Translucent rare earth oxide sintered article and method for production thereof

• US 6,825,144 B2
• Filed: 02/28/2003
• Issued: 11/30/2004
• Est. Priority Date: 07/05/2001
• Status: Active Grant

• Current Assignee: Konoshima Chemical Co., Ltd.
• Original Assignee: Konoshima Chemical Co., Ltd.
• Inventors: Hideki, Yagi, Takagimi, Yanagitani
• Primary Examiner(s): GROUP, KARL E
• Application Number:
  US10/363,352
• Publication Number:
  US 20030183991A1
• Time in Patent Office: 641 Days
• Field of Search: 501/152, 264/681
• US Class Current: 501/152
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3218 Aluminium (oxy)hydroxides, e.g. boehmite, gibbsite, alumina sol
• CPC Class Codes: C04B 2235/3222 Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3418 Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
• CPC Class Codes: C04B 2235/402 Aluminium
• CPC Class Codes: C04B 2235/404 Refractory metals
• CPC Class Codes: C04B 2235/5409 expressed by specific surface values
• CPC Class Codes: C04B 2235/6021 Extrusion moulding
• CPC Class Codes: C04B 2235/608 Green bodies or pre-forms with well-defined density
• CPC Class Codes: C04B 2235/656 characterised by specific heating conditions during heat treatment
• CPC Class Codes: C04B 2235/6562 Heating rate
• CPC Class Codes: C04B 2235/658 Atmosphere during thermal treatment
• CPC Class Codes: C04B 2235/6581 Total pressure below 1 atmosphere, e.g. vacuum
• CPC Class Codes: C04B 2235/6582 Hydrogen containing atmosphere
• 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 2235/728 Silicon content
• CPC Class Codes: C04B 2235/77 : Density
• CPC Class Codes: C04B 2235/786 : Micrometer sized grains, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/80 : Phases present in the sintered or melt-cast ceramic products other than the main phase
• CPC Class Codes: C04B 2235/87 : Grain boundary phases intentionally being absent
• CPC Class Codes: C04B 2235/9653 : Translucent or transparent ceramics other than alumina
• CPC Class Codes: C04B 35/50 : based on rare-earth compounds non-oxide rare earth compounds C04B35/5156
• CPC Class Codes: C04B 35/505 : based on yttrium oxide
• CPC Class Codes: C04B 35/638 : Removal thereof

Abstract

A high-purity rare earth metal oxide material powder of purity of 99.9% or over, of which Al content is 5-100 wtppm in metal weight and Si content is 10 wtppm or under in metal weight, and a binder are used to prepare a molding body of which molding density is 58% or over of the theoretical density. The binder is eliminated by thermal treatment, and then the molding body is sintered in an atmosphere of hydrogen or a rare gas or a mixture of them or in a vacuum at a temperature being not lower than 1450° C. and not higher than 1700° C. for 0.5 hour or over to prepare A transparent sintered rare earth metal oxide body represented by a general formula R₂O₃ (R being at least one element of a group comprising Y, Dy, Ho, Er, Tm, Yb and Lu).

Claims

1. A transparent sintered rare earth metal oxide body represented by a general formula R₂O₃ (R being at least one element of a group comprising Y, Dy, Ho, Er, Tm, Yb, and Lu), having an in-line spectral transmission not less than 80% taken at a wavelength range of 500 nm-6 μ

m beyond a specific absorption wavelength on a thickness of 1 mm of the sintered body, and including 5-100 wtppm of Al in metal weight.

2. A transparent sintered rare earth metal oxide body of claim 1, characterized in that a mean grain size of the sintered body is 2-20 μ

m.

3. A transparent sintered rare earth metal oxide body of claim 2, characterized in that a Si content of the sintered body is not more than 10 wtppm in metal weight.

4. A transparent sintered rare earth metal oxide body of claim 1, characterized in that a mean grain size of the sintered body is 2-20 μ

m and grain boundaries in the sintered body are substantially free from deposited foreign phases containing Al.

5. A transparent sintered rare earth metal oxide body of claim 3, characterized in that each content of CaO and MgO is less than 5 wtppm.

6. A transparent sintered rare earth metal oxide body of claim 3, characterized in that said sintered body is a laser oscillator material containing a laser active element.

7. A production method of a transparent sintered rare earth metal oxide body represented by a general formula R₂O₃ (R being at least one element of a group comprising Y, Dy, Ho, Er, Tm, Yb, and Lu), comprising

a step for preparing a molding body having molding density of not less than 58% of a theoretical density from a rare earth metal oxide material powder and a binder, wherein the rare earth metal oxide material powder has a purity of not less than 99.9%, a Al content of 5-100 wtppm in metal weight, and a Si content of not more than 10 wtppm in metal weight and

a step for sintering the molding body in an atmosphere of hydrogen, a rare gas, or a mixture of them, or in a vacuum at a temperature not lower than 1450°

C. and not higher than 1700°

C. for not less than 0.5 hour, after eliminating the binder from the molding body by thermal treatment.

8. A production method of a transparent sintered rare earth metal oxide body of claim 7, characterized in that the molding body is sintered to have a 2-20 μ

m mean grain size.

9. A production method of a transparent sintered rare earth metal oxide body of claim 8, characterized in that the molding body is sintered to be substantially free from deposition of foreign phases containing Al at grain boundaries.