Browsing by Author "Zubillaga, O."
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Item Alternative rigidisation method for inflatable structures(2008) Markaide, N.; Marcos, J.; Zubillaga, O.; Tecnalia Research & Innovation; SISTEMAS FOTOVOLTAICOSThermally rigidised thermoset composites and UV rigidised composites are methods that have been widely studied in inflatable structures. However, these methods based on chemical rigidisation present some awbacks, as for example the influence of space environment in polymerisation and thus, in final properties obtained in the composite. Alternative and promising methods are passive cooled thermoplastics. The aim of this project has been to conduct further research in this new rigidisation technology. A study of different materials has been performed based on the final properties required in space conditions, but also properties specifically needed for folding, inflation and rigidisation steps. Thus, the approach has been planned in two phases. The first phase covers a material study and testing at coupon level, which has allowed the optimisation of the rigidisation process. The second phase deals with the manufacturing, testing and validation of a reduced size breadboard, consisting of a solar array composed by two lateral flexible solar panels (membranes) supported by a central rigidisable boom.Item Anodic films containing polyaniline and nanoparticles for corrosion protection of AA2024T3 aluminium alloy(2009-02-25) Zubillaga, O.; Cano, F. J.; Azkarate, I.; Molchan, I. S.; Thompson, G. E.; Skeldon, P.; SISTEMAS FOTOVOLTAICOS; SG; Tecnalia Research & InnovationAnodic alumina films containing polyaniline and either TiO2 or ZrO2 nanoparticles were electrochemically synthesised on an AA2024T3 aluminium alloy by a single step anodising procedure in an oxalic acid electrolyte. The morphology and composition of the films were examined by SEM, TEM, GDOES and XPS. The resultant coatings, of thickness about 2.2 μm, displayed a nanoparticle-rich layer in the near surface-regions, of thickness in the range 100-250 nm. Potentiodynamic polarisation behaviour revealed that the polyaniline and TiO2-containing films on the AA2024T3 aluminium alloy show a passive current density two orders of magnitude lower than for films with ZrO2 nanoparticles and films without nanoparticles. The coatings with TiO2 nanoparticles, but without polyaniline, showed intermediate behaviour, with a passive current density one order of magnitude lower than the coatings with polyaniline and TiO2 nanoparticles. The improved barrier protection offered by the TiO2 nanoparticle containing coatings is attributed to the presence of the nanoparticle-rich layer formed on the outer part of the coating that blocks access to the pores of the anodic alumina film.Item Corrosion performance of anodic films containing polyaniline and TiO2 nanoparticles on AA3105 aluminium alloy(2008-08-15) Zubillaga, O.; Cano, F. J.; Azkarate, I.; Molchan, I. S.; Thompson, G. E.; Cabral, A. M.; Morais, P. J.; SISTEMAS FOTOVOLTAICOS; SG; Tecnalia Research & InnovationThe corrosion protection afforded to an AA3105 aluminium alloy supporting an anodic film with incorporated polyaniline and TiO2 nanoparticles has been examined. The films were synthesised by simultaneous anodizing and electropolymerisation of aniline in the presence of nanoparticles. The morphology and composition of the films were probed by TEM, SEM, rf-GDOES and XPS. The resultant coatings comprised a thin porous anodic film of 2-3 μm thickness, with an outer hybrid polyaniline/TiO2 layer of several tens nanometres thickness, with the dimensions of TiO2 nanoparticles being below 10 nm. Electrochemical impedance spectroscopy analysis and salt spray testing revealed that TiO2 containing films provide improved corrosion protection to the AA3105 aluminium alloy compared with the film without nanoparticles. The improved protection provided by the coatings containing TiO2 nanoparticles is attributed to the TiO2 particle-rich thin film layer formed on the outer part of the coating that acts as a blocking barrier layer for the anodic porous aluminium oxide film.Item Polyaniline and nanoparticle containing anodic films for corrosion protection of 2024T3 aluminium alloy(2009-11) Zubillaga, O.; Cano, F. J.; Azkarate, I.; Imbuluzqueta, G.; Insausti, M.; SISTEMAS FOTOVOLTAICOS; SG; Tecnalia Research & Innovation; MATERIALES PARA CONDICIONES EXTREMASAnodic alumina films containing polyaniline and TiO2 or ZrO 2 nanoparticles were electrochemically synthesised on an AA2024T3 aluminium alloy in a single step anodising process carried out in oxalic acid electrolyte containing aniline and nanoparticles. The morphology and composition of the films were examined by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The resultant coatings, with a thickness of ∼2·5 mm, presented a polyaniline and nanoparticle rich layer in the near surface region, with a thickness in the range of 150-250 nm. The electrochemical polarisation curves revealed that the TiO2 containing films provide improved corrosion protection to the AA2024T3 aluminium alloy, showing a passive current density two orders of magnitude lower than the films with ZrO2 nanoparticles and the films without nanoparticles. The improved corrosion protection offered by the TiO2 nanoparticle containing coatings is attributed to the presence of the nanoparticle rich layer formed on the outer part of the coating, which acts as a barrier layer that blocks the pores of the anodic alumina film.Item Synthesis of anodic films in the presence of aniline and TiO2 nanoparticles on AA2024-T3 aluminium alloy(2009-10-30) Zubillaga, O.; Cano, F. J.; Azkarate, I.; Molchan, I. S.; Thompson, G. E.; Skeldon, P.; SISTEMAS FOTOVOLTAICOS; SG; Tecnalia Research & InnovationCoatings, comprising an inner porous anodic alumina film and an outer polyaniline/TiO2 nanoparticle layer, were electrochemically synthesised on an AA2024-T3 aluminium alloy by single-step, anodic polarisation in an oxalic acid-based electrolyte. The morphology and composition of the coatings were examined by TEM, SEM and XPS, with the size and zeta-potential of the TiO2 nanoparticles in the oxalic acid solution also measured. Observation of the growth of the coating during of anodic polarisation revealed that a distinct, two-layered coating is formed from the early stages of polarisation, with the anodic film forming at a constant rate and the outer layer developing at a rate that decreases markedly with times beyond about 30 min. Nanoparticles, agglomerated in the electrolyte, migrate to the anode due to the negative zeta-potential and form the nanoparticle-containing layer at the surface of anodic film. Such particles are not incorporated in the pores due to agglomeration and disordered film porosity at the outer layer of the anodic film.