abstract

• The atmospheric corrosion of the Zn-2 lwt%25Al-2wt%25Cu (Zn-21Al-2Cu) alloy exposed to an urban atmosphere was investigated after different outdoor exposition periods. The corrosion rate, determined by weight loss, was slightly higher for the ternary alloy than that for zinc and very superior to the one measured with aluminum. The results of the electrochemical methods used, such as corrosion potential, polarization resistance (Rp), potentiostatic and potentiodynamic polarizations, demonstrated a greater corrosion resistance of the surveyed materials as a consequence of the presence of corrosion product layers on the metallic surface. This greater corrosion resistance increased with the outdoor exposure time. However, in a direct comparison between both types of methods, the Rp values showed results that are contrary to those obtained by weight loss. Through scanning electron an exfoliation or layer corrosion was detected in the ternary alloy, which had not been reported up to now in these alloys with relatively low aluminum contents. By means of x-rays diffraction the compounds present in the corrosion products for the ternary alloy (essentially water-soluble sulfates) could be identified whether those present on zinc and aluminum could not. © 2000 by NACE International.

authors

• Domínguez Espinos Octavio
• Hernández Hernández Luis Salvador
• Miranda Vidales Juana María

publication date

• 2000-01-01

published in

• NACE - International Corrosion Conference Series  Proceedings

keywords

• Aluminum; Atmospheric corrosion; Corrosion products; Galvanized steel; Polarization resistance; Scanning electron microscopy; Sulfur dioxide; Urban environment; X-ray diffraction; Zinc-aluminum-copper alloys Aluminum; Aluminum copper alloys; Atmospheric corrosion; Binary alloys; Copper corrosion; Corrosion rate; Corrosion resistance; Galvanizing; Intergranular corrosion; Polarization; Scanning electron microscopy; Steel corrosion; Sulfur dioxide; Ternary alloys; X ray diffraction; Zinc alloys; Corrosion products; Galvanized steels; Polarization resistances; Urban environments; Zinc-aluminum; Aluminum corrosion

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volume

• 2000-March