Structural and mechanical properties of nano and micro al2o3-cbn composites prepared by spark plasma sintering

Patent metadata

Field	Value
Publication number	US-2019119166-A1
Application number	US-201715788914-A
Country	US
Kind code	A1
Filing date	Oct 20, 2017
Priority date	Oct 20, 2017
Publication date	Apr 25, 2019
Grant date	—

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

1 . A method for making an alumina-cubic boron nitride (“Al 2 O 3 -cBN”) composite comprising spark plasma sintering cBN particles with nano-sized alumina particles; 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 2 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.

15 . An Al 2 O 3 -cBN or Al 2 O 3 -cBN/Ni composite, wherein at least 99 wt % of the boron nitride is cBN as determined by XRD and/or Raman spectroscopy.

16 . An Al 2 O 3 -cBN composite according to claim 15 .

17 . An Al 2 O 3 -cBN/Ni composite according to claim 15 .

18 . An Al 2 O 3 -cBN or Al 2 O 3 -cBN/Ni composite produced by the method of claim 1 , wherein at least 99 wt % of the boron nitride is cBN as determined by XRD and Raman spectroscopy.

19 . A material comprising the Al 2 O 3 -cBN/Ni composite of claim 15 .

20 . The material of claim 19 which is an abrasive, tool, vehicular part, aerospace component, engine component, turbine component, break-ring, nozzle, reactor component, high temperature refractory shape, glass forming tool or refractory, mold, die, refractory for metal forming, furnace vent, stack or fixture.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

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

Classifications

• C04B2235/6562

  Heating rate · CPC title

• C22C29/00

  Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides {(C22C26/00 takes precedence)} · CPC title

• C04B35/64

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

• C04B2235/5445

  submicron sized, i.e. from 0,1 to 1 micron · CPC title

• C04B35/117 Primary

  Composites · CPC title