Aluminum nitride powder and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-12384678-B2
Application number	US-202117798383-A
Country	US
Kind code	B2
Filing date	Feb 4, 2021
Priority date	Feb 10, 2020
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

Provided is an aluminum nitride powder useful as a raw material when an aluminum nitride sintered body excellent as an insulating high thermal conductive member is manufactured, particularly, by press molding. An aluminum nitride powder includes particles having a sphericity of 0.8 or more, in which a median size D 50 obtained by a laser diffraction method is 0.5 to 1.5 μm, a ratio D 90 /D 50 of a particle size D 90 corresponding to a cumulative undersize distribution of 90% to the D 50 is 2.2 or less, a BET specific surface area is 2 to 4 m 2 /g, and a total oxygen concentration is 0.6 to 1.2% by mass.

First claim

The invention claimed is:

1. An aluminum nitride powder comprising primary particles having a sphericity of 0.8 or more, wherein
a median size D 50 obtained by a laser diffraction method is 0.5 to 1.5 μm, a ratio D 90 /D 50 of a particle size D 90 corresponding to a cumulative undersize distribution of 90% to the D 50 is 2.0 or less, and a particle size D 10 corresponding to a cumulative undersize distribution of 10% is ranged from 0.62 μm to 0.66 μm,
a BET specific surface area is 2 to 4 m 2 /g,
a total oxygen content is 0.6 to 1.2% by mass, and
a pressurized bulk density is 1.62 g/cm 3 or greater,
wherein the aluminum nitride powder is prepared by:
reducing and nitriding a raw material powder containing an aluminum oxide powder and a carbon powder under nitrogen to produce a synthetic powder containing aluminum nitride aggregated particles and a carbon powder;
disintegrating the synthetic powder in a disintegrating treatment without using a medium to produce a disintegrated synthetic powder; and
oxidizing off excess carbon from the disintegrated synthetic powder to obtain the aluminum nitride powder.

2. The aluminum nitride powder according to claim 1 , wherein a degree of aggregation calculated from the median size D 50 and the BET specific surface area by the following formula is within a range of 1.1 to 2.2
Degree of aggregation= D 50 /D BET ,
wherein D BET =6/(ρ×S),
wherein:
S: BET specific surface area,
D BET : primary particle size calculated from BET specific surface area,
D 50 : a median size obtained by laser diffraction method, and
ρ: true specific gravity of AlN (3.26 g/cm 3 ).

3. The aluminum nitride powder of claim 1 , wherein the disintegrating treatment is performed with an ejector.

4. The aluminum nitride powder of claim 1 , wherein the pressurized bulk density of the aluminum nitride powder is from 1.62 g/cm 3 to 1.66 g/cm 3 .

Assignees

• Tokuyama Corp

Inventors

• Tagashira Yoshinori
• Yamashita Yoshiaki
• Hamamoto Masato

Classifications

• C01P2006/12

  Surface area · CPC title

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title

• C01P2004/50

  Agglomerated particles · CPC title

• C01P2004/32

  Spheres · CPC title