# US 11,078,416 B2 · Transparent fluorescent sialon ceramic and method of producing same

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- Number: US 11,078,416 B2
- Document ID: US11078416B2
- Status: Granted
- Kind: B2
- Application number: 15/123,552
- Filed: 2015-03-06
- Published: 2017-03-16
- Granted: 2021-08-03
- Earliest claimed: 2014-03-06
- Assignees: National University Corporation Yokohama National University; Kanagawa Institute of Industrial Science and Technology
- Applicants: Kanagawa Academy of Science and Technology; National University Corporation YOKOHAMA National University
- Inventors: Takuma Takahashi; Junichi Tatami; Yuki Sano; Takehiko Tanaka; Masahiro Yokouchi
- Web page: https://patentgrep.com/patent/US11078416B2

## CPC

- C09K 11/7792: {Aluminates}
- C04B 35/597: based on silicon oxynitride, {e.g. SIALONS}
- C04B 35/62625: {Wet mixtures}
- C04B 35/62695: {Granulation or pelletising (devices for shaping artificial aggregates from ceramic mixtures B28B1/004)}
- C04B 35/6303: {Inorganic additives}
- C04B 35/638: Removal thereof
- C04B 35/645: Pressure sintering
- C09K 11/025: {non-luminescent particle coatings or suspension media}
- C09K 11/0883: {Arsenides; Nitrides; Phosphides}
- C09K 11/7721: {Aluminates}
- C09K 11/7734: {Aluminates}
- C09K 11/7774: {Aluminates}
- C04B 2235/3203: Lithium oxide or oxide-forming salts thereof
- C04B 2235/3205: Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3224: Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
- C04B 2235/3225: Yttrium oxide or oxide-forming salts thereof
- C04B 2235/3244: Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
- C04B 2235/3865: Aluminium nitrides
- C04B 2235/3873: Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
- C04B 2235/5436: micrometer sized, i.e. from 1 to 100 micron
- C04B 2235/5445: submicron sized, i.e. from 0,1 to 1 micron
- C04B 2235/604: Pressing at temperatures other than sintering temperatures
- C04B 2235/658: Atmosphere during thermal treatment
- C04B 2235/6562: Heating rate
- C04B 2235/6581: Total pressure below 1 atmosphere, e.g. vacuum
- C04B 2235/6586: Processes characterised by the flow of gas
- C04B 2235/661: Multi-step sintering
- C04B 2235/9646: Optical properties
- C04B 2235/9653: Translucent or transparent ceramics other than alumina
- H01L 33/502
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- H01L

## Abstract

Provided are a transparent fluorescent sialon ceramic having fluorescence and optical transparency; and a method of producing the same. Such a transparent fluorescent sialon ceramic includes a sialon phosphor which contains a matrix formed of a silicon nitride compound represented by the formula Mx(Si,Al)y(N,O)z (here, M represents at least one selected from the group consisting of Li, alkaline earth metals, and rare earth metals, 0≤x/z<3, and 0<y/z<1) and a luminescent center element.

## Claims

### Claim 1

A fluorescent sialon ceramic consisting of:
a sialon phosphor in the form of a sintered bulk body, the sialon phosphor consisting of a matrix formed of β-sialon represented by the formula (Si,Al)6(N,O)8, and a luminescent center element,
wherein the linear transmittance of visible light of the sintered bulk body is 11% or greater at a wavelength of 800 nm as measured with respect to a test specimen of the sintered bulk body having a thickness of 100 μm.

### Claim 2 (depends on 1)

A method of producing a fluorescent sialon ceramic according to claim 1, the method comprising:
preparing a primary molded body by uniaxial press molding of a mixture which contains at least silicon nitride powder, a substance serving as a luminescent center element source, and a sintering aid;
preparing a secondary molded body by cold isostatic press molding of the primary molded body;
preparing a sintered bulk body by pre-sintering the secondary molded body in a nitrogen atmosphere; and
performing a pressure-sintering treatment on the sintered bulk body in a nitrogen atmosphere.

### Claim 3 (depends on 2)

The method of producing a fluorescent sialon ceramic according to claim 2, wherein at least one member selected from the group consisting of rare earth oxides, alkaline earth metal oxides, aluminum oxide, aluminum nitride, silicon oxide, and hafnium oxide is used as the sintering aid.

### Claim 4 (depends on 1)

The fluorescent sialon ceramic according to claim 1, wherein the luminescent center element is one selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Gd, Cr, Sn, Cu, Zn, Ga, Ge, As, Ag, Cd, In, Sb, Au, Hg, Tl, Pb, Bi, and Fe.