Method for forming sintered ceramic material

Patent metadata

Field	Value
Publication number	US-10364192-B2
Application number	US-201815917127-A
Country	US
Kind code	B2
Filing date	Mar 9, 2018
Priority date	Mar 18, 2016
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

A Ca—SiAlON ceramic with enhanced mechanical properties and a method employing micron-sized and submicron precursors to form the Ca—SiAlON ceramic. The Ca—SiAlON ceramic comprises not more than 42 wt % silicon, relative to the total weight of the Ca—SiAlON ceramic. The method employs submicron particles and also allows for substituting a portion of aluminum nitride with aluminum to form the Ca—SiAlON ceramic with enhanced mechanical properties.

First claim

The invention claimed is:

1. A process for forming a sintered Ca-SiAlON ceramic containing aluminum particles, comprising:
mixing
calcium oxide;
silicon nitride;
alumina;
aluminum nitride; and
1.8 wt % to 10 wt % of aluminum particles to form a powder mixture, wherein wt % is based on the total weight of the powder mixture;

spark plasma sintering the powder mixture under a uniaxial pressure of from 20 to 55 MPa to form the sintered Ca-SiAlON ceramic; and
cooling the sintered Ca-SiAlON ceramic to a temperature ranging from 20-40° C.

2. The process of claim 1 , wherein the spark plasma sintering is performed in an atmosphere consisting essentially of nitrogen gas.

3. The process of claim 1 , wherein the mixing is at least one of sonication and ball milling.

4. The process of claim 1 , wherein the mixing proceeds for 10-30 minutes.

5. The process of claim 1 , wherein the calcium oxide is in the form of particles with a diameter ranging from 1-200 nm.

6. The process of claim 1 , wherein an amount of the silicon nitride ranges from 40 wt % to less than 80 wt % relative to a total weight of the powder mixture.

7. The process of claim 1 , wherein the silicon nitride is α-Si 3 N 4 and in the form of particles with a diameter ranging from 1-200 nm.

8. The process of claim 1 , wherein the silicon nitride is amorphous and in the form of particles with a diameter ranging from 1-100 nm.

9. The process of claim 1 , wherein the alumina is in the form of particles with a diameter ranging from 1-200 nm.

10. The process of claim 1 , wherein the aluminum nitride is in the form of particles with a diameter ranging from 1-200 nm.

11. The process of claim 1 , wherein the aluminum particles have a diameter ranging from 10-100 μm.

12. The process of claim 1 , wherein the spark plasma sintering is performed at a temperature ranging from 1400-1600° C.

13. The process of claim 1 , wherein the spark plasma sintering comprises heating the powder mixture at a rate ranging from 5-600° C./min.

14. The process of claim 1 , wherein the spark plasma sintering comprises heating the powder mixture at a rate ranging from 90-110° C./min.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Hakeem Abbas Saeed
• Laoui Tahar
• Almaliki Moath Mohammad
• Raja Khan Awais Muhammad
• Patel Faheemuddin

Classifications

• C04B2235/5454

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

• C04B2235/6562

  Heating rate · CPC title

• C04B2235/767

  Hexagonal symmetry, e.g. beta-Si3N4, beta-Sialon, alpha-SiC or hexa-ferrites · CPC title

• C04B2235/3878

  Alpha silicon nitrides · CPC title

• C04B35/645

  Pressure sintering · CPC title