Sialon composite and cutting tools made thereof

Patent metadata

Field	Value
Publication number	US-10221102-B2
Application number	US-201615567262-A
Country	US
Kind code	B2
Filing date	Apr 22, 2016
Priority date	Apr 24, 2015
Publication date	Mar 5, 2019
Grant date	Mar 5, 2019

Abstract

A SiAlON composite includes a SiAlON phase including α-SiAlON phase, β-SiAlON phase and grain boundary phase. The SiAlON composite is prepared from a starting powder mixture including a silicon nitride powder and at least one powder providing aluminum, oxygen, nitrogen, yttrium (Y) and erbium (Er) to the SiAlON composite. The SiAlON composite contains the SiAlON phase of at least 90 vol %, z-value of the β-SiAlON phase ranges between 0.27 and 0.36 and thermal diffusivity of the SiAlON composite is equal to or greater than 2.4 (mm2/sec) and equal to or less than 5.2 (mm2/sec).

First claim

The invention claimed is:

1. A SiAlON composite comprising a SiAlON phase including α-SiAlON phase, β-SiAlON phase and grain boundary phase,
wherein the SiAlON composite is prepared from a starting powder mixture including a silicon nitride powder and at least one powder providing aluminum, oxygen, nitrogen, yttrium (Y) and erbium (Er) to the SiAlON composite,
wherein the SiAlON composite contains the SiAlON phase of at least 90 vol %,
wherein z-value of the β-SiAlON phase ranges between 0.27 and 0.36,
wherein a thermal diffusivity of the SiAlON composite is equal to or greater than 2.4 (mm 2 /sec) and equal to or less than 5.2 (mm 2 /sec),
wherein the starting powder mixture includes alumina (Al 2 O 2 ), yttria (Y 2 O 3 ) and erbia (Er 2 O 3 ), and
wherein the sum of contents of the alumina, the yttria and the erbia ranges from 8.87 wt % to 11.83 wt %.

2. The SiAlON composite of claim 1 , wherein a thermal conductivity of the SiAlON composite is equal to or greater than 8.2 (W/(m·K)) and equal to or less than 11.4 (W/(m·K)).

3. The SiAlON composite of claim 1 , wherein a thermal expansion coefficient of the SiAlON composite is equal to or greater than 3.4 (10 −6 /K) and equal to or less than 4.0 (10 −6 /K).

4. The SiAlON composite of claim 1 , wherein a ratio of the α-SiAlON phase to the SiAlON phase is equal to or greater than 21.75% and equal to or less than 48.5%.

5. The SiAlON composite of claim 1 , wherein the sum of contents of the yttria and the erbia ranges between 6.08 wt % to 9.12 wt %.

6. The SiAlON composite of claim 1 , wherein a Vickers hardness of the SiAlON composite is between 16.6 and 18.7 GPa at room temperature, and a fracture toughness of the SiAlON composite is between 4.1 and 5.4 MPam 0.5 .

7. A metal machining cutting tool, comprising the SiAlON composite according to claim 1 .

8. A SiAlON composite comprising a SiAlON phase including α-SiAlON phase, β-SiAlON phase and grain boundary phase,
wherein the SiAlON composite contains the SiAlON phase of at least 90 vol %,
wherein z-value of the β-SiAlON phase ranges between 0.27 and 0.36,
wherein a thermal diffusivity of the SiAlON composite is equal to or greater than 2.4 (mm 2 /sec) and equal to or less than 5.2 (mm 2 /sec),
wherein a thermal conductivity of the SiAlON composite is equal to or greater than 8.2 (W/(m·K)) and equal to or less than 11.4 (W/(m·K)),
a thermal expansion coefficient of the SiAlON composite is equal to or greater than 3.4 (10 −6 /K) and equal to or less than 4.0 (10 −6 /K),
wherein the starting powder mixture includes alumina (Al 2 O 3 ), yttria (Y 2 O 3 ) and erbia (Er 2 O 3 ), and
wherein the sum of contents of the alumina, the yttria and the erbia ranges from 8.87 wt % to 11.83 wt %.

9. The SiAlON composite of claim 8 , wherein a ratio of the α-SiAlON phase to the SiAlON phase is equal to or greater than 21.75% and equal to or less than 48.5%.

10. The SiAlON composite of claim 9 , wherein a Vickers hardness of the SiAlON composite is between 16.6 and 18.7 GPa at room temperature, and a fracture toughness of the SiAlON composite is between 4.1 and 5.4 MPam 0.5 .

11. The SiAlON composite of claim 8 , wherein
the starting powder mixture includes a silicon nitride powder and at least one powder providing aluminum, oxygen, nitrogen, yttrium (Y) and erbium (Er) to the SiAlON composite.

12. The SiAlON composite of claim 11 , wherein the sum of contents of the yttria and the erbia ranges between 6.08 wt % to 9.12 wt %.

13. A SiAlON composite comprising a SiAlON phase including α-SiAlON phase, β-SiAlON phase and grain boundary phase,
wherein the SiAlON composite contains the SiAlON phase of at least 90 vol %,
wherein the SiAlON composite includes both yttrium (Y) and erbium (Er),
wherein z-value of the β-SiAlON phase ranges between 0.27 and 0.36,
wherein a thermal diffusivity of the SiAlON composite is equal to or greater than 2.4 (mm 2 /sec) and equal to or less than 5.2 (mm 2 /sec),
wherein a thermal conductivity of the SiAlON composite is equal to or greater than 8.2 (W/(m·K)) and equal to or less than 11.4 (W/(m·K)), and
a thermal expansion coefficient of the SiAlON composite is equal to or greater than 3.4 (10 −6 /K) and equal to or less than 4.0 (10 −6 /K).

14. The SiAlON composite of claim 13 , wherein a ratio of the α-SiAlON phase to the SiAlON phase is equal to or greater than 21.75% and equal to or less than 48.5%.

15. The SiAlON composite of claim 14 , wherein a Vickers hardness of the SiAlON composite is between 16.6 and 18.7 GPa at room temperature, and a fracture toughness of the SiAlON composite is between 4.1 and 5.4 MPam 0.5 .

Assignees

• Taegu Tec Ltd

Inventors

• Chun Sung Su
• Lee Dae Yeop
• Park Geun Ho
• Hong Chang Hoon

Classifications

• C04B2235/606

  Drying · CPC title

• C04B2235/766

  Trigonal symmetry, e.g. alpha-Si3N4 or alpha-Sialon · CPC title

• B23C5/00

  Milling-cutters (for cutting gear-teeth B23F21/12) · CPC title

• C04B2235/3224

  Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide · CPC title

• C04B2235/96

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