Anodized coating over aluminum and aluminum alloy coated substrates
AssigneeHenkel AG & Co. KGaA
InventorShawn E. Dolan
Life of this patent
Estimating the term…
Abstract
Using aqueous electrolytes containing complex fluorides or oxyfluorides such as fluorozirconates and fluorotitanates, ferrous metal articles and non-metallic articles having a first coating containing aluminum may be rapidly anodized to form a second protective surface coating. White coatings may be formed on articles using pulsed direct current or alternating current.
Claims40
A method of forming an second protective coating on a surface of an article having a first protective coating comprising an aluminum or aluminum alloy coating, said method comprising:
- A) providing an anodizing solution comprised of water and one or more additional components selected from the group consisting of:
- a) water-soluble complex fluorides,
- b) water-soluble complex oxyfluorides,
- c) water-dispersible complex fluorides, and
- d) water-dispersible complex oxyfluorides of elements selected from the group consisting of Ti, Zr, Hf, Sn, Al, Ge and B and mixtures thereof;
- B) providing a cathode in contact with said anodizing solution;
- C) placing an article having a first protective coating comprising aluminum or aluminum alloy on at least one surface of the article as an anode in said anodizing solution;
- and
- D) passing a current between the anode and cathode through said anodizing solution for a time effective to form a second protective coating on the at least one surface having the first protective coating.
A method of forming a second protective coating on an article comprised predominantly of ferrous material and having a first protective coating comprising aluminum, said method comprising:
- A) providing an anodizing solution comprised of water and a water-soluble complex fluoride and/or oxyfluoride of an element selected from the group consisting of Ti, Zr, and combinations thereof;
- B) providing a cathode in contact with said anodizing solution;
- C) placing an article comprised predominantly of ferrous material and having a first protective coating comprising aluminum on at least one surface of the article as an anode in said anodizing solution;
- and
- D) passing a direct current or an alternating current between the anode and the cathode for a time effective to form a second protective coating on the at least one surface having the first protective coating.
A method of forming an second protective coating on a surface of an article having a first protective coating comprising an aluminum or aluminum alloy coating, said method comprising:
- A) providing an anodizing solution, said anodizing solution having been prepared by dissolving a water-soluble complex fluoride or oxyfluoride of an element selected from the group consisting of Ti, Zr, Hf, Sn, Ge, B and combinations thereof and an inorganic acid or salt thereof that contains fluorine but does not contain any of the elements Ti, Zr, Hf, Sn, Ge or B in water and said anodizing solution having a pH of from about 2 to about 6;
- B) providing a cathode in contact with said anodizing solution;
- C) placing an article having a first protective coating comprising an aluminum or aluminum alloy coating on at least one surface of the article as an anode in said anodizing solution;
- and
- D) passing a pulsed direct current or an alternating current between the anode and the cathode for a time effective to form a second protective coating on the at least one surface having the first protective coating.
A method of forming a white protective coating on a surface of an article having a first protective coating comprising aluminum, said method comprising:
- A) providing an anodizing solution, said anodizing solution having been prepared by combining a water-soluble complex fluoride of zirconium or salt thereof and an oxide, hydroxide, carbonate or alkoxide of zirconium in water and said anodizing solution having a pH of from about 3 to 5;
- B) providing a cathode in contact with said anodizing solution;
- C) placing an article having a first protective coating comprising aluminum on at least one surface of the article as an anode in said anodizing solution;
- and
- D) passing a pulsed direct current or an alternating current between the anode and the cathode for a time effective to form a white protective coating on the at least one surface having the first protective coating.
Dependencies are inferred from the claim text.