Abstract:
A multi-layer tube (10) comprises a metal tube (12) having an outer surface (13) and a zinc layer (14) bonded to the metal tube outer surface (13), wherein the zinc layer (14) is selected from the group consisting of zinc plating, zinc nickel alloys, zinc cobalt alloys, zinc aluminum alloys, and mixtures thereof. A surface treatment layer (16) is bonded to the zinc layer (14), wherein the surface treatment layer (16) is selected from the group consisting of a zinz/aluminum/rare earth alloy, phosphate, chromate and mixtures thereof. A first polymeric layer (18) is bonded to the surface treatment layer (16), wherein the first polymeric layer (18) is selected from the group consisting of a thermoplastic elastomer, an ionomer, a nylon, a fluoropolymer, and mixtures thereof. A second polymeric layer (22) is bonded to the first polymeric layer (18), wherein the second polymeric layer (22) is selected from the group consisting of a nylon, a thermoplastic elastomer, a fluoropolymer, and mixtures thereof. A process for manufacturing a multi-layer tubing (10) for conveying fluids in a vehicle system comprises the step of extruding multiple layers of a melt-processible thermoplastic to a pretreated metal tube (12) having an external surface (13) with at least a zinc based coating (14) and a sealant coating on top of the zinc based coating (14).