Low-temperature plasma treatment has been used in the last years as a useful tool to modify the surface properties of different materials, in special of polymers. In the present work low temperature plasma was used to treat the surface of asymmetric porous substrates of polysulfone (PSf) membranes. The main purpose of this work was to study the influence of the exposure time and the power supplied to argon plasma on the permeability properties of the membranes. Three rf power levels, respectively 5, 10 and 15 W were used. Treatment time ranged from 1 to 50 min. Reduction of single gas permeability was observed with Ar plasma treatments at low energy bombardment (5 W) and short exposure time (20 min). Higher power and/or higher plasma exposition time causes a degradation process begins. The chemical and structural characterization of the membranes before and after the surface modification was done by AFM, SEM and XPS.

TiCxNy coatings deposited on high-speed steel substrates have been used to enhance the tribological properties of cutting tools (hardness, wear resistance, etc.) as well as their corrosion resistance in an aggressive environment. These layers are usually produced by plasma deposition techniques (PVD or CVD), and different coating properties can be obtained with each method. In this work, TiCxNy films were deposited on AISI M2 high-speed steel substrates by the reactive magnetron sputtering technique. A series of samples with a variety of reactive gas mixtures (nitrogen and methane), substrate biases, and deposition temperatures was produced. As a result, coatings with different chemical compositions were deposited for each group of deposition parameters. Gas mixture composition and substrate bias directly affected the chemical composition of the coating, while deposition temperature influenced the chemical composition of TiCxNy layers to a very low extent.

Hard thin TiN, TiCxNy and CrN films deposited by Physical Vapor Deposition (PVD) techniques onto steel substrates were immersed in an aggressive environment and evaluated by Atomic Force Microscopy (AFM) and Electrochemical Impedance Spectroscopy (EIS). The mechanical and electrochemical behavior, as well as the microstructure of TiCxNy depended directly on the contents of carbon and nitrogen in the coating. The best results were obtained with stoichiometric coatings that are presented in this work. Although a small amount of pinholes could be observed, the electrochemical performance of TiN film was poorer than the stoichiometric TiCxNy coating. However, the CrN films showed the highest initial and residual corrosion resistance values, probably due to their dense structure.