Superlubricity coating containing carbon nanotubes

Patent metadata

Field	Value
Publication number	US-11970764-B2
Application number	US-202017090216-A
Country	US
Kind code	B2
Filing date	Nov 5, 2020
Priority date	Nov 6, 2019
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

Abstract

A method for producing a structure containing an array of MWCNTs on a metal substrate, comprising: (i) subjecting a metal substrate to a surface oxidation process at a first elevated temperature in an oxygen-containing atmosphere and under a first reduced pressure; (ii) subjecting the metal substrate to a surface reduction process at a second elevated temperature in a reducing atmosphere and under a second reduced pressure of at least 0.01 atm and less than 1 atm to result in reduction of the surface of said metal substrate, wherein the reducing atmosphere contains hydrogen gas; (iii) subjecting the metal substrate to a third reduced pressure of no more than 0.1 atm; and (iv) contacting the metal substrate, while at the third reduced pressure and under an inert or reducing atmosphere, with an organic substance at a third elevated temperature for suitable time to produce the MWCNTs on the metal substrate.

First claim

What is claimed is:

1. A method for producing a structure containing an array of multi-walled carbon nanotubes on a metal substrate, the method comprising:
(i) subjecting a metal substrate to a surface oxidation process in which the metal substrate is subjected to a first temperature of 600-1000° C. in an O 2 -containing atmosphere and under a first reduced pressure of at least 0.01 atm and less than 1 atm to result in oxidation of a surface of said metal substrate, wherein said first temperature is at least 100° C. below the melting point of the metal;
(ii) subjecting the metal substrate to a surface reduction process in which the metal substrate is subjected to a second temperature of 600-1000° C. in a reducing atmosphere and under a second reduced pressure of at least 0.01 atm and less than 1 atm to result in reduction of the surface of said metal substrate, wherein said reducing atmosphere contains hydrogen gas;
(iii) subjecting the metal substrate to a third reduced pressure of no more than 0.1 atm; and
(iv) contacting the metal substrate, while at the third reduced pressure and under an inert or reducing atmosphere, with an organic substance at a third temperature of 700-900° C. for at least 1 minute, to result in production of said structure containing an array of multi-walled carbon nanotubes on said metal substrate.

2. The method of claim 1 , further comprising: (v) cooling the metal substrate to room temperature under an inert or reducing atmosphere after completion of step (iv).

3. The method of claim 1 , wherein an externally provided metallic, metal salt, or metal oxide catalyst is excluded.

4. The method of claim 1 , wherein step (i) comprises subjecting the metal substrate to a surface oxidation process in which the metal substrate is elevated in temperature from room temperature to said first temperature of 600-1000° C. at a temperature ramp rate of no more than 50° C./min in an O 2 -containing atmosphere and under a first reduced pressure of at least 0.1 atm and less than 1 atm to result in oxidation of a surface of said metal substrate, wherein said first temperature is at least 100° C. below the melting point of the metal.

5. The method of claim 4 , wherein said temperature ramp rate is no more than 40° C./min.

6. The method of claim 4 , wherein said temperature ramp rate is no more than 30° C./min.

7. The method of claim 4 , wherein said temperature ramp rate is within a range of 5-50° C/min.

8. The method of claim 1 , wherein the organic substance in step (iv) has a molecular weight of up to 500 g/mol.

9. The method of claim 1 , wherein the organic substance in step (iv) is an alcohol or hydrocarbon.

10. The method of claim 1 , wherein said metal substrate has an iron-based composition.

11. The method of claim 1 , wherein said iron-based composition is steel.

12. The method of claim 11 , wherein said steel is stainless steel.

13. The method of claim 11 , wherein said steel is tool steel.

14. The method of claim 11 , wherein said steel is an alloy steel.

15. The method of claim 1 , wherein the multi-walled carbon nanotubes are aligned substantially perpendicular to said metal substrate and substantially parallel to each other.

Assignees

• Ut Battelle Llc

Inventors

• Ihala Gamaralalage Chanaka Kapila Kumara
• Qu Jun
• Menchhofer Paul A

Classifications

• C23C16/0218 Primary

  in a reactive atmosphere (C23C16/0227 takes precedence) · CPC title

• C01B32/168

  After-treatment · CPC title

• C21D8/0278 Primary

  involving a particular surface treatment  (C21D8/0294 takes precedence) · CPC title

• C23C16/52

  Controlling or regulating the coating process {(C23C16/45557, C23C16/279 take precedence)} · CPC title

• C23C16/56

  After-treatment · CPC title