| abstract |
An outer coating (9) for an underground piping member (7) made from iron, in particular cast iron, the outer coating comprising a first porous layer (11) and a second porous layer (13) disposed on the first layer and capable of plugging the pores of the first layer, the outer coating being characterised in that: the first layer comprises substantially pure zinc or an alloy or pseudo-alloy of zinc, the alloy or pseudo-alloy comprising, in terms of mass, at least 50% zinc, and preferably between 0.5% and 40% aluminium, and the second layer comprises a one-component paint in the aqueous phase made from at least one synthetic resin emulsion, dispersed or dissolved in water. A corresponding coated piping member and method for depositing the coating. |