Trivalent Chromium Electroplating Solution and an Operational Method Thereof

• US 20090211914A1
• Filed: 02/21/2008
• Published: 08/27/2009
• Est. Priority Date: 02/21/2008
• Status: Abandoned Application

• Current Assignee: Chang GUNG University
• Original Assignee: Chang GUNG University
• Inventors: Hsu, Chun-Ching, Liu, Yu-Wei, Huang, Ching-An, Chen, Chao-Yu
• Application Number:
  US12/034,721
• Publication Number:
  US 20090211914A1
• Time in Patent Office: Days
• US Class Current: 205/289
• CPC Class Codes: C25D 3/06 from solutions of trivalent chromium
• CPC Class Codes: C25D 3/56 of alloys
• CPC Class Codes: C25D 5/18 Electroplating using modulated, pulsed or reversing current
• CPC Class Codes: C25D 5/611 Smooth layers
• CPC Class Codes: C25D 5/627 Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance

Abstract

A trivalent chromium-based electroplating solution in accordance with the present invention a trivalent chromium salt, a bivalent nickel salt, a complex agent, a conductive salt, a buffering agent and an additive for electroplating a chromium-nickel alloy deposit on a component. By using the lowly toxic trivalent chromium to substitute highly toxic hexavalent chromium, an electroplating procedure with the present trivalent chromium-based electroplating solution has less pollution and high current efficiency to allow the electroplating performing at the room temperature.

Claims

1. A trivalent chromium electroplating solution comprising a water solution added with 0.1-1.2 mole/L of a trivalent chromium salt;

0.1-0.8 mole/L of a bivalent nickel salt;

0.1-4.0 mole/L of a complex agent;

1.0-3.0 mole/L of a conductive salt;

0.1-0.8 mole/L of a buffering agent; and

0.01-0.30 mole/L of an additive.

2. The trivalent chromium electroplating solution as claimed in claim 1, wherein the trivalent chromium salt selected from the group consisting of chromium chloride, chromium sulfate, or a hydrate of each forgoing salt.

3. The trivalent chromium electroplating solution as claimed in claim 1, wherein the bivalent nickel salt is selected from the group consisting of nickel chloride, nickel sulfate, or a hydrate of each forgoing salt.

4. The trivalent chromium electroplating solution as claimed in claim 1, wherein the complex agent is selected from the group consisting of urea (carbamide), glycine (aminoacetic acid), hydroxyacetic acid, formic acid or a dissoluble salt of each forgoing acid.

5. The trivalent chromium electroplating solution as claimed in claim 1, wherein the conductive salt is selected from the group consisting of ammonium chloride, sodium chloride, potassium chloride, magnesium chloride, ammonium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate or a mixture of forgoing salts.

6. The trivalent chromium electroplating solution as claimed in claim 1, wherein the buffering agent is selected from the group consisting of boric acid, aluminum chloride, aluminum sulfate or a mixture of foregoing components.

7. The trivalent chromium electroplating solution as claimed in claim 1, wherein the additive is selected from the group consisting of ammonium bromide, sodium bromide, potassium bromide or a mixture of foregoing components.

8. An electroplating procedure with a trivalent chromium-based electroplating solution comprising a water solution added with 0.1-1.2 mole/L of a trivalent chromium salt;

0.1-0.8 mole/L of a bivalent nickel salt;

0.1-4.0 mole/L of a complex agent;

1.0-3.0 mole/L of a conductive salt;

0.1-0.8 mole/L of a buffering agent; and

0.01-0.30 mole/L of an additive to deposit a chromium-nickel coating layer, the operational method comprising steps of;

arranging a component, auxiliary electrodes, and the trivalent chromium-based electroplating solution in a tank;

setting the component and the auxiliary electrodes to contact the trivalent chromium-based electroplating solution; and

providing a fixed current or potential between the component and the auxiliary electrodes by an additional power supplier.

9. The operational method as claimed in claim 8, wherein a temperature of component surfaces lies in a range from 1°

C. to 50°

C.

10. The operational method as claimed in claim 8, wherein the fixed current provided by the additional power supplier has a range from 1 to 90 ampere per square decimeter.

11. The electroplating procedure as claimed in claim 8, wherein the auxiliary electrodes are made of material selected from the group comprising a titanium mesh coated with platinum, platinum, graphite and stainless steel.