Browsing by Keyword "Nanozirconia"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
Item The effect of the addition of carbon nanotubes in the hydrothermal synthesis and in the thermal phase stability of nanozirconia(2010-04) Garmendia, N.; Arteche, A.; García, A.; Bustero, I.; Obieta, I.; Mercado; PRINTEX; Tecnalia Research & InnovationThe yttria partially stabilized zirconia is a very attractive material for orthopaedic applications. It exhibits excellent biocompatibility, high fracture toughness, high strength and low wear rates. But case studies show that delayed failure can occur in vivo due to crack propagation. Carbon nanotubes could avoid the slow crack propagation and enhance the toughness of the ceramic material used for prostheses fabrication. In this work, X-ray diffraction has been used to study the influence of the addition of MWCNT on the hydrothermal synthesis of tetragonal zirconia nanoparticles and on the phase stability of the CNT-nanozirconia nanocomposite with the temperature. First, the influence of the processing variables on the hydrothermal synthesis has been studied. The theoretical mathematical models that relate the percentage of tetragonal zirconia nanocrystals and the relative crystallinity with the processing variables in the range of analyzed values have been obtained. The values that give the maximum percentage and crystallinity of tetragonal phase in the studied range have been established. No significant differences were observed in the crystalline phases obtained when adding MWCNT during the synthesis. Nanozirconia partially coated MWCNT synthesized under the optimized parameters were added to commercially available nanozirconia particles and their influence in the phase stability of the zirconia with the temperature was studied by XRD. It was concluded that the addition of the carbon nanotubes delays both the monoclinic phase decomposition and the grain growth.Item Nanozirconia partially coated MWNT: Nanostructural characerization and cytotoxicity and lixivation study(2008) Garmendia, N.; Bilbao, L.; Muñoz, R.; Goikoetxea, L.; García, A.; Bustero, I.; Olalde, B.; Garagorri, N.; Obieta, I.; PRINTEX; Biomateriales; Tecnalia Research & InnovationCarbon nanotubes could avoid the crack propagation and enhance the toughness of the ceramic material used for prostheses applications. So nanozirconia partially coated carbon nanotubes have been obtained via hydrothermal synthesis of zirconia nanoparticles in presence of multiwall carbon nanotubes. The as covered nanotubes should have a better wettability in the ceramic matrix and improve the dispersion of the CNTs in the nanocomposite, which results in a new ceramic biomaterial with a longer lifetime and better reliability. The obtained product has been structurally characterized by several techniques such as FTIR, XRD, SEM, AFM, EELS, XPS and TGA. The citotoxicity of the sintered product was studied by the change in the pH and ICP-AES in in-vitro biocompatibility tests.Item XRD study of the effect of the processing variables on the synthesis of nanozirconia in the presence of MWCNT(2009-02) Garmendia, N.; Arteche, A.; García, A.; Bustero, I.; Obieta, I.; Mercado; PRINTEX; Tecnalia Research & InnovationSeveral challenges must be solved to obtain an effective introduction of carbon nanotubes in a ceramic matrix. Dispersion, good load transfer, and wettability are the major issues to be overcome to obtain good final properties of a zirconia nanocomposite. We have developed a process to coat multi-wall carbon nanotubes with nanozirconia to deal with these challenges. The process is based on the hydrothermal synthesis of tetragonal zirconia nanoparticles in the presence of multi-wall carbon nanotubes (MWCNT). In this work, X-ray diffraction has been used to study the influence of the processing variables in order to optimize this process. The theoretical mathematical models that relate the percentage of tetragonal zirconia and their crystallinity in relation to the processing variables have been extracted.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.