Corrosion resistant powder coated metal tube and process for making the same

A corrosion resistant tube, comprising:

• a metal tube having an outer surface;
• and
• zinc layer electrostatically bonded to the metal tube outer surface, wherein the zinc layer has a thickness ranging between about 10 microns and about 75 microns, and wherein the zinc layer is a zinc epoxy powder coating having a specific gravity (calculated) of 2.94, and a particle size (Alpine Jet Sieve) using test method ASTM D3451 (% retained) of:
• +200 Mesh:
• 0-5%;
• and +325 Mesh:
• 5-30%, and wherein the zinc epoxy powder coating has a salt spray resistance (vertical scribe) using test method ASTM B 117 of greater than about 4000 hours.

A corrosion resistant tube, comprising:

• a metal tube having an outer surface;
• a zinc layer electrostatically bonded to the metal tube outer surface, wherein the zinc layer has a thickness ranging between about 10 microns and about 75 microns, and wherein the zinc layer is a zinc epoxy powder coating having a specific gravity (calculated) of 2.94, and a particle size (Alpine Jet Sieve) using test method ASTM D3451 (% retained) of:
• +200 Mesh:
• 0-5%;
• and +325 Mesh:
• 5-30%, and wherein the zinc epoxy powder coating has a salt spray resistance (vertical scribe) using test method ASTM B 117 of greater than about 4000 hours;
• a polymeric layer electrostatically bonded to the zinc layer, wherein the polymeric layer comprises powdered thermoplastic materials selected from the group consisting of powdered nylons, powdered fluoropolymers, powdered polyesters, and mixtures thereof;
• and
• a second polymeric layer electrostatically bonded to the polymeric layer, wherein the second polymeric layer comprises powdered thermoplastic materials selected from the group consisting of powdered nylons, powdered fluoropolymers, powdered polyesters, and mixtures thereof.

A corrosion resistant tube, comprising:

• a metal tube having an outer surface;
• a zinc layer bonded to the metal tube outer surface, wherein the zinc layer 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 bonded to the zinc layer, wherein the surface treatment layer is selected from the group consisting of a zinc/aluminum/rare earth alloy, phosphate, chromate, and mixtures thereof;
• and
• a polymeric layer electrostatically bonded to the surface treatment layer, wherein the polymeric layer comprises powdered thermoplastic materials selected from the group consisting of powdered nylons, powdered fluoropolymers, powdered polyesters, and mixtures thereof.

A corrosion resistant tube, comprising:

• a metal tube having an outer surface;
• a zinc layer bonded to the metal tube outer surface, wherein the zinc layer 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 bonded to the zinc layer, wherein the surface treatment layer is selected from the group consisting of a zinc/aluminum/rare earth alloy, phosphate, chromate, and mixtures thereof;
• a polymeric layer electrostatically bonded to the surface treatment layer, wherein the polymeric layer is selected from the group consisting of powdered polyvinylidene fluoride, powdered Nylon 12, and mixtures thereof;
• and
• a second polymeric layer electrostatically bonded to the polymeric layer, wherein the second polymeric layer is selected from the group consisting of powdered polyvinylidene fluoride, powdered Nylon 12, and mixtures thereof.

A corrosion resistant tube, comprising:

• a metal tube having an outer surface;
• a polymeric layer electrostatically bonded to the metal tube outer surface, wherein the polymeric layer comprises powdered thermoplastic materials selected from the group consisting of powdered nylons, powdered fluoropolymers, powdered polyesters, and mixtures thereof;
• and
• a second polymeric layer electrostatically bonded to the polymeric layer, wherein the second polymeric layer comprises powdered thermoplastic materials selected from the group consisting of powdered nylons, powdered fluoropolymers, powdered polyesters, and mixtures thereof.