Alumina sintered body and base substrate for optical device

Patent metadata

Field	Value
Publication number	US-10336625-B2
Application number	US-201715797127-A
Country	US
Kind code	B2
Filing date	Oct 30, 2017
Priority date	May 13, 2015
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

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.

First claim

What is claimed is:

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 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, and
a volume fraction of the pores having a diameter of 0.2 to 0.6 μm in 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 μm long×372.0 μm 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 μm is 50 or less.

3. The alumina sintered body according to claim 1 ,
wherein when a field of view of 1340.4 μm long×1607.0 μm wide is photographed with a 500-fold magnification and the photograph is visually observed, a number of pores having a diameter of 1 μm 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 μm.

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 .

Assignees

• Ngk Insulators Ltd

Inventors

• Matsushima Kiyoshi
• Watanabe Morimichi
• Sato Kei
• Nanataki Tsutomu

Classifications

• C01P2006/80

  Compositional purity · CPC title

• C04B2235/788

  Aspect ratio of the grains · CPC title

• C04B2235/6025

  Tape casting, e.g. with a doctor blade · CPC title

• C04B2235/604

  Pressing at temperatures other than sintering temperatures · CPC title

• G01N23/207

  Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions · CPC title