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The changes in the magnetic properties of [Ni.sub.5][Fe.sub.68.5][Si.sub.13.5][B.sub.9][Nb.sub.3][Cu.sub.1] amorphous alloy after thermal treatment are reported. The findings observe that the substitution of a small number of Fe atoms by Ni ones leads to an improvement of the soft magnetic characteristics of the alloy.

Microcrystalline, magnetization and saturation magnetostriction measurements in [Fe.sub.73.5-x][Ni.sub.x][Si.sub.13.5][B.sub.9][Nb.sub.3]Cu.sub.1] alloy ribbons (x=5, 10, and 20) treated by current annealing and stress-current annealing are described. The saturation magnetostriction has decreased with the thermal treatment, which has agreed with the microstructural behavior, although some discrepancies are found for samples with x = 5.

PEMFCs are considered to be clean and efficient electrochemical energy sources. Nevertheless, the commercialization of PEMFCs needs to tackle the high cost of the catalyst layers that contain platinum-based electrocatalysts. The reduction of the platinum content is therefore one of the challenging goals to achieve within fuel cells technologies. The amorphous bi-metallic electro-catalysts studied in this work were Ni59Nb40Pt0.6X0.4 (X = Pd, Rh, Ru, Co) and they were produced by Mechanical Alloying (MA) and used as anodes onto Nafion XL (DuPont™) perfluorinated membranes. A commercial Pt/C catalyst was used on the cathode side. The operating conditions have been 100% relative humidity (RH) and gas and cell temperatures of 25 °C, 40 °C, 60 °C and 80 °C. Experiments were carried out on a single PEM fuel cell with an active area of 25 cm2. These electro-catalysts were characterized by both physical and chemical techniques, such as Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDX). The results showed that at 80 °C, the anode amorphous electrocatalyst based on Ni59Nb40Pt0.6Pd0.4 is the one that provides the best performance in terms of power and current. [ABSTRACT FROM AUTHOR]

Abstract: Carbon supports are widely used as electro-catalyst supports in low-temperature fuel cells. As the structure and physical properties of these supports have an influence on their properties, the aim is to find a simple method to obtain supports with suitable porosity, good conductivity and stable in fuel cell environment. In this work, a method for chemical activation of Vulcan® XC72R has been developed to obtain a support for Ni59Nb40Pt0.6Ru0.4 catalysts in MEAs. With fixed work conditions such as carbon/KOH ratio, N2 flow, heating rate, time and treatment temperature as a starting point, different washing procedures to remove the Potassium compounds for the resulting material have been devised. Results show that the activation treatment improves the behavior of the supports and the importance of the washing method on the removal of the alkaline compounds. Samples washed using HCl and HNO3 solutions (VKCl and VKN) show much better results than those that were solely washed using deionized water (VKOH). This could be explained by the fact that Potassium compounds with low solubility in water could be blocking the access to some of the created porosity and removal could be improved in the presence on an acid solution. [Copyright &y& Elsevier]

Abstract: Direct Alcohol Fuel Cells (DAFC) are considered an attractive option to the utilization of fossil fuels. At the same time, the growing impulse in the promotion of the use of energy from renewable sources is gaining a most important role. Platinum is regarded as one of the best catalysts but its cost is high and it shows susceptibility towards CO poisoning. These problems can be minimized using cocatalysts. In this work, ethanol and bioethanol electro-oxidation has been studied using two amorphous tricatalytic alloys: Ni59Nb40Pt0.6Sn0.2X0.2 (X = Pd, Co) as anodes. Tolerance to CO has also been studied. Alloys were prepared by mechanical alloying and characterized by several techniques such as DSC, XRD and SEM. The results show that amorphous catalysts are effective for ethanol as well as for bioethanol electro-oxidation. When comparing the effect of cobalt and tin as cocatalysts, the tests show that cobalt leads to a higher catalytic activity. [Copyright &y& Elsevier]