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From hot forging to thixoforging: FEM analysis of thixoforging process for steering piston production

In this paper evolution from hot forging to thixoforging process is proposed and talked over. A realcase study is presented, namely a steel-made steering piston produced by thixoforging technique is considered and some parameter has been numerically analyzed. The transition between the traditional forging process and the new one involves several transformations and presents difficulties mainly due to the high working temperature.

Growth of AlN by Reactive Gas Injection of Nitrogen in an AlMg Matrix

The primary objective of the present research was to provide a fundamental understanding of the processing science necessary to fabricate the Aluminum Nitride (AIN) reinforced Aluminum-Magnesium (AIMg) composites via Reactive Gas (N2) Injection in the AIMg alloy melt. Aluminum nitride (AlN) matrix composites were prepared by a novel approach. It was possible to produce a considerable amount of AIN particles in the AI alloy matrix at a reaction temperature as low as 900 °C utilizing the in-situ nitration reaction process developed in the present study.

Influence of the preparation method on Pt3Cu/C electrocatalysts for the oxygen reduction reaction

Pt3Cu nanoparticles are deposited on multi wall carbon nanotubes (MWCNT) according to three different types of synthesis: a thermal reduction using an aprotic solvent (“thermal method”, TM), a chemical reduction using sodium borohydride (“chemical method”, CM), and an alloy method (“alloy method”, AM). The catalysts are characterized by means of BET, FESEM, EDX, XRD, ICP-MS and XPS analyses. The obtained catalysts display a Pt loading of 19.6–19.8 wt.%, with a Pt/Cu atomic ratio of 2.60–2.80. The electrocatalytic activity towards ORR is assessed by RDE in acid conditions (0.1 M HClO4).

Semi-empirical evaluation of PEMFC electro-catalytic activity

The investigation of the performance of small single PEMFC was carried out by employing a purposely designed test bench with complete control of the operational parameters. A MEA preparation method was also developed constituting the base for testing new electrocatalytic materials or improved electrode assembling techniques. Beyond determining the polarization curves, other tests have been carried out like electrical resistance measurement by the current interruption method and voltammetric characterization.

Platinum catalyst supported on mesoporous carbon for PEMFC

Ordered mesoporous carbon (OMC)was used as catalyst (Pt) support in polymer electrolyte membrane fuel cells (PEMFC) with the aim of increasing its effectiveness towards the oxygen reduction reaction (ORR). The mesoporous carbon (CMK3 type) was synthesized as inverse replica of a silica template (SBA-15). Platinization was achieved by impregnation with chloroplatinic acid hexahydrate, H 2PtCl 6, followed by a reduction in H 2 flow at 573K. Samples containing 20wt% in Pt were prepared and characterized by ICP, XRD and HRTEM analysis.

Mesoporous carbons as low temperature fuel cell Platinum catalyst supports

Platinum catalysts supported on ordered mesoporous carbons (OMC) are described. The mesoporous carbon support, CMK3 type, was synthesised as an inverse replica of a SBA-15 silica template. The platinum catalysts (i.e. Pt 20 wt% and Pt 10 wt%, respectively), obtained through a conventional wet impregnation method, have been investigated to determine their structural characteristics and electrochemical behaviour.

Ordered mesoporous carbons as catalyst support for PEM Fuel Cells

Preliminary results on Pt-based electrocatalysts prepared with CMK3 mesoporous carbons are presented. The electrocatalytic performance towards the oxygen reduction reaction (ORR) was compared to that of commercial Pt/C-Vulcan catalysts with the same Pt content. Polarisation tests were carried out with a single PEM fuel cell containing the Pt/OMC cathodes. The analysis of these tests, based on a semi-empirical determination of the various polarisation terms, showed an interesting catalytic activity for ORR for the cathodes prepared with mesoporous carbon supports.

Nanostructured bimetallic alloys prepared via mechanochemicalsynthesis as PEMFC electrocatalysts for automotive applications

Pt–Co alloys prepared by high energy ball milling synthesis were tested as electrocatalysts for hydrogen fueled Polymer Electrolyte Membrane Fuel Cells (PEMFC). In the present contribution we report on the first results regarding the electrochemical behaviour of two samples of Pt–Co alloys. One sample contains 20 wt.% alloy Pt:Co in the molar ratio 0.25:0.75 and C 80 wt.% and the second one Pt:Co in the molar ratio 0.75:0.25 and C 80 wt.%.