Electroplated composite coating

• US 20070158619A1
• Filed: 01/12/2006
• Published: 07/12/2007
• Est. Priority Date: 01/12/2006
• Status: Abandoned Application

• Current Assignee: GM Global Technology Operations Incorporated (General Motors Company), Zhejiang University
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company), Zhejiang University
• Inventors: Wang, Yucong, Olk, Charles, Tu, Jian-Ping, Chen, Wei-Xiang, Xu, Zhu-De
• Application Number:
  US11/330,508
• Publication Number:
  US 20070158619A1
• Time in Patent Office: Days
• US Class Current: 252/500
• CPC Class Codes: C25D 15/02 Combined electrolytic and electrophoretic processes with charged materials
• CPC Class Codes: C25D 5/50 by heat-treatment

Abstract

An electroplated composite coating is deposited on a substrate using an electroplating solution that includes metal cations of a metallic matrix to be deposited and carbon nanotubes. The composite coating includes the metallic matrix and carbon nanotubes disposed in the matrix to improve coating mechanical and tribological properties.

Claims

9. Electroplated composite coating, comprising a metallic matrix and carbon nanotubes disposed in the matrix.

1. Method of forming a composite coating on a substrate, comprising providing an electroplating solution that includes metal cations of a metallic matrix to be deposited and carbon nanotubes, disposing the substrate as a cathode in the electroplating solution of an electrolytic cell, and operating the electrolytic cell in a manner to electrodeposit a coating comprising the metallic matrix having the carbon nanotubes disposed therein on the substrate.

2. The method of claim 1 wherein a dispersing agent is provided in the electroplating solution effective to disperse the carbon nanotubes in the electroplating solution such that the carbon nanotubes are dispersed in the metallic matrix.

3. The method of claim 1 wherein a length to diameter ratio of the carbon nanotubes is provided to enhance dispersion of the carbon nanotubes in the solution.

4. The method of claim 3 wherein the carbon nanotubes are pretreated prior to introduction into the electroplating solution to provide said length to diameter ratio.

5. The method of claim 1 including the additional step of depositing a metallic bond-coat on the substrate before the composite coating is electrodeposited such that the bond-coat comprises an interlayer between the substrate and the composite coating.

6. The method of claim 1 wherein the electroplating solution includes carbon nanotubes in an amount from 1 to 6 g/L of solution.

7. The method of claim 1 wherein cathodic current density is in the range of about 1 to about 6 A/dm².

8. The method of claim 1 further including heat treating the composite coating to form hardening precipitates in the matrix.

10. The coating of claim 9 wherein the carbon nanotubes are present in an amount from about 5 to about 16 volume % of the coating.

11. The coating of claim 9 wherein the carbon nanotubes have an outer diameter from about 20 to about 50 nanometers.

12. The coating of claim 9 having a thickness of less than about 30 micrometers.

13. The coating of claim 9 wherein the carbon nanotubes include a length to diameter ratio of about 5 to about 100.

13-1. The coating of claim 9 which is heat treated to provide hardening precipitates in the matrix.

14. A coated article, comprising a substrate and an electroplated composite coating on the substrate, said composite coating comprising a metallic matrix and carbon nanotubes disposed in the matrix.

15. The article of claim 14 wherein the carbon nanotubes are present in an amount from about 5 to about 16 volume % of the coating.

16. The article of claim 14 wherein the carbon nanotubes have an outer diameter from 20 to 50 nanometers.

17. The article of claim 16 wherein the coating has a thickness of less than about 30 micrometers.

18. The article of claim 14 wherein the carbon nanotubes include a length to diameter ratio of about 5 to about 100.

19. The article of claim 14 wherein the matrix includes a hardening precipitates.

20. The article of claim 14 including a metallic inlayer between the substrate and the composite coating.