Method for producing coprecipitated multicomponent oxide powder precursors

• US 5,298,654 A
• Filed: 03/01/1993
• Issued: 03/29/1994
• Est. Priority Date: 11/30/1990
• Status: Expired due to Fees

• Current Assignee: Mark R. Deguire, Warren H. Philipp
• Original Assignee: Case Western Reserve University
• Inventors: Philipp, Warren H., DeGuire, Mark R.
• Primary Examiner(s): Killos, Paul J.
• Application Number:
  US08/024,650
• Time in Patent Office: 393 Days
• Field of Search: 562/597
• US Class Current: 562/597
• CPC Class Codes: C01B 13/185 Preparing mixtures of oxides
• CPC Class Codes: C01G 29/006 Compounds containing, besides bismuth, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01G 3/006 Compounds containing, besides copper, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01G 49/009 Compounds containing, besides iron, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2006/80 Compositional purity
• CPC Class Codes: Y10S 505/734 From organometallic precursors, e.g. acetylacetonates
• CPC Class Codes: Y10S 505/738 by precipitating

Abstract

Guanidine oxalate is used as a precipitating agent in the coprecipitation of multicomponent oxide powder precursors. A solution of a soluble inorganic salt is combined with a solution of guanidine oxalate. A resultant metal oxalate is precipitated from the solution and can thereafter be subjected to heat to convert the metal oxalate into a multicomponent ceramic powder.

Claims

1. A method for coprecipitating metal oxalate precursors for multicomponent metal oxide powders, comprising the steps of:

synthesizing and isolating guanidine oxalate;

purifying the isolated guanidine oxalate by recrystallization;

dissolving purified guanidine oxalate in water at a temperature below about 25°

C. to provide a guanidine oxalate solution;

mixing the guanidine oxalate solution with a solution comprising a soluble metal salt and water to form a resulting solution; and

precipitating a metal oxalate from the resulting solution.

2. A method for coprecipitating metal oxalate precursors for multicomponent metal oxide powders, according to claim 1, wherein the soluble metal salt includes an oxidizing anion.

3. A method for coprecipitating metal oxalate precursors for multicomponent metal oxide powders, according to claim 1, wherein the guanidine oxalate solution is comprised of guanidine oxalate, water and a water soluble alcohol having 1-3 carbon atoms per molecule.

4. A method for coprecipitating metal oxalate precursors for multicomponent metal oxide powders, according to claim 3, wherein the alcohol is ethanol.

5. A method for coprecipitating metal oxalate precursors for multicomponent metal oxide powders, according to claim 3, wherein the alcohol is methanol.

6. A method for coprecipitating metal oxalate precursors for multicomponent metal oxide powders, according to claim 1, wherein the step of purifying includes the steps of:

suspending guanidine oxalate in hot alcohol;

adding water to dissolve the guanidine oxalate to form a nearly saturated solution; and

cooling the nearly saturated solution to drystallize the guanidine oxalate.

7. A method for precipitating multicomponent oxide precursors, comprising the steps of:

synthesizing stoichiometric guanidine oxalate according to a process including a step of adding oxalic acid to a solution of guanidine carbonate;

purifying the stoichiometric guanidine oxalate;

adding the purified guanidine oxalate to a solution comprising water or water and alcohol to provide a guanidine oxalate solution;

mixing the guanidine oxalate solution with an aqueous soluble metal salt solution to form a resultant solution having a temperature of less than about 25°

C.;

precipitating a substantially homogeneous metal oxalate product from said resulting solution.

8. A method for coprecipitating multicomponent oxide precursors, according to claim 7, wherein the soluble inorganic salt solution includes more than one type of metal ion.

9. A method for coprecipitating multicomponent oxide precursors, according to claim 8, wherein more than one type of metal oxalate precipitates from the resultant solution.

10. A method for coprecipitating multicomponent oxide precursors, according to claim 7, wherein the guanidine oxalate is synthesized according to the steps of:

adding a stoichiometric amount of concentrated oxalic acid solution to a concentrated solution of guanidine carbonate to provide a resultant solution;

evaporating the resultant solution to leave a residue;

dissolving the residue in water;

removing insoluble colloidal impurities; and

filtering the guanidine oxalate from the solution.

11. A method for precipitating multicomponent oxide precursors, according to claim 7, wherein the step of purifying includes the step of:

recrystallizing the guanidine oxalate from an alcohol/water solution.