WO2016085799A1 - Revêtement résistant à la corrosion à séchage sur site pour substrats revêtus de zinc ou d'alliage de zinc - Google Patents
Revêtement résistant à la corrosion à séchage sur site pour substrats revêtus de zinc ou d'alliage de zinc Download PDFInfo
- Publication number
- WO2016085799A1 WO2016085799A1 PCT/US2015/061813 US2015061813W WO2016085799A1 WO 2016085799 A1 WO2016085799 A1 WO 2016085799A1 US 2015061813 W US2015061813 W US 2015061813W WO 2016085799 A1 WO2016085799 A1 WO 2016085799A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- zinc
- corrosion
- coating
- metal component
- chromium
- Prior art date
Links
- 238000000576 coating method Methods 0.000 title claims abstract description 394
- 239000011248 coating agent Substances 0.000 title claims abstract description 389
- 238000005260 corrosion Methods 0.000 title claims abstract description 290
- 230000007797 corrosion Effects 0.000 title claims abstract description 290
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 title claims abstract description 190
- 239000011701 zinc Substances 0.000 title claims abstract description 190
- 229910052725 zinc Inorganic materials 0.000 title claims abstract description 190
- 239000000758 substrate Substances 0.000 title claims abstract description 173
- 229910001297 Zn alloy Inorganic materials 0.000 title claims abstract description 172
- 229910052751 metal Inorganic materials 0.000 claims abstract description 405
- 239000002184 metal Substances 0.000 claims abstract description 405
- 239000000243 solution Substances 0.000 claims abstract description 129
- 238000000034 method Methods 0.000 claims abstract description 123
- 239000000203 mixture Substances 0.000 claims abstract description 119
- 230000008569 process Effects 0.000 claims abstract description 118
- 150000001875 compounds Chemical class 0.000 claims abstract description 98
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 70
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 63
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 63
- 239000011651 chromium Substances 0.000 claims abstract description 63
- -1 silicate compound Chemical class 0.000 claims abstract description 51
- 239000004925 Acrylic resin Substances 0.000 claims abstract description 34
- 229920000178 Acrylic resin Polymers 0.000 claims abstract description 34
- 229910000165 zinc phosphate Inorganic materials 0.000 claims abstract description 29
- 239000007864 aqueous solution Substances 0.000 claims abstract description 28
- LRXTYHSAJDENHV-UHFFFAOYSA-H zinc phosphate Chemical compound [Zn+2].[Zn+2].[Zn+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LRXTYHSAJDENHV-UHFFFAOYSA-H 0.000 claims abstract description 28
- 239000000126 substance Substances 0.000 claims abstract description 20
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 claims description 47
- ZWPVWTIRZYDPKW-UHFFFAOYSA-N chromium(VI) oxide peroxide Inorganic materials [O-2].[O-][Cr]([O-])(=O)=O ZWPVWTIRZYDPKW-UHFFFAOYSA-N 0.000 claims description 21
- 238000010438 heat treatment Methods 0.000 claims description 16
- 238000006243 chemical reaction Methods 0.000 claims description 15
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims description 14
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 claims description 14
- PXLIDIMHPNPGMH-UHFFFAOYSA-N sodium chromate Chemical compound [Na+].[Na+].[O-][Cr]([O-])(=O)=O PXLIDIMHPNPGMH-UHFFFAOYSA-N 0.000 claims description 14
- 229910045601 alloy Inorganic materials 0.000 claims description 9
- 239000000956 alloy Substances 0.000 claims description 9
- 239000003973 paint Substances 0.000 claims description 9
- 229910000640 Fe alloy Inorganic materials 0.000 claims description 8
- SOCTUWSJJQCPFX-UHFFFAOYSA-N dichromate(2-) Chemical compound [O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O SOCTUWSJJQCPFX-UHFFFAOYSA-N 0.000 claims description 8
- KFZAUHNPPZCSCR-UHFFFAOYSA-N iron zinc Chemical compound [Fe].[Zn] KFZAUHNPPZCSCR-UHFFFAOYSA-N 0.000 claims description 8
- QLOKJRIVRGCVIM-UHFFFAOYSA-N 1-[(4-methylsulfanylphenyl)methyl]piperazine Chemical compound C1=CC(SC)=CC=C1CN1CCNCC1 QLOKJRIVRGCVIM-UHFFFAOYSA-N 0.000 claims description 7
- 229910021564 Chromium(III) fluoride Inorganic materials 0.000 claims description 7
- 229910000861 Mg alloy Inorganic materials 0.000 claims description 7
- 239000004111 Potassium silicate Substances 0.000 claims description 7
- 229910000611 Zinc aluminium Inorganic materials 0.000 claims description 7
- HXFVOUUOTHJFPX-UHFFFAOYSA-N alumane;zinc Chemical compound [AlH3].[Zn] HXFVOUUOTHJFPX-UHFFFAOYSA-N 0.000 claims description 7
- CXOWYMLTGOFURZ-UHFFFAOYSA-N azanylidynechromium Chemical compound [Cr]#N CXOWYMLTGOFURZ-UHFFFAOYSA-N 0.000 claims description 7
- QFFVPLLCYGOFPU-UHFFFAOYSA-N barium chromate Chemical compound [Ba+2].[O-][Cr]([O-])(=O)=O QFFVPLLCYGOFPU-UHFFFAOYSA-N 0.000 claims description 7
- 229940083898 barium chromate Drugs 0.000 claims description 7
- BCFSVSISUGYRMF-UHFFFAOYSA-N calcium;dioxido(dioxo)chromium;dihydrate Chemical compound O.O.[Ca+2].[O-][Cr]([O-])(=O)=O BCFSVSISUGYRMF-UHFFFAOYSA-N 0.000 claims description 7
- OIDPCXKPHYRNKH-UHFFFAOYSA-J chrome alum Chemical compound [K]OS(=O)(=O)O[Cr]1OS(=O)(=O)O1 OIDPCXKPHYRNKH-UHFFFAOYSA-J 0.000 claims description 7
- WBKDDMYJLXVBNI-UHFFFAOYSA-K chromium(3+);2-ethylhexanoate Chemical compound [Cr+3].CCCCC(CC)C([O-])=O.CCCCC(CC)C([O-])=O.CCCCC(CC)C([O-])=O WBKDDMYJLXVBNI-UHFFFAOYSA-K 0.000 claims description 7
- DBULDCSVZCUQIR-UHFFFAOYSA-N chromium(3+);trisulfide Chemical compound [S-2].[S-2].[S-2].[Cr+3].[Cr+3] DBULDCSVZCUQIR-UHFFFAOYSA-N 0.000 claims description 7
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical compound [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 claims description 7
- 229910000356 chromium(III) sulfate Inorganic materials 0.000 claims description 7
- 239000011696 chromium(III) sulphate Substances 0.000 claims description 7
- 235000015217 chromium(III) sulphate Nutrition 0.000 claims description 7
- VQWFNAGFNGABOH-UHFFFAOYSA-K chromium(iii) hydroxide Chemical compound [OH-].[OH-].[OH-].[Cr+3] VQWFNAGFNGABOH-UHFFFAOYSA-K 0.000 claims description 7
- AHXGRMIPHCAXFP-UHFFFAOYSA-L chromyl dichloride Chemical compound Cl[Cr](Cl)(=O)=O AHXGRMIPHCAXFP-UHFFFAOYSA-L 0.000 claims description 7
- 229910052913 potassium silicate Inorganic materials 0.000 claims description 7
- 235000019353 potassium silicate Nutrition 0.000 claims description 7
- 238000005507 spraying Methods 0.000 claims description 7
- KAVBMPSEABAPIE-UHFFFAOYSA-K trichlorochromium;hydrate Chemical compound O.Cl[Cr](Cl)Cl KAVBMPSEABAPIE-UHFFFAOYSA-K 0.000 claims description 7
- FTBATIJJKIIOTP-UHFFFAOYSA-K trifluorochromium Chemical compound F[Cr](F)F FTBATIJJKIIOTP-UHFFFAOYSA-K 0.000 claims description 7
- 238000005096 rolling process Methods 0.000 claims description 6
- BFGKITSFLPAWGI-UHFFFAOYSA-N chromium(3+) Chemical compound [Cr+3] BFGKITSFLPAWGI-UHFFFAOYSA-N 0.000 abstract description 22
- UUMMHAPECIIHJR-UHFFFAOYSA-N chromium(4+) Chemical class [Cr+4] UUMMHAPECIIHJR-UHFFFAOYSA-N 0.000 abstract 1
- 150000003839 salts Chemical class 0.000 description 93
- 239000007921 spray Substances 0.000 description 75
- 229910000831 Steel Inorganic materials 0.000 description 31
- 239000010959 steel Substances 0.000 description 31
- 238000012360 testing method Methods 0.000 description 27
- 229940077935 zinc phosphate Drugs 0.000 description 16
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 10
- 229910001335 Galvanized steel Inorganic materials 0.000 description 8
- 239000008397 galvanized steel Substances 0.000 description 8
- 238000005246 galvanizing Methods 0.000 description 8
- 239000000047 product Substances 0.000 description 6
- UGZADUVQMDAIAO-UHFFFAOYSA-L zinc hydroxide Chemical compound [OH-].[OH-].[Zn+2] UGZADUVQMDAIAO-UHFFFAOYSA-L 0.000 description 5
- 229940007718 zinc hydroxide Drugs 0.000 description 5
- 229910021511 zinc hydroxide Inorganic materials 0.000 description 5
- 239000011787 zinc oxide Substances 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 239000002920 hazardous waste Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 230000000007 visual effect Effects 0.000 description 4
- 229910000975 Carbon steel Inorganic materials 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 239000010962 carbon steel Substances 0.000 description 3
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 description 3
- 239000008199 coating composition Substances 0.000 description 3
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 231100001261 hazardous Toxicity 0.000 description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000003618 dip coating Methods 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 238000009533 lab test Methods 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
- 238000006748 scratching Methods 0.000 description 2
- 230000002393 scratching effect Effects 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 230000004580 weight loss Effects 0.000 description 2
- 241001163841 Albugo ipomoeae-panduratae Species 0.000 description 1
- 241000221535 Pucciniales Species 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- FMRLDPWIRHBCCC-UHFFFAOYSA-L Zinc carbonate Chemical group [Zn+2].[O-]C([O-])=O FMRLDPWIRHBCCC-UHFFFAOYSA-L 0.000 description 1
- KCZFLPPCFOHPNI-UHFFFAOYSA-N alumane;iron Chemical compound [AlH3].[Fe] KCZFLPPCFOHPNI-UHFFFAOYSA-N 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- FJMNNXLGOUYVHO-UHFFFAOYSA-N aluminum zinc Chemical compound [Al].[Zn] FJMNNXLGOUYVHO-UHFFFAOYSA-N 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 238000004210 cathodic protection Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 210000003298 dental enamel Anatomy 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000004070 electrodeposition Methods 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000005244 galvannealing Methods 0.000 description 1
- 230000009931 harmful effect Effects 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000011253 protective coating Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 238000007763 reverse roll coating Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 150000003751 zinc Chemical class 0.000 description 1
- 239000011667 zinc carbonate Substances 0.000 description 1
- 235000004416 zinc carbonate Nutrition 0.000 description 1
- 229910000010 zinc carbonate Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/48—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
- C23C22/53—Treatment of zinc or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/08—Anti-corrosive paints
- C09D5/082—Anti-corrosive paints characterised by the anti-corrosive pigment
- C09D5/084—Inorganic compounds
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/06—Zinc or cadmium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/26—After-treatment
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/24—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing hexavalent chromium compounds
- C23C22/33—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing hexavalent chromium compounds containing also phosphates
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2222/00—Aspects relating to chemical surface treatment of metallic material by reaction of the surface with a reactive medium
- C23C2222/10—Use of solutions containing trivalent chromium but free of hexavalent chromium
Definitions
- This invention relates to a process for making a corrosion-resistant coating for zinc or zinc-alloy coated substrates meeting the American Society of Testing and Materials International ASTM B117-11 (hereinafter ASTM B117) standard for continuous salt spray tests of metals and coated metals.
- ASTM B117 standard for continuous salt spray tests of metals and coated metals.
- the ASTM B117 standard as last amended in August 2011 is incorporated herein by reference.
- Coils of steel strip may be hot-dip galvanized in a continuous line, immersing the steel strip in a molten zinc bath at speeds of up to 600 feet per minute.
- the specified coating thickness is controlled by air "knives", which remove the excess coating deposited on the steel as it exits the molten zinc bath.
- Galvanized steel is used in applications requiring the strength of steel combined with the corrosion resistance of zinc.
- the continuous galvanizing process can apply a number of different coatings that vary in thickness, appearance, and alloy composition.
- the term "galvanized” refers to the standard continuous coating having the primary component being zinc.
- the finished zinc or zinc-alloy coating has good formability and corrosion resistance, and provides excellent sacrificial protection.
- the zinc or zinc-alloy coating is applied in conjunction with annealing of the metal substrate, as explained below. These products are often referred to as being galvannealed.
- Electrogalvanization comprises immersing a steel substrate in a zinc and saline solution with a zinc anode, the steel substrate acting as the conductor. When electricity is passed through circuit a zinc coating is deposited onto the surface of the steel substrate.
- thermal diffusion galvanizing the metal substrate is tumbled with a mixture of zinc powder and accelerator chemicals, generally sand, and heated to slightly below the melting point of zinc.
- Galvanized steel results from the combined processes of galvanizing and annealing to produce specialized sheets of steel.
- galvannealed metal substrate steel is subjected to the hot-dip galvanizing process to form a zinc-coated steel with a very fine grayish matte finish.
- the coated steel is then heated, to above the recrystallization temperature, maintained at a suitable temperature for a period of time, and then cooled.
- the heating and cooling alter the properties of the steel, such as strength and ductility.
- the zinc coating of galvanized steel does not flake off when formed, stamped, and bent.
- the very fine matte finish acts as a primer, allowing paint to adhere more easily, while affording rust protection.
- Zinc coatings protect steel by providing a physical barrier as well as cathodic protection to the underlying steel.
- the main mechanism by which galvanized coatings protect steel is by providing an impervious barrier that does not allow moisture to contact the steel. Without moisture (the necessary electrolyte), there is no corrosion.
- base steel is exposed, e.g., by cutting, scratching or abrading, the exposed steel is still protected by the sacrificial corrosion of the zinc coating adjacent to the exposed steel due to zinc being more electronegative (more reactive) than steel in the galvanic series, causing zinc to oxidize before the steel.
- Zinc acting as a sacrificial anode is an advantage absent from paint, enamel, powder coatings and other corrosion preventative methods.
- the process herein described may be applicable not only to galvanized steel, but also to galvannealed carbon steel, which is steel which has been coated with zinc, for example, by a hot-dipped process, which converts the coating into a zinc-iron alloy, and subsequently annealed. Conversion to this alloy results in a non-spangle matte finish which makes the sheet suitable for painting after fabrication.
- the present process may be applicable to steel which has been subjected to a galvalume® process, in which carbon steel sheet is coated with an aluminum-zinc alloy by a continuous hot-dipped process.
- the nominal coating composition is about 55% aluminum and 45% zinc optionally plus a small addition of silicon (added to at least improve coating adhesion to the steel substrate). This process may be applicable to any form of galvanized metal substrate, including galvalume® coatings.
- zinc corrosion products will cause many harmful effects.
- zinc oxide prevents paint from adhering to the metal as well as accelerates further corrosion of the metal which is unsightly to any galvanized coating's appearance.
- Pure water contains essentially no dissolved minerals and the zinc will react quickly with pure water to form zinc hydroxide, a bulky white and relatively unstable oxide of zinc.
- pure water e.g., rain, dew or condensation, etc.
- the water will continue to react with the zinc and progressively consume the coating. Therefore, a process for making zinc or zinc-alloy corrosion-resistant metal components with not only exponentially enhanced corrosion- resistance, but also with enhanced adhesion to pre-paints is wanted.
- Some commercially available compositions have the capacity to passivate galvanized metal substrates, reducing the formation of zinc corrosion products. These passivators usually utilize a dichromate or chromate composition, typically applied through immersion. Most of these commercially available products provide limited protection to corrosion. An untreated surface will show signs of corrosion after 0.5 hours of exposure to a neutral salt spray according to ASTM specification A1003/A1004, and a thin chromate film produced by a dip procedure will usually show signs of corrosion after 12 to 75 hours of exposure to the salt spray environment. As such, there is a need for a corrosion-resistant coating to provide corrosion resistance exceeding 75 hours of exposure to salt spray environment.
- the hot-dip coating process produces many hazardous by-products.
- a zinc-phosphate coating is applied to a galvanized metal substrate, via spray coating or dip coating, it must be followed by a rinse step to remove any excess coating composition.
- the zinc-phosphating rinse water must then be treated to remove any hazardous components.
- the resultant is a sludge, rich in hazardous components which must be disposed of as hazardous waste according to guidelines set forth by the Environmental Protection Agency (EPA). Sludge also forms in the dipping tanks which must be removed and disposed of according to EPA guidelines. Furthermore, the dipping tanks themselves have a finite lifetime and also must be disposed of according to EPA guidelines. Disposal of hazardous waste is very expensive and time consuming. Therefore, there is presently a need for a coating for a galvanized metal substrate which does not produce hazardous waste byproducts which requires laborious and expensive disposal.
- the presently disclosed corrosion-resistant coating provides enhanced corrosion resistance to the salt spray environment, that may exceed 1,000 hours of protection for metal substrates having a zinc or zinc-alloy surface coating, and over 144 hours for cold-reduced metal substrates having a zinc or zinc-alloy coating. Furthermore, the presently disclosed corrosion-resistant coating provides for a dry-in-place application, negating the requirement for hazardous waste disposal.
- a process for making a corrosion-resistant metal component comprising the steps of: combining at least one zinc phosphate forming compound and at least one chromium forming compound with water to form a first solution; separately combining at least one silicate compound with water to form a second solution; combining the first solution with the second solution such as to form a mixed aqueous solution; combining the mixed aqueous solution with at least one acrylic resin to form a coating mixture; and applying the coating mixture to a metal substrate having a zinc or zinc-alloy surface to form a coating on the metal substrate forming a covalent bond with the zinc or zinc-alloy surface of the metal substrate, the coating providing chemical resistance for at least 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy surface of the metal substrate has a weight of 0.04 oz/ft 2 (12.2g/m 2 ).
- the order in which the above-described components are mixed provides a coating with chemical resistance for at least 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy surface of the metal substrate has a weight of 0.04 oz/ft 2 (12.2g/m 2 ).
- the order of mixing the components determines the coating composition.
- the order of mixing the components is key for the reaction between the coating mixture and the zinc or zinc-alloy surface of the metal substrate.
- the coating mixture reacts in-situ with the zinc or zinc-alloy surface of the metal substrate forming a covalent bond with the zinc or zinc-alloy surface.
- covalent bond is defined as the bond formed between the zinc or zinc-alloy substrate forming the zinc phosphate compound, the chromate forming compound, and silicate compound, providing a corrosion resistance of at least 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy surface of the metal substrate has a weight of 0.04 oz/ft 2 (12.2g/m 2 ).
- the coated metal substrate may be heated to further the reaction between the applied coating mixture and the surface of the metal substrate.
- the zinc or zinc-alloy surface may be selected from the group consisting of zinc, zinc alloy, zinc-aluminum alloy, zinc-iron alloy, zinc-aluminum-magnesium alloy and combination thereof.
- the chromium forming compound may comprise of a trivalent chromium forming compound (i.e. chromium (III)).
- the trivalent chromium forming compound may be selected from the group consisting of chromium chloride hydrate, chromium (III) potassium sulfate, chromium hydroxide, chromium (III) fluoride, chromium (III) sulfate, chromium (III) sulfide, chromium (III) oxide, chromium (III) 2-ethylhexanoate, chromium (III) nitride, chromium tricarbonyl and mixtures thereof.
- the chromium forming compound may also comprise of a hexavalent chromium forming compound (i.e chromium (VI)).
- the hexavalent chromium forming compound may be selected from the group consisting of chromium (VI) halides, hexafluoride, chromyl chloride, sodium chromate, chromium (VI) peroxide, sodium chromate, chromium (VI) oxide, dichromate, potassium chromate, calcium chromate, barium chromate, chromium (VI) oxide peroxide, and mixtures thereof.
- the at least one silicate compound may comprise a potassium silicate compound.
- the first solution may comprise not less than 4 and not more than 27 percent by weight of the at least one zinc phosphate forming compound; not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and balance water.
- the first solution may comprise not less than 5 and not more than 27 percent by weight of the at least one zinc phosphate forming compound; not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and balance water.
- the second solution may comprise not less than 10 and not more than 50 percent by weight of at least one silicate compound, and balance water. The first solution and the second solution may be combined as to form a mixed aqueous solution.
- the mixed aqueous solution may be combined with at least one acrylic resin to form a coating mixture.
- the coating mixture may have a pH value of not greater than 2.5.
- the at least one resin may have a pH value of not greater than 3.5.
- the coating mixture solution may comprise not less than 20 and not more than 95 percent by weight of the first solution; not less than 5 and not more than 12 percent by weight of the second solution; not less than 5 and not more than 30 percent by weight of the at least one acrylic resin; and balance water.
- a process for making a corrosion-resistant metal component comprising the steps of: combining water, at least one zinc phosphate forming compound and at least one chromium forming compound to form a first solution; separately combining at least one silicate compound with water to form a second solution; combining the first solution with the second solution such as to form a coating mixture; and, applying the coating mixture to a metal substrate having a zinc or zinc-alloy surface to form a coating on the metal substrate forming a covalent bond with the zinc or zinc-alloy substrate, the coating providing chemical resistance for at least 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy surface of the metal substrate has a weight of 0.04 oz/ft 2 (12.2g/ m2) .
- the coating mixture reacts with the zinc or zinc-alloy surface of the metal substrate forming a covalent bond with the zinc or zinc-alloy surface.
- the coated metal substrate may be heated to further the reaction between the applied coating mixture and the surface of the metal substrate.
- the metal substrate may have a zinc or zinc-alloy surface.
- the zinc or zinc-alloy surface may be selected from the group consisting of zinc, zinc alloy, zinc-aluminum alloy, zinc-iron alloy, zinc-aluminum-magnesium alloy and combination thereof.
- the at least one chromium forming compound may comprise of a trivalent chromium forming compound (i.e. chromium (III)).
- the trivalent chromium forming compound may be selected from the group consisting of chromium chloride hydrate, chromium (III) potassium sulfate, chromium hydroxide, chromium (III) fluoride, chromium (III) sulfate, chromium (III) sulfide, chromium (III) oxide, chromium (III) 2-ethylhexanoate, chromium (III) nitride, chromium tricarbonyl and mixtures thereof.
- the chromium forming compound may comprise of a hexavalent chromium forming compound (i.e. chromium (VI)).
- the hexavalent chromium forming compound may be selected from the group consisting of chromium (VI) halides, hexafluoride, chromyl chloride, sodium chromate, chromium (VI) peroxide, sodium chromate, chromium (VI) oxide, dichromate, potassium chromate, calcium chromate, barium chromate, chromium (VI) oxide peroxide, and mixtures thereof.
- the at least one silicate compound may comprise a potassium silicate compound.
- the first solution may comprise not less than 4 and not more than 27 percent by weight of the at least one zinc phosphate forming compound; not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and balance water.
- the first solution may comprise not less than 5 and not more than 27 percent by weight of the at least one zinc phosphate forming compound; not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and balance water.
- the second solution may comprise not less than 10 and not more than 50 percent by weight of at least one silicate compound, and balance water.
- the first solution and the second solution may be combined as to form a coating mixture.
- the coating mixture may comprise not less than 20 and not more than 95 percent by weight of the first solution; not less than 5 and not more than 12 percent by weight of the second solution; and balance water.
- a process for making a corrosion-resistant metal component coating comprising the steps of: combining water, at least one zinc phosphate forming compound and at least one chromium forming compound to form a first solution; separately combining at least one silicate compound with water to form a second solution; combining the first solution with the second solution such as to form a mixed aqueous solution; and, combining the mixed aqueous solution with at least one acrylic resin to form a corrosion resistant metal component coating mixture for applying to a metal substrate having a zinc or zinc-alloy surface to form a coating on the metal substrate that reacts with the zinc or zinc- alloy surface forming a covalent bond with the zinc or zinc-alloy substrate, the coating providing chemical resistance for at least 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy surface of the metal substrate has a weight of 0.04 oz/ft 2 (12.20g/m 2 ).
- the first solution and the second solution may be combined to form a coating mixture and the coating mixture may be applied to a metal substrate having a zinc or zinc-alloy surface to form a coating on the metal substrate forming a covalent bond with the zinc or zinc-alloy substrate, the coating providing chemical resistance for at least 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy surface of the metal substrate has a weight of 0.04 oz/ft 2 (12.20g/m 2 ).
- the first solution may comprise not less than 4 and not more than 27 percent by weight of the at least one zinc phosphate forming compound; not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and the balance comprising water.
- the first solution may comprise not less than 5 and not more than 27 percent by weight of the at least one zinc phosphate forming compound; not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and the balance comprising water.
- the second solution may comprise not less than 10 and not more than 50 percent by weight of at least one silicate compound, and the balance comprising water.
- the first solution and the second solution may be combined as to form a mixed aqueous solution.
- the mixed aqueous solution may be combined with at least one acrylic resin to form a coating mixture.
- the coating mixture solution may comprise not less than 20 and not more than 95 percent by weight of the first solution; not less than 5 and not more than 12 percent by weight of the second solution; not less than 5 and not more than 30 percent by weight of the at least one acrylic resin; and balance water.
- the first solution and the second solution may be combined as to form a coating mixture.
- the coating mixture may comprise not less than 20 and not more than 95 percent by weight of the first solution; not less than 5 and not more than 12 percent by weight of the second solution; and the balance comprising water.
- the coating mixture may be applied in various manners such as by rolling the coating mixture onto the metal component surface, by spraying the coating mixture onto the metal component surface, or by submersing at least a portion of the metal substrate with a zinc or zinc-alloy surface into a bath of the coating mixture.
- FIG. 1 is a schematic side-view of an apparatus to provide a dry-in-place application of the presently disclosed corrosion-resistant metal component coating, and a heating apparatus to further the reactive process.
- FIG. 2 is a photograph of Hot-Dip Galvanized (HDG) G-60 non-chemically treated (“NCT”) panels exposed to the salt spray environment for up to 120 hours.
- FIG. 3 is a photograph of galvannealed panels coated with a solution of the presently disclosed corrosion-resistant metal component coating comprising chromium (VI), exposed to the salt spray environment for up to 1008 hours.
- FIG. 4 is a photograph of uncoated galvannealed panels exposed to the salt spray environment for up to 96 hours.
- FIG. 5 is a photograph of galvannealed panels, coated with a solution of the presently disclosed corrosion-resistant metal component coating comprising chromium (VI), exposed to the salt spray environment for up to 1512 hours.
- chromium VI
- FIG. 6 is a photograph of HDG G-40 non-chemically treated (“NCT”) metal substrate panels exposed to salt spray for up to 144 hours.
- FIG. 7 is a photograph of metal substrate panels, having a zinc or zinc-alloy surface, coated with a solution of the presently disclosed corrosion-resistant metal component coating comprising chromium (III), cold-reduced by 15% to 23%, and exposed to the salt spray environment for up to 144 hours.
- chromium (III) chromium
- FIG. 8a is a photograph of the top view of metal substrate panels, having a zinc or zinc-alloy surface, coated with a solution of the presently disclosed corrosion-resistant metal component coating comprising the presently disclosed corrosion-resistant metal component coating comprising chromium (VI) compounds, cold-reduced by 16% to 23%, and exposed to the salt spray environment for up to 120 hours.
- a solution of the presently disclosed corrosion-resistant metal component coating comprising the presently disclosed corrosion-resistant metal component coating comprising chromium (VI) compounds, cold-reduced by 16% to 23%, and exposed to the salt spray environment for up to 120 hours.
- VI chromium
- FIG. 8b is a photograph of the bottom view of metal substrate panels, having a zinc or zinc-alloy surface, coated with a solution of the presently disclosed corrosion- resistant metal component coating comprising chromium (VI), cold-reduced by 16% to 23%, and exposed to the salt spray environment for up to 120 hours.
- chromium VI
- FIG. 9a is a photograph of the top view of finished formed studs, having a zinc or zinc-alloy surface, coated with a solution of the presently disclosed corrosion-resistant metal component coating comprising chromium (VI), cold-reduced by 16% to 23%, and exposed to the salt spray environment for up to 120 hours.
- chromium VI
- FIG. 9b is a photograph of the bottom view of finished formed studs, having a zinc or zinc-alloy surface, coated with a solution of the presently disclosed corrosion- resistant metal component coating comprising chromium (VI), cold-reduced by 16% to 23%, and exposed to salt spray for up to 120 hours.
- a solution of the presently disclosed corrosion- resistant metal component coating comprising chromium (VI), cold-reduced by 16% to 23%, and exposed to salt spray for up to 120 hours.
- FIG. 10 is a photograph of uncoated HDG G-40 non-chemically treated (“NCT") finished formed studs exposed to the salt spray environment for up to 120 hours.
- FIG. 11a is a photograph of the top view of finished formed studs, having a zinc or zinc-alloy surface, coated with a solution of the presently disclosed corrosion-resistant metal component coating comprising chromium (III), cold-reduced by 23% to 24%, and exposed to the salt spray environment for up to 120 hours.
- NCT non-chemically treated
- FIG. lib is a photograph of the bottom view of finished formed studs, having a zinc or zinc-alloy surface, coated with a solution of the presently disclosed corrosion- resistant metal component coating comprising the presently disclosed corrosion-resistant metal component coating comprising chromium (III) compounds, cold-reduced by 23% to 24%, and exposed to the salt spray environment for up to 120 hours.
- FIG. 12a is a photograph of the top view of finished formed studs, having a zinc or zinc-alloy surface, coated with a solution of the presently disclosed corrosion-resistant metal component coating comprising chromium (VI), cold-reduced by 23% to 24%, and exposed to the salt spray environment for up to 120 hours.
- chromium VI
- FIG. 12b is a photograph of the bottom view of finished formed studs, having a zinc or zinc-alloy surface, coated with a solution of the presently disclosed corrosion- resistant metal component coating comprising chromium (VI), cold-reduced by 23% to 24%, and exposed to the salt spray environment for up to 120 hours.
- a solution of the presently disclosed corrosion- resistant metal component coating comprising chromium (VI), cold-reduced by 23% to 24%, and exposed to the salt spray environment for up to 120 hours.
- FIG. 13 shows scanning Electron Microscope (SEM) images of the interaction between the presently disclosed corrosion-resistant metal component coating and a zinc or zinc-alloy coated metal substrate surface.
- FIG. 14 is a photograph of a metal substrate, having a zinc or zinc-alloy surface, coated with a solution of the presently disclosed corrosion-resistant metal component coating, having water-repellant properties.
- a process for making a corrosion-resistant coating for zinc or zinc-alloy coated substrates and a process for making a corrosion-resistant metal component. Also disclosed is a corrosion-resistant metal component having a corrosion- resistant coating providing chemical resistance.
- the corrosion-resistant coating mixture provides chemical resistance for at least 150 hours in accordance with ASTM B117 standards for a metal substrate having a zinc or zinc-alloy coating weight of 0.04 oz/ft 2 (12.20 g/m 2 ).
- the coating mixture provides corrosion resistance for varying periods of time depending on the coating weight of the zinc or zinc- alloy surface of the metal substrate and the coating weight of the corrosion-resistant coating applied to the zinc or zinc-alloy surface of the metal substrate.
- the phosphate coating component may be a phosphate composition including, for example, phosphoric acid to react with the zinc or zinc-alloy surface of the metal substrate.
- the metric of chemical resistance for at least 150 hours in accordance with ASTM B117 standards for metal substrate having a zinc or zinc-alloy surface with a coating weight of 0.04 oz/ft 2 (12.20g/m 2 ) is a benchmark which provides the effectiveness of the presently disclosed corrosion-resistant coating and process for making a corrosion-resistant component, and it is not a limitation to a particular zinc or zinc-alloy coating weight on a metal substrate.
- the present process includes a corrosion-resistant coating mixture providing chemical resistance to a metal substrate having a zinc or zinc-alloy surface for at least 75 hours in accordance with ASTM B117 standards where the metal substrate having a zinc or zinc-alloy surface with a coating weight of 0.02 oz/ft 2 (6.10 g/m 2 ).
- the ASTM B117 standard is a widely used standardized salt spray environment cabinet test. Such a salt spray test is used to evaluate the relative corrosive, or chemical, resistance of coated and uncoated materials exposed to a salt spray fog, of 1-2 ml/hr, at an elevated temperature of 95 °F (35 °C).
- the ASTM B117 standard specifies that specimens are to be placed within an enclosed salt spray cabinet or chamber and subjected to continuous indirect spray of neutral (pH 6.5-7.2) salt water solution. Such a climate may be constantly maintained throughout the salt spray test period.
- the water used in the salt spray test is compliant with ASTM D1193 Specification for Reagent Water, Type VI.
- a salt usually sodium chloride, is added to the water to achieve a solution comprising 5% salt solution.
- ASTM B117 the default position for the specimens within the salt spray chamber is at an angle of 15-30 degrees from the vertical, positioned such that condensation from one specimen will not drip onto another specimen.
- Metal substrates having a zinc or zinc-alloy surfaces were coated with the presently disclosed corrosion-resistant metal component coating by the presently disclosed process for making a corrosion-resistant metal component coating comprising the steps of: combining at least one zinc phosphate forming compound and at least one chromium forming compound with water to form a first solution; separately combining at least one silicate compound with water to form a second solution; combining the first solution with the second solution such as to form a coating mixture; and, applying the coating mixture to a metal substrate with a zinc or zinc-alloy surface to form a coating on the metal substrate that reacts with the zinc or zinc-alloy forming a covalent bond with the zinc or zinc-alloy surface to provide a metal substrate with a corrosion-resistant coating mixture providing chemical resistance for at least 150 hours in accordance with ASTM B117 standards for a zinc or zinc- alloy coating weight of 0.04 oz/ft 2 (12.20 g/m 2 ).
- the at least one silicate compound may comprise a potassium silicate compound.
- the first solution and the second solution may be combined to form a mixed aqueous solution.
- the mixed aqueous solution may be further combined with at least one acrylic resin to form a coating mixture to be applied to a metal substrate having a zinc or zinc-alloy surface forming a coating on the metal substrate that reacts with the zinc or zinc-alloy forming a covalent bond with the zinc or zinc-alloy surface of the metal substrate to provide a corrosion-resistant coating providing chemical resistance for at least 150 hours in accordance with ASTM B117 standards for a zinc or zinc-alloy coating weight of 0.04 oz/ft 2 (12.20 g/m 2 ).
- a process for making a corrosion-resistant metal component comprising the step of applying a corrosion-resistant coating to a metal substrate having a zinc or zinc-alloy surface to provide a metal component having a corrosion- resistant coating providing a chemical resistance of more than 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy coating of the metal substrate has a weight of 0.04oz/ft 2 (12.20 g/m 2 ), the corrosion-resistant coating comprising a mixed aqueous solution, the mixed aqueous solution comprising a first solution and a second solution, the first solution comprising water, at least one zinc phosphate forming compound and at least one chromium forming compound, the second solution comprising at least one silicate compound and water.
- the corrosion-resistant coating may further comprise at least one acrylic resin.
- a corrosion-resistant metal component comprising a metal component having a zinc or zinc-alloy coating; and a corrosion-resistant coating with chemical resistance for more than 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy coating of the metal substrate has a weight of 0.04 oz/ft 2 (12.20 g/m 2 ), wherein the corrosion- resistant coating comprises a first solution and a second solution, wherein the first solution comprises water, at least one zinc phosphate forming compound and at least one chromium forming compound; and wherein the second solution comprises at least one silicate compound and water.
- the corrosion- resistant coating may further comprise at least one acrylic resin.
- the first solution may comprise between 4 percent and 27 percent by weight of the at least one zinc phosphate forming compound; between 5 percent and 27 percent by weight of chromium forming compound; and balance water. In another embodiment, the first solution may comprise between 5 percent and 27 percent by weight of the at least one zinc phosphate forming compound; between 5 percent and 27 percent by weight of chromium forming compound; and balance water.
- the second solution may comprise between 10 percent and 50 percent by weight of at least one silicate compound and balance water.
- the corrosion-resistant metal component coating may comprise between 20 percent and 95 percent by weight of the first solution; between 5 percent and 12 percent by weight of the second solution; between 5 percent and 30 percent by weight of acrylic resin; and balance water. As used in this disclosure, a range specified as between two end points is inclusive of the end points specified.
- the first solution may be combined with the second solution to form a mixed aqueous solution.
- the mixed aqueous solution may be combined with a least one acrylic resin.
- the mixed aqueous solution may not include the acrylic resin.
- the at least one acrylic resin may have a pH value of no greater than 3.5.
- the corrosion-resistant metal component coating mixture may have a pH value equal to or below 2.5.
- the coating mixture may have a pH value between 1.0 and 2.5, inclusive.
- the acrylic resin may be mixed into the aqueous solution in parts adding a first part of the acrylic resin into the aqueous solution and completing the mixing of the acrylic resin into the aqueous solution.
- the aqueous solution with the first part of acrylic resin may be mixed for a period of time, for example 20 minutes, before a second part of acrylic resin is mixed into the aqueous solution. This process may be repeated until all of the desired amount of acrylic resin is mixed into the aqueous solution. Further, after all of the desired amount of acrylic resin has been mixed into the aqueous solution, the solution may be mixed for a further period of time so that the solution may have an even consistency, making it easier to transport.
- the corrosion-resistant metal component coating may comprise at least one chromium forming compound.
- the chromium forming compound may comprise of a trivalent chromium forming compound.
- the trivalent chromium forming compound may be selected from the group consisting of chromium chloride hydrate, chromium (III) potassium sulfate, chromium hydroxide, chromium (III) fluoride, chromium (III) sulfate, chromium (III) sulfide, chromium (III) oxide, chromium (III) 2-ethylhexanoate, chromium (III) nitride, chromium tricarbonyl and mixtures thereof.
- the chromium forming compound may comprise of a hexavalent chromium forming compound.
- the hexavalent chromium forming compound may be selected from the group consisting of chromium (VI) halides, hexafluoride, chromyl chloride, sodium chromate, chromium (VI) peroxide, sodium chromate, chromium (VI) oxide, dichromate, potassium chromate, calcium chromate, barium chromate, chromium (VI) oxide peroxide, and mixtures thereof.
- the corrosion-resistant metal component coating may be applied to a metal component having a zinc or zinc-alloy surface in a number of processes.
- the coating may be applied through immersion, such that the metal component having a zinc or zinc-alloy surface is immersed into a bath of the presently disclosed corrosion-resistant coating, or the corrosion-resistant coating may be sprayed onto the zinc or zinc-alloy surface of the metal component, with or without the aid of electrolysis.
- the presently disclosed corrosion-resistant metal component coating may be applied in a dry-in- place process, as shown in FIG. 1.
- a coil 8 comprising metal strip component 10 may be provided.
- the metal component strip 10 having a zinc or zinc-alloy surface 11 is uncoiled from coil 8, and the metal strip component 10 may be transported through the dry-in-place process by a series of strip transfer rolls 16.
- the metal strip component 10 passed through an alkaline cleaner 14, where mill surface oils, which may interfere with the reaction between the zinc or zinc-alloy surface 11 of the metal strip component 10 and the presently disclosed corrosion-resistant coating, are removed from the surface of the metal strip component 10 in preparation for receiving the corrosion-resistant coating.
- the metal strip 10 is then passed, via strip transfer rolls 16 through rinses 15a and 15b, neutralizing the pH level of the zinc or zinc-alloy surface 11 of the metal strip 10 after having been passed through the alkaline cleaner 14.
- the metal strip 10 proceeds via strip transfer rolls 16 through the coater 21.
- the coater 21 applies the corrosion-resistant metal component coating 20 to the metal strip 10 using reverse-roll coating application method.
- the coating rolls 12 rotate such that the direction of rotation of the coating rolls opposes the direction of travel of the metal strip 10 proceeding through the coater 21.
- Corrosion-resistant metal component coating 20 is held in the coating trays 19 and is picked up from the coating trays 19 by pick-up rolls 18.
- the pick-up rolls 18 and the coating rolls 12 rotate at different velocities, allowing corrosion-resistant metal component coating 20 to be transferred from the pick-up rolls 18 to the coating rolls 12.
- the speed differential between the coating rolls 12 and the pick-up rolls 18 controls the thickness (coating weight) of the corrosion-resistant metal component coating 20 as it is applied to the strip 10 having a zinc or zinc-alloy surface
- the rolls 12 may be adapted to coat only one surface 11 of the metal strip component 10, alternatively, as shown in FIG. 1, the rolls 12 may be adapted such that two or more sides of the metal component 10 may be coated simultaneously.
- the corrosion-resistant metal component coating may be provided to the rolls 12 through passageways [not shown] in the center of the rolls 12, the passageways having ports 14 allowing the corrosion-resistant coating 15 to travel outward toward the surface of the rolls
- the corrosion-resistant coating 15 may be applied to the surface of the rolls 12 directly, via an applicator, or sprayed onto the rolls 12.
- a reaction may occur between the zinc or zinc-alloy surface 11 and the corrosion-resistant coating 20.
- the process for making a corrosion-resistant metal component may further comprise the step of heating the coated metal substrate 10 to further the reaction between the applied coating mixture 20 and the zinc or zinc-alloy surface 11 of the metal substrate 10.
- Such heating may be provided by a heating apparatus 17, where the metal substrate 10 is passed, via transfer rolls 16, through the heating apparatus 17 to finalize the reaction.
- the heating apparatus 17 may be an infrared heating apparatus capable of heating the surface 11 of the metal component 10.
- the heating apparatus 17 may heat the surface 11 of the metal component 10 to a temperature of between 170 °F - 210 °F. In other embodiments, the heating apparatus 17 may heat the surface 11 of the metal component 10 to a higher temperature as desired of up to approximately 700 °F.
- the metal strip component 10 may be passed through the coating applicator rolls 12 and the heating apparatus 17 at a speed of approximately 600 ft/min (3.06 m/s). Finally, the coated metal strip component 10 may be re-coiled into coil 9, for later transportation.
- the metal strip component 10 having a zinc or zinc-alloy coating, coated with the corrosion-resistant coating 20 will have comparable electrical conductivity to metal strip 10 having a zinc or zinc-alloy coating, without the corrosion-resistant coating 20. Therefore, the coated galvanize metal substrate provides comparable weldability characteristics as the non- coated galvanized metal substrates.
- the metal strip component 10 may be subsequently heated to temperatures of at least 700 °F and maintain the corrosion-resistance necessary to satisfy ASTM A-1004/A- 1004M-99 and ASTM A-1003/A-1003M-05 testing standards for galvannealed metal substrates 10, or equivalent standards for other forms of galvanized metal substrates 10, including galvalumed® metal substrates.
- ASTM A-1004/A-1004M-99 and ASTM A- 1003/A-1003M-05 testing standards are incorporated herein by reference.
- ASTM A-1004/A-1004M-99 and ASTM A-1003/ A- 1003M-05 All corrosion testing practices were performed in compliance with ASTM A-1004/A-1004M-99 and ASTM A-1003/ A- 1003M-05. While ASTM A-1004/A-1004M-99 and ASTM A-1003/ A-1003M-05 are directed to galvennealed panels, one of ordinary skill in the art will understand that the testing under ASTM A-1004/A-1004M-99 and ASTM A-1003/ A-1003M-05 is a benchmark, and will appreciate that the presently disclosed corrosion-resistant metal component coating may be applied to all forms of galvanized metal substrate, including, but not limited to, hot-dipped galvanized, galvannealed, electrogalvanized, and galvalume, and meet or exceed the associated ASTM standards.
- the zinc or zinc-alloy surface is selected from the group consisting of zinc, zinc alloy, zinc-aluminum alloy, zinc-iron alloy, zinc-aluminum- magnesium alloy and combination thereof.
- ASTM A-1003/A-1003M-05 the expected corrosion characteristic for metallic coated sheet steels with nonstructural or non- load-bearing applications is a minimum of 75 hours with less than 10% loss of metallic coating from the surface of the laboratory test samples. The loss of metallic coating from the surface of the laboratory test samples was determined by measuring the percent of red corrosion present after specific times of exposure to the salt spray environment according to ASTM B117.
- FIG. 2 shows two HDG G-60 (NCT) panels that have been exposed to the salt spray environment according to ASTM B117 for a period of 120 hours.
- NCT HDG G-60
- galvannealed metal sheets were exposed to a salt fog environment meeting the requirements of ASTM B117 for periods of 312 hours, 504 hours, 744 hours, and 1008 hours.
- the uncoated HDG G-60 (NCT) metal substrate panels showed extensive visible corrosion after 120 hours of exposure to salt spray, presenting red corrosion over 50% of the surface area of the metal substrate panels after 120 hours of exposure to the salt spray environment.
- FIG. 1 shows two HDG G-60 (NCT) panels that have been exposed to the salt spray environment according to ASTM B117 for a period of 120 hours.
- FIG. 3 shows four galvannealed panels coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (VI) compounds after being exposed to the salt spray environment for 312 hours, 504 hours, 744 hours and 1008 hours.
- the galvannealed panels coated with the presently disclosed corrosion-resistant metal component coating do not show any visible red corrosion after being exposed to the salt spray environment for 1008 hours.
- Zero percent (0%) of the surface area of all four galvannealed panels coated with the presently disclosed corrosion-resistant coating presented red corrosion after 1008 hours of exposure to the salt spray environment.
- Galvannealed panels coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (VI) compounds, without the optional acrylic resin, from different production runs were also exposed to the salt fog environment meeting the requirements of ASTM B117 for periods of 312 hours, 504 hours, 744 hours, and 1008 hours.
- Table 1 provides a summary of the percent of surface area of the panels affected by red corrosion for galvannealed panels coated with the presently disclosed corrosion- resistant coating after being exposed to a salt fog environment. All galvannealed panels coated with the corrosion-resistant coating showed zero percent (0%) of surface area affected by red corrosion for up to 1008 hours of exposure to the salt spray environment.
- HDG G-60 (NCT) metal substrate panels showed red corrosion over 50% of their surface area after just 120 hours of exposure to the salt spray environment.
- FIG. 5 shows five galvannealed panels coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (VI) compounds and acrylic resin after being exposed to salt spray for up to 1512 hours.
- VI chromium
- none of the galvannealed panels coated with the presently disclosed corrosion-resistant metal component coating comprising acrylic resin showed any visible appearance of red corrosion after being exposed to salt spray for up to 1512 hours.
- Zero percent (0%) of the surface area of the galvannealed panels coated with the presently disclosed corrosion-resistant coating showed signs of red corrosion.
- Coating galvannealed metal sheets with the presently disclosed corrosion-resistant metal component coating showed no indication of corrosion when exposed to over 1512 hours of the salt spray environment.
- the presently disclosed corrosion-resistant metal component coating comprising chromium (III) or chromium (VI) compounds may also be applied to metal substrates, having a zinc or zinc-alloy surface, that are to be cold- reduced and provide enhanced corrosion protection after the reducing process.
- the zinc or zinc-alloy coated panels were reduced and exposed to a salt fog environment meeting the standards of ASTM B117. Referring to FIG.
- metal panels, having a zinc or zinc-alloy surface were coated with the presently disclosed corrosion-resistant coating comprising acrylic resin, cold-reduced by 15% to 23%, and were exposed to a salt fog for periods of 48 hours, 75 hours, 96 hours, 120 hours, and 144 hours.
- the HDG G-40 (NCT) metal substrate panels showed visual corrosion after 75 hours of exposure to the salt spray environment. Red corrosion became more visible as the exposure to the salt spray environment increased.
- the standard HDG G-40 (NCT) metal substrate panels showed 1%, 25%, 50%, and 75% of surface area affected by red corrosion after 72 hours, 96 hours, 120 hours, and 144 hours of exposure to the salt spray environment, respectively.
- metal panels having a zinc or zinc- alloy surface, which have been coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (III) compounds and acrylic resin and then cold- reduced by 15% to 23%.
- the coated galvanized panels were then subjected to 48 hours, 75 hours, 96 hours, 120 hours, and 144 hours of salt spray testing. Zero percent (0%) of the surface area of the cold-reduced coated galvanized panels were affected by red corrosion.
- Table 2 provides a summary of tests performed, showing the percent of red corrosion for zinc-alloy coated panels coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (III) compounds and acrylic resin, having been cold-reduced after coating by 15% to 23% and exposed to a salt fog environment meeting the requirements of ASTM B117, for periods of 48 hours, 75 hours, 96 hours, 120 hours, and 144 hours. All zinc-alloy coated panels, coated with the presently disclosed corrosion-resistant metal component coating, and reduced after coating by 15% to 23%, showed zero percent (0%) surface area of the panels affected by red corrosion after being exposed to salt spray for up to 120 hours.
- the panels, having a zinc or zinc-alloy surface, coated with the presently disclosed corrosion-resistant metal component coating, and cold- reduced after coating by 15% to 23% exceeded the ASTM A-1003/A-1003M standards by presenting less than three percent (3%) of red corrosion after 144 hours of exposure to the salt spray environment.
- the zinc-alloy coated panels coated with the presently disclosed corrosion-resistant metal component coating, and cold-reduced by 15% to 23% showed complete resistance to corrosion for up to 120 hours of salt spray, and red rust over less than 3% of the surface area at 144 hours salt spray compared to red corrosion over 75% of the surface area of the HDG G-40 (NCT) panels after 144 hours of exposure to the salt spray environment.
- FIGS. 8a-b zinc or zinc-alloy coated panels were cold-reduced by 16% to 23% after being coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (VI) compounds and acrylic resin.
- Uncoated zinc or zinc-alloy coated panels were exposed to a salt fog environment meeting the requirements of ASTM B117 for periods of 48 hours, 75 hours, 96 hours, and 120 hours.
- the HDG G-40 (NCT) metal substrate panels showed visual corrosion after 48 hours of exposure to the salt spray environment. Red corrosion became more visible as the exposure to the salt spray environment increased.
- FIG. 8a shows the top view of zinc-alloy coated metal panels coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (VI) compounds and cold-reduced after coating by 16% to 23% and then exposed to salt spray for 48 hours, 75 hours, 96 hours, and 120 hours.
- FIG. 8a shows the top view of zinc-alloy coated metal panels coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (VI) compounds and cold-reduced after coating by 16% to 23% and then exposed to salt spray for 48 hours, 75 hours, 96 hours, and 120 hours.
- VI chromium
- Zinc-alloy panels coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (VI) compounds and cold-reduced after coating by 16% to 23% from different production runs were exposed to the salt fog environment.
- Table 3 provides a summary of the percent of surface area affected by red corrosion for zinc- alloy coated panels coated with the presently disclosed corrosion-resistant metal component coating, and cold-reduced after coating by 16% to 23% and exposed to the salt fog environment meeting the requirements of ASTM B117, for periods of 48 hours, 75 hours, 96 hours, and 120 hours. All zinc-alloy panels that were coated with the presently disclosed corrosion-resistant metal component coating, and were cold-reduced after coating by 16% to 23% showed zero percent (0%) of surface area affected by red corrosion.
- FIGS. 9a-b show finished formed studs, having a zinc-alloy surface, coated with the presently disclosed corrosion- resistant metal component coating comprising chromium (VI) compounds and cold-reduced after coating by 16% to 23% were exposed to a salt fog environment meeting the requirements of ASTM B117 for periods of 75 hours, 96 hours, and 120 hours.
- the top part of the finished formed studs, having a zinc- alloy surface, coated with the presently disclosed corrosion-resistant metal component coating, and cold-reduced after coating by 16% to 23% showed zero percent (0%) of surface area affected by red corrosion after being exposed to the salt spray environment for 75 hours, 96 hours, and 120 hours.
- FIG. 9a show finished formed studs, having a zinc-alloy surface, coated with the presently disclosed corrosion- resistant metal component coating comprising chromium (VI) compounds and cold-reduced after coating by 16% to 23% were exposed to a salt fog environment meeting the requirements of ASTM B117 for periods of 75 hours, 96 hours
- 9b shows the bottom part of the finished formed studs, having a zinc-alloy surface, coated with the presently disclosed corrosion- resistant metal component coating comprising chromium (VI) compounds and cold-reduced after coating by 16% to 23%.
- chromium (VI) compounds chromium compounds
- FIGS. 10 through 12 illustrate metal substrates having a zinc or zinc-alloy surface, coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (III) or chromium (VI) compounds, cold-reduced by 23% to 24% after coating and subject to the salt spray testing environment.
- the presently disclosed corrosion-resistant metal component coating comprising chromium (III) or chromium (VI) compounds, cold-reduced by 23% to 24% after coating and subject to the salt spray testing environment.
- HDG G-40 (NCT) finished formed studs having been subjected to the salt spray testing environment for up to 120 hours.
- the HDG G-40 (NCT) finished formed studs showed visual corrosion after 96 hours of exposure to the salt spray environment.
- the HDG G-40 (NCT) finished formed studs presented 5% and 25% of red corrosion after 96 hours and 120 hours of salt spray environment exposure, respectively.
- finished formed studs made with zinc-alloy coated metal substrate coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (III) compounds and cold-reduced by 23% to 24% after coating have enhanced corrosion resistance.
- both top and bottom views of the finished formed studs, having a zinc-alloy surface, coated with the presently disclosed corrosion-resistant metal component coating presented zero percent (0%) of surface area affected by red corrosion after being exposed to salt spray for 75 hours, 96 hours, and 120 hours.
- FIGS. 12a-b illustrate finished formed studs, having a zinc-alloy surface, coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (VI) compounds, cold-reduced by 23% to 24% after coating, and exposed to the salt fog environment meeting the requirements of ASTM B117, for periods of 75 hours, 96 hours, and 120 hours. As illustrated in FIGS.
- the effectiveness of the presently disclosed corrosion-resistant metal component coating comprising chromium (III) or chromium (VI) compounds to protect galvanized metal substrates, such as hot-dip galvanized metal substrates or galvannealed metal substrates, from corrosion is dependent upon the thickness of the zinc or zinc-alloy coating and the thickness of the presently disclosed corrosion-resistant metal component coating.
- Table 4 provides a summary of the number hours achieved under the salt spray testing environment with less than ten percent (10%) of weight loss for HDG G-30 metal substrates coated with the presently disclosed corrosion-resistant metal component coating.
- the effectiveness of the presently disclosed corrosion-resistant metal component coating comprising chromium (III) or chromium (VI) compounds to protect galvannealed metal substrates from corrosion is dependent upon the coating thickness of the presently disclosed corrosion-resistant metal component coating.
- Table 5 provides a summary of the number of hours of salt spray testing achieved with less than ten percent (10%) of weight loss after exposing galvannealed A-25 or A-40 metal substrates coated with the presently disclosed corrosion- resistant metal component coating comprising chromium (III) or chromium (VI) compounds to a salt fog environment meeting the requirements of ASTM B117.
- the application of the presently disclosed corrosion-resistant metal component coating comprising chromium (III) or chromium (VI) compounds, to the metal substrates having a zinc or zinc-alloy surface, significantly enhances the ability of the metal substrate to resist corrosion.
- the presently disclosed corrosion-resistant metal component coating interacts with the zinc or zinc-alloy coated metal substrate.
- the Scanning Electron Microscope (SEM) images in FIG. 13 show the reaction between the presently disclosed corrosion-resistant metal component coating and the zinc or zinc-alloy surface of the metal substrate. Such a reaction forms a covalent bond, as defined herein between the presently disclosed corrosion-resistant coating and the zinc or zinc-alloy surface.
- the SEM images show the imperfections (i.e. fractures and/or porosity) that exist in zinc or zinc-alloy surface.
- the coating mixture may penetrate down into any deep cracks and voids in the zinc coating.
- the reaction between the corrosion-resistant metal component coating and the zinc or zinc-alloy surface of the metal substrate may seal off exterior corrosion sources and protect the zinc layer as well as the carbon steel base metal.
- the coating mixture may be applied by rolling the coating mixture onto the metal component surface. This direct mode of application may decrease the amount of residual coating mixture.
- the coating mixture may be applied by spraying the coating mixture onto the metal component surface, or alternatively, the coating mixture may be applied by submersing at least a portion of the metal substrate with a zinc or zinc-alloy surface into a bath of the presently disclosed corrosion-resistant metal component coating.
- the metal substrates having a zinc or zinc-alloy surface and coated with the presently disclosed corrosion-resistant metal component coating comprising chromium (III) or chromium (VI) compounds may be water-repellant.
- Water- repellency provides extra protection for the zinc or zinc-alloy substrate against corrosion.
- newly exposed zinc reacts with oxygen to form a very thin zinc oxide layer.
- zinc reacts with water resulting in the formation of zinc hydroxide, when dry, this becomes zinc oxide.
- Zinc oxide prevents paint from adhering to the metal as well as accelerates further corrosion of the metal which is unsightly to any galvanized coating's appearance.
- pure water contains essentially no dissolved minerals and the zinc will react quickly with pure water to form zinc hydroxide, a bulky white and relatively unstable oxide of inc.
- pure water e.g., rain, dew or condensation, etc.
- the water may continue to react with the zinc and progressively consume the zinc or zinc-alloy coating.
- the presently disclosed corrosion-resistant coating may be self-healing.
- the coating protecting a metal substrate from corrosion may protect the metal substrate even if the metal substrate is cut, scratched or abraded.
- a metal substrate may become scratched when being cold-rolled using rollers which have surface defects imparting scratches onto the surface of the molten metal. Scratching of the metal substrate may remove the corrosion-resistant coating from that portion, exposing the metal substrate. It is desirable that a corrosion-resistant coating will protect the exposed portion of the metal substrate.
- One such method of protection is to provide sufficient corrosion-resistant coating material that part of the coating may remain non-reacted with the zinc or zinc-alloy surface. The non- reacted coating may then react with the scratched, exposed, portion of the metal substrate forming a protective coating over it.
- the corrosion- resistant coating is self-healing.
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Abstract
L'invention concerne un procédé de fabrication d'un constituant métallique résistant à la corrosion. Le procédé ayant les étapes consistant : à combiner de l'eau, au moins un composé formant du phosphate de zinc et au moins un composé formant du chrome, étant des composés de chrome (III) ou de chrome (IV), pour former une première solution; la combinaison séparément d'au moins un composé de silicate avec de l'eau pour former une seconde solution; à combiner la première solution avec la deuxième solution de manière à former une solution aqueuse mixte; à éventuellement combiner la solution aqueuse mixte avec au moins une résine acrylique pour former un mélange de revêtement; et, à appliquer le mélange de revêtement à la surface en zinc ou alliage de zinc du substrat métallique formant une liaison covalente avec la surface en zinc ou alliage de zinc, et le revêtement procurant une résistance chimique pendant au moins 150 heures conformément à la norme ASTM B117 où le revêtement de zinc ou d'alliage de zinc du substrat métallique a un poids de 0,04 oz/ft2 (12,20g/m2).
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US14/553,864 US20150176135A1 (en) | 2011-11-28 | 2014-11-25 | Dry-in-place corrosion-resistant coating for zinc or zinc-alloy coated substrates |
US14/553,864 | 2014-11-25 |
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WO2016085799A1 true WO2016085799A1 (fr) | 2016-06-02 |
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PCT/US2015/061813 WO2016085799A1 (fr) | 2014-11-25 | 2015-11-20 | Revêtement résistant à la corrosion à séchage sur site pour substrats revêtus de zinc ou d'alliage de zinc |
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US20100151257A1 (en) * | 2008-01-24 | 2010-06-17 | Yuken Industry Co., Ltd. | Member Having an Anticorrosive Coating, Method of Manufacturing the Member, and Paint Composition for Manufacturing the Member |
US20130136947A1 (en) * | 2011-11-28 | 2013-05-30 | Eco-Green Coatings, L.L.C. | Dry-in-place corrosion-resistant coating for zinc or zinc-alloy coated substrates |
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US20100151257A1 (en) * | 2008-01-24 | 2010-06-17 | Yuken Industry Co., Ltd. | Member Having an Anticorrosive Coating, Method of Manufacturing the Member, and Paint Composition for Manufacturing the Member |
US20130136947A1 (en) * | 2011-11-28 | 2013-05-30 | Eco-Green Coatings, L.L.C. | Dry-in-place corrosion-resistant coating for zinc or zinc-alloy coated substrates |
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