CBN composite formation method including consolidation

Patent metadata

Field	Value
Publication number	US-10843971-B2
Application number	US-201916507122-A
Country	US
Kind code	B2
Filing date	Jul 10, 2019
Priority date	Oct 20, 2017
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

Conventional sintering processes convert a portion of cBN to hBN which is softer than cBN which negatively affects functional properties of an alumina composite. The invention is directed to method for making an alumina-cubic boron nitride (Al2O3-cBN) composite that contains substantially no hexagonal boron nitride (hBN) by non-conventional spark plasma sintering of cBN with nano-sized alumina particles. The invention is also directed to Al2O3-cBN/Ni composites, which contain substantially no hBN, and which exhibit superior physical and mechanical properties compared to alumina composites containing higher amounts of hBN.

First claim

The invention claimed is:

1. A method for making an alumina-cubic boron nitride (“Al 2 O 3 -cBN”) composite comprising:
forming a mixture of cBN particles and nano-sized alumina particles;
consolidating the mixture;
spark plasma sintering the mixture of the cBN particles and the nano-sized alumina particles at constant pressure to form the alumina-cubic boron nitride composite;
wherein an average particle size of the nano-sized alumina particles is no more than 50 nm.

2. The method of claim 1 , wherein the cBN particles are substantially cBN without a nickel coating.

3. The method of claim 1 , wherein the cBN particles are coated with nickel.

4. The method of claim 1 , wherein the cBN particles are coated with nickel and comprise 20-80 wt % nickel, based on a total weight of the nickel-coated cBN particles.

5. The method of claim 1 , wherein the cBN particles are coated with nickel and comprise 50-70 wt % nickel, based on a total weight of the nickel-coated cBN particles.

6. The method of claim 1 , wherein an average particle size of the nano-sized alumina particles is no more than 25 nm.

7. The method of claim 1 , wherein an average particle size of the nano-sized alumina particles is no more than 10 nm.

8. The method of claim 1 , wherein an average particle size of the nano-sized alumina particles is no more than 5 nm.

9. The method of claim 1 , wherein an average particle size of the nano-sized alumina particles is no more than 2 nm.

10. The method of claim 1 , wherein an average particle size of the cBN particles ranges from 1 to 100 μm.

11. The method of claim 1 , wherein an average particle size of the cBN particles ranges from 5 to 50 μm.

12. The method of claim 1 that produces an alumina-cubic boron nitride (Al 2 O 3 -cBN) or alumina-cubic boron nitride/nickel (Al 2 O 3 -cBN/Ni) composite having a higher Vickers hardness than an otherwise identical composite that was not spark plasma sintered at 1,200-1,600° C.

13. The method of claim 1 that produces an alumina-cubic boron nitride (Al 2 O 3 -cBN) or alumina-cubic boron nitride/nickel (Al 2 O 3 -cBN/Ni) composite having a higher Vickers hardness than an otherwise identical composite sintered from alumina particles having an average particle size of 1,000 nm.

14. The method of claim 1 that produces an alumina-cubic boron nitride (Al 2 O 3 -cBN) or alumina-cubic boron nitride/nickel (Al 2 O 3 -cBN/Ni) composite having a higher Vickers hardness than an otherwise identical composite sintered from cBN particles that are not coated with nickel, wherein the spark plasma sintering is performed at a temperature above 1,350° C. and wherein at least 99 wt. % of the boron nitride in the composite is cBN or less than 1 wt. % of the boron nitride is hBN.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Hakeem Abbas Saeed
• Laoui Tahar
• Irshad Hafiz Muzammil
• Ahmed Bilal Anjum
• Ehsan Muhammad Ali

Classifications

• C04B35/62842

  Metals · CPC title

• C04B35/64

  Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F}) · CPC title

• C04B2235/5454

  nanometer sized, i.e. below 100 nm · CPC title

• C04B2235/666

  Applying a current during sintering, e.g. plasma sintering [SPS], electrical resistance heating or pulse electric current sintering [PECS] · CPC title

• C04B2235/96

  Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance · CPC title