Methods and materials for electroplating aluminum in ionic liquids

Patent metadata

Field	Value
Publication number	US-9903034-B2
Application number	US-201314087876-A
Country	US
Kind code	B2
Filing date	Nov 22, 2013
Priority date	Nov 22, 2013
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A method of depositing aluminum onto a substrate is disclosed. In this method, the substrate is disposed as cathode in an electrochemical cell with an anode and a liquid electrodeposition composition comprising an ionic liquid and a source of aluminum, and aluminum is electroplated onto the substrate. Residual water content in the electroplating bath is controlled by exposure to light in the presence of a photo-oxidation catalyst to decompose the water or species associated with water.

First claim

The invention claimed is:

1. A method of depositing aluminum onto a substrate, comprising
disposing a substrate as cathode and an anode in an electroplating bath that includes an ionic liquid, a source of aluminum, and greater than 0.1 wt. % but less than 1 wt. % of water;
electroplating aluminum onto the substrate in the electroplating bath; and
exposing the electroplating bath to light in the presence of a photo-oxidation catalyst to decompose water.

2. The method of claim 1 , wherein the photo-oxidation catalyst is dissolved in the ionic liquid.

3. The method of claim 1 , wherein the electroplating bath comprises a first phase comprising the ionic liquid and the source of aluminum, and a second barrier phase between the ionic liquid phase and a gas space.

4. The method of claim 3 , wherein the photo-oxidation catalyst is in the barrier phase.

5. The method of claim 1 , wherein the photo-oxidation catalyst is immobilized on a catalyst support in contact with the ionic liquid.

6. The method of claim 1 , wherein the photo-oxidation catalyst is a polyoxometalate, a biochemical photo-oxidation catalyst, metal polypyridyl photocatalysts (ruthenium bipyridine Ru(bpy) 3 2+ /Ru(bpy) 3 3+ ), ruthenium blue dimer, or 7,7,8,8-tetracyanoquinodimethane.

7. The method of claim 6 , wherein the photo-oxidation catalyst is a polyoxometalate.

8. The method of claim 7 , wherein the polyoxometalate is a polyoxomolybdate or a Keggin structure polyoxotungstate.

9. The method of claim 7 , wherein the polyoxometalate is a Keggin structure polyoxotungstate.

10. The method of claim 7 , wherein the polyoxometalate is [P 2 W 18 O 62 ] 6− .

11. The method of claim 1 , further comprising contacting the electroplating bath with a purge gas to remove HCl and oxygen byproducts.

12. The method of claim 10 , wherein the cathode substrate includes steels, aluminum alloys, nickel and/or nickel super-alloys.

13. The method of claim 1 , wherein
the ionic liquid has cations and anions,
the cations comprising imidazolium, pyridinium, tetraalkylammonium, pyrrolidinium, trialkylsulfonium, pyrazolium, thiazolium, oxazolium, pyridazinium, pyrimidinium, pyrazinium, or a combination comprising at least one of the foregoing; and
the anions comprising chloroaluminate, tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, bis(trifluoromethylsulfonyl)imide, trifluoroethanoate, nitrate, SCN, HSO 4 , HCO 3 , CH 3 SO 3 , CH 3 CH 2 SO 4 , (CH 3 (CH 2 ) 30 ) 2 POO, (CF 3 SO 2 ) 2 N, dicyanamide, (CF 3 CF 2 SO 2 ) 2 N, L-(+)-lactate, CH 3 SO 4 , CH 3 COO, or a combination comprising at least one of the foregoing; and

the photo-oxidation catalyst is a polyoxometalate, a biochemical photo-oxidation catalyst, metal polypyridyl photocatalysts (ruthenium bipyridine Ru(bpy) 3 2+ /Ru(bpy) 3 3+ ), ruthenium blue dimer, or 7,7,8,8-tetracyanoquinodimethane.

14. The method of claim 1 , wherein exposing the electroplating bath to light in the presence of a photo-oxidation catalyst occurs continuously during the electroplating.

15. The method of claim 1 , wherein exposing the electroplating bath to light in the presence of a photo-oxidation catalyst occurs periodically during the electroplating.

16. A method of depositing aluminum onto a substrate, comprising disposing an anode and a substrate as cathode in an electroplating bath that includes an ionic liquid, a source of aluminum, and less than 1 wt. % of water;
electroplating aluminum onto the substrate in the electroplating bath; and
exposing the electroplating bath to light in the presence of a photo-oxidation catalyst to decompose water when or after electroplating commences.

Assignees

• Sikorsky Aircraft Corp

Inventors

• Chen Lei
• Yu Xiaomei
• Fallon William P

Classifications

• C25D3/665 Primary

  from ionic liquids · CPC title

• C25D5/003

  Electroplating using gases, e.g. pressure influence · CPC title

• C25D3/44

  Aluminium · CPC title

• C25D5/006 Primary

  Chemistry & Metallurgy · mapped topic

• C25D21/18

  of electrolytes (C25D21/22 takes precedence) · CPC title