Reviewand long-term corrosion analysis of coatings based onZinc-Aluminium-Magnesiumalloys,as an alternative to traditional zinc-based coatings for cable trunking systemsinelectrical installations

Abstract

A review of the state of the art is presented regarding metal coatings based on zinc-aluminium-magnesium alloys, for protection against corrosion in metallic trunking systems, as an alternative to traditional zinc-based metal coatings. This revision covers its evolution over time, the different qualities and designations existing in the market, its structure and composition, the international standards that regulate them, the main commercialized brands and their characteristics, the main metallic trunking manufacturers that offer said alloys, and finally, an analysis of the resistance to corrosion based on field tests and accelerated corrosion tests which have been part of this investigation. From this analysis, a mathematical model has been determined for the estimation of long-term corrosion, in which the logarithmic behavior of the corrosion-time function is evidenced. All in all, the article pretends, on one hand, to be a compendium of the key aspects to consider in this type of alloys and on the other hand, to give support to the project engineer in the decision makingprocess, which supposes the election of this type of coating versus zinc-based coatings, providing the most relevant aspects to be considered, in such a way as to ensure compliance with the specifications of the project, in terms of resistance to corrosion

Keywords

• Atmospheric corrosion
• coatings
• project
• trunking
• ZM alloys