ALUMINA SINTERED BODY AND BASE SUBSTRATE FOR OPTICAL DEVICE

• US 20180044195A1
• Filed: 10/30/2017
• Published: 02/15/2018
• Est. Priority Date: 05/13/2015
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: MATSUSHIMA, Kiyoshi, Watanabe, Morimichi, Sato, Kei, Nanataki, Tsutomu
• Granted Patent: US 10,336,625 B2
• Time in Patent Office: Days
• CPC Class Codes: C01F 7/02 Aluminium oxide; Aluminium hydroxide; Aluminates
• CPC Class Codes: C01F 7/442 in presence of a calcination additive
• CPC Class Codes: C01P 2002/60 Compounds characterised by their crystallite size
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/22 with a polygonal circumferential shape
• CPC Class Codes: C01P 2004/54 Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2006/14 Pore volume
• CPC Class Codes: C01P 2006/16 Pore diameter
• CPC Class Codes: C01P 2006/60 Optical properties, e.g. expressed in CIELAB-values
• CPC Class Codes: C01P 2006/80 Compositional purity
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/322 Transition aluminas, e.g. delta or gamma aluminas
• CPC Class Codes: C04B 2235/445 Fluoride containing anions, e.g. fluosilicate
• CPC Class Codes: C04B 2235/5292 Flakes, platelets or plates
• CPC Class Codes: C04B 2235/5296 with a defined aspect ratio, e.g. indicating sphericity
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/6025 : Tape casting, e.g. with a doctor blade
• CPC Class Codes: C04B 2235/604 : Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/6567 : Treatment time
• CPC Class Codes: C04B 2235/658 : Atmosphere during thermal treatment
• CPC Class Codes: C04B 2235/72 : Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
• CPC Class Codes: C04B 2235/725 : Metal content
• CPC Class Codes: C04B 2235/786 : Micrometer sized grains, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/787 : Oriented grains
• CPC Class Codes: C04B 2235/788 : Aspect ratio of the grains
• CPC Class Codes: C04B 35/115 : Translucent or transparent products
• CPC Class Codes: C04B 35/632 : Organic additives
• CPC Class Codes: C04B 35/6342 : Polyvinylacetals, e.g. polyvinylbutyral [PVB]
• CPC Class Codes: C04B 35/645 : Pressure sintering
• CPC Class Codes: G01N 23/207 : Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions
• CPC Class Codes: G02B 1/02 : made of crystals, e.g. rock-salt, semi-conductors G02B1/08 takes precedence

Abstract

An alumina sintered body according to the present invention includes a surface having a degree of c-plane orientation of 5% or more, the degree of c-plane orientation being determined by a Lotgering method using an X-ray diffraction profile obtained through X-ray irradiation at 2θ=20° to 70°. The alumina sintered body contains Mg and F, a Mg/F mass ratio is 0.05 to 3500, and a Mg content is 30 to 3500 ppm by mass. The alumina sintered body has a crystal grain size of 15 to 200 μm. When a field of view of 370.0 μm long×372.0 μm wide is photographed with a 1000-fold magnification and the photograph is visually observed, a number of pores having a diameter of 0.2 to 0.6 μm is 250 or less.

Claims

1. An alumina sintered body comprising:

a surface having a degree of c-plane orientation of 5% or more, the degree of c-plane orientation being determined by a Lotgering method using an X-ray diffraction profile obtained through X-ray irradiation at 2θ

=20°

to 70°

,

wherein the alumina sintered body contains Mg and F, a Mg/F mass ratio is 0.05 to 3500, and a Mg content is 30 to 3500 ppm by mass,

the alumina sintered body has a crystal grain size of 15 to 200 μ

m,

when a field of view of 370.0 μ

m long×

372.0 μ

m wide is photographed with a 1000-fold magnification and the photograph is visually observed, a number of pores having a diameter of 0.2 to 0.6 μ

m is 250 or less, and

a volume fraction of the pores having a diameter of 0.2 to 0.6 μ

m to the alumina sintered body is 130 ppm by volume or less.

2. The alumina sintered body according to claim 1,

wherein when a field of view of 370.0 μ

m long×

372.0 μ

m wide is photographed using a scanning electron microscope with a 1000-fold magnification and the photograph is visually observed, a number of foreign substances having a diameter of 0.2 to 0.6 μ

m is 50 or less.

3. The alumina sintered body according to claim 1,

wherein when a field of view of 1340.4 μ

m long×

1607.0 μ

m wide is photographed with a 500-fold magnification and the photograph is visually observed, a number of pores having a diameter of 1 μ

m or more is 50 or less.

4. The alumina sintered body according to claim 1,

wherein the alumina sintered body has, at a thickness of 0.5 mm, an in-line transmittance at 450 to 1000 nm of 60% or more.

5. The alumina sintered body according to claim 4,

wherein the in-line transmittance is 80% or more.

6. The alumina sintered body according to claim 1,

wherein a F content is 200 ppm or less.

7. The alumina sintered body according to claim 1,

wherein contents of impurity elements other than Mg, C, and F are 50 ppm or less.

8. The alumina sintered body according to claim 1,

wherein the Mg/F mass ratio is 0.2 to 3.5 and the Mg content is 100 to 1500 ppm by mass.

9. The alumina sintered body according to claim 1,

wherein the crystal grain size is 20 to 100 μ

m.

10. The alumina sintered body according to claim 1,

wherein an XRC full width at half maximum in rocking curve measurement is 15°

or less.

11. A base substrate for an optical device, comprising the alumina sintered body according to claim 1.