorption. The adsorption capacity of phenol onto H103 was much larger than that of XAD-4 due to its average pore diameter. The pseudo-first-order rate equation can characterize the adsorption of phenol onto H103 and XAD-4. The rate constant k1 for XAD-4 is greater than the one of H103 at the same condition, consistent with the shorter required time for XAD-4.

Abstract: Abstract. Recycled aggregate—rural building material wastes pretreated by cement mortar—are applied into concrete with different replacement rates: 0, 25%, 50%, 75%, and 100%. Results from measurements of compressive strength, cleavage tensile strength, mass loss after fast freeze-thaw cycles, and compressive strength loss indicate that a different recycled aggregate replacement rate certainly influences concrete mechanical properties and frost resistance. Recycled aggregate replacement rates less than 75% performs better than common concrete. Data from the 100% replacement rate is worse than that of rates less than 75% but still satisfy the general demands of GB standard on C30 concrete.

Abstract: To tackle the computing efficiency and robustness problems caused by the reliability index approach (RIA) in reliability-based multidisciplinary design optimization (RBMDO), a new performance measure approach-based method for RBMDO is proposed. Meanwhile, the traditional triple-level nested flowchart of RBMDO is decoupled through the main idea of sequential optimization and reliability assessment (SORA). Both deterministic multidisciplinary design optimization and the multidisciplinary reliability analysis are executed by collaborative optimization (CO). Finally, the proposed method is verified through the design example of gear transmission.

Abstract: A new electron-rich unit, 2,7-di(5-bromothiophen-2-yl)-10-hexadecyl- phenoxa-zine, has been prepared in high yield over four steps. The compound with good solubility, electronic and optical properties may be a candidate for D-A type organic polymers.

Abstract: In order to produce low oxygen steel with high quality, converter slag-tapping, slag oxidability and oxygen activity have been analyzed. In addition, modifying and adding process of slag, control of slag oxidability and bottom argon-blowing in ladle were studied as well. On this basis, refining process which is beneficial to low oxygen steel producing with converter-continuous casting process has been developed. The results show that content of T[O] in steel is not more than 15×10^-6.

Abstract: Polycyclic aromatic hydrocarbons (PAHs) are discharged into the atmosphere during coking process. They are the typical persistent organic pollutants with their teratogenic, carcinogenetic, and mutagenic. The writer studied the PAHs in blending coal coking process through laboratory sampling and high-performance liquid chromatography analysis, observed and summarized the generation regularity and emission characteristics of PAHs in three kinds of blending coal coking process, and provided the foundation data for the control of PAHs in coking process.