Browsing by Keyword "Tribology"
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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 Microstructural, mechanical and tribological properties of CrA1YN coatings deposited by magnetron sputtering(2009) Brizuela, Marta; García-Luis, Alberto; Corengia, Pablo; González-Santamaría, Daniel; Muñoz, Roberto; González, Javier Jesús; INGENIERÍA DE SUPERFICIES; TECNOLOGÍAS DE HIDRÓGENO; GENERALCrAlYN coatings were synthesized by reactive magnetron sputtering. The aim of this research is to study the influence of the nitrogen flow at constant total gas flows on the chemical, structural and tribo-mechanical properties of the CrAlYN coatings. The nitrogen flow has an important effect on the deposition growth rate, the crystalline structure and the mechanical properties of the CrAlYN coatings. AU the coatings present a NaCl fee lattice structure but increase in the nitrogen flow changes the coating texture. Coatings morphology also changes from a columnar to an equiaxial structure. Coating hardness decreases with increase in the nitrogen flow. AU the coatings studied showed a similar tribological behaviour with a mean friction coefficient against steel between 0.47 and 0.53 without showing a clear correlation with the coatings' mechanical properties.Item Nitriding of titanium by hollow cathode assisted active screen plasma and its electro-tribological properties(2021-04-15) Domínguez-Meister, Santiago; Ibáñez, Iñigo; Dianova, Anastasia; Brizuela, Marta; Braceras, Iñigo; Tecnalia Research & Innovation; INGENIERÍA DE SUPERFICIESTitanium presents good corrosion resistance, a high strength-to-weight ratio, but poor tribological properties. However, these can be enhanced by nitriding processes. Hollow cathode assisted active screen plasma has proved to be an effective and fast nitriding technique. In this work, the effect of process parameters (hollow cathode induced temperature and plasma intensity, electrical bias…) on the resulting surface microstructure (XRD, SEM/EDS), finishing and hardness of titanium (TiGr4) have been studied. Additionally, the electro-tribological properties have been evaluated on a ball on cylinder reciprocating configuration. The results show that hollow cathode assisted active screen plasma nitriding of titanium can produce titanium nitride surfaces with thicknesses far exceeding those typical in PVD coatings. Moreover, higher plasma processing intensities can generate same layer thicknesses at lower temperatures, minimizing the deleterious effect on grain size growth. Finally, monitoring of the electrical contact resistance can provide valuable information concerning the evolution of the status of the surfaces.Item Oversizing Thread Diagnosis in Tapping Operation(2021-03-25) Gil Del Val, Alain; Veiga, Fernando; Penalva, Mariluz; Arizmendi, Miguel; Tecnalia Research & Innovation; FABRIC_INTELAutomotive, railway and aerospace sectors require a high level of quality on the thread profiles in their manufacturing systems knowing that the tapping process is a complex manufacturing process and the last operation in a manufacturing cell. Therefore, a multivariate statistical process control chart, for each tap, is presented based on the principal components of the torque signal directly measured from spindle motor drive to diagnosis the thread profile quality. This on-line multivariate control chart has implemented an alarm to avoid defected screw threads (oversized). Therefore, it could work automatically without any operator intervention assessing the thread quality and the safety is guaranteed during the tapping process.Item Tailored synthesis of TiC/a-C nanocomposite tribological coatings(2005-10-25) Martínez-Martínez, D.; López-Cartes, C.; Justo, A.; Fernández, A.; Sánchez-López, J.C.; García-Luis, A.; Brizuela, Marta; Onate, J.I.; TECNOLOGÍAS DE HIDRÓGENO; INGENIERÍA DE SUPERFICIES; Tecnalia Research & InnovationComposite coatings made of nanocrystalline TiC (nc-TiC) particles and amorphous carbon (a-C) have been prepared in a double magnetron sputtering system using graphite and titanium targets under Ar bombardment. Chemical composition and microstructure of coatings were studied by transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), and x-ray diffraction (XRD) for a set of samples prepared varying the ratio and intensity of power applied to each magnetron. Changes in coatings microstructure, from a quasipolycrystalline TiC to a nanocomposite formed by nanocrystals of TiC embedded in an amorphous matrix of carbon (nc-TiC/a-C), are observed depending on the synthesis conditions. Tribological and mechanical properties of coatings were tested using a pin-on-disk tribometer and an ultramicrohardness indenter, respectively. Coatings with moderate hardness (7-27 GPa), low friction (0.1-0.2), and low wear rates (k similar to 10(-7) mm(3)/N m) were obtained. A percentage between 15% and 30% of TiC is found as an optimum value to get a good compromise between good mechanical and tribological properties. Finally, a mapping of the mechanical and tribological properties of the nc-TiC/a-C system is presented for the synthesis conditions employedItem Tribología de nuevas capas autolubricantes producidas mediante PVD(2005) Oñate, J. I.; Brizuela, M.; Garcĩa-Luis, A.; Braceras, I.; Pacheco, S.; Viviente, J. L.; Tecnalia Research & Innovation; INGENIERÍA DE SUPERFICIES; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSLas capas de MoS2 depositadas mediante PVD tienen baja fricción en vacío pero se degradan con facilidad al aire, especialmente en presencia de humedad. Este trabajo describe el desarrollo de nuevas capas de MoS^ modificadas con WC. En ensayos de "bola sobre disco" a 0,75 GPa, las capas presentaron una fricción muy baja y estable (< 0,04) en vacío. Se obtuvo una durabilidad superior a 1 millón de ciclos, mostrando un desgaste de 1,3 X 10e-16 me3 /Nm, mejorado respecto a otras capas de MoS2. El coeficiente de fricción aumentó a 0,15 y la durabilidad disminuyó hasta 1 a 3 x 10e5 ciclos en aire hasta 70 % HR.El análisis superficial mostró ratios de S/Mo superiores a 1,2, con menos del 2 % de oxígeno, demostrando carácter lubricante.Item The vacuum tribology model (VTM) of tribolab(2003) Garmendia, I.; Landaberea, A.; Anglada, E.; Fernández-Sanz, R.; Santiago, R.; Herrada, F.; Encinas, J. M.; CIRMETALTriboLAB is a tribology instrument that is planned for installation in the EuteF Flight Segment Platform [1], along with several other European scientific instruments. Eutef will be fixed onto an Express Pallet Adapter (ExPA), which provides standard structural, mechanical, electrical and communications interfaces to the Columbus External Payload Facility of the International Space Station (ISS). As a part of the model philosophy, a vacuum tribological model (VTM) has been developed to generate "on ground" tribological data of selected lubricants. The idea is to compare the results obtained "on ground" with those that will be produced in the space, in order to investigate the different behaviors of same tribological films and to be able to compare the performance of specific lubricants in Low Earth Orbit (LEO) conditions. The VTM is composed of six double experiment cells that perform respectively ball bearing (BB) experiments (with liquid and solid lubrication) and pin-on-disk (PoD) tests of solid lubricants. Thin films of alloyed MoS 2 are being tested in the VTM under controlled vacuum conditions. In this work, the two sections of the VTM are described.