Boron nitride nanotube-magnesium alloy composites and manufacturing methods thereof

Patent metadata

Field	Value
Publication number	US-11131007-B1
Application number	US-202117177663-A
Country	US
Kind code	B1
Filing date	Feb 17, 2021
Priority date	Jun 30, 2020
Publication date	Sep 28, 2021
Grant date	Sep 28, 2021

Abstract

Boron nitride nanotube (BNNT)-magnesium (Mg) alloy composites and methods of fabricating the same are provided. The BNNT-Mg alloy composites can have a sandwich structure and can be fabricated by high-pressure spark plasma sintering. A mat of BNNTs can be sputter-coated with Mg, and then sandwiched between Mg alloy particles, followed by a sintering step. The BNNTs can include a hexagonal boron nitride phase.

First claim

What is claimed is:

1. A method of fabricating a boron nitride nanotube (BNNT)-magnesium (Mg) alloy composite, the method comprising:
providing a mat of BNNTs;
sputter-coating the mat of BNNTs with Mg to give a sputter-coated mat;
sandwiching the sputter-coated mat between layers of an Mg alloy; and
sintering the sputter-coated mat and the Mg alloy to give the BNNT-Mg alloy composite,
the BNNTs of the BNNT-Mg alloy composite having an aspect ratio of at least 3,000, and
the BNNT-Mg alloy composite having crack-bridging ability due to the BNNTs of the BNNT-Mg alloy composite resisting crack propagation and crack opening.

2. The method according to claim 1 , the crack-bridging ability of the BNNT-Mg alloy composite being further due to chemical bonding between the BNNTs of the BNNT-Mg alloy composite and the Mg alloy of the BNNT-Mg alloy composite.

3. The method according to claim 2 , the chemical bonding between the BNNTs of the BNNT-Mg alloy composite and the Mg alloy of the BNNT-Mg alloy composite being due to the sputter-coating of the mat and due to interfacial reactions between the BNNTs of the BNNT-Mg alloy composite and the Mg alloy of the BNNT-Mg alloy composite.

4. The method according to claim 1 , the high pressure sintering being spark plasma sintering (SPS) performed at a pressure of at least 400 megaPascal (MPa).

5. The method according to claim 4 , the high pressure SPS being performed at a temperature of at least 400° C. and for a time period of at least 10 minutes.

6. The method according to claim 1 , the layers of the Mg alloy comprising powder of the Mg alloy.

7. The method according to claim 1 , the Mg alloy comprising Mg, aluminum (Al), and zinc (Zn).

8. The method according to claim 1 , the Mg alloy being AZ31.

9. The method according to claim 1 , the mat of BNNTs comprising a porosity of at least 75%, and
the BNNTs of the mat of BNNTs having a diameter in a range of from 5 nanometers (nm) to 15 nm and a length of at least 50 micrometers (μm).

10. The method according to claim 1 , the sputter-coated mat comprising a layer of Mg on both an upper surface and a lower surface thereof, each layer of Mg having a thickness of at least 1 μm and a purity of Mg of at least 99.9%.

11. The method according to claim 1 , the BNNT-Mg alloy composite comprising BNNTs in a range of from 0.5 wt % to 5 wt %.

12. The method according to claim 1 , the BNNT-Mg alloy composite comprising:
a nano-phase of magnesium nitride (Mg 3 N 2 ) and a nano-phase of aluminum nitride (AlN) between the Mg alloy and the BNNTs; and
a hexagonal boron nitride phase in the BNNTs.

13. The method according to claim 1 , the Mg alloy comprising about 96 wt % Mg.

14. A method of fabricating a boron nitride nanotube (BNNT)-magnesium (Mg) alloy composite, the method comprising:
providing a mat of BNNTs;
sputter-coating the mat of BNNTs with Mg to give a sputter-coated mat;
sandwiching the sputter-coated mat between layers of an Mg alloy; and
sintering the sputter-coated mat and the Mg alloy to give the BNNT-Mg alloy composite,
the Mg alloy comprising about 96 wt % Mg.

15. The method according to claim 14 , the BNNTs of the BNNT-Mg alloy composite having an aspect ratio of at least 3,000.

16. The method according to claim 14 , the BNNT-Mg alloy composite having crack-bridging ability due to the BNNTs of the BNNT-Mg alloy composite resisting crack propagation and crack opening,
the crack-bridging ability of the BNNT-Mg alloy composite being further due to chemical bonding between the BNNTs of the BNNT-Mg alloy composite and the Mg alloy of the BNNT-Mg alloy composite, and
the chemical bonding between the BNNTs of the BNNT-Mg alloy composite and the Mg alloy of the BNNT-Mg alloy composite being due to the sputter-coating of the mat and due to interfacial reactions between the BNNTs of the BNNT-Mg alloy composite and the Mg alloy of the BNNT-Mg alloy composite.

17. The method according to claim 14 , the high pressure sintering being spark plasma sintering (SPS) performed at a pressure of at least 400 megaPascal (MPa), and
the high pressure SPS being performed at a temperature of at least 400° C. and for a time period of at least 10 minutes.

18. The method according to claim 14 , the BNNT-Mg alloy composite comprising:
a nano-phase of magnesium nitride (Mg 3 N 2 ) and a nano-phase of aluminum nitride (AlN) between the Mg alloy and the BNNTs; and
a hexagonal boron nitride phase in the BNNTs.

19. The method according to claim 14 , the layers of the Mg alloy comprising powder of the Mg alloy,
the Mg alloy comprising Mg, aluminum (Al), and zinc (Zn),
the mat of BNNTs comprising a porosity of at least 75%,
the BNNTs of the mat of BNNTs having a diameter in a range of from 5 nanometers (nm) to 15 nm and a length of at least 50 micrometers (μm),
the sputter-coated mat comprising a layer of Mg on both an upper surface and a lower surface thereof, each layer of Mg having a thickness of at least 1 μm and a purity of Mg of at least 99.9%, and
the BNNT-Mg alloy composite comprising BNNTs in a range of from 0.5 wt % to 5 wt %.

20. A method of fabricating a boron nitride nanotube (BNNT)-magnesium (Mg) alloy composite, the method comprising:
providing a mat of BNNTs;
sputter-coating the mat of BNNTs with Mg to give a sputter-coated mat;
sandwiching the sputter-coated mat between layers of an Mg alloy; and
sintering the sputter-coated mat and the Mg alloy to give the BNNT-Mg alloy composite,
the BNNTs of the BNNT-Mg alloy composite having an aspect ratio of at least 3,000,
the BNNT-Mg alloy composite having crack-bridging ability due to the BNNTs of the BNNT-Mg alloy composite resisting crack propagation and crack opening,
the crack-bridging ability of the BNNT-Mg alloy composite being further due to chemical bonding between the BNNTs of the BNNT-Mg alloy composite and the Mg alloy of the BNNT-Mg alloy composite,
the chemical bonding between the BNNTs of the BNNT-Mg alloy composite and the Mg alloy of the BNNT-Mg alloy composite being due to the sputter-coating of the mat and due to interfacial reactions between the BNNTs of the BNNT-Mg alloy composite and the Mg alloy of the BNNT-Mg alloy composite,
the sintering being high pressure spark plasma sintering (SPS) performed at a pressure of about 400 megaPascal (MPa), a temperature of about 400° C., and for a time period of about 10 minutes,
the layers of the Mg alloy comprising powder of the Mg alloy,
the Mg alloy being AZ31,
the mat of BNNTs comprising a porosity of at least 75%,
the BNNTs of the mat of BNNTs having a diameter of about 10 nanometers (nm) and a length of at least 75 micrometers (μm),
the sputter-coated mat comprising a layer of Mg on both an upper surface and a lower surface thereof, each layer of Mg having a thickness of at least 1 μm and a purity of Mg of at least 99.9%,
the BNNT-Mg alloy composite comprising 1 wt %, and
the BNNT-Mg alloy composite further comprising:
a nano-phase of magnesium nitride (Mg 3 N 2 ) and a nano-phase of aluminum nitride (AlN) between the Mg alloy and the BNNTs; and
a hexagonal boron nitride phase in the BNNTs.

Assignees

• Agarwal Arvind
• NAUTIYAL Pranjal
• Boesl Benjamin Peter
• The Florida International Univ Board Of Trustees

Inventors

• Agarwal Arvind
• NAUTIYAL Pranjal
• Boesl Benjamin Peter

Classifications

• C22C1/05 Primary

  Mixtures of metal powder with non-metallic powder (C22C1/08 takes precedence) · CPC title

• C22C1/0408

  Light metal alloys · CPC title

• B22F2003/1051

  by electric discharge · CPC title

• B22F2207/01

  Composition gradients · CPC title

• C23C14/5806

  Thermal treatment · CPC title