Evaluation of corrosion of long-term exposed aluminium conductor / Hodnocení korozního napadení hliníkových vodičù po dlouhodobé expozici

The goal of the study was to assess corrosion of a cable bundle after a forty-year exposure to atmosphere. The assessed bundle consisted of a galvanized steel wire carrying core and aluminium external guide wires. Optical microscopy, electron dispersive microscopy and X-ray diffraction techniques were used for the assessment. Aluminium oxide was identified to be the most prevailing aluminium corrosion product. The average residual thickness of the steel wire zinc coat was 33 μm, even though there were locations where the zinc coat corroded through totally. Service life of aluminium wires is limited predominantly by the pitting corrosion rate, which reached 5 μm/ year.