# US 8,541,330 B2 · Method of producing transparent ceramics

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,541,330 B2
- Document ID: US8541330B2
- Status: Granted
- Kind: B2
- Application number: 12/728,865
- Filed: 2010-03-22
- Published: 2010-09-30
- Granted: 2013-09-24
- Earliest claimed: 2009-03-31
- Assignees: Schott AG
- Applicants: Yvonne Menke; Akio Ikesue
- Inventors: Yvonne Menke; Akio Ikesue
- Web page: https://patentgrep.com/patent/US8541330B2

## CPC

- C04B 35/486: Fine ceramics
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- C04B 35/6455: {Hot isostatic pressing}
- 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 2235/3232: Titanium oxides or titanates, e.g. rutile or anatase
- C04B 2235/3244: Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
- C04B 2235/3418: Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
- C04B 2235/445: Fluoride containing anions, e.g. fluosilicate
- C04B 2235/5445: submicron sized, i.e. from 0,1 to 1 micron
- C04B 2235/5454: nanometer sized, i.e. below 100 nm
- C04B 2235/549: the particle size being expressed by crystallite size or primary particle size
- C04B 2235/604: Pressing at temperatures other than sintering temperatures
- C04B 2235/656: characterised by specific heating conditions during heat treatment
- C04B 2235/658: Atmosphere during thermal treatment
- C04B 2235/6581: Total pressure below 1 atmosphere, e.g. vacuum
- C04B 2235/6582: Hydrogen containing atmosphere
- C04B 2235/661: Multi-step sintering
- C04B 2235/663: Oxidative annealing
- C04B 2235/762: Cubic symmetry, e.g. beta-SiC
- C04B 2235/77: Density
- C04B 2235/786: Micrometer sized grains, i.e. from 1 to 100 micron
- C04B 2235/9653: Translucent or transparent ceramics other than alumina
- C04B 2235/9661: Colour
- 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
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

The method of making a transparent ceramic includes making a molded body from a powder mixture of starting materials, which include one or more sintering aids. The sintering aids can include SiO2, TiO2, ZrO2, HfO2, Al2O3 and/or fluorides. The transparent ceramic is made by pre-sintering the molded body at temperatures between 500° C. to 900° C., subsequently sintering in vacuum at temperatures between 1400° C. and 1900° C. and then pressurizing the sintered molded body at a pressure of from 10 to 198 MPa followed by annealing. The optoceramic material contains crystals with a stoichiometry of A2+XBYBYDZE7, wherein −1.15≦x≦+1.1, 0≦y≦3, 0≦z≦1.6 and 3x+4y+5z=8; and wherein A is a trivalent rare earth cation, B is a tetravalent cation, D is a pentavalent cation and E is a divalent anion.

## Claims

### Claim 1

A method of producing an optoceramic material, said method comprising the step of manufacturing a molded body from a powder mixture of starting materials, wherein said starting materials include at least one sintering aid selected from the group consisting of SiO2, TiO2, ZrO2, HfO2, Al2O3 and fluorides;
wherein the optoceramic material produced by said method comprises at least 99% by weight of single crystals with a cubic crystal structure analogous to that of pyrochlore or fluorite and with a stoichiometry of A2+xByDzE7, wherein −1.15≦X≦+1.1, 0 ≦Y≦3, 0≦Z≦1.6 and 3X+4Y+5Z=8;
wherein A is at least one trivalent rare earth cation, B is at least one tetravalent cation, D is at least one pentavalent cation and E is at least one divalent anion;
wherein the optoceramic material produced by the method has an average grain size in a range from 5 to 300 μm and is very densely sintered; and
wherein a sample of the optoceramic material that has a thickness of 5 mm has an internal transmittance that is at least 50% at a wavelength of 400 nm and at least 60% at a wavelength of 600 nm.

### Claim 2 (depends on 1)

The method according to claim 1, wherein A is selected from the group consisting of Y, Gd, Yb, Lu, Sc, La and mixtures of these elements.

### Claim 3 (depends on 1)

The method according to claim 1, wherein B is selected from the group consisting of Zr, Ti, Hf, Sn, Ge and mixtures of these elements.

### Claim 4 (depends on 1)

The method according to claim 1, further comprising the step of pre-sintering the molded body to form a pre-sintered molded body.

### Claim 5 (depends on 4)

The method according to claim 4, wherein the pre-sintering takes place at temperatures between 500° C. and 900° C.

### Claim 6 (depends on 4)

The method as defined in claim 4, further comprising the step of sintering of the pre-sintered molded body in vacuum.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the sintering takes place at temperatures between 1400° C. 1900° C.

### Claim 8 (depends on 6)

The method according to claim 6, further comprising pressurizing the sintered molded body formed by the sintering.

### Claim 9 (depends on 8)

The method according to claim 8, wherein the pressurizing of the sintered molded body takes place at temperatures between 1400° C. and 2000° C. and at pressures between 10 and 198 MPa.

### Claim 10 (depends on 8)

The method according to claim 8, further comprising annealing the sintered molded body at temperatures between 600 and 1600° C. in an atmosphere that comprises oxygen after the pressurizing.

### Claim 11 (depends on 1)

The method according to claim 1, wherein said starting materials comprise from 0.01 to 3% by weight of said at least one sintering aid.

### Claim 12 (depends on 1)

The method according to claim 1, wherein said starting materials comprise from 0.01 to 10% by weight of said at least one sintering aid.

### Claim 13

A method of producing an optoceramic material, said method comprising the step of manufacturing a molded body from a powder mixture of starting materials, wherein said starting materials include an effective amount of at least one sintering aid that improves optical properties of said optoceramic material produced by the method;
wherein said at least one sintering aid is selected from the group consisting of SiO2, TiO2, ZrO2, HfO2, Al2O3 and fluorides; and
wherein the optoceramic material produced by said method comprises at least 99% by weight of crystals with a cubic crystal structure analogous to that of pyrochiore or fluorite and with a stoichiometry of A2+xByDzE7, wherein −1.15≦X≦+1.1, 0≦Y≦3, 0≦Z≦1.6 and 3X+4Y+5Z=8;
wherein A is at least one trivalent rare earth cation, B is at least one tetravalent cation, D is at least one pentavalent cation and E is at least one divalent anion;
wherein the optoceramic material produced by the method has an average grain size in a range from 5 to 300 μm and is very densely sintered; and
wherein a sample of the optoceramic material that has a thickness of 5 mm has an internal transmittance that is at least 50% at a wavelength of 400 nm and at least 60% at a wavelength of 600 nm.