2004nendo akigakki nihongokyoiku jissenkenkyu (6) no jisshujugyohokoku- kinobunkei ni motozuku bunpo no jugyo no tenkai-

5 páginas.Graphitic materials obtained at low temperatures are interesting for a wide range of industrial applications including bipolar plates. In this work, graphite based nanocomposites have been obtained starting from carbon nanofibers and a mixture of carbon nanofibers with 20 vol.% of alumina nanopowders. High density carbon components were obtained by using Spark Plasma Sintering at temperatures as low as 1500–1800°C for this kind of materials. The effect of spark plasma sintering parameters on the final density, and the mechanical and electrical properties of resulting nanocomposites have been investigated. Pure carbon nanofibers with around 90% of theoretical density and fracture strength of 60 MPa have been obtained at temperatures as low as 1500°C applying a pressure of 80 MPa during sintering. It has been proved that attrition milling is a suitable method for preparing homogeneous mixtures of carbon nanofibers and alumina powders.Peer reviewe

Nanocomposites of silver nanoparticles embedded in glass nanofibres obtained by laser spinning

Nanocomposites made of non-woven glass fibres with diameters ranging from tens of nanometers up to several micrometers, containing silver nanoparticles, were successfully fabricated by the laser spinning technique. Pellets of a soda-lime silicate glass containing silver nanoparticles with varying concentrations (5 and 10 wt%) were used as a precursor. The process followed to obtain the silver nanofibres did not agglomerate significantly the metallic nanoparticles, and the average particle size is still lower than 50 nm. This is the first time that glass nanofibres containing silver nanoparticles have been obtained following a process different from electrospinning of a sol–gel, thus avoiding the limitations of this method and opening a new route to composite nanomaterials. Antibacterial efficiency of the nanosilver glass fibres, tested against one of the most common Gram negative bacteria, was greater than 99.99% compared to the glass fibres free of silver. The silver nanoparticles are well-dispersed not only on the surface but are also embedded into the uniform nanofibres, which leads to a long lasting durable antimicrobial effect. All these novel characteristics will potentially open up a whole new range of applications.Xunta de Galicia | Ref. 10DPI303014PRMinisterio de Ciencia e Innovación | Ref. MAT2009-14542-C02-0

Performance of a New Al2O3/Ce-TZP Ceramic Nanocomposite Dental Implant: A Pilot Study in Dogs

Although titanium remains as the prevalent material in dental implant manufacturing new zirconia-based materials that overcome the major drawbacks of the standard 3Y–yttria partially-stabilized zirconia (Y-TZP) are now emerging. In this study, a new ceramic nanocomposite made of alumina and ceria-stabilized TZP (ZCe-A) has been used to produce dental implants with the mechanic and topographic characteristics of a pilot implant design to evaluate bone and soft tissue integration in a dog model (n = 5). Histological cross-section analysis of the implanted ceramic fixations (n = 15) showed not only perfect biocompatibility, but also a high rate of osseous integration (defined as the percentage of bone to implant contact) and soft tissue attachment. This clinical success, in combination with the superior mechanical properties achieved by this Al2O3/Ce-TZP nanocomposite, may place this material as an improved alternative of traditional 3Y-TZP dental implants

Las materias primas en la sinterización de compuestos alúmina-circona dopados con alcóxido de circonio.

The colloidal processing route was used with the purpose of modifying the surface of alumina particles with a zirconium alkoxide; once calcinated they produced nanostructured composite powders of alumina-zirconia. These, were then suitably processed so that nanocomposite materials with a homogeneous distribution of a second phase of tetragonal zirconia nanoparticles within the alumina matrix were obtained. The study of dynamic sintering is presented and the differences between alumina composites produced with different raw materials (Taimei TM-DAR, Sasol SPA 0.5 and Sumitomo AA04) were established.Se utilizó el método coloidal con el fin de modificar la superficie de las partículas de alúmina con un alcóxido de circonio; una vez calcinadas dieron origen a los polvos compuestos nanoestructurados de alúmina-circona, luego fueron procesados convenientemente y permitieron obtener materiales nanocompuestos con una distribución homogénea de una segunda fase en la matriz de alúmina de nanopartículas de ZrO2 tetragonal. Se presenta el estudio dinámico de la sinterización y se establecen las diferencias existentes entre los materiales compuestos de matriz de alúmina elaborados con diferentes materias primas: Taimei TM-DAR, Sasol SPA 0.5 y Sumitomo AA04