Method for producing transparent ceramic, transparent ceramic, magneto-optical device and rare earth oxide powder for sintering

Patent metadata

Field	Value
Publication number	US-2017205643-A1
Application number	US-201515313885-A
Country	US
Kind code	A1
Filing date	Jun 1, 2015
Priority date	Jun 4, 2014
Publication date	Jul 20, 2017
Grant date	—

Abstract

A starting material powder, which contains a rare earth oxide that is composed of terbium oxide and at least one other rare earth oxide selected from among yttrium oxide, scandium oxide and oxides of lanthanide rare earth elements (excluding terbium) and a sintering assistant that is formed of an oxide of at least one element selected from among group 2 elements and group 4 elements, is produced by having (a) terbium ions, (b) ions of at least one other rare earth element selected from among yttrium ions, scandium ions and lanthanide rare earth ions (excluding terbium ions) and (c) ions of at least one element selected from among group 2 elements and group 4 elements coprecipitate in an aqueous solution containing the components (a)-(c), then filtering and separating the coprecipitate, and subjecting the separated coprecipitate to thermal dehydration.

First claim

1 . A method for producing a transparent ceramic containing terbium oxide (chemical formula: Tb 2 O 3 ) and at least one other rare earth oxide selected from among yttrium oxide, scandium oxide and oxides of lanthanide rare earth elements (excluding terbium) as main components, the method comprising:
subjecting an aqueous solution containing (a) terbium ions, (b) ions of at least one other rare earth element selected from among yttrium ions, scandium ions and lanthanide rare earth ions (excluding terbium ions) and (c) ions of at least one element selected from among Group 2 elements and Group 4 elements to co-precipitation of the components (a), (b) and (c), filtration and separation of the co-precipitate and thermal dehydration, to form a raw material powder containing a rare earth oxide including terbium oxide and at least one other rare earth oxide selected from among yttrium oxide, scandium oxide and oxides of lanthanide rare earth elements (excluding terbium), the molar ratio of terbium oxide being at least 40 mol % and the balance being the other rare earth oxide, and a sintering aid including an oxide of at least one element selected from among Group 2 elements and Group 4 elements; forming a molded body using the raw material powder; then firing the molded body; and subjecting the fired molded body to pressure firing.

2 . The method for producing a transparent ceramic of claim 1 , wherein the raw material powder contains more than 0.5 parts by weight and up to 5 parts by weight of the sintering aid per 100 parts by weight of the rare earth oxide.

3 . The method for producing a transparent ceramic of claim 1 , wherein the component (c) is ions of at least one element selected from among titanium ions, zirconium ions, hafnium ions, calcium ions and magnesium ions.

4 . The method for producing a transparent ceramic of claim 1 , further comprising subjecting the pressure-fired molded body to a heat treatment at 1,500 to 2,000° C. in a non-oxidizing atmosphere.

5 . The method for producing a transparent ceramic of claim 1 , wherein the molded body is calcined before the firing.

6 . A transparent ceramic produced by the method for producing a transparent ceramic of claim 1 , the transparent ceramic containing a rare earth oxide including terbium oxide (chemical formula: Tb 2 O 3 ) and an oxide of at least one other rare earth element selected from among yttrium oxide, scandium oxide and oxides of lanthanide rare earth elements (excluding terbium), the molar ratio of terbium oxide being at least 40 mol % and the balance being the other rare earth oxide, and a sintering aid including an oxide of at least one element selected from among Group 2 elements and Group 4 elements.

7 . The transparent ceramic of claim 6 , wherein the content of the sintering aid is more than 0.5 parts by weight and up to 5 parts by weight per 100 parts by weight of the rare earth oxide.

8 . The transparent ceramic of claim 6 , wherein the sintering aid is an oxide of at least one element selected from among titanium, zirconium, hafnium, calcium and magnesium.

9 . The transparent ceramic of claim 6 , wherein an insertion loss at a wavelength of 1,064 nm inclusive of a reflection loss at an end face in a plane of at least 90% of a measurement surface in a thickness direction of a 10 mm-thick sample is up to 0.97 dB.

10 . A magneto-optical device configured by using the transparent ceramic of claim 6 .

11 . A magneto-optical device wherein the transparent ceramic of claim 6 is used as a Faraday rotator.

12 . The magneto-optical device of claim 11 , for an optical isolator for use in a wavelength region of 1,064±40 nm, wherein polarizing materials are provided on front and rear sides of the Faraday rotator.

13 . A rare earth oxide powder for sintering containing a rare earth oxide including terbium oxide and at least one other rare earth oxide selected from among yttrium oxide, scandium oxide and oxides of lanthanide rare earth elements (excluding terbium), the molar ratio of terbium oxide being at least 40 mol % and the balance being the other rare earth oxide, and a sintering aid including an oxide of at least one element selected from among Group 2 elements and Group 4 elements, the rare earth oxide powder obtained by subjecting an aqueous solution containing (a) terbium ions, (b) ions of at least one other rare earth element selected from among yttrium ions, scandium ions and lanthanide rare earth ions (excluding terbium ions) and (c) ions of at least one element selected from among Group 2 elements and Group 4 elements to co-precipitation of the components (a), (b) and (c), filtration and separation of the co-precipitate and thermal dehydration.

Assignees

• Shinetsu Chemical Co

Inventors

• Makikawa Shinji
• Aoki Shinji
• Nojima Yoshihiro

Classifications

• C04B35/645

  Pressure sintering · CPC title

• G02B27/28

  for polarising (used in stereoscopes G02B30/25) · CPC title

• G02F1/093

  used as non-reciprocal devices, e.g. optical isolators, circulators (G02F1/0955 takes precedence) · CPC title

• C04B35/6303

  Inorganic additives · CPC title

• C04B35/50

  based on rare-earth compounds {(non-oxide rare earth compounds C04B35/5156)} · CPC title