Browsing by Keyword "Aerospace"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Design of Corrosion Protective and Antistatic Hybrid Sol-Gel Coatings on 6XXX AlMgSi Alloys for Aerospace Application(2020-04-30) Agustín-Sáenz, Cecilia; Santa Coloma, Patricia; Fernández-Carretero, Francisco J.; Brusciotti, Fabiola; Brizuela, Marta; Tecnalia Research & Innovation; VALORIZACIÓN DE RESIDUOS; TECNOLOGÍAS DE HIDRÓGENO; INGENIERÍA DE SUPERFICIESAn inorganic–organic coating based on glycidyl-functionalized silica and zirconia was synthesized by sol-gel technology to protect three types of AlMgSi (6XXX series) alloys against corrosion in aerospace applications. Different parameters such as the solid content, the organic/inorganic ratio of the sols and the deposition conditions were studied with the aim to achieve a tradeoff between the corrosion protection, antistatic performance and low vacuum-induced outgassing. Those parameters directly influence the thickness and the density of the coatings, and therefore the barrier effect against corrosion and the contact electrical resistance, which are affected in opposite ways. To obtain a low contact electrical resistance, silver nanowires (NW) with a high aspect ratio were loaded in the sol-gel matrix with the aim to create a conductive path through the hybrid coating with a low concentration of NWs. The coatings were adapted for AA6063, AA6061 and AA6082, and they all showed an outstanding anti-corrosion performance in different artificial weathering tests, whereas electrochemical impedance spectroscopy permitted the identification of the most critical parameters affecting water uptake. An antistatic performance was demonstrated by the low contact electrical resistance of the coated AA6061 and AA6063 alloys, although the incorporation of NWs showed a detrimental effect on the corrosion protection compared with the unloaded coatingItem Joining of ceramic matrix composites to high temperature ceramics for thermal protection systems(2016-02-01) Jiménez, C.; Mergia, K.; Lagos, M.A.; Yialouris, P.; Agote, Iñigo; Liedtke, V.; Messoloras, S.; Panayiotatos, Y.; Padovano, E.; Badini, C.; Wilhelmi, C.; Bárcena, Jorge; EXTREMATThe current work reports a novel approach for the integration of external protective SIC multilayers with ceramic matrix composite (C-f/SiC) with the view of application in aerospace heat protection systems. The integration method is based on diffusion brazing bonding. As a joining agent the MAX-Phase Ti3SiC2, produced by self-propagating high temperature synthesis, has been employed. The pressure applied during the joining process and its effect on the microstructure of the integrated structure is discussed. Microstructural analysis of the resulting joints is conducted using scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray diffraction measurements. Analysis of the joints showed that the bonds are uniform, dense, with few crack vertical to the interface which are not detrimental for the performance of the joints. Ground re-entry tests showed that the joints survive 5 re-entry cycles at 1391 and 1794 degrees C without any detectable damage. (C) 2015 Elsevier Ltd. All rights reserved.Item Performance of cork and ceramic matrix composite joints for re-entry thermal protection structures(2017-01-01) Triantou, K.; Perez, B.; Marinou, A.; Florez, S.; Mergia, K.; Vekinis, G.; Barcena, J.; Rotärmel, W.; Zuber, C.; de Montbrun, À.; de Montbrun, Montbrun; POLIMEROS; EXTREMATIn view of spacecraft re-entry applications into planetary atmospheres, hybrid thermal protection systems based on cork and ceramic matrix composites are investigated. Joints of NORCOAT LIÈGE cork with C/Csingle bondSiC ceramic matrix composite were fabricated using a) high temperature commercial inorganic adhesives and b) in-situ polymerization of the cork on top of the CMC. Mechanical shear tests under ambient conditions and in liquid nitrogen are carried out. The ultimate shear strength of all the adhesive joints at room temperature varies between 0.52 and 0.78 MPa and is similar to that of the in-situ joints. At liquid nitrogen temperature the shear strength is enhanced by up to 80%, but the ultimate shear strain decreases up to 55%. The failure mode is discussed for the two types of the fabrication procedure.