Light metal anodization
OwnerShawn E. Dolaninventor
Life of this patent
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Abstract
Using pulsed current and relatively low peak ceiling voltage, articles containing light metals such as magnesium may be rapidly anodized to form protective surface coatings. The anodizing solutions employed may contain phosphate, permanganate, silicate, zirconate, titanate and/or complex fluoride, optionally with other components present.
Claims51
A method of forming a protective coating on a surface of a light metal-containing article, said method comprising:
- A) providing an anodizing solution comprised of water and one or more additional components selected from one of the following:
- a) water-soluble or water-dispersible oxysalt containing at least one element selected from the group consisting of P, Si, Mn, Zr, Ti, V and Hf;
- or
- b) water-soluble or water-dispersible complex fluoride of an element selected from the group consisting of Ti, Zr, Hf, Si, Sn, Al, Ge and B;
- B) providing a cathode in contact with said anodizing solution;
- C) placing said light metal-containing article as an anode in said anodizing solution;
- and
- D) passing a pulsed current having a peak ceiling voltage of not more than 150 volts between the anode and cathode though said anodizing solution for a time effective to form said protective coating on said surface.
A method of forming a protective coating on a surface of a metallic article comprised of aluminum, magnesium or a mixture thereof, said method comprising:
- A) providing an anodizing solution comprised of water and a concentration of phosphorus atoms in the form of phosphate that is at least 0.3 M but essentially free of ammonia, chromium, permanganate, borate, sulfate, free fluoride and free chloride;
- B) providing a cathode in contact with said anodizing solution;
- C) placing said metallic article as an anode in said anodizing solution;
- and
- D) passing a pulsed direct current having a peak ceiling voltage of not more than 100 volts between the anode and the cathode for a time effective to generate a visible light-emitting discharge and form said protective coating on said surface.
A method of forming a protective coating on a surface of a metallic article comprised of aluminum, magnesium or a mixture thereof, said method comprising:
- A) providing an anodizing solution comprised of water and a water-soluble silicate;
- B) providing a cathode in contact with said anodizing solution;
- C) placing said metallic article as an anode in said anodizing solution;
- and
- D) passing a pulsed direct current having a maximum of no more than 50 volts between the anode and the cathode to generate a visible light-emitting discharge and to form said protective coating on said surface.
A method of forming a protective coating on a surface of a metallic article comprised of aluminum, magnesium or a mixture thereof, said method comprising:
- A) providing an anodizing solution comprised of water and a water-soluble complex fluoride of an element selected from the group consisting of Ti, Zr, Hf, Si, Sn, Al, Ge, B and combinations thereof;
- B) providing a cathode in contact with said anodizing solution;
- C) placing said metallic article as an anode in said anodizing solution;
- and
- D) passing a pulsed direct current having a peak ceiling voltage of not more than 100 volts between the anode and the cathode for a time effective to generate a visible light-emitting discharge and to form said protective coating on said surface.
A method of forming a protective coating on a surface of a metallic article comprised of aluminum, magnesium or a mixture thereof, said method comprising:
- A) providing an anodizing solution, said anodizing solution having been prepared by dissolving a water-soluble complex fluoride of an element selected from the group consisting of Ti, Zr, Hf, Si, 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, Si, Sn, Ge or B in water and said anodizing solution having a pH of from about 3 to about 11;
- B) providing a cathode in contact with said anodizing solution;
- C) placing said metallic article as an anode in said anodizing solution;
- and
- D) passing a pulsed direct current having a peak ceiling voltage of not more than 100 volts between the anode and the cathode for a time effective to generate a visible light-emitting discharge and form said protective coating on said surface.
A method of forming a protective coating on a surface of a metallic article comprised of aluminum, magnesium or a mixture thereof, said method comprising
- A) providing an anodizing solution comprised of water and a water-soluble permanganate;
- B) providing a cathode in contact with said anonizing solution;
- C) placing said metallic article as an anode in said anodizing solution;
- and
- D) passing a pulsed direct current having a peak ceiling voltage of not more than 125 volts between he anode and the cathode for a time effective to generate a visible light-emitting discharge and form said protective coating on said surface.
A method of forming a protective coating on a surface of a metallic article comprised of aluminum, magnesium or a mixture thereof, said method comprising
- A) providing an anodizing solution, said anodizing solution having been prepared by dissolving a water-soluble complex fluoride of zirconnium 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 said metallic article as an anode in said anodizing solution;
- and
- D) passing a pulsed direct current having a ceiling voltage of not more than 125 volts between the anode and the carbide for a time effective to generate a visible light-emitting discharge and form said protective coating on said surface.
Dependencies are inferred from the claim text.