Browsing by Author "Imbuluzqueta, G."
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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 Zirconia coating of carbon nanotubes by a hydrothermal method(2008-11) Garmendia, N.; Bilbao, L.; Muñoz, R.; Imbuluzqueta, G.; García, A.; Bustero, I.; Calvo-Barrio, L.; Arbiol, J.; Obieta, I.; PRINTEX; SISTEMAS FOTOVOLTAICOS; Tecnalia Research & InnovationCarbon nanotubes have unique mechanical properties that open attractive possibilities in many fields, such as the biomedical one. Currently, zirconia ceramics are widely used as femoral heads, but case studies show that delayed failure can occur in vivo due to crack propagation. Nanotubes could avoid the slow crack propagation and enhance the toughness of the ceramic material used for prostheses fabrication. In this work, single-wall carbon nanotubes and multi-wall carbon nanotubes have been partially coated with nanozirconia via hydrothermal synthesis and characterized by several techniques: X-ray diffraction, infrared spectroscopy, scanning electron microscope, transmission electron microscope, electron energy loss spectra, X-ray photoelectronic spectroscopy and atomic force microscopy. By means of these techniques, the existence of bonds between zirconium and the carbon nanotube has been proved. The as covered nanotubes should offer a better wettability in the ceramic matrix and improve the dispersion of the carbon nanotubes, to obtain the desired new ceramic biomaterial with a longer lifetime and better reliability.