Method for producing β-sialon fluorescent material

Patent metadata

Field	Value
Publication number	US-10385267-B2
Application number	US-201615378690-A
Country	US
Kind code	B2
Filing date	Dec 14, 2016
Priority date	Dec 15, 2015
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

A method for producing β-sialon fluorescent material having excellent emission intensity is provided. The method for producing β-sialon fluorescent material includes providing a composition comprising silicon nitride that contains aluminum, an oxygen atom, and europium, heat treating the composition, and contacting the heat-treated composition with a basic substance.

First claim

What is claimed is:

1. A method for producing a β-sialon fluorescent material, the method comprising:
providing a composition comprising silicon nitride that contains aluminium, an oxygen atom, and europium;
heat treating the composition,
contacting the heat-treated composition with a basic substance, and
washing the composition, which has been contacted with the basic substance, with a liquid medium,
wherein the washing removes a basic compound attached to a surface of the fluorescent material.

2. The method according to claim 1 , wherein the basic substance comprises at least one selected from the group consisting of LiOH, NaOH, KOH, RbOH, CsOH and NH 3 .

3. The method according to claim 1 , wherein the contacting of the heat-treated composition with the basic substance takes place at a temperature of not less than 50° C. and not more than 650° C.

4. The method according to claim 3 , wherein the contacting of the heat-treated composition with the basic substance comprises a contact at a first temperature and a contact at a second temperature higher than the first temperature.

5. The method according to claim 1 , wherein the contacting of the heat-treated composition with the basic substance comprises mixing the heat-treated composition with a solution of the basic substance, and removing at least part of a solvent present in the solution.

6. The method according to claim 1 , wherein a weight ratio of the basic substance brought into contact with the heat-treated composition is not less than 0.5 wt % relative to the heat-treated composition.

7. The method according to claim 1 , wherein the heat treating the composition takes place in the presence of a europium compound.

8. The method according to claim 1 , wherein the heat treating the composition takes place at a temperature of not less than 1300° C. and not more than 1600° C.

9. The method according to claim 1 , wherein the heat treating the composition takes place in a rare gas atmosphere.

10. The method according to claim 1 , wherein the providing of the composition comprises heat treating a mixture comprising an aluminum compound, a europium compound and a silicon nitride.

11. The method according to claim 1 , further comprising heat treating the composition in a nitrogen atmosphere between the providing and the heat treating of the composition.

12. The method according to claim 1 , wherein the composition has a composition represented by a formula: Si 6-z Al z O z N 8-z :Eu, wherein z satisfies 0<z≤4.2.

13. The method according to claim 1 , wherein the liquid medium is acidic.

14. The method according to claim 1 , wherein the method comprises more than one washings.

15. The method according to claim 14 , wherein the more than one washings include at least one washing using an acidic solution.

16. The method according to claim 1 , wherein a contact time in the contacting is not less than 0.1 hour and not more than 48 hours.

17. The method according to claim 5 , wherein a concentration of the basic substance in the solution of the basic substance is not less than 0.1 wt % and not more than 80 wt %.

18. The method according to claim 5 , wherein a rate of removal of the solvent is not less than 1 wt %.

Assignees

• Nichia Corp

Inventors

• MORIKAWA Motoharu
• Hosokawa Shoji

Classifications

• C09K11/0883 Primary

  Arsenides; Nitrides; Phosphides · CPC title

• C09K11/7734 Primary

  Aluminates · CPC title

• C09K11/77348 Primary

  Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides · CPC title