Method for preparing spherical aluminum oxynitride powder

Patent metadata

Field	Value
Publication number	US-10144645-B1
Application number	US-201715661045-A
Country	US
Kind code	B1
Filing date	Jul 27, 2017
Priority date	Jul 27, 2017
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

A method for preparing spherical aluminum oxynitride powder, comprising the steps of (A) providing an alumina powder and a resin, both of which are then dispersed and dissolved in a solvent to form a mixed slurry; (B) subjecting the mixed slurry to spray drying to form a spherical powder; (C) subjecting the spherical powder to a carbonization treatment under an inert atmosphere to form a carbonized spherical powder; (D) subjecting the carbonized spherical powder to carbothermic reduction in a nitrogen-containing atmosphere at a temperature of 1450° C. to 1550° C.; (E) keeping the spherical powder that has been subjected to carbothermic reduction in the nitrogen-containing atmosphere to carry out a nitridation reaction at a temperature of 1700° C. to 1730° C., forming a nitrided spherical aluminum oxynitride powder; (F) subjecting the nitrided spherical aluminum oxynitride powder to decarbonization in an oxygen-containing atmosphere to form the spherical aluminum oxynitride powder.

First claim

What is claimed is:

1. A method for preparing spherical aluminum oxynitride powder, comprising the steps of:
(A) providing an alumina powder and a resin, both of which are then dispersed and dissolved in a solvent to form a mixed slurry;
(B) subjecting the mixed slurry to spray drying to form a spherical powder;
(C) subjecting the spherical powder to a carbonization treatment under an inert atmosphere to form a carbonized spherical powder;
(D) subjecting the carbonized spherical powder to carbothermic reduction in a nitrogen-containing atmosphere at a temperature of 1450° C. to 1550° C.;
(E) keeping the spherical powder that has been subjected to carbothermic reduction in the nitrogen-containing atmosphere to carry out a nitridation reaction at a temperature of 1700° C. to 1730° C., forming a nitrided spherical aluminum oxynitride powder;
(F) subjecting the nitrided spherical aluminum oxynitride powder to decarbonization in an oxygen-containing atmosphere.

2. The method for preparing spherical aluminum oxynitride powder of claim 1 , wherein the crystal structure of the alumina powder is selected from the group consisting of α-alumina phase, γ-alumina phase, δ-alumina phase, or the combinations thereof.

3. The method for preparing spherical aluminum oxynitride powder of claim 1 , wherein the resin is selected from the group consisting of a phenolic resin, an epoxy resin, a polyester resin, polymethylmethacrylate, polytetrafluoroethylene, and a melamine-formaldehyde resin.

4. The method for preparing spherical aluminum oxynitride powder of claim 1 , wherein the solvent is selected from the group consisting of water, methanol, ethanol, isopropanol, n-butanol or aqueous acetone.

5. The method for preparing spherical aluminum oxynitride powder of claim 1 , wherein the weight ratio of the alumina powder to the resin is 1:0.05 to 1:0.25.

6. The method for preparing spherical aluminum oxynitride powder of claim 1 , wherein the mixed slurry is mixed by stirring or ball milling at step (A).

7. The method for preparing spherical aluminum oxynitride powder of claim 1 , wherein the carbonization treatment at step (C) is carried out at a temperature of 500° C. to 700° C.

8. The method for preparing spherical aluminum oxynitride powder of claim 1 , wherein the time for carbothermic reduction at step (D) is 1 to 5 hours.

9. The method for preparing spherical aluminum oxynitride powder of claim 1 , wherein the time for the nitridation reaction at step (E) is 1 to 5 hours.

10. The method for preparing spherical aluminum oxynitride powder of claim 1 , wherein the nitrogen-containing atmosphere at step (D) and step (E) is pure nitrogen, a mixed gas of nitrogen and hydrogen, or a mixed gas of nitrogen and ammonia.

Assignees

• Nat Chung Shan Inst Science & Tech

Inventors

• Lai Kuan-Ting
• Wu Chun-Te
• Shih Cheng-Hung
• Kuo Yang-Kuo
• Leu Lea-Hwung

Classifications

• C01B21/0825 Primary

  Aluminium oxynitrides · CPC title

• C01P2004/32

  Spheres · CPC title