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.

Se obtuvieron películas delgadas de nitruro de carbono amorfo empleando arco pulsado y variando la temperatura del sustrato a temperatura ambiente, 100, 150 y 200 °C. Los enlaces de las estructuras se investigaron empleando la técnica de espectroscopía infrarroja por transformada de Fourier (FTIR) y espectroscopía Raman. Se identificaron bandas de nitrilos en aproximadamente 2200 cm-1. Se observó una reducción en la concentración de los enlaces sp³ y del desorden estructural de las películas. La relación entre las intensidades de las bandas D y G aumentó con la temperatura del sustrato desde temperatura ambiente hasta 100°C; sin embargo, a una temperatura crítica de 150°C, esta tendencia desapareció y las películas se tornaron amorfas. Se observó un pico ubicado en aproximadamente 1610 cm-1 en las películas crecidas a 100°C, 150°C y 200 °C; además, las películas crecidas a 150 °C presentaron la rugosidad más baja y mayores durezas y hemocompatibilidad.

Amorphous carbon nitride films have been obtained by pulsed cathodic arc at substrate temperatures of 20, 100, 150 and 200 °C. Film structure was investigated by Fourier Transformed infrared spectroscopy (FTIR) and Raman spectroscopy. Nitrile bands at approximately 2200 cm-1 were identified in all films. As the temperature increased a reduction in the concentration of sp³ bonds and a decrease in the structure disorder were observed. The relative intensity ratio of Raman D and G bands increased as the substrate temperature increased from 20 to 100°C. Nevertheless, at a critical temperature of 150°C, this trend was broken, and the film became amorphous. A peak at approximately 1610 cm-1 of films grown at 100°C, 150°C and 200 °C suggests that CNx is dominated by a relatively ordered graphite ring like glassy carbon. Moreover, the film grown at 150 °C presented the lowest roughness and the highest hardness and hemocompatibility

Se produjeron descargas eléctricas en un sistema de arco pulsado a baja presión, con una corriente máxima de 100 A con pulsos de 30 ms. Las descargas se llevaron a cabo aplicando un voltaje de 104 V entre los electrodos. Los materiales utilizados como cátodo fueron Ti, Zr, Ni, Cu, Mo y W. La morfología de cátodos después de la descarga fue estudiada mediante la técnica de microscopía electrónica de barrido (SEM). Los cátodos de Ti y Zr presentaron la mayor erosión. Por otra parte, se observaron cráteres circulares sobre cátodos de Ni y Mo y se analizó una región del cátodo Zr, con alta erosión y gran cantidad de cráteres. Se midió el voltaje de descarga para cada material, obteniendo valores de voltaje del arco. Finalmente, se observaron las relaciones entre los voltajes de arco y algunas características del material como punto de fusión y de ebullición, presentando una tendencia exponencial.

Electrical discharges in a pulsed vacuum arc system at low pressure were produced using a peak current of 100A with pulses of 30 ms. Discharges were carried out applying a voltage of 104 V between the electrodes. Materials used as cathodes were Ti, Zr, Ni, Cu, Mo, and W. The cathodes' morphology after the discharge production was studied using the scanning electron microscopy (SEM) technique. Ti and Zr presented the highest erosion. Moreover, circular craters on Ni and Mo cathodes were observed and a region of the Zr cathode, with high erosion and a high quantity of craters was analyzed. The discharge voltage for each material was measured, obtaining arc voltage values. Finally, relationships between arc voltages and some material characteristics such as the melting point and the boiling point were observed, presenting an exponential tendency.

Utilizando la técnica PAPVD (Plasma Assisted Physical Vapor Deposition) por arco pulsado se crecieron películas delgadas de ZnO sobre sustratos de vidrio. Las películas fueron crecidas variando el voltaje de la descarga, la presión del gas y el número de descargas. Las propiedades estructurales tales como: cristalinidad, microestructura y rugosidad superficial fueron investigadas por Difracción de Rayos X, Microscopía Electrónica de Barrido en Ambiente y Microscopía de Fuerza Atómica. Se encontró que el material depositado es efectivamente ZnO, con una estructura cristalina hexagonal, una orientación preferencial en la dirección (002), alta textura cristalográfica, parámetros de red promedio de a = 3,250495 Å y c =5,21608 Å, espesores con valores del orden de los cientos de nanómetros, tamaño de grano promedio del orden de 0,529 mm y rugosidad promedio de 98,6 Å, además, se detectó la presencia de irregularidades, grietas y microgotas en la superficie de las mismas.

Using the PAPVD (Plasma Assisted Physical Vapor Deposition) technique by pulsed arc, were grown films of ZnO on glasses substrates. The films were grown by varying the voltage of the discharge, the pressure of the gas and the number of discharges. The structural properties, such as crystallinity, microstructure, and surface roughness of ZnO films, were investigated using X Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). It was found that the material deposited is effectivitly ZnO, with a hexagonal crystalline structure, with a preferential orientation in planes (002), high crystallographic texture, parameters of net average of a0=3,250495 Å and c0=5,21608 Å, thickness of the films finding values in the order of hundred of nanometers, size of grain average of 0,529 mm, and roughness average of 98,6 Å. Also it was detected the presence of irregularities, cracks and micro-droplets in the surface of the films.