FRCU - GIS: Grupo de Ingeniería de Superficies - Artículos

Permanent URI for this collectionhttp://48.217.138.120/handle/20.500.12272/812

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Subject: search.filters.subject.Nitriding

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    Characterization of DLC coatings over nitrided stainless steel with and without nitriding pre-treatment using annealing cycles
    (2019-04-02) Dalibón Bähler, Eugenia Laura; Czerwiec, Thierry; Trava-Airoldi, Vladimir Jesús; Ghafoor, Naureen; Rogström, Lina; Odén, Magnus; Brühl, Sonia Patricia
    Amorphous hydrogenated diamond-like carbon (DLC) coatings were deposited using plasma assisted chemical vapour deposition (PACVD) on precipitation hardening (PH) stainless steel. Plasma nitriding has been used as pre-treatment to enhance adhesion and mechanical properties. Chemical and mechanical properties of DLC coatings are dependent on the hydrogen content and so on the relation between sp3 /sp2 bondings. The bondings and the structure of the DLC film change with temperature. In this work, a study of the thermal degradation and the evolution of the mechanical properties of DLC coatings over PH stainless steel have been carried out, including the effect of an additional nitrided layer. Nitrided and non-nitrided steel samples were subjected to the same coated in the same conditions, and they were submitted to the same thermal cycles, heating from room temperature to 600 C in several steps. After each cycle, Raman spectra and surface topography measurements were performed ◦ and analyzed. Nanohardness measurements and tribological tests, using a pin-on-disc machine, were carried out to analyze variations in the friction coefficient and the wear resistance. The duplex sample, with nitriding as pre-treatment showed a better thermal stability. For duplex sample, the coating properties, such as adhesion, and friction coefficient were sustained after annealing at higher temperatures; whereas it was not the case for only coated sample.
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    Comparación del comportamiento al desgaste de un acero AISI 1045 nitrurado y seguido de un temple por inducción
    (2016-10) Schierloh, Gonzalo José; Regis, Matías Sebastián; Charadía, Raúl; Dalibón Bähler, Eugenia Laura; Brühl, Sonia Patricia
    Se estudió el comportamiento al desgaste del acero AISI1045 con un tratamiento de nitruración iónica y posterior temple por inducción. Se midió dureza en superficie y perfil en profundidad. Se analizó la microestructura y evaluó el comportamiento al desgaste. Como resultado de la nitruración se obtuvo una zona formada por una capa de compuestos seguida por una zona de difusión de nitrógeno. La dureza superficial del acero templado y revenido aumentó en un 50% y, con el temple por inducción posterior, resultó aún superior con incremento en la dureza del núcleo. El comportamiento al desgaste resultó mejor que la del acero sólo nitrurado, debido al incremento de la capacidad de soporte de carga del sistema.
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    Tribological and corrosion Behavior of Duplex Coated AISI 316L using plasma based ion implantation and deposItion
    (2020) Vaca, Laura Silvia; Quintana, Juan Pablo; Vega, Daniel; Márquez, Adriana Beatriz; Brühl, Sonia Patricia
    The implementation of a duplex process, which combines plasma nitriding with hard coatings obtained by cathodic arc, on stainless steel substrates has faced adhesion problems that affected the wear and corrosion behavior of the treated surfaces. One variation of the cathodic arc process, which could improve the adhesion, is its combination with plasma ion implantation. This work presents results of the wear and corrosion behavior of duplex TiTiN bilayer coatings obtained by cathodic arc deposition combined with ion implantation (PBII&D) on plasma nitrided AISI 316L stainless steel In order to compare the application of PBII&D in duplex processes against conventional cathodic arc deposition, other two types of samples were obtained; one group of samples was coated using the same experimental device with the substrate at floating potential and the other one with a commercial PVD system. The coatings were characterized by SEM, XRD, and nanoindentation. The adhesion was evaluated by the Scratch Test and Rockwell C indentation. The wear resistance was analyzed by the pin-on-disk test and the corrosion behavior was evaluated by means of anodic polarization tests in NaCl solution, as well as by the Salt pray Fog Test. The PBII&D bilayer coatings showed better adhesion while the commercial PVD TiN coatings presented the smallest wear volume loss, but the delamination inside and around the track evidenced adhesion problems. Corrosion resistance was improved in all coatings benchmarked against nitride substrates, but PBII&D processes offered better protection.