Evaluation of Corrosion Resistance of Thin Films Used in the Aeronautical Industry Deposited by Sputtering

In the aircraft and aerospace industry new materials have been developed in the form of a thin film coatings obtained by physical vapor deposition (PVD) technique like sputtering due to the nanometer level improvement in the properties of bulk materials which are use in some components of steam turbines, due to the passage of gases, severe weathers and high temperatures, usually associated with microstructure degradation, corrosion, wear and creep. For the present work, thin films of chromium were grown in situ on substrates of titanium grade 5 and aluminum 2024, with the technique of magnetron sputtering, at three deposit temperatures, with the objective to reduce the particle size and increase resistance to corrosion. The films were microstructurally characterized by scanning electron microscope to analyze the thickness of the film, and X-ray diffraction to obtain the phase analysis. The behavior to the corrosion was established by means of the techniques of potentiodynamic polarization curves and electrochemical noise. The results of the micrographs showed that the effect of the deposition temperature in the thin films homogenize the size of the particles with increasing temperature. The study of X-rays diffraction showed that as the temperature of the substratum increases the phases are clearly defined. The results of Potentiodynamic polarization curves have allowed demonstrating that the films help in decreasing the corrosion susceptibility of this material. Likewise, the technique of electrochemical noise indicated the type of corrosion that it would be present in an aggressive environment such as used.