Methods and systems for aluminum electroplating

Patent metadata

Field	Value
Publication number	US-11136686-B2
Application number	US-201615744022-A
Country	US
Kind code	B2
Filing date	Jul 15, 2016
Priority date	Jul 16, 2015
Publication date	Oct 5, 2021
Grant date	Oct 5, 2021

Abstract

Systems and methods for coating a metallic component are provided. In one embodiment, a metallic coating may be disposed in a plating bath comprising AlBr3. The metallic coating may be coupled with, or configured as, a working electrode. A counter electrode formed of aluminum may be disposed within the plating bath. An electric current may be applied between the two electrodes resulting in the electrodeposition of aluminum on the metallic component. In one particular embodiment, the plating bath may include LiBr, KBr and CsBr, with AlBr3 being present in an amount of approximately 80 percent or greater by weight. Various types of metals may be coated with aluminum using embodiments of the present disclosure. Additionally, the methods and systems described herein are amenable to coating of complex geometries.

First claim

What is claimed is:

1. A system, comprising:
a primary crucible containing a plating melt, the plating melt comprising a bromide salt mixture comprising AlBr 3 and a eutectic melt of first bromide salts, the first bromide salts comprising LiBr, KBr, and CsBr, wherein the bromide salt mixture is configured to have a melting temperature greater than 300° C.; and
an electrode assembly comprising:
a working electrode configured to receive a metallic workpiece such that at least a portion of the metallic workpiece is disposed within the plating melt, and
a counter electrode comprising aluminum.

2. The system of claim 1 , wherein the plating melt comprises a homogeneous melt of AlBr3 and the first bromide salts.

3. The system of claim 1 , further comprising a heating element configured to maintain a temperature of the plating melt within an operating temperature range between approximately 325° C. and 400° C.

4. The system of claim 1 , wherein the plating melt is at least 10 percent AlBr3 by weight.

5. The system of claim 1 , wherein the plating melt is approximately 80 percent AlBr 3 by weight.

6. The system of claim 1 , further comprising:
a heater operably coupled to the primary crucible;
wherein a homogenous melt of the first bromide salts and the AlBr 3 is produced by raising a temperature of the mixture of the first bromide salts and the AlBr 3 to a homogeneous melt temperature.

7. The system of claim 1 , further comprising:
a heater operably coupled to the primary crucible;
wherein the plating melt is prepared by:
producing a first melt product, comprising raising a temperature of the first bromide salts to a eutectic melt temperature configured to produce a eutectic melt of the first bromide salts prior to incorporation of the AlBr 3 ; and
producing a homogeneous melt of the first bromide salts and the AlBr 3 in response to incorporation of the AlBr 3 into the first melt product, the AlBr 3 incorporated in response to a temperature of the first melt product falling to a baseline temperature lower than the eutectic melt temperature.

8. The system of claim 7 , further comprising:
a cooling system;
wherein preparing the plating melt further comprises reducing the temperature of the first melt product in response to maintaining the first bromide salts at the eutectic melt temperature for a determined time.

9. The system of claim 1 , further comprising a heater, wherein preparing the plating melt comprises:
maintaining a temperature of the mixture comprising the first bromide salts and the AlBr 3 at an intermediate temperature for a determined time period; and
raising the temperature of the mixture from the intermediate temperature to a homogeneous melt temperature in response to maintaining the mixture at the intermediate temperature for the determined time period, wherein the homogeneous melt temperature is between about 550° C. and about 750° C.

10. The system of claim 9 , wherein:
the mixture comprises a powdered salt mixture,
the determined time period is about an hour, and
the intermediate temperature is about 150° C.

11. The system of claim 1 , further comprising:
a furnace well;
a secondary crucible positioned within a lower interior portion of the furnace well, wherein the primary crucible is disposed on a support member configured to position the primary crucible at least partially within an interior volume of the secondary crucible, and wherein the primary crucible is electrically insulated from the secondary crucible;
a first heat baffle positioned between the lower interior portion of the furnace well and an upper interior portion of the furnace well; and
a second heat baffle located above the upper interior portion of the furnace well.

12. The system of claim 1 , further comprising:
a temperature measurement device configured to measure a temperature of contents of the primary crucible; and
an electrical power supply operably coupled to the electrode assembly.

13. The system of claim 12 , wherein the temperature measurement device comprises a thermocouple, and wherein the electrical power supply comprises one or more of a potentiostat and a direct current power supply unit.

14. The system of claim 1 , further comprising;
a potentiostat configured to apply a voltage to the electrode assembly; and
a control device configured to control the voltage applied by the potentiostat.

15. The system of claim 14 , wherein the electrode assembly further comprises a reference electrode, and wherein the potentiostat is configured to control a voltage difference applied between the working electrode and the reference electrode.

16. The system of claim 1 , wherein the workpiece comprises one or more of stainless steel, mild steel, tool steel, aluminum, zirconium, neodymium-iron-boron, nickel-titanium, copper, and brass.

17. A system, comprising:
a primary crucible containing a plating bath, the plating bath comprising a melt of an electrolyte salt mixture, the electrolyte salt mixture comprising aluminum bromide and eutectic salts, the eutectic salts comprising lithium bromide, potassium bromide, and cesium bromide, wherein a melting temperature of the electrolyte salt mixture is greater than about 300° C.;
a heating element configured to maintain the plating bath at an electroplating temperature; and
an electrode assembly comprising:
a working electrode configured to position a metallic workpiece such that at least a portion of a surface of the metallic workpiece is in contact with the plating bath, and
a counter electrode comprising aluminum.

18. The system of claim 17 , wherein the electrolyte salt mixture is at least 10% aluminum bromide by weight.

19. The system of claim 18 , wherein producing the plating bath comprises:
heating a first mixture of the lithium bromide, potassium bromide and cesium bromide to about 750° C., wherein the aluminum bromide is added to the first mixture to produce a second mixture responsive to cooling the first mixture to about 100° C.; and
heating the second mixture to the electroplating temperature to produce the plating bath, the electroplating temperature between about 325° C. and about 400° C.

20. The system of claim 17 , wherein the plating bath comprises a homogeneous melt of the aluminum bromide and the eutectic salts.

21. The system of claim 17 , wherein the plating bath is at least 80 percent aluminum bromide by weight.

22. An electroplating apparatus, comprising:
an electrolyte composition comprising aluminum bromide and a eutectic mixture comprising lithium bromide, potassium bromide, and cesium bromide, wherein the electrolyte composition comprises between 10% and 90% aluminum bromide by weight and has a melting temperature above about 300° C.;
a primary crucible comprising a melt of the electrolyte composition;
a working electrode configured to position a metallic workpiece such that at least a portion of the metallic workpiece is disposed within the melt of the electrolyte composition; and
a counter electrode comprising aluminum.

23. A system, comprising:
a plating bath comprising a melt of an electrolyte salt comprising aluminum bromide and a eutectic composition comprising lithium bromide, potassium bromide, and cesium bromide, the electrolyte salt having a melting temperature greater than about 300° C.;
a working electrode configured to hold a metallic workpiece such that at least a portion of the metallic workpiece is submerged within the plat

Assignees

• Battelle Energy Alliance Llc

Inventors

• Tripathy Prabhat K
• Fredrickson Guy L
• Dufek Eric J
• Wurth Laura A
• Herring J Stephen

Classifications

• C25D5/50

  by heat-treatment · CPC title

• C25D17/10

  Electrodes {, e.g. composition, counter electrode} · CPC title

• C25D3/66 Primary

  from melts · CPC title

• C25D21/12

  Process control or regulation (controlling or regulating in general G05) · CPC title

• C25D21/02

  Heating or cooling · CPC title