Zn-based composite-plated metallic material and plating method
AssigneeNihon Parkerizing Co., Ltd.
InventorsKazuhiko Mori, Toshi Miyawaki
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Abstract
Disclosed is a Zn-based composite-plated metallic material, comprising a plating layer on a metal substrate. The plating layer consists essentially of (1) Zn or as Zn alloy electroplated onto a metallic substrate and (2) the cathodic precipitation reaction product of aluminum, calcium, magnesium, strontium, titanium, zirconium, molybdenum, and/or tungsten. The latter metal constitutes 0.002 to 10% by weight of the plating layer. The cathodic precipitation-reaction product may be hydroxide, hydroxide hydrate or a phosphate.
Claims14
A method for plating a Zn-based composite-plated metallic material on a metallic substrate, comprising:
- preparing a plating solution containing Zn ions and titanium ions which are only in the form of tetravalent Ti.sup.4+ and an oxidizer selected from the group consisting of hydrogen peroxide, oxyacid of nitrogen and oxyacid of halogen;
- bringing said metallic material as a cathode into contact with said plating solution;
- adjusting the pH of said plating solution to such a value that the tetravalent Ti.sup.4+ is maintained dissolved in the body of the plating solution;
- raising pH in the vicinity of the cathode in the presence of said oxidizer;
- precipitating said tetravalent Ti.sup.4+ ions in said vicinity of said cathode;
- and,
- electrodepositing a plating layer which consists essentially of Zn or Zn alloy and a hydroxide, hydroxide hydrate or phosphate of titanium.
A method for plating a Zn-based composite-plated metallic material on a metallic material substrate, comprising:
- preparing a plating solution containing Zn ions, aluminum ions which are only in the form of trivalent Al.sup.3+, and an oxidizer selected from the group consisting of hydrogen peroxide, oxyacid of nitrogen and oxyacid of halogen;
- bringing said metallic material as a cathode into contact with said plating solution;
- adjusting pH of said plating solution to such a value that the trivalent Al.sup.3+ is maintained dissolved in the body of the plating solution;
- raising pH in the vicinity of the cathode;
- precipitating said trivalent Al.sup.3+ ions in said vicinity of said cathode;
- and,
- electrodepositing a plating layer which consists essentially of Zn or Zn alloy and a hydroxide, hydroxide hydrate or phosphate of aluminum.
A method for plating a Zn-based composite-plated metallic material on a metallic material substrate, comprising:
- preparing a plating solution containing Zn ions, at least one element selected from the group consisting of Ca.sup.2+, Mg.sup.2+, Sr.sup.2+, Zr.sup.4+, Cr.sup.3+, Mo.sup.3+, and W.sup.6+ ions, and an oxidizer selected from the group consisting of a hydrogen peroxide, an oxyacid of nitrogen and an oxyacid of halogen;
- bringing said metallic material as a cathode into contact with said plating solution;
- adjusting pH of said plating solution to such a value that said ions are maintained dissolved in the body of the plating solution;
- precipitating ions of said at least one element in said vicinity of said cathode;
- and
- electrodepositing a plating layer which consists essentially of Zn or Zn alloy and a hydroxide, hydroxide hydrate or phosphate of said at least one element.
Dependencies are inferred from the claim text.