ELECTROPLATING METHOD FOR MAGNESIUM AND MAGNESIUM ALLOY

• US 20100025255A1
• Filed: 07/07/2009
• Published: 02/04/2010
• Est. Priority Date: 07/30/2008
• Status: Abandoned Application

• Current Assignee: FIH (Hong Kong) Limited (Hon Hai Precision Industry Co., Ltd.), Shenzhen Futaihong Precision Industrial Company Limited (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: FIH (Hong Kong) Limited (Hon Hai Precision Industry Co., Ltd.), Shenzhen Futaihong Precision Industrial Company Limited (Hon Hai Precision Industry Co., Ltd.)
• Inventors: QU, HONG-JUN, CHEN, CHENG-SHIN, WANG, REN-NING, SU, JONG-YI
• Application Number:
  US12/498,455
• Publication Number:
  US 20100025255A1
• Time in Patent Office: Days
• US Class Current: 205/176
• CPC Class Codes: C23C 18/1653 Two or more layers with at least one layer obtained by electroless plating and one layer obtained by electroplating
• CPC Class Codes: C23C 18/1844 with use of organic or inorganic compounds other than metals, first
• CPC Class Codes: C23C 18/36 using hypophosphites
• CPC Class Codes: C25D 3/06 from solutions of trivalent chromium
• CPC Class Codes: C25D 3/12 of nickel or cobalt
• CPC Class Codes: C25D 3/38 of copper
• CPC Class Codes: C25D 5/14 two or more layers being of nickel or chromium, e.g. duplex or triplex layers
• CPC Class Codes: C25D 5/42 of light metals
• CPC Class Codes: C25D 5/48 After-treatment of electroplated surfaces
• CPC Class Codes: C25D 5/627 Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance

Abstract

An electroplating method for magnesium and magnesium alloys, comprising: providing a magnesium or magnesium alloy substrate and pre-treating it to be cleaned; roughening the surface of the substrate; activating the surface of the substrate; chemically plating the substrate to form a nickel coating on its surface; and electroplating the substrate to form, in order, a first nickel coating, a copper coating, a second nickel coating, and a chromium coating on the chemically produced nickel coating.

Claims

1. An electroplating method for magnesium and magnesium alloys, comprising:

providing a magnesium or magnesium alloy substrate and pre-treating it to be cleaned;

roughening the surface of the substrate;

activating the surface of the substrate;

chemically plating the substrate to form a nickel coating on its surface; and

electroplating the substrate to form, in order, a first nickel coating, a copper coating, a second nickel coating, and a chromium coating on the chemically produced nickel coating.

2. The electroplating method as claimed in claim 1, wherein roughening the surface of the substrate is carried out by dipping the substrate in a roughening solution containing pyrophosphate in a mass concentration of about 350-450 g/L and sodium carbonate in a mass concentration of about 50-100 g/L for about 10-30 minutes at about 55-65°

C.

3. The electroplating method as claimed in claim 1, wherein activating the surface of the substrate is carried out by dipping the substrate in an activating solution containing hydrofluoric acid in a concentration by volume of about 150-300 ml/L for about 1-5 minutes at about 30-40°

C.

4. The electroplating method as claimed in claim 1, wherein chemically plating the substrate is carried out by immersing the substrate in a solution containing sodium hypophosphite in a mass concentration of about 10-30 g/L and basic nickel carbonate in a mass concentration of about 20-50 g/L for about 20-60 minutes at about 70-90°

C.

5. The electroplating method as claimed in claim 1, wherein electroplating the substrate to form the first nickel coating is carried out in a first electrolyte containing a nickel sulphate component in a mass concentration of about 240-300 g/L, a nickel chloride component in a mass concentration of about 30-50 g/L, and a boric acid component in a mass concentration of about 30-50 g/L at about 50-55°

C.;

the electric current density through the first electrolyte is about 1-4 A/dm²; and

the electroplating lasts for about 4-10 minutes.

6. The electroplating method as claimed in claim 1, wherein electroplating the substrate to form the copper coating is carried out in a second electrolyte containing a copper sulphate component in a mass concentration of about 180-220 g/L, and a sulfuric acid component in a mass concentration of about 40-80 g/L at about 20-25°

C.;

the electric current density through the second electrolyte is about 1-3 A/dm²; and

the electroplating lasts for about 5-30 minutes.

7. The electroplating method as claimed in claim 5, wherein electroplating the substrate to form the second nickel coating is carried out in substantially the same way as was the forming the first nickel coating.

8. The electroplating method as claimed in claim 1, wherein electroplating the substrate to form the chromium coating is carried out in a third electrolyte containing a chromium sulphate component in a mass concentration of about 240-300 g/L, and a boric acid component in a mass concentration of about 70-90 g/L at about 30-50°

C.;

the electric current density through the third electrolyte is about 1-15 A/dm²; and

the electroplating lasts for about 1-15 minutes.

9. The electroplating method as claimed in claim 8, wherein the substrate is subjected to neutralization treatment after the electroplating process in a neutralization solution including a sulfuric acid component in a concentration by volume of about 20-50 ml/L, and an oxydol component in a concentration by volume of about 50-100 ml/L for about 1-3 minutes at about 20-30°

C.

10. The electroplating method as claimed in claim 1, wherein pre-treating the substrate includes degreasing and cleaning the substrate.