Advanced Materials Research Vols. 989-994

Abstract: Polishing was performed by using a self-made 40kw electrolysis and plasma polishing machine, and the test specimens were SUS304 stainless steel sheets. Roughness, micro-morphology, surface chemical composition and corrosion resistance of the specimens were analyzed. The results show the surface roughness value decreases quickly from R_a=0.573μm to R_a=0.115μm in first 10 minutes polishing. After 30 minutes polishing, the surface roughness value decreases to R_a=0.066μm. Microdefects on the surface are removed obtaining the smooth surface and Cr content of the surface increases slightly as well as the other elements content is nearly unchanged after the polishing, so the corrosion resistance measured by electrochemical analyzer is improved.

Abstract: Hydroxyapatite (HAP) is an effective adsorbent for removing heavy metal ions. In this study, HAP was prepared by sol-gel method and used for removing Cu²⁺ from aqueous solution. Initial concentration of Cu²⁺ in the aqueous solution was evaluated as an important parameter determining uptake. The removal efficiency and the adsorption capacity of HAP for Cu²⁺ were investigated. EDS analysis indicated the presence of Cu²⁺ on the HAP surface.

Abstract: Li_0.95Na_0.05Ti₂(PO₄)₃/C nanocomposite was prepared by sol-gel method.The structure and morphology of the samples were characterized by XRD, SEM which showed the particles had typical NASICON structure and diameter range from 400~500nm. The electrochemical performance were tested by cyclic voltammetry and galvanostatic charge–discharge. Results show Li_0.95Na_0.05Ti₂(PO₄)₃/C nanocomposite exhibitsmuch better electrochemical performance than bare Li_0.95Na_0.05Ti₂(PO₄)_3.

Abstract: Formation mechanism of TiC in Al matrix at a rather low melting temperature using in situ technology was studied. And effect of the melting temperature on the microstructure of in-situ TiC/Al composite was investigated. The results indicate that, the resultants of TiC and Al₃Ti were found out in the matrix; however, no evidence showed that Al₄C₃, a resultant phase existed probably in TiC/Al composite in accordance with the relative reference, was found out. Compared to the sample of T750, more TiC and less Al₃Ti existed in the sample of T850, and morphography of Al₃Ti changed from block to bar with the increasing melting temperature. The melting temperature affected extremely the reaction speed and the resultants.

Abstract: Effect of Cr element on microstructure of Al-3.2Mg alloys was investigated using optical microscopy, scanning electron microscopy (SEM) and EDS. Moreover, the tensile and hardness test were carried out. The results show that a minor additive of Cr can refine effectively the secondary dendrite arm spacing and decrease the number of coarse interdendritic structures. In the whole series of the alloys, the secondary dendrite arm spacing of Al–3.2Mg-0.1Cr alloy was the smallest, and the spacing presented an increasing trend with the Cr content. With high levels of Cr, the intermetallic compounds are formed by Cr with Al, Mg and Fe, the shape of the second phase particles were transformed from bulky bone shape to fine bone shape and long striped. The strength and the hardness of Al–3.2Mg alloys were greatly improved when the additions of Cr were 0.05% and 0.1%, but the ductility of the alloys remained at a low level by adding 0.05%Cr. Therefore, combining with the comprehensive properties and the microstructure, the best addition of Cr in the alloy was 0.10% in the whole series.

Abstract: A sort of Aluminum-metal coating, which is characterized by a bi-layered structure of Fe₂O₃+Cr₂O₃+Al plus NiO+Al layers, was successfully prepared on steel substrate by melting-casting technique. The microstructure, the bonding status of the interface between the coating and the substrate, and the element distribution of the coating were studied. The results indicate that, there is an excellent bonding between the coating and the substrate, and no hole and gap in the composite is found out. Moreover, there is obvious element diffusion in the interface. The coating is composed of block phase, columnar grain, and dendrites. In addition, the elements present a uniform distribution in the interface but an obvious segregation in the middle of the coating.

Abstract: In this paper, inorganic/graphene and polymer/graphene composites are mainly introduced. Compared to single component, the inorganic or polymer additions have great improvement on the electrochemical performance and provide the possibility of their application in supercapacitor. The latest application of graphene based composites in supercapacitor is overviewed as well.

Abstract: Atmospheric-pressure dielectric barrier discharge (DBD) plasma was used to fabricate Pt/C electrocatalysts. The influences of the pretreatment of the activated carbon support and the preparing method on the properties of the Pt/C electrocatalysts were investigated. The composition of the Pt/C samples was characterized by X-ray diffraction (XRD). The electrocatalytic activity of the Pt/C samples was evaluating by measuring the cyclic voltammograms. The results showed that higher dispersion of Pt nanoparticles was obtained on the activated carbon support pretreated by HNO₃, and higher reduction rate of Pt ions was obtained in Pt/C prepared by DBD plasma. As a consequence, the Pt/C samples with the activated carbon support pre-oxidized by HNO₃ and reduced by DBD plasma exhibited the highest electrocatalytic activity.

Abstract: Atmospheric-pressure dielectric barrier discharge (DBD) cold plasma was used to prepare high performance Au/P25 catalysts (Au/P25-P). XRD and UV-Vis DRS spectra for Au/P25 catalysts were performed. The results indicated that the size of Au nanoparticles in Au/P25-P was smaller than that prepared by conventional thermal impregnation method (Au/P25-H). The temperature-dependent CO oxidation was performed to investigate the activity of Au/P25 catalysts. Au/P25-P gave excellent catalytic activity for CO oxidation than that of Au/P25-H. This may be attributed to the smaller size of Au nanoparticles in Au/P25-P.

Abstract: Inverse emulsion copolymerization of DMDAAC with AM has been investigated by the dilatometer technique using the mixture of Span-80 and Tween-80 as the composite emulsifier and 2,2’-azobis (2-methylpropionconidine) dihydro chloride as the initiator. In inverse emulsion copolymerization, the influences of the concentrations of monomers, emulsifier and initiator and initial temperature on polymerization rate and the intrinsic viscosity of polymer have been examined. Its kinetics can be expressed as,. The overall activation energy for the rate of polymerization was determined with a dilatometer as 20.33 kJ/mol over the temperature range 35-55°C.