# US 5,346,538 A · Molding of sintered strontium/calcium indate and the use thereof

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- Number: US 5,346,538 A
- Document ID: US5346538A
- Status: Granted
- Kind: A
- Application number: 07/720,494
- Filed: 1991-06-27
- Granted: 1994-09-13
- Earliest claimed: 1988-12-29
- Assignees: Hoechst Aktiengesellschaft
- Inventors: Winfried Becker
- Web page: https://patentgrep.com/patent/US5346538A

## CPC

- C01G 15/006: {Compounds containing gallium, indium or thallium, with or without oxygen or hydrogen, and containing two or more other elements}
- C01G 15/00: Compounds of gallium, indium or thallium
- C04B 35/01: based on oxide ceramics
- C04B 35/653: Processes involving a melting step
- Y10S 505/782: Bismuth-, e.g. BiCaSrCuO
- Y10S 505/785: Composition containing superconducting material and diverse nonsuperconducting material
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Alkaline earth metal indates of the formula (Sr,Ca)In.sub.2 O.sub.4 can be converted by sintering or fusing into compact moldings which, owing to their stability are suitable even at temperatures of at least 800.degree. C. as reaction vessels for chemical reactions in the presence of bismuth (III) oxide and/or alkaline earth metal oxides.

## Claims

### Claim 1

A method for using a molding for performing a chemical reaction in the presence of molten bismuth (III) oxide at temperatures of at least 800.degree. C.; said method comprising forming a reaction vessel from the molding wherein the molding is composed of sintered indate or indate solidified from a melt of the formula (Sr,Ca)In.sub.2 O.sub.4 ; and conducting the reaction in the vessel; wherein the bismuth (III) oxide is present in the vessel and does not react with the indate.

### Claim 2

A method for using a molding for performing a chemical reaction in the presence of alkaline earth metal oxide at temperatures of at least 800.degree. C; said method comprising forming a reaction vessel from the molding wherein the molding is composed of sintered indate or indate solidified from a melt of the formula (Sr,Ca)In.sub.2 O.sub.4 ; and conducting the reaction in the vessel; wherein the alkaline earth metal oxide is present in the vessel and does not react with the indate.

### Claim 3

A method of using a molding in the preparation of high-T.sub.c -superconducting oxidic material from oxidic material comprising the oxides of Bi, Sr, Ca and Cu, said method comprising reacting the oxidic material in the molding, wherein the molding is of compact indate of the formula (Sr,Ca)In.sub.2 O.sub.4, said reacting comprising thermally treating the oxidic material in the molding at a temperature.gtoreq.800.degree. C; and no reaction occurs between the oxidic material and the indate.

### Claim 4 (depends on 3)

A method as claimed in claim 3, wherein the molding is prepared by compacting a fine powder selected from the group consisting of calcium indate, strontium indate, an indate of the formula Sr.sub.x Ca.sub.1-x In.sub.2 O.sub.4 with 0<x<1 and mixtures thereof; and, heating the compacted fine powder for a sufficient time at a temperature from 1000 to 1500.degree. C.

### Claim 5 (depends on 1)

A method as claimed in claim 1, wherein the sintered indate is prepared by sintering or fusing a pulverulent equimolar mixture of In.sub.2 O.sub.3 and an alkaline earth metal oxide selected from the group consisting of CaO and SrO.

### Claim 6 (depends on 3)

A method as claimed in claim 3, wherein the molding has the shape of a plate.

### Claim 7 (depends on 6)

A method as claimed in claim 6, wherein the contacting of the oxidic material with the molding is by coating the oxidic material as a layer onto the surface of the plate.

### Claim 8 (depends on 4)

A method as claimed in claim 4, wherein the fine powder additionally comprises a binder.