CORROSION STUDY OF A Zn–22Al–2Cu ALLOY WITH THE SURFACE MODIFIED BY AN Y2O3 THIN FILM

Samples of Zn–22Al–2Cu (zinalco) alloys with and without a thin film of Y 2 O 3 were submitted to corrosion by potentiodynamic polarization and analyzed by means of Tafel extrapolation. In addition, in-depth profiles by Ar ion sputtering and Auger electron spectroscopy were obtained. Samples with Y 2 O 3 -deposited film and subjected to potentiodynamic polarization present an improvement in corrosion resistance up to 75% in pH = 4.5 aerated water as compared to samples without the Y 2 O 3 deposit. The variations in electrochemical parameters are explained by the spectroscopic in-depth profile measurements.