Mechanical and tribological properties of CrN coatings grown on steel substrates AISI 304 and AISI 4140 using the magnetron sputtering technique were analyzed. Coatings were grown at two pressures of work, 0.4 and 4.0 Pa. The films grown on AISI 304 at a pressure of work of 0.4 showed the highest hardness because it presented a larger grain size and lower roughness. For CrN synthesized at 0.4 Pa, the surface damage was lower during the tribological test. Adherence studies were also carried out, obtaining Lc1 and Lc2 for coatings produced at both pressures and on both substrates. Better adherence behavior was observed for films grown at a low pressure because these films were thicker (~890 nm).

Monolayers of Ti and TiN coatings, as well as a Ti/TiN bilayer coating, were deposited on AISI M2 steel substrates using the PVD cathodic arc technique. The coatings had a thickness close to 5 μm and an average roughness between 98.6 and 110.1 μm due to the presence of microdroplets on the surface. The crystalline structure of the materials was analyzed using Grazing Incidence X-ray Diffraction (GIXRD) with an increase in temperature to study the dynamics of oxide formation. A phase composition study was conducted using the Rietveld refinement method. At the temperatures where critical growth of titanium oxides, both anatase and rutile, was observed, pin-on-disk tests were performed to study the tribological properties of the materials at high temperatures. It was determined that the oxidation temperature of Ti is around 450 °C, promoting the formation of a combination of anatase and rutile. However, the formation of rutile inhibits the formation of anatase, which is stable above 600 °C. In contrast, TiN showed an oxidation temperature of 550 °C, with an exclusive growth of the rutile phase. The Ti/TiN bilayer exhibited mixed behavior, with the initial growth of anatase promoted by Ti, followed by the formation of rutile. Oxidation and tribo-oxidation dominated the wear behavior of the surfaces, showing a transition from mechanisms related to abrasion at low and medium temperatures to a combination of abrasion and adhesion mechanisms at high temperatures (800 °C).

In this paper using Density Functional Theory (DFT), the principal carbonallo tropic crystalline structures (Diamond, graphite, nanotube y fullerene-C60) were simulated. The results shows diamond sp3 bonds formation between carbon atomsand low reactivity, indicating low probability of lateral compound formation and high mechanical properties. Interplanar weakness was evidentin graphite structure, which is related to solid lubrication process. Carbon-Carbon metallic bonds and polarizations at the edges of the structure were observed in Armchair Carbon Nanotube, stabilizing the system which allows the nanotube continuous growth. In fullerene C60structureaFaraday nano-gauge behavior was confirmed, together withlowprobability of interatomic polarization, indicating high structural stability. Besides Total Energy (TE) and Nuclear Repulsion Energy (NRE) values were used to perform energetic comparisons between different structures, allowing the study of electronic stability and their relationship to mechanical properties.

Se depositaron recubrimientos de Ti-Si-N mediante DC Magnetrón Sputtering reactivo, sobre sustratos de acero inoxidable AISI 304, variando el flujo de N2, con el fin de estudiar su efecto en las propiedades estructurales, mecánicas y tribológicas. Los recubrimientos se depositaron utilizando un blanco de Ti-Si (90-10 % at.) con 99,999% de pureza. La caracterización estructural se realizó por medio de Difracción de Rayos X (XRD), con lo cual se encontraron los picos correspondientes a cristalitos de TiN. Al no encontrar evidencias de la formación de las fases Ti-Si-N, Ti-Si, Ti o Si libre, se determinó que el compuesto está formado por granos cristalinos de TiN en una matriz amorfa de SiN. Dicho resultado está apoyado en análisis realizados por FTIR y EDS. Las propiedades mecánicas fueron estudiadas por medio de nanoindentación, obteniendo valores de dureza alrededor de 23 GPa cuando se utilizan bajos flujos de N2.