Browsing by Keyword "XPS"
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Item Changes in tribological properties of an AISI 440C martensitic stainless steel after ion implantation of carbon at very high doses(1996-09) Alonso, F.; García, A.; Ugarte, J. J.; Viviente, J. L.; Oñate, J. I.; Baranda, P. S.; Cooper, C. V.; Centros PRE-FUSION TECNALIA - (FORMER); TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS; Tecnalia Research & InnovationIon implantation of N+ or C+ has been proven to be a suitable technique for improving tribological properties of steels. In the case of C+ implantation at very high doses, amorphization and a carbonaceous layer can be formed on the surface, the latter of which reduces adhesion when like-on-like material contact conditions occur, thereby decreasing surface wear and friction. A study to determine the influence of C+ ion implantation at very high doses (exceeding 1018 ions cm-2) on tribo-mechanical properties of AISI 440C steel is presented in this work. Ball-on-disc wear and friction tests using an AISI 440C steel ball showed a decrease of wear with increasing dose of more than one order of magnitude. A reduction in friction coefficient was also measured, from 1.0 down to 0.4. C 1s spectra from XPS analyses showed the presence of C-C bonds in the ion-implanted samples, suggesting the formation of a graphitic layer on the surface, responsible for the decrease in surface wear and friction after ion implantation.Item Decrease of Staphylococcal adhesion on surgical stainless steel after Si ion implantation(2014-08-15) Braceras, Iñigo; Pacha-Olivenza, Miguel A.; Calzado-Martín, Alicia; Multigner, Marta; Vera, Carolina; Broncano, Luis Labajos; Gallardo-Moreno, Amparo M.; González-Carrasco, José Luis; Vilaboa, Nuria; González-Martín, M. Luisa; INGENIERÍA DE SUPERFICIES; Biomateriales316LVM austenitic stainless steel is often the material of choice on temporal musculoskeletal implants and surgical tools as it combines good mechanical properties and acceptable corrosion resistance to the physiologic media, being additionally relatively inexpensive. This study has aimed at improving the resistance to bacterial colonization of this surgical stainless steel, without compromising its biocompatibility and resistance. To achieve this aim, the effect of Si ion implantation on 316LVM has been studied. First, the effect of the ion implantation parameters (50 keV; fluence: 2.5-5 × 10 16 ions/cm 2 ; angle of incidence: 45-90°) has been assessed in terms of depth profiling of chemical composition by XPS and nano-topography evaluation by AFM. The in vitro biocompatibility of the alloy has been evaluated with human mesenchymal stem cells. Finally, bacterial adhesion of Staphylococcus epidermidis and Staphylococcus aureus on these surfaces has been assessed. Reduction of bacterial adhesion on Si implanted 316LVM is dependent on the implantation conditions as well as the features of the bacterial strains, offering a promising implantable biomaterial in terms of biocompatibility, mechanical properties and resistance to bacterial colonization. The effects of surface composition and nano-topography on bacterial adhesion, directly related to ion implantation conditions, are also discussed.Item In vivo low-density bone apposition on different implant surface materials(2009-03) Braceras, I.; De Maeztu, M. A.; Alava, J. I.; Gay-Escoda, C.; INGENIERÍA DE SUPERFICIESDuring osseointegration, new bone may be laid down on the implant surface and/or on the old bone surface; the former is known as contact osteogenesis and the latter as distance osteogenesis. Implant surface topography and material composition affect this process. The present study evaluates Ca and P apposition onto three different dental implant material surfaces (carbon monoxide (CO) ion implantation on Ti6Al4V, sand blasting and acid etching on commercially pure titanium and untreated Ti6Al4V) on the mandibles of beagles after healing periods of 3 and 6 months. Energy dispersive spectroscopy is useful for identifying low-density bone relative to surrounding mature bone, allowing for discrimination of the osteogenesis source. Low-density bone was only found at the apical end; there was none on the surface of untreated implants. Low-density bone arising from mature bone towards the implant at month 3 (i.e. distance osteogenesis) was only present on the CO ion implanted samples, due to the modification of the surface nano-topography and the chemistry and structure of the material.