Films were deposited onto AISI 430 stainless steel substrates by dip-coating technique. The aim is to reach the AISI 304L stainless steel anti-corrosion properties by a coated AISI 430 stainless steel system. Sol formulation is done from the starting precursors tetraethylorthosilicate (TEOS) and 3(trimethoxysilyl)propyl methacrylate (MAP). After the hydrolysis of these precursors, sol-gel reactions occur before the addition (or not) of a controlled quantity of cerium nitrate. The addition of the PEG (polyethylene glycol), used as plasticizer has been studied in this paper and both physical and chemical properties of the synthesized hybrid films were studied by varying PEG ratios. Based on SEM observations and mass gain measurements, the thickness of the films has been adjustable. Another parameter plays a key role: the drying step of the whole system. It has been investigated and optimized in this paper to lead to coatings with a high barrier effect. The efficiency of the anti-corrosion protection of hybrid-coated stainless steel was investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) after immersion of the material in a 3.5% NaCl solution. Double-layered systems were successfully developed and a good compromise between PEG content and drying conditions has been found. Potentiodynamic polarization curves showed that the hybrid coating prepared using a TEOS/MAP/PEG yielded the best anti-corrosion performances. It acts as an efficient barrier similar to AISI 304 stainless steel used as reference, increasing the total impedance and significantly reducing the current densities.

International audienceThe increasing importance of developments in the mechanical industry requires a constant evolution of skills, particularly in the area of functionalization and protection of metallic alloy surfaces. The wear of materials is one of the causes of loss of profitability. This study aims to develop solutions to extend the lifetime of stainless steel 304 L. In this work, we have achieved to optimize protective coatings on stainless steel against wear, using sol-gel method associated with dip-coating technique. Three routes have been proposed to achieve this type of coating, a single sol precursor of silica or alumina and a mixture of sols precursors of both oxides. The results of tribological tests show that silica coating does not provide a performance gain towards the stainless steel protection. Alumina coating even as thin film is very efficient to resist against wear. Wear track widths on the sample is reduced by a factor 2, and the wear volume of the counterface is decreased by a factor 30, corresponding to a total wear volume reduction of a factor 7. The combination of both oxides seems to be a very promising way for such kind of application. With silica/alumina coating, we have obtained a reduction ofwidths wear track of a factor 1.5 and a decrease of friction coefficient as compared to alumina coating

OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible.

Carbon/alumina coatings on stainless steel are prepared by a sol-gel route, using either carbon nanotubes (8 walls on average) or graphite flakes. The friction coefficient against a steel ball is decreased by a factor of 4-5 compared to pure alumina and wear is reduced by a factor of 2 with graphite flakes. A Raman spectroscopy study of selected specimens outside and inside the worn surface shows that the carbon nanotubes are not dramatically damaged whereas the graphite flakes are broken into graphene layers. The reasons why graphite is more effective than the carbon nanotubes, for the same carbon content, to improve the tribological behavior are discussed.

International audienceThe automotive product is increasingly restricted by environmental regulations, including reducing emissions of CO2 and pollutants in exhaust pipes of vehicles. One solution implemented in the automotive industry are plug-in hybrid electric vehicles (PHEV) that use an electric traction battery. To help vehicle manufacturers in their choice of traction battery from an environmental point of view, a simulation method of environmental impacts generated by the use phase is proposed in this paper. This method takes into account the possible usages of the vehicle and potential developments of electric mix, with the formulation of a constraint satisfaction problem (CSP) solved using constraint programming (CP) techniques. The sensitivity of five parameters is investigated: the electricity mix used to charge the battery, the battery mass, electric consumptions, the autonomy in " all-electric mode " , and the share of total travel in " all-electric mode ". Power grid is the most differentiating parameter for global warming and PHEV generates less impact if less used in " all-electric mode " on a high carbon intensity power grid. Lastly, CSP acausal modeling makes it possible to process different simulations with the same model

While the European regulation on the end-of-life vehicle is more and more strict, the introduction of innovations makes the material composition of vehicles evolve and can lead to a risk for approval on the recoverability of the vehicle. We set up a preventive tool named OSIRIS to evaluate the impact of an innovation on the recyclability rate of a vehicle. The innovation teams and the vehicle project leaders may obtain a tendency of this impact. It is supported 1) by a modular point of view of the vehicle, 2) by a simplifying assumption for fixing a module, and 3) on a management of the end-oflife options. By testing this approach on a hybrid motorization, we show that the uncertainty resulting from the simplifying hypothesis is less than 0.20% when the initial and innovative solutions have a mass difference less than 40-60 kg. 1 Context Since the end of the 90's, the car has become one of the most regulated products, for example on pollutants (European Parliament, Council, 2007) and carbon dioxide emissions (European Parliament, Council, 2009) during the use. The analysis of (Schipper, 2011) shows that, since the 80's, in spite of the reduction of fuel consumption relative to the vehicle mass, the vehicle mass and power have never stopped to increase because of the rise in the levels of service expected by the customer. According to

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OATAO is an open access repository that collects the work of some Toulouse researchers and makes it freely available over the web where possible.