METHODS FOR MAKING COATED THREADED METALLIC

• US 20120168317A1
• Filed: 12/23/2011
• Published: 07/05/2012
• Est. Priority Date: 12/27/2010
• Status: Abandoned Application

• Current Assignee: Fontana Fasteners R.D. S.R.L.
• Original Assignee: Fontana Fasteners R.D. S.R.L.
• Inventors: FONTANA, Luigi, GRASSI, Carlo
• Application Number:
  US13/336,341
• Publication Number:
  US 20120168317A1
• Time in Patent Office: Days
• US Class Current: 205/194
• CPC Class Codes: B05D 1/18 performed by dipping
• CPC Class Codes: B05D 2350/65 metal layer
• CPC Class Codes: B05D 7/14 to metal, e.g. car bodies involving a chemical reaction between the metal and the coating C23
• CPC Class Codes: B05D 7/586 each layer being cured, at least partially, separately
• CPC Class Codes: C25D 17/002 Cell separation, e.g. membranes, diaphragms
• CPC Class Codes: C25D 17/008 Current shielding devices
• CPC Class Codes: C25D 3/565 containing more than 50% by weight of zinc
• CPC Class Codes: C25D 5/48 After-treatment of electroplated surfaces

Abstract

Methods for coating threaded metallic pieces which include using a threaded metallic piece as a cathode of an electrolytic cell in a bath which includes Zn ion and whereby electro-deposition of a first layer containing Zn takes place followed by deposition of a second layer of a polyester-based paint are provided. Such processes are especially useful for components of the automobile industry, such as wheel screws.

Claims

1. A method for coating a threaded metallic piece, comprising:

providing a bath which comprises Zn ions,

introducing the metallic piece into the bath, wherein the metallic piece acts as a cathode of an electrolytic cell and wherein electro-deposition of a first layer comprising Zn is brought about on the surface of the metallic piece, and

applying on the piece coated by the first layer a second layer of a polyester-based paint.

2. The method of claim 1, wherein the electrolytic cell comprises membranes screening the electrodes.

3. The method of claim 1, wherein the bath further comprises Ni ions and wherein the first layer comprises Zn and Ni.

4. The method of claim 1, wherein the metallic piece is subjected to treatments of degreasing and/or pickling prior to the electro-deposition.

5. The method of claim 1, wherein the metallic piece is subjected to a treatment of passivation after the electro-deposition and prior to the application of the second layer of paint.

6. The method of claim 1, wherein the second layer of paint is applied in two coats.

7. The method of claim 6, wherein the application of each coat of paint comprises immersing the metallic piece in a bath of paint, centrifuging and baking.

8. The method of claim 1, wherein the metallic piece is a wheel screw.

9. The method of claim 1, wherein the first layer has a thickness between about 8 and about 12 μ

m, and the second layer has a thickness between about 11 and about 14 μ

m.

10. The method of claim 1, wherein the paint comprises a black pigment.