ABSTRACT In this work, Ti-316L stainless steel was produced, and its electrochemical behavior was characterized. Ti-steel alloys were produced using an induction furnace, by mixing commercial Ti and 316L stainless steel. X-ray diffraction analyses showed the presence of both the materials, Ti and 316L, in the samples produced. The elemental composition of the materials was determined by optical emission spectroscopy and energy-dispersive spectroscopy, which showed similar quantities of both the elements. Both commercial 316L stainless steel and Ti–steel were studied in simulated biological fluid for imitate a like composition of body blood plasma. Electrochemical experiments conducted at 37°C indicated the stable passive polarization behavior of the Ti-steel alloy. Furthermore, the electrochemical behavior of the 316L stainless steel was also analyzed for comparison purposes. Corrosion velocities were determined using the Tafel method and corrosion resistances were obtained using the electrochemical impedance spectroscopy. The Ti-steel exhibited better protection capacity, compared with the commercial 316L steel. The corrosion velocity and the passive current density of the Ti–steel alloy were lower than those exhibited by the 316L stainless steel.

ABSTRACT In this work, a study of hydroxyapatite (HAp) powders obtained using both, porcine bones and chemical precursors was carried put. In the case of HAp obtained by means of porcine bones, physical processes as cooking, washing and milling were developed, for removing the organic material from the bones; after that, the powders were submitted to a thermal treatment at 800 °C, during 12 h. This procedure was carried out without adding chemical alkalines that are harmful for the environment and the human health. On the other hand, HAp powders were also synthetized using the chemical precipitation method widely reported, showing successful results. Moreover, both kind of powders were characterized using x ray diffraction, Fourier transformer infrared spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. Furthermore, the bioactivity of the materials was determined using the simulated biological fluid (SBF) method. Results showed that the natural HAp exhibited better crystallographic properties. Moreover, according to these results, HAp obtained from porcine bones contains traces of elements as Na and Mg that are favorable for the bioactivity, according to the materials behavior when they are immersed in SBF.

ABSTRACT In this work, titanium doped tungsten disulfide thin films (WS2-Ti) were deposited on AISI 304 stainless-steel substrates using the magnetron co-sputtering DC technique. Films were produced with varying titanium-cathode power from 0 to 25 W. The titanium content of the WS2 structure was determined using energy dispersive spectroscopy (EDS), thereby obtaining a maximum of 10% for the sample grown at 25 W. X-ray diffraction (XRD) results indicated, for the pure sample, the presence of a hexagonal phase of high intensity on the (103) plane. However, with the addition of titanium, the WS2 crystallinity was reduced; nevertheless, when the titanium content was equal to 10%, nanocomposite formation was promoted. This effect was observed in TEM (transmission electron microscopy) images. Finally, the tribological behavior was determined using a ball on disk (BOD) test. With this method, friction coefficient curves were obtained with respect to the number of cycles, allowing the measurement of friction coefficient values of 0.1 for the pure sample and 0.15 for the sample grown at 5 W. Because of the low thickness of the samples, all of them failed during the first cycles.

TixAl1-xN coatings were grown using the triode magnetron sputtering technique with various bias voltages between -40 V and -150 V. As the bias voltage increased, an increase in the Al atomic percentage was observed, presenting a competition with Ti and producing structural changes. Moreover, the grain size and roughness were also strongly influenced by the bias voltage. It was observed that coatings with concentrations of approximately 25% Al and 75% Ti exhibited an optimum mixture of mechanical and tribological properties. The average coefÞcient of friction was low for the TiAlN coating that was grown at -40 V. Additionally, the critical load was obtained by measuring the adhesion using the scratch test.