For the development of optimized coating-substrate systems one needs fast and reliable methods which permit the characterization of both intrinsic corrosion resistance and porosity. In the present paper electrochemical procedures for the determination of porosity are developed and applied to the study of Ti and TiN coatings on brass and of TIN/Ti duplex coatings. In a first approach the porosity was obtained from a comparison of the dc polarization resistance of the uncoated and coated substrate at constant potential. In another approach the ratio of current maxima observed during dissolution of the brass substrate in presence and absence of a coating was taken as a measure of porosity. The third method used impedance spectroscopy for the determination of the polarization resistance in the presence and absence of a coating. All methods gave consistent results that were well reproducible. The lowest porosity was found for duplex coatings and for titanium coatings deposited under application of a bias voltage. The electrochemical methods used in this study are well suited for the characterization of the porosity of passive physically vapor deposited coatings deposited on electrochemically active substrates. InfroductionCoatings produced by physical vapor deposition (PVD) find many functional and decorative applications. Sputterdeposited hard coatings, for example, are routinely applied to high quality cutting tools, drills, and other objects. In the

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Wire ropes, due to their construction, combine two very interesting properties: high axial strength and flexibility in bending. However, the assemblage of wires to form flexible ropes results in the sliding of contacting wires and the creation of wear scars, which can act as stress risers and reduce the fatigue life of ropes. Therefore, in order to understand the fatigue behavior of wire ropes, the degradation that occurs between the wires and the strands has to be studied first. In this study, after identifying the main wear patterns for a polymer-covered stranded rope, the wear evolution along the number of cycles and the effect of the sheave diameter in the preferential wear sites were analyzed. The tests were carried out in a custommade Bending over Sheave (BoS) fatigue test bench and short segments of the rope were analyzed by Scanning Electron Microscope (SEM) and confocal imaging profilometry in order to characterize the wear scars. The worn volume and the wear scar depth were selected as the most suitable parameters to characterize the wear behavior of wires. In addition, the importance of the polymeric cover and sheave diameter was proved: a reduction of the sheave diameter results in a bigger wear rate (lm 3 /cycle).