Method of producing nitride fluorescent material

Patent metadata

Field	Value
Publication number	US-10781370-B2
Application number	US-201715842133-A
Country	US
Kind code	B2
Filing date	Dec 14, 2017
Priority date	Dec 15, 2016
Publication date	Sep 22, 2020
Grant date	Sep 22, 2020

Abstract

Provided is a production method of a nitride fluorescent material capable of producing a nitride fluorescent material having a higher emission intensity. The production method is for producing a nitride fluorescent material having a composition containing at least one element M a selected from the group consisting of Sr, Ca, Ba and Mg, at least one element M b selected from the group consisting of Li, Na and K, at least one element M c selected from the group consisting of Eu, Ce, Tb and Mn, and Al and N, which includes subjecting a raw material mixture containing elements constituting the composition of the nitride fluorescent material, along with SrF 2 and/or LiF added thereto as a flux, to a heat treatment, wherein the amount of the flux is in a range of 5.0% by mass or more and 15% by mass or less relative to the total amount, 100% by mass of the raw material mixture and the flux.

First claim

The invention claimed is:

1. A method of producing a nitride fluorescent material having a composition containing at least one element Ma selected from the group consisting of Sr, Ca, Ba and Mg, at least one element M b selected from the group consisting of Li, Na and K, at least one element M C selected from the group consisting of Eu, Ce, Tb and Mn, and Al and N, comprising:
subjecting a raw material mixture containing elements constituting the composition of the nitride fluorescent material, along with SrF 2 and/or LiF added thereto as a flux, to a heat treatment to obtain a heat-treated product, wherein an amount of the flux is in a range of 5.0% by mass or more and 15% by mass or less relative to a total mass amount of the raw material mixture and the flux,
wherein the heat treatment is carried out in an atmosphere containing a nitrogen gas, and a pressure for the heat treatment is in a range of 0.2 MPa or more and 200 MPa or less as a gauge pressure.

2. The method of producing a nitride fluorescent material according to claim 1 , wherein the nitride fluorescent material has a composition represented by formula (I):
M a w M b x Eu y Al 3 N z   (I)

wherein M a is at least one element selected from the group consisting of Sr, Ca, Ba, and Mg; M b is at least one element selected from the group consisting of Li, Na, and K; and w, x, y, and z each are numbers satisfying 0.8≤w<1.1, 0.5≤x≤1.8, 0.001<y≤0.1, and 1.5≤z≤5.0.

3. The method of producing a nitride fluorescent material according to claim 2 , wherein the element M a contains at least Sr and the element M b contains at least Li.

4. The method of producing a nitride fluorescent material according to claim 1 , wherein a temperature for the heat treatment is in a range of 1,000° C. or higher and 1,400° C. or lower.

5. The method of producing a nitride fluorescent material according to claim 1 , wherein a temperature for the heat treatment is in a range of 1,000° C. or higher and 1,300° C. or lower.

6. The method of producing a nitride fluorescent material according to claim 1 , wherein the amount of the flux is in a range of 9.0% by mass or more to a total mass amount of the raw material mixture and the flux.

7. The method of producing a nitride fluorescent material according to claim 2 , wherein y and z each are numbers satisfying 0.001<y≤0.02, and 2.0≤z≤4.0.

8. The method of producing a nitride fluorescent material according to claim 2 , wherein y and z each are numbers satisfying 0.002≤y≤0.015, and 2.0≤z≤4.0.

9. The method of producing a nitride fluorescent material according to claim 1 , wherein the raw material mixture containing a metal of Sr or a first metal compound containing at least Sr, a metal of Li or a second metal compound contains at least Li, a metal of Eu or a third compound containing Eu, and a metal of Al or a Al-containing metal compound.

10. The method of producing a nitride fluorescent material according to claim 9 , wherein the first metal compound containing at least Sr is at least one selected from the group consisting of SrN 2 , SrN, Sr 3 N 2 , SrH 2 , SrF 2 , an imide compound including Sr, and an amide compound including Sr,
the second metal compound containing Li is at least one selected from the group consisting of Li 3 N, LiN 3 , LiH, and LiAlH 4 ,
the third metal compound containing Eu is at least one selected from the group consisting of Eu 2 O 3 , EuN, and EuF 3 , and
the Al-containing metal compound is at least one selected from the group consisting of AlH 3 , AlF 3 and LiAlH 4 .

11. The method of producing a nitride fluorescent material according to claim 1 , wherein the heat treatment is a two-stage heat treatment, wherein a first-stage heat treatment is carried out in a range of 800° C. or higher and 1,000° C. or lower, followed by gradual heating, and a second-stage heat treatment that is carried out in a range of 1,000° C. or higher and 1,400° C. or lower.

12. The method of producing a nitride fluorescent material according to claim 1 , wherein a content of the nitrogen gas in the atmosphere for the heat treatment is 70% by volume or more.

13. The method of producing a nitride fluorescent material according to claim 1 , wherein the pressure for the heat treatment is in a range of 0.8 MPa or more and 1.0 MPa or less as a gauge pressure.

14. The method of producing a nitride fluorescent material according to claim 1 , the method further comprises grinding the heat-treated product after the heat treatment.

15. The method of producing a nitride fluorescent material according to claim 1 , the method comprises subjecting the heat-treated product to classification after the heat treatment.

16. The method of producing a nitride fluorescent material according to claim 1 , wherein an average particle diameter of the nitride fluorescent material is in a range of 4.0 μm or more and 30 μm or less.

17. The method of producing a nitride fluorescent material according to claim 1 , wherein the nitride fluorescent material absorbs light having a wavelength range of 400 nm or more and 570 nm or less, and emits fluorescence having an emission peak wavelength in a wavelength range of 630 nm or more and 670 nm or less.

Assignees

• Nichia Corp

Inventors

• Wakui Sadakazu
• Yoshida Shigeki
• Hosokawa Shoji

Classifications

• C01F7/78

  Compounds containing aluminium, with or without oxygen or hydrogen, and containing two or more other elements (aluminates C01F7/02; compounds containing aluminium, fluorine and alkali or alkaline earth metals C01F7/54; nitrates containing other cations besides aluminium C01F7/66; sulfides, sulfites or sulfates containing other cations besides aluminium C01F7/70 - C01F7/74) · CPC title

• C09K11/77346

  Aluminium Nitrides or Aluminium Oxynitrides · CPC title

• C01P2004/61

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

• C09K11/7728 Primary

  containing europium · CPC title

• C01P2004/03

  obtained by SEM · CPC title