Multifunctional cerium-based nanomaterials and methods for producing the same

Patent metadata

Field	Value
Publication number	US-10434498-B2
Application number	US-201715724389-A
Country	US
Kind code	B2
Filing date	Oct 4, 2017
Priority date	Jun 17, 2013
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

Embodiments relate to a cerium-containing nano-coating composition, the composition including an amorphous matrix including one or more of cerium oxide, cerium hydroxide, and cerium phosphate; and crystalline regions including one or more of crystalline cerium oxide, crystalline cerium hydroxide, and crystalline cerium phosphate. The diameter of each crystalline region is less than about 50 nanometers.

First claim

What is claimed is:

1. A method for producing a composition having a cerium-containing conversion coating on a substrate, the method comprising:
immersing a metal substrate in a cerium-containing aqueous bath;
spontaneously depositing a nano-coating on the substrate, wherein the nano-coating includes:
an amorphous matrix including one or more of cerium oxide, cerium hydroxide, and cerium phosphate; and
crystalline regions including one or more of crystalline cerium oxide and crystalline cerium hydroxide; and

immersing the nano-coated substrate in a phosphate-containing solution sufficient to convert the deposited nano-coating to a phosphated nano-coating including:
an amorphous matrix including one or more of cerium oxide, cerium hydroxide, and cerium phosphate; and
crystalline regions including one or more of crystalline cerium oxide, crystalline cerium hydroxide, and crystalline cerium phosphate.

2. The method of claim 1 , further comprising preparing the substrate prior to immersion by one or more of grinding, acid treatment, and alkaline treatment.

3. The method of claim 1 , wherein the substrate comprises one or more of aluminum or magnesium.

4. The method of claim 3 , wherein the substrate comprises one of an AZ31 alloy, an AZ61 alloy, an AZ91 alloy, an AM30 alloy, an AM60 alloy, an AA 7075-T6 alloy, an AA 2024-T3 alloy, and Al-clad alloys.

5. The method of claim 1 , wherein the aqueous bath further comprises one or more of an accelerator and anti-bubbling agent.

6. The method of claim 1 , wherein the diameter of each crystalline region of the phosphated nano-coating is less than 50 nanometers.

7. The method of claim 2 , wherein preparing the substrate comprises surface grinding followed by acid treatment and then followed by alkaline immersion cleaning.

8. The method of claim 2 , wherein preparing the substrate comprises acid treatment followed by alkaline immersion cleaning.

9. The method of claim 2 , wherein acid treatment comprises treating using one or more of sulfuric acid, nitric acid, and hydrofluoric acid.

10. The method of claim 1 , wherein the cerium-containing aqueous bath comprises about 0.1 wt. % to about 2.0 wt. % elemental cerium.

11. The method of claim 1 , wherein the cerium-containing aqueous bath comprises one or more of CeCl 3 .7H 2 O and Ce(NO 3 ) 3 .6H 2 O as cerium sources.

12. The method of claim 1 , where the cerium-containing aqueous bath comprises one or more of Ce(III) and Ce(IV) species.

13. The method of claim 5 , wherein the accelerator comprises an organic accelerator.

14. The method of claim 5 , wherein the anti-bubbling agent comprises one or more of organic and synthetic gelatins.

15. The method of claim 5 , wherein the anti-bubbling agent is present in amounts from about 10 ppm to about 1,000 ppm.

16. A method for producing a composition having a cerium-containing conversion coating on a substrate, the method comprising:
immersing a metal substrate in a cerium-containing aqueous bath; and
spontaneously depositing a nano-coating on the substrate, wherein the nano-coating includes:
an amorphous matrix including one or more of cerium oxide, cerium hydroxide, and cerium phosphate; and
crystalline regions including one or more of crystalline cerium oxide and crystalline cerium hydroxide.

17. The method of claim 16 , further comprising preparing the substrate prior to immersion by one or more of grinding, acid treatment, and alkaline treatment.

18. The method of claim 16 , wherein the substrate comprises one or more of aluminum or magnesium.

19. The method of claim 16 , wherein the aqueous bath further comprises one or more of an accelerator and anti-bubbling agent.

20. The method of claim 17 , wherein preparing the substrate comprises acid treatment followed by alkaline immersion cleaning.

Assignees

• Univ Missouri

Inventors

• O'Keefe Matthew J
• Castano Londono Carlos E
• Fahrenholtz William G

Classifications

• B01J37/28

  Phosphorising · CPC title

• C22C23/02

  with aluminium as the next major constituent · CPC title

• B01J23/10 Primary

  of rare earths · CPC title

• C23C22/48

  not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates · CPC title

• B01J37/0225

  of metal substrates · CPC title