Examinando por Autor "Bolívar-Osorio, F. J. (Francisco Javier)"

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  • Miniatura
    PublicaciónAcceso abierto
    Influencia de los recubrimientos dúplex sobre las propiedades mecánicas y resistencia al desgaste del acero AISI 4140 bonificado
    (2013-10-28) Bolívar-Osorio, F. J. (Francisco Javier); Bejarano-Gaitán, G. (Gilberto); Gómez-Botero, M. A. (Maryory Astrid)
    The AISI 4140 steel is a low chrome/molybdenum alloyed steel with high tensile strength and good toughness, which is normally used for the manufacture of machine parts such as gears, crank shafts, camshafts, etc. However, its wear resistance is quite limited and this is usually improved by nitriding surface treatment. The purpose of this study was to increase the mechanical properties and wear resistance of 4140 steel by applying a DUPLEX surface treatment consisting of a liquid nitriding (known as Teniffer) followed by the deposition of a titanium nitride (TiN) hard coating. The crystalline microstructure was evaluated by Xray diffraction (XRD), morphology and elemental chemical composition was determined by microscopy SEM and energy dispersive X-ray spectroscopy (EDS), tribological properties were tested using a tribometer type ballondisc and micro hardness was determined by the Vickers method.
  • Miniatura
    PublicaciónAcceso abierto
    Propiedades mecánicas y comportamiento tribológico de recubrimientos multicapa de CRN/TIN
    (2013-11-15) Gómez-Botero, M. A. (Maryory Astrid); Bejarano-Gaitán, G. (Gilberto); Cano, D. A. (Diego Alejandro); Osorio, Jaime Alberto; Bolívar-Osorio, F. J. (Francisco Javier)
    Multilayer coatings represent a promising class of protective coatings due to the improvement in tribological, mechanical, and anticorrosive properties conferred to the coated surfaces. This has motivated the research, development and implementation of these materials in many industrial applications; nowadays the requirements of the industry are not satisfied with materials that have a good property, but a combination of good properties for most of the applications. In this work CrN/TiN multilayer coatings were deposited by magnetron sputtering; the variation of number of coating bilayers with 4 μm total thickness was of 10, 40, 80 and 100. The grain size and the roughness of coatings were determined by means of atomic force microscopy; micro hardness and scratch adhesion tests were performed, the friction coefficients were evaluated in a ball on disk tribometer, and the abrasive wear resistance was determined by Calotest method. for the sample with 10 bilayers to 29.8 GPa for the sample with CrN / TiN 100 bilayers..