Method of making an alumina-silicate oxynitride and cubic boron nitride ceramic composite

Patent metadata

Field	Value
Publication number	US-10167234-B2
Application number	US-201715833020-A
Country	US
Kind code	B2
Filing date	Dec 6, 2017
Priority date	Dec 6, 2016
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

Abstract

A method for producing a composite of cubic boron nitride dispersed in a SiAlON ceramic. This method involves mixing silicon nitride nanoparticles, aluminum nitride nanoparticles, silica nanoparticles, calcium oxide nanoparticles, and cubic boron nitride microparticles to produce a mixture. The cubic boron nitride may be coated with nickel. The mixture is sintered to produce the composite, and this sintering may involve spark plasma sintering and/or sintering at a relatively low temperature. The composite may comprise a mixture of Ca-α-SiAlON and β-SiAlON ceramic reinforced by boron nitride in either or both cubic and hexagonal phases.

First claim

The invention claimed is:

1. A method for producing a composite of cubic boron nitride (cBN) dispersed in a SiAlON ceramic, the method comprising:
mixing
silicon nitride nanoparticles,
aluminum nitride nanoparticles,
silica nanoparticles,
calcium oxide nanoparticles, and
cubic boron nitride (cBN) microparticles to produce a mixture, and

sintering the mixture to produce the composite.

2. The method of claim 1 , wherein the mixing involves sonication.

3. The method of claim 1 , wherein the mixing involves ball milling.

4. The method of claim 1 , wherein the cBN microparticles have a largest linear dimension of 10-50 μm and are present in the mixture at a weight percentage of 5-40 wt %, relative to a total weight of the mixture.

5. The method of claim 4 , wherein the mixture comprises nickel, the nickel located on an exterior surface of the cBN microparticles.

6. The method of claim 5 , wherein the cBN microparticles are coated with nickel and comprise 20-80 wt % nickel, based on a total weight of the cBN microparticles.

7. The method of claim 6 , wherein the composite has a higher fracture toughness than an otherwise identical composite sintered from cBN microparticles that do not have nickel.

8. The method of claim 1 , wherein the silicon nitride nanoparticles comprise α-Si 3 N 4 .

9. The method of claim 1 , wherein the aluminum nitride nanoparticles have a longest linear dimension of 30-120 nm.

10. The method of claim 1 , wherein the aluminum nitride nanoparticles have a longest linear dimension of 30-70 nm.

11. The method of claim 10 , wherein the composite has a higher fracture toughness than an otherwise identical composite produced from other aluminum nitride nanoparticles having a longest linear dimension of 85-500 nm.

12. The method of claim 10 , wherein at least 75 wt % of the SiAlON ceramic is in a β phase, relative to a total weight of the SiAlON ceramic.

13. The method of claim 10 , wherein the composite comprises boron nitride, and 40-95 wt % of the boron nitride relative to a total weight of the boron nitride is hexagonal boron nitride (hBN) as determined by XRD and/or Raman spectroscopy.

14. The method of claim 1 , wherein the sintering is a spark plasma sintering process.

15. The method of claim 1 , wherein the sintering is performed at a temperature ranging from 1400-1600° C.

16. The method of claim 1 , wherein the sintering comprises heating the mixture at a rate ranging from 5-600° C./min.

17. The method of claim 1 , wherein the sintering comprises heating the mixture at a rate ranging from 90-110° C./min.

18. The method of claim 1 , wherein the sintering comprises applying a uniaxial pressure ranging from 30-80 MPa to the mixture.

19. The method of claim 1 , wherein the composite has a Vickers hardness (HV 10 ) of 8-25 GPa.

20. The method of claim 1 , wherein the composite has a fracture toughness of 5-13 MPa√m.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

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

Classifications

• C04B2235/3878

  Alpha silicon nitrides · CPC title

• C04B2235/762

  Cubic symmetry, e.g. beta-SiC · CPC title

• C04B35/62615

  High energy or reactive ball milling · CPC title

• C04B2235/6567

  Treatment time · CPC title

• C04B35/597

  based on silicon oxynitride, {e.g. SIALONS} · CPC title