Diagramas de equilibrio cuaternarios ZrO2-Al2O3-SiO2-(CaO, MgO, TiO2). Una poderosa herramienta para el desarrollo de nuevos materiales por sinterización reactiva

En este articulo se exponen, discuten y evalúan los trabajos que sobre materiales de Mullita-Circona obtenidos por sinterización reactiva dirigió e inspiro Salvador de Aza sobre la base de los diagramas de equilibrio de fase multicomponentes ZrO2-Al2O3-SiO2-(CaO, MgO, TiO2). Se analiza su impacto en distintas áreas de la ciencia y tecnología cerámicas tales como chamotas refractarias, industria del aluminio, etc. También se proponen posibles campos de aplicación futura como es el caso de prótesis dentales sustituyendo a los materiales de circona parcialmente estabilizada con tierras raras.Peer reviewe

Inhibitory effect on in vitro Streptococcus oralis biofilm of a soda-lime glass containing silver nanoparticles coating on titanium alloy

This is an open-access article.-- et al.This paper reports the effect of soda-lime-glass-nAg coating on the viability of an in vitro biofilm of Streptococcus oralis. Three strains (ATCC 35037 and two clinical isolates from periodontitis patients) were grown on coated with glass, glass containing silver nanoparticles, and uncoated titanium alloy disks. Two different methods were used to quantify biofilm formation abilities: crystal violet staining and determination of viable counts. The influence of the surface morphology on the cell attachment was studied. The surface morphology was characterized by scanning electron microscopy (SEM) and using a profilometer. SEM was also used to study the formation and the development of biofilm on the coated and uncoated disks. At least a >99.7% inocula reduction of biofilm respect to titanium disks and also to glass coated disks was observed in the glass-nAg coated disks for all the studied strains. A quantitative evaluation of the release of silver was conducted in vitro to test whether and to what extend the biocidal agent (silver) could leach from the coating. These findings suggest that the biofilm formation of S. oralis strains is highly inhibited by the glass-nAg and may be useful for materials which require durable antibacterial effect on their surfaces, as it is the case of dental implants. © 2012 Cabal et al.This work was supported by the Spanish Ministry of Science and Innovation under the project MAT2009-14542-C02-01.Peer Reviewe

Nanotechnology in joint replacement

El pdf del artículo es la versión post-print.This paper reviews the most relevant achievements and new developments in the field of nanomaterials and their possible impact on the fabrication of a new generation of reliable and longer lasting implants for joint replacement. Special emphasis is given to the role of nanocomposites with different microstructural designs: micro-nano composites, nano-nano composites, macro-micro-nano composites as well as bioinspired hierarchical composite materials. These nanostructured materials have opened up an exciting avenue in the design of non-metallic biocompatible, crack growth resistant, tough, and mechanically resistant implants with a lifespan close to the life expectancy of the patients. Copyright (c) 2009 John Wiley & Sons, Inc.Authors would like to acknowledge the European Commission for its financial support under contract IP Nanoker, Contract number NMP3-CT-2005-515784.Peer Reviewe

Grafeno, el Nobel de Física 2010 y su paso por la reunión del grupo de estado sólido de la RSEF

3 páginas.-- Artículo publicado en revista de divulgación en la sección: "La vida de la Ciencia".Peer reviewe

Ceramic-metal bionanocomposites for improved performance of medical implants

Poster presented at the 8th International Conference on Energy - Materials - Nanotechnology that was held in Orlado (Unitted States) on 22-25th November 2014.The most obvious advantage of cermets is that they can favorably combine the often dissimilar properties of ceramic and metal components in one material. Because of the many possible combinations of components this field is very creative, since it provides the opportunity to invent an almost unlimited set of new materials with a large spectrum of properties and with multifunctionallity. For instance, these new materials can be used in biomedical field for a new generation of reliable and longer lasting implants with biointegration (osteoinduction, osteoconduction and osseointegration), antibacterial activity, high mechanical properties (fatigue resistance, hardness, wear resistance), mechanical compatibility, etc. Multifunctionality within a material can be integrated on several dimensional scales with increasing interconnectivity between phases and engineering difficulty as the scale decreases. This possibility clearly reveals the power of nanocomposite materials to generate complex multifunctional structures that are hierarchically organized at the nano-, micro-, and meso-levels to meet the overall system goals. Our group has recently succeeded in the development by conventional powder processing of a new macro-micro-nano biocermet with high mechanical behavior, similar to the one of natural bone [1-5]. In this new generation of zirconia-alumina-/Nb-Ta nanocomposite, biomultifunctional synergism (biointegration, biomechanical, biocompatibility) with mechanisms operating at different scales is achieved

Microstructure and mechanical properties of ZrO2 ceramics toughened by 5-20 vol% Ta metallic particles fabricated by pressureless sintering

ZrO2-based composites toughened by 5, 10, 15 and 20 vol% lamellar shape Ta metallic particles were made by pressureless sintering. The microstructure and mechanical properties of these novel ceramic-metal composites have been studied. With only 15 vol%, the toughness of ZrO2-Ta composites was increased from 9.1 of monolithic zirconia to 14 MPa m 1/2 and the average bend strength was 700 MPa. Our results have demonstrated that zirconia transformation and ductile phase toughening concepts can get together to enhance the fracture toughness of zirconia-based materials with high strength. © 2013 Elsevier Ltd and Techna Group S.r.l.This work was supported by the Spanish Ministry of Science and Innovation (MICINN) under the Projects MAT2009-14542-C02-01 and MAT2012-38645. A. Smirnov has been supported by JAE-Pre Programme 2010.Peer Reviewe

Aging effect on the tribological behavior of a novel 3Y-TZP/ nb biocomposite against ultra high molecular weight polyethylene

El pdf del artículo es la versión pre-print.The aim of this study was to evaluate the friction and wear behavior of ultra high molecular weight polyethylene (UHMWPE) against 3Y-TZP and a novel 3Y-TZP/niobium (Nb) biocomposite. The ceramic and the biocomposite materials were subjected to an accelerated aging process to evaluate the changes in the tribological behavior after this treatment. To carry out the tribological tests, a reciprocating pin-on-flat contact configuration was used. The results show a lower friction coefficient and wear rate for biocomposite/UHMWPE couples than those for 3Y-TZP/UHMWPE couples. The present study demonstrates that the excellent wear properties of this new biocomposite should never be influenced by aging. Based on these data, the potential of zirconia-Nb as an alternative bearing biomaterial is discussed. © 2012 The American Ceramic Society.Peer Reviewe

Tribological behavior of a novel alumina/nano-zirconia/niobium biocomposite against ultra high molecular weight polyethylene

The present work has studied the dry sliding behavior of Al2O3-nZrO2-Nb micro-nanobiocomposites against ultrahigh molecular weight polyethylene (UHMWPE) in air. The tests were carried out with a reciprocating wear tester with an applied load of 30N, a sliding speed of 0.06m/s and sliding distance up to 10km. Under the adopted testing conditions, the ceramic-metal composite against UHMWPE shows one and a half order of magnitude lower wear rate than the monolithic alumina; and friction coefficient as low as half of that for pure alumina-UHMWPE system. This behavior is related with: (a) the improvement in mechanical properties (toughness and strength) that will lead to the corresponding improvement in wear properties, and (b) the formation of a self-lubricating layer that will provide sufficient lubrication in order to considerably reduce the friction, as compared to monolithic alumina against UHMWPE combination. © 2013 Elsevier B.V.This work was supported by the Spanish Ministry of Science and Innovation (MICINN) under the project MAT2009-14542-C02-01 and by the Spanish Ministry of Economy and Competitiveness under the project MAT2012-38645. C.F. Gutierrez-Gonzalez acknowledges CSIC and ESF for the concession of a JAE-Doc 2009 grant.Peer Reviewe

Tribological behaviour of biocermets against ultra high molecular weight polyethelene (UHMWPE) under dry and simulated body fluid condition

Trabajo presentado al 8th International Workshop on Interfaces: "At the boundary between natural and synthetic materials", celebrado del 26 de junio al 1 de julio de 2011 en Santiago de Compostela (España).Peer reviewe

High wear resistance white ceramic glaze containing needle like zircon single crystals by the addition of sepiolite n-ZrO2

Sepiolite with homogeneous zirconia nanoparticles distribution has been added to a transparent ceramic glaze to study opacification, mechanical and wear resistance properties. It has been observed that monodispersed zircon single crystals with needle-like shape have been formed in the ceramic glaze. These in situ zircon single crystals give white color and increase opacification (L= 94 vs L= 90), mechanical properties (hardness and toughness) and wear resistance by a factor of 4 compared to the commercial crystalline glaze containing a similar fraction of micrometer commercial zircon. © 2013 Elsevier Ltd.This research has been supported by the Spanish Ministry of Science and Innovation under project DOMINO (CENIT-2007-1001).Peer Reviewe