Coating for the mitigation of metal whiskers

Patent metadata

Field	Value
Publication number	US-10913869-B2
Application number	US-201816185863-A
Country	US
Kind code	B2
Filing date	Nov 9, 2018
Priority date	Jun 7, 2016
Publication date	Feb 9, 2021
Grant date	Feb 9, 2021

Abstract

A coating for mitigating metal whiskers on a metal surface includes a polymeric coating material; and a metal ion complexing agent impregnated within the polymeric coating material, the metal ion complexing agent having a standard reduction potential (E°) that is greater than a metal in the metal surface.

First claim

What is claimed is:

1. A coating for mitigating metal whiskers on a metal surface, comprising:
a polymeric coating material arranged on the metal surface, the metal surface being a surface of an electronic component or device; and
a metal ion complexing agent impregnated within the polymeric coating material, the metal ion complexing agent comprising two Schiff base functional groups that chelate a metal ion, and having a standard reduction potential (E°) that is greater than a metal in the metal surface, such that the metal in the metal surface can be oxidized to displace the metal ion in the metal ion complexing agent;
wherein the metal ion complexing agent has the following structure:

wherein R 1 and R 2 are each independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, or a combination thereof; and a substitution on a substituted alkyl group, alkenyl group, alkynyl group, aryl group, or cycloalkyl group is an acrylate group, an acyl halide group, an amide group, an amine group, a carboxylate group, a carboxylate thiol group, an epoxy group, an ester group, an ether group, a halogen, a hydroxamic acid group, a hydroxyl group, a nitrate group, a nitrile group, a phosphate group, a phosphine group, a phosphonic acid group, a silane group, a sulfate group, a sulfide group, a sulfite group, a thiolate group, an azide group, an acetal group, an aldehyde group, a diene group, an imine group, or any combination thereof.

2. The coating of claim 1 , wherein tin in a tin whisker can displace the metal ion.

3. The coating of claim 2 , wherein the metal ion is a silver ion.

4. The coating of claim 2 , wherein the metal ion is a gold ion.

5. The coating of claim 2 , wherein the metal ion is a platinum ion.

6. The coating of claim 2 , wherein the metal ion is a palladium ion.

7. The coating of claim 2 , wherein the metal ion is a copper ion.

8. The coating of claim 2 , wherein the metal ion is a cerium ion.

9. The coating of claim 2 , wherein the metal ion is a rhodium ion.

10. The coating of claim 1 , wherein the metal of the metal surface is tin, and the E° of the metal ion complexing agent is greater than −0.14 volts.

11. The coating of claim 1 , wherein the metal of the metal surface is nickel, and the E° of the metal ion complexing agent is greater than −0.25 volts.

12. The coating of claim 1 , wherein the coating is disposed on a tin surface comprising about 97 to about 100 atomic % (at. %) tin.

13. The coating of claim 1 , wherein the metal ion complexing agent chelates tin.

14. The coating of claim 1 , wherein the polymeric coating has a thickness in a range from about 0.1 to about 20 millimeters (mm).

15. The coating of claim 1 , wherein the metal surface comprises tin.

16. The coating of claim 1 , wherein the metal surface comprises pure or substantially pure tin.

17. A coating for mitigating metal whiskers on a metal surface, comprising:
a polymeric coating material arranged on the metal surface, the metal surface being a surface of an electronic component or device; and
a metal ion complexing agent impregnated within the polymeric coating material, the metal ion complexing agent comprising two Schiff base functional groups that chelate a metal ion, and having a standard reduction potential (E°) that is greater than a metal in the metal surface, such that the metal in the metal surface can be oxidized to displace the metal ion in the metal ion complexing agent;

wherein the metal ion complexing agent has the following structure:

Assignees

• Raytheon Co

Inventors

• Smith David R
• Deppert Thomas M
• Mollberg William C
• Wolf Frank A

Classifications

• C09D165/04

  Polyxylylenes · CPC title

• C08K5/29

  Compounds containing {one or more} carbon-to-nitrogen double bonds · CPC title

• C09D183/04

  Polysiloxanes · CPC title

• C09D133/02

  Homopolymers or copolymers of acids; Metal or ammonium salts thereof · CPC title

• H05K2201/09872

  Insulating conformal coating · CPC title