摘要 |
A metal surface is coated with a coating comprising, in succession starting from the metal: optionally, a primer layer; optionally, a tie layer; and a polyamide-based layer consisting of a blend of a polyamide and of a polyolefin functionalized by an unsaturated carboxylic acid anhydride. Advantageously, the metal surface is the outer surface of a tube, particularly a small-diameter pipe having, for example, an outside diameter of 4 to 50 mm. The metal may be any metal, but the coating is very useful for steel and its alloys and for aluminium and its alloys. The optionally, a tie layer; aluminium may be anodized. Thus, the coated surface can comprise aluminium, the anodizing layer, the optional primer, the optional tie and the PA-based layer. The steel may be coated with zinc or a Zn-based alloy (such as, for example, a Zn-Al or Zn-Fe mixture) or with aluminium or an Al-based alloy and/or treated by chromatizing or phosphatizing. Thus, the coated surface can comprise steel, the optional zinc or aluminium layer, the optional chromatizing or phosphatizing treatment layer, the optional primer, the optional tie and the PA-based layer. Preferably, the chromatizing is carried out with Cr<SUP>III</SUP>.
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