Résumé : |
Fine zinc powder was recommended for use in paints as long ago as 1840. But it is only in the past 50 years, with the development of zinc-rich paints based on synthetic and inorganic paint resins, that zinc powder has become commonly used, specifically in paints for heavy-duty corrosion protection.
The main applications for coatings containing zinc are the long-term corrosion protection of industrial and marine constructions (such as steel infrastructure, pipelines, bridges, windmills, and offshore drilling platforms) and the temporary protection of steel sheets (shop primers) during newbuilding of ships. Zinc coatings are specified in standards such as ISO 12944, Norsok M-501, SSPC-Paint 20, and the new IMO Performance Standard for Protective Coatings (PSPC).
Zinc primers are considered to be the most effective anti-corrosion paint systems in use and have proven their excellent performance over many decades. The thickness of the zinc primers can vary between 10 and 120 microns ; the higher the thickness and the higher the zinc powder content are in the paint, the longer the corrosion protection of the steel will last. This article reviews types of zinc powder and how they are made, types and composition of zinc primers, the corrosion protection mechanisms of zinc primers, suitable uses of the primers, and tips on application. |