Aluminum nitride particle

Patent metadata

Field	Value
Publication number	US-11325830-B2
Application number	US-201816608576-A
Country	US
Kind code	B2
Filing date	Apr 27, 2018
Priority date	Apr 27, 2017
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

An aluminum nitride particle including: a plurality of planes randomly arranged in a surface of the particle, the plurality of planes forming an obtuse ridge part or an obtuse valley part in the surface of the particle, the plurality of planes being observable in a scanning electron micrograph with 500 times magnification; wherein the particle has a longer diameter L of 20 to 200 μm; a ratio L/D of the longer diameter L (unit: μm) to a shorter diameter D (unit: μm) of the particle is 1 to 1.25; and the plurality of planes comprise a first plane, wherein an area S (unit: μm2) of the first plane satisfies S/L≥1.0 μm.

First claim

We claim:

1. An aluminum nitride particle comprising:
a plurality of planes randomly arranged in a surface of the particle, the plurality of planes forming an obtuse ridge part or an obtuse valley part in the surface of the particle, the plurality of planes being observable in a scanning electron micrograph with 500 times magnification,
wherein the particle has a longer diameter L of 20 to 200 μm;
a ratio L/D of the longer diameter L (unit: μm) to a shorter diameter D (unit: μm) of the particle is 1 to 1.25; and
the plurality of planes comprise a first plane, wherein an area S (unit: μm 2 ) of the first plane satisfies S/L≥1.0 μm.

2. The aluminum nitride particle according to claim 1 ,
wherein a content of rare earth metal impurities in the particle is no more than 1 mass ppm in terms of metal.

3. The aluminum nitride particle according to claim 1 ,
wherein the particle does not comprise a void having a diameter of no less than 5 μm.

4. The aluminum nitride particle according to claim 1 ,
wherein the plurality of planes comprise a second plane, wherein an area S (unit: μm 2 ) of the second plane satisfies S/L 2 ≥0.05.

5. An aluminum nitride powder comprising:
the aluminum nitride particle as in claim 1 , in an amount of no less than 40 volume %.

6. The aluminum nitride powder according to claim 5 ,
wherein a content of rare earth metal impurities is no more than 1 mass ppm in terms of metal on the basis of the total mass of the aluminum nitride powder.

7. A filler for a resin, the filler consisting of the aluminum nitride powder as in claim 5 .

8. A resin composition comprising:
the filler for a resin as in claim 7 ; and
a resin,
wherein a content W particle of the aluminum nitride particle in the resin composition is 300 to 1000 parts by weight per 100 parts by weight of the resin; and
the content W particle (unit: parts by weight) of the aluminum nitride particle is calculated by the following formula (2):

W
particle

=

W
powder

×

R
V

1
⁢
0
⁢
0

(
2
)

wherein W powder (unit: parts by weight) is a content of the aluminum nitride powder in the resin composition; and Rv (unit: volume %) is a content of the aluminum nitride particle in the aluminum nitride powder.

9. A method for producing the aluminum nitride powder of claim 5 , the method comprising:
(i) carrying out reduction nitridation of an alumina powder, the (i) comprising heating a raw material mixture in a nitrogen gas-containing atmosphere, the raw material mixture comprising the alumina powder, a carbon powder, and a sulfur component; and
(ii) after completion of the reduction nitridation, keeping, for no less than 1 hour, a product of the reduction nitridation at a temperature within ±30° C. of a heating temperature at a time the reduction nitridation is completed in an atmosphere such that an aluminum nitride powder formed in the (i) is not oxidized,
the (i) comprising:
(i-a) carrying out the reduction nitridation in the nitrogen gas-containing atmosphere being a mixed gas of 55 to 30 volume % of nitrogen gas and 45 to 70 volume % of a diluting gas, at least while a nitridation ratio is 5 to 50%.

10. The method according to claim 9 ,
wherein a content of the sulfur component in the raw material mixture is 1.0 to 20 parts by weight in terms of sulfur per 100 parts by weight of the alumina powder in the raw material mixture.

11. A method for producing the aluminum nitride powder of claim 5 , the method comprising:
(i) carrying out reduction nitridation of an alumina powder, the (i) comprising heating a raw material mixture in a nitrogen gas-containing atmosphere, the raw material mixture comprising the alumina powder, a carbon powder, and a sulfur component; and
(ii) after completion of the reduction nitridation, keeping, for no less than 1 hour, a product of the reduction nitridation at a temperature within ±30° C. of a heating temperature at a time the reduction nitridation is completed in an atmosphere such that an aluminum nitride powder formed in the (i) is not oxidized,
the (i) comprising:
(i-b1) placing the raw material mixture in a setter and placing the setter in a reactor, the setter comprising:
a boat-shaped vessel, a top of the vessel being open;
a lid closing the top of the vessel;
a first opening arranged on an upstream side in a gas flow direction in the reactor such that a gas can be introduced into the setter; and
a second opening arranged on a downstream side in the gas flow direction in the reactor such that a gas can flow out of the setter;

(i-b2) supplying nitrogen gas or a mixed gas comprising nitrogen gas and a diluting gas into the reactor;
(i-b3) making part of a gas supplied into the reactor flow into the setter through the first opening;
(i-b4) forming the nitrogen gas-containing atmosphere in the setter, from a gas flowing into the setter from the first opening and carbon monoxide gas generated by the reduction nitridation; and
(i-b5) carrying out the reduction nitridation in the nitrogen gas-containing atmosphere in the setter, while maintaining conditions such that an average nitrogen gas content p avr N2 in the nitrogen gas-containing atmosphere in the setter calculated by the following formula (3) becomes 55 to 30 volume % and such that an average diluting gas content p avr dilute in the nitrogen gas-containing atmosphere in the setter calculated by the following formula (4) becomes 45 to 70 volume %, at least while a nitridation ratio is 5 to 50%:

p

N
2

avr

=

1
2

⁢

(

p

N
2

in

+

1
⁢
0
⁢
0
×

Assignees

• Tokuyama Corp

Inventors

• Kuramoto Akimasa
• Kanechika Yukihiro

Classifications

• C01P2006/80

  Compositional purity · CPC title

• C01B21/072 Primary

  with aluminium · CPC title

• C08K3/28

  Nitrogen-containing compounds · CPC title

• C09C1/40 Primary

  Compounds of aluminium {(C09C1/0009, C09C1/0015, C09C1/0078, C09C1/32 take precedence)} · CPC title

• C01P2004/54

  Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension · CPC title