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Mansoor M.,Institute of Industrial Control System | Kinloch I.,University of Manchester | Derby B.,University of Manchester
Key Engineering Materials | Year: 2010

The production of substrates coated with carbon nanotubes (CNTs) in well-defined patterns is desirable for sensor applications. In the present work, nickel based catalytic inks were prepared and printed on silicon substrates using inkjet delivery. Subsequently, the substrates were subjected to calcination and chemical vapour deposition for the growth of aligned CNTs. Scanning electron microscopy, transmission electron microscopy and Raman spectroscopy were used to characterize the CNTs. Various concentrations and formulations of ink preparations were studied to investigate the effect of these parameters on the growth and structure of the CNTs. Source

Ahmad M.,Bahauddin Zakariya University | Ahmad M.,Zhejiang University | Ahmed E.,Bahauddin Zakariya University | Hong Z.L.,Zhejiang University | And 4 more authors.
Applied Surface Science | Year: 2013

Copper doped ZnO nanoparticles embedded on multi-walled carbon nanotubes (CNTs) were successfully synthesized using a facile, nontoxic sol method. The resulting visible light-responsive Cu-doped ZnO/CNTs composites were characterized using powder X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM), transmission electron microscope (TEM), scanning electron microscope (SEM) with energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS) and Brunauer Emmett Teller (BET) surface area analyzer. Optical properties of Cu-doped ZnO/CNTs nanocomposites, studied using UV-vis diffuse reflectance spectroscopy and photoluminescence spectroscopy (PL), which exhibited extended light absorption in visible light region and possessed better charge separation capability, respectively as compared to Cu-doped ZnO, pure ZnO and ZnO/CNTs composite. The photocatalytic activity was tested by degradation of methyl orange (MO) dye under visible light irradiation. The results demonstrated that Cu-doped ZnO/CNTs nanocomposites effectively bleached out MO, showing an impressive photocatalytic enhancement over ZnO, commercial ZnO, Cu-doped ZnO nanoparticles and ZnO/CNTs nanocomposites. Chemical oxygen demand (COD) of textile wastewater was also measured before and after the photocatalysis experiment under sunlight to evaluate the mineralization of wastewater. The significant decrease in COD of the treated effluent revealed a complete destruction of the organic molecules along with color removal. This dramatically enhanced photoactivity of nanocomposite photocatalysts was attributed to greater adsorptivity of dyes, extended light absorption and increased charge separation efficiency due to excellent electrical properties of carbon nanotubes and the large surface area. © 2013 Elsevier B.V. All rights reserved. Source

Nusair Khan A.,Institute of Industrial Control System
Key Engineering Materials | Year: 2010

Titanium aluminides intermetallic compounds have received great attention during the past decade, since they have the potential, in aircraft and automotive engines, to replace the high density Ni-base superalloys However, these intermetallics possess poor oxidation properties at high temperatures. Previous studies showed that protective alumina scale formation on ?-TiAl can be obtained by small additions (around 2 at.%) of Ag. In the present study, a number of cast Ti-Al-Si alloys were investigated in relation to transient oxide formation in air at 1300oC. After various oxidation times the oxide composition, microstructure and morphology were studied by combining a number of analysis techniques. The TiAl-Si alloys appear to form Al Ti and Si oxides. However, the formation of silicon oxide at the interface of base metal and scale slows down the oxidation rate significantly. Source

Ahmad Z.,Zhejiang University | Ahmad Z.,Institute of Industrial Control System | Ma T.,Zhejiang University | Tao S.,Zhejiang University | Yan M.,Zhejiang University
Journal of Magnetism and Magnetic Materials | Year: 2012

The Fe 63B 23Nd 7Y 3Nb 3Cr 1 nanocomposite magnets in the form of sheets have been prepared by copper mold casting technique. The phase evolution, crystal structure, microstructural and magnetic properties have been investigated in the as-cast and annealed states. The as-cast sheets show magnetically soft behaviors which become magnetically hard by thermal annealing. The optimal annealed microstructure was composed of nanosize soft magnetic α-Fe (1929 nm) and hard magnetic Nd 2Fe 14B (4555 nm) grains. The best hard magnetic properties such as intrinsic coercivity, jH c of 1119 kA/m, remanence, B r of 0.44 T, magnetic induction to saturation magnetization ratio, M r/M s=0.61 and maximum energy product, (BH) max of 55 kJ/m 3 was obtained after annealing at 680 °C for 15 min. The annealing treatment above 680 °C results in non-ideal phase grains growth, which degrade the magnetic properties. © 2011 Elsevier B.V. All rights reserved. Source

Ahmad Z.,Zhejiang University | Ahmad Z.,Institute of Industrial Control System | Ul Haq A.,International Islamic University, Islamabad | Yan M.,Zhejiang University | Iqbal Z.,Quaid-i-Azam University
Journal of Magnetism and Magnetic Materials | Year: 2012

Magnetic phase evolution, crystallographic texture, microstructure and magnetic properties of Fe-28Cr-15Co-3.5Mo-1.8Ti alloy have been investigated by X-ray diffractometry, scanning transmission electron microscopy and magnetometry techniques as a function of processing conditions. Heat treatment conditions for obtaining optimum textural, microstructural and magnetic properties have been established by the experimentations. The Goss {110}〈001〉 and cube type {001}〈010〉 textures have been developed in an optimal treated Fe-28Cr-15Co-3.5Mo-1.8Ti magnets. The coercive force in Fe-28Cr-15Co-3.5Mo-1.8Ti magnets depends critically on the shape anisotropy of rod-like Fe Co Ti-rich α 1 particles and remanence on the alignment and elongation of α 1 particles parallel to applied magnetic field 〈100〉 directions. The optimum magnetic properties obtained in Fe-28Cr-15Co-3.5Mo-1. 8Ti alloy are intrinsic coercive force, iH c, of 78.8 kA/m (990 Oe), remanence, B r of 1.12 T (11.2 kG) and energy product, (BH) max of 52.5 kJ/m 3 (6.5 MGOe). The development of Fe-28Cr-15Co-3.5Mo-1.8Ti magnets as well as characterization of texture, microstructural and magnetic properties in the current study would be helpful in designing the new Fe-Cr-Co-Mo based magnets suitable for scientific and technological applications. © 2012 Elsevier B.V. All rights reserved. Source

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