High-Efficiency Electrodeposition of Large Scale ZnO Nanorod Arrays for Thin Transparent Electrodes

In the present work an effective technique to synthesize large-scale c-axis oriented ZnO nanorod (NR) arrays is presented. The manuscript reports a single-step cathodic electrodeposition, either in aqueous and organic electrolytes, to fill up ultra-thin anodic nanoporous alumina templates. Prior to growing, self-ordered hexagonal array of cylindrical nanopores have been fabricated by anodizing Al thin films previously deposited onto ITOglass substrates. The diameter and the aspect ratio of the vertically aligned nanopores are about 60 nm and 8:1, respectively. The results of this work demonstrate that using dimethyl sulfoxide (DMSO) as an electrolyte leads to a growth more homogeneous in shape and crystallinity, and with 60 deposition efficiency - the highest by now in literature. This fact is most probably due to a better infiltration of the alumina nanopores by this electrolyte. SEM and XRD analysis were employed for the study of morphology and crystalline structure of the obtained ZnO NR. These measurements showed furthermore that ZnO nanorod arrays are uniformly embedded into the hexagonally ordered nanopores of the anodic alumina membrane. DMSO proved to be an optimal electrolyte to obtain single-crystalline ZnO NR arrays, highly transparent in visible light range (80 transmittance). © 2011 The Electrochemical Society.The authors thank for the financial support by the European Commission, DG Research through the program PEOPLE, by the project no. MRTN-CT-2006-035884.Pullini, D.; Pruna, AI.; Zanin, S.; Busquets Mataix, DJ. (2012). High-Efficiency Electrodeposition of Large Scale ZnO Nanorod Arrays for Thin Transparent Electrodes. Journal of The Electrochemical Society. 159(2):45-51. doi:10.1149/2.093202jesS4551159

Microstructural change of the HAZ in an MIG welded bond on an AA7020 aluminium alloy: stress corrosion crack growth rate in dissimilar metal welds

[EN] Many researchers have undertaken studies into the mechanical behaviour of the welded bond,1,2 others have devoted their attentions to metallurgical phenomena, whether concerning phenomena inherent to the area immediately surrounding the weld interface or concerning models or simulations of the welded structure;3,4 in addition, there are those who have made comparisons between different welding methods2 or who have dedicated their time to post-welding treatments.5 However, very few researchers have devoted their attentions to studying microstructural change throughout the HAZ on welded test pieces.Bloem, C.; Salvador Moya, MD.; Amigó, V.; Busquets Mataix, DJ. (2004). Microstructural change of the HAZ in an MIG welded bond on an AA7020 aluminium alloy: stress corrosion crack growth rate in dissimilar metal welds. Welding International. 18(7):538-542. doi:10.1533/wint.2004.3287S53854218

Tribological study of FeCuCrgraphite alloy and cast iron railway brake shoes

[EN] A new class of materials is being installed in railway brake blocks to substitute classic cast iron in order to reduce the rolling noise produced by the roughness of the tread-wheel surface. The tribological properties of cast iron and Fe-Cu-Cr-graphite sintered alloy brake shoes were analyzed. Kinetic friction coefficient (mu) and wear were monitored by means of a pin-on-disc technique. The sintered alloy brake showed an increase in mu at higher braking velocities while the cast iron brake exhibited a decrease in mu. Wear was greater on the sintered alloy, explained by its low shear strength which decreased due to its low thermal conductivity. The roughness produced by the sintered brake shoes in wheel-tread surface was 10 times lower than that produced by cast iron. (c) 2009 Elsevier B.V. All rights reserved.Ferrer Giménez, C.; Pascual Guillamón, M.; Busquets Mataix, DJ.; Rayón, E. (2010). Tribological study of FeCuCrgraphite alloy and cast iron railway brake shoes. Wear. 268(5):784-789. doi:10.1016/j.wear.2009.12.014S784789268

Stiffness variation of porous titanium developed using space holder method

The excellent properties of Ti have resulted in its generalised use for bone implants. However, Ti is very stiff in comparison with human cortical bone, and this creates problems of bone weakening and loosening of the implant. This article discusses the mechanical properties (flexural and compressive strength, and stiffness) of porous Ti-6Al-4V specimens developed using the space holder method. These properties are examined relative to the production process parameters: compacting pressure and sintering time, as well as temperature, and the addition of spacer and its particle size. It is seen that when spacer is added, compressive strength decreases with the application of compacting pressure and that these are the most influential parameters. The developed pieces show a closed and unconnected porosity. Small additions of spacer (25 vol.-%) reduce stiffness to around half of that shown by the solid material, and the resulting pieces are strong enough to be used as bone substitute. © 2011 Institute of Materials, Minerals and Mining.The authors wish to thank the Spanish Ministry of Science and Innovation for the support received under project no. PET2008_0158_02. The translation of this article was funded by the Universidad Politecnica de Valencia.Reig Cerdá, L.; Amigó Borrás, V.; Busquets Mataix, DJ.; Calero, JA. (2011). Stiffness variation of porous titanium developed using space holder method. Powder Metallurgy. 54(3):389-392. https://doi.org/10.1179/003258910X12707304455068S389392543RYAN, G., PANDIT, A., & APATSIDIS, D. (2006). Fabrication methods of porous metals for use in orthopaedic applications. Biomaterials, 27(13), 2651-2670. doi:10.1016/j.biomaterials.2005.12.002in ‘ASM handbook’, Vol. 2, ‘Properties and selection: nonferrous alloys and special-purpose materials’, 1170; 1990, Materials Park, OH, ASM International.Asaoka, K., & Kon, M. (2003). Sintered Porous Titanium and Titanium Alloys as Advanced Biomaterials. Materials Science Forum, 426-432, 3079-3084. doi:10.4028/www.scientific.net/msf.426-432.3079Niinomi, M. (2008). Mechanical biocompatibilities of titanium alloys for biomedical applications. Journal of the Mechanical Behavior of Biomedical Materials, 1(1), 30-42. doi:10.1016/j.jmbbm.2007.07.001Rack, H. J., & Qazi, J. I. (2006). Titanium alloys for biomedical applications. Materials Science and Engineering: C, 26(8), 1269-1277. doi:10.1016/j.msec.2005.08.032Köhl M, Bram M, Buckremer HP, Stöver D: Proc. Conf. Euro PM2007, Toulouse, France, October 2007, European Powder Metallurgy Association, 129–134.Bram M, Bogdanski SH, Koller M, Buchkremer HP, Stover D: Proc. Conf. Euro PM2005, Prague, Czech Republic, October 2005, European Powder Metallurgy Association, 517–522.Reig L, Amigó V, Busquets D, Salvador MD, Calero JA: Proc. Conf. Sintering 2008, La Jolla, CA, USA, November 2008, American Ceramic Society. 273–282.Degischer, H., & Kriszt, B. (Eds.). (2002). Handbook of Cellular Metals. doi:10.1002/3527600558Comín M, Peris JL, Prat JM, Decoz JR, Vera PM, JV: Hoyos: ‘Biomecánica de la fractura ósea y técnicas de reparación’, 66–69; 1999, Valencia, Publicaciones UPV.Gibson LJ, Ashby MF: ‘Cellular solids: structure and properties’, 175–231; 1999, Cambridge, Cambridge University Press.Making metal foams. (2000). Metal Foams, 6-23. doi:10.1016/b978-075067219-1/50004-0Esen, Z., & Bor, Ş. (2007). Processing of titanium foams using magnesium spacer particles. Scripta Materialia, 56(5), 341-344. doi:10.1016/j.scriptamat.2006.11.010Leyens, C., & Peters, M. (Eds.). (2003). Titanium and Titanium Alloys. doi:10.1002/3527602119Lütjering G, Williams JC: ‘Titanium’, 2nd edn, 13–51; 2007, Berlin, Springer, Engineering Materials and Processes

Modification of the properties of Al2O3/TZ-3YS thermal barrier coating by the addition of silicon carbide particles and fructose

Al2O3/TZ-3YS coatings developed by suspension plasma spraying were studied in the present work. Mechanical and thermal characterization was realized to evaluate the suitability of thermal barrier coatings. In addition, SiC particle reinforcement was evaluated for its effect on the mechanical properties of the coating. The problem with SiC reinforcement is its high melting point that causes a large amount of unmolten material to be deposited on the coating. One possible solution followed in the present study consists of including fructose as an additive in order to modify the suspension characteristics. The results conclude that the use of fructose as an additive increases the mechanical and thermal properties (from 1.0 to 1.6 W/m·K), since the microstructure is modified, and results in a lower porosity (17%) compared to the SiC coating (25%)

Materiales compuestos: tipos y clasificación

Definición y descripción de las familias más habituales de materiales compuestos y su clasificación.https://polimedia.upv.es/visor/?id=9f29c50f-fcc5-ef4f-b10d-11c787c405c0Busquets Mataix, DJ. (2008). Materiales compuestos: tipos y clasificación. http://hdl.handle.net/10251/127

Determinación de las estructuras cristalinas: Difracción de rayos X

Descripción de la técnica de difracción de rayos X aplicada a la determinación de las estructuras cristalinas más habituales en materiales metálicos: cúbicas centrada en caras, cúbica centrada en el cuerpo y hexagonal compactahttps://polimedia.upv.es/visor/?id=bc6e5368-2d78-1544-907c-45c9da6281f0Busquets Mataix, DJ. (2008). Determinación de las estructuras cristalinas: Difracción de rayos X. http://hdl.handle.net/10251/129

Materiales poliméricos: estructura

Descripción de la estructura molecular de los materiales poliméricos y los factores de influencia de ésta en sus propiedades.https://polimedia.upv.es/visor/?id=336d6453-3bce-534a-85b8-e7731e2c0b9fBusquets Mataix, DJ. (2008). Materiales poliméricos: estructura. http://hdl.handle.net/10251/128

El Ensayo de Fluencia

Descripción de cómo se realiza el ensayo de fluencia para la determinación de las propiedades mecánicas de los materiales a alta temperaturahttps://polimedia.upv.es/visor/?id=7f389c07-4c3d-8e4d-bd5d-2b4833aebfd9Busquets Mataix, DJ. (2008). El Ensayo de Fluencia. http://hdl.handle.net/10251/127

Problema. 2º Ley de Fick

Problema práctico sobre la aplicación de la 2ª ley de Fick al caso de la cementación gaseosa de los aceros.https://polimedia.upv.es/visor/?id=4c1d9362-397d-0c4f-bce2-ed46da712e2bBusquets Mataix, DJ. (2009). Problema. 2º Ley de Fick. http://hdl.handle.net/10251/538