US4724038A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing single crystal binary metal oxides of improved purity
Assignee: The AT&T MVPD Group LLC
•
Filing: 1986-06-02
•
Granted: 1988-02-09
•
Expires: 2006-06-02
Abstract
Abstract A method is disclosed for the growth of single crystals of a binary metal oxides of the formula ABO 3 where A is an alkali or alkaline earth metal, B is at least one element selected from titanium, niobium and tantalum. A mixture comprising the constituent components of the ABO 3 crystal is prepared using a basic oxide or carbonate of A and a stoichiometric excess of an acidic oxide of B. The mixture is heated at an elevated temperature to form a melt and is thereafter exposed to a reactive atmosphere of a mixture of gaseous carbon monoxide and carbon dioxide. Crystal growth from the melt is effected by a top-seeded crystal pulling technique.
Inventors
- 👤 Ricardo C. Pastor
- 👤 Luisa E. Gorre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:10
CPC Classifications
C; C30; C30B; C30B15/00; C30B29/00; C30B29/10; C30B29/16; C30B29/22; C30B29/30; C30B29/32; Y; Y10; Y10S; Y10S117/00; Y10S117/906; Y10S117/912
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
146 words
A method for the growth of a single crystal binary metal oxide of the formula ABO 3 wherein A is an alkali or alkaline earth metal, B is at least one element selected from the group consisting of titanium, niobium and tantalum comprising the steps of: (a) preparing a mixture of a basic oxide or carbonate of A and an amount of an acidic oxide of B which is in excess of the stoichiometric amount required to form the ABO 3 crystal; (b) heating the mixture to an elevated temperature of from 700° C. to 900° C. to prepare a melt; (c) exposing the melt to a reactive atmosphere of a mixture of carbon monoxide and carbon dioxide for a period time sufficient to effect single crystal growth of substantially pure, ABO 3 crystal; and (d) growing a single crystal of substantially pure ABO 3 .
Claim 2
Independent Claim
146 words
A method for the growth of a single crystal binary metal oxide of the formula ABO 3 wherein A is an alkali or alkaline earth metal, B is at least one element selected from the group consisting of titanium, niobium and tantalum comprising the steps of: (a) preparing a mixture of a basic oxide or carbonate of A and an amount of an acidic oxide of B which is in excess of the stoichiometric amount required to form the ABO 3 crystal; (b) heating the mixture to an elevated temperature of from 700° C. to 900° C. to prepare a melt; (c) exposing the melt to a reactive atmosphere of a mixture of carbon monoxide and carbon dioxide for a period time sufficient to effect single crystal growth of substantially pure, ABO 3 crystal; and (d) growing a single crystal of substantially pure ABO 3 .
Claim 3
Dependent Claim
27 words
The method in accordance with claim 1 wherein the melt includes an excess of the acidic B-oxide constituent ranging from about 10 to about 20 mole percent.
Claim 4
Dependent Claim
18 words
The method in accordance with claim 1 wherein basic oxide or carbonate of the A constituent is BaO.
Claim 5
Dependent Claim
17 words
The method in accordance with claim 1 wherein the acidic B oxide constituent is TiO 2 .
Claim 6
Dependent Claim
17 words
The method in accordance with claim 1 wherein the melt is heated at its isothermal melt temperature.
Claim 7
Dependent Claim
22 words
The method in accordance with claim 1 wherein ABO 3 is BaTiO 3 and the melt is isothermally heated at 700° C.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein crystal growth is initiated by top-seeding the melt.
Claim 9
Dependent Claim
21 words
The method of claim 1 wherein the molar ratio of CO/CO 2 gaseous atmosphere is of about 7:1 to about 1:9.
References Cited (Backward Citations)
US2696651A
Cited
JPS4714335Y1
Cited
JPS4835160A
Cited
US4144117A
Cited
JPS5542238A
Cited
JPS5556097A
Cited
US4439265A
Cited
JPS5895690A
Cited
US4609694A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-08 | 1991-08-10 | 1992-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-08 | 1995-08-10 | 1996-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-08 | 1999-08-10 | 2000-02-09 | $7700.00 | Window Closed / Lapsed |