OUTER COATING FOR AN UNDERGROUND PIPING MEMBER MADE FROM IRON, COATED PIPING MEMBER AND METHOD FOR DEPOSITING THE COATING

摘要

The invention relates to an outer coating (9) for an underground piping element (7) made from iron, in particular cast iron, the outer coating having a first porous layer (11) and a second porous layer (13) positioned on the first layer and able to plug the pores of the first layer, the outer coating being characterized in that: the first layer includes a substantially pure zinc or a zine alloy or pseudo-alloy, the alloy or pseudo-alloy including, in terms of mass, at least 50% zinc, preferably between 0.5% and 40% aluminum, and the second layer comprises a one-component paint in the aqueous phase made from at least one synthetic resin emulsified, dispersed or dissolved in water. The invention also relates to a corresponding coated piping element and method for depositing the coating.