Method of Preparing Ceramic Powders

• US 20100285947A1
• Filed: 05/10/2010
• Published: 11/11/2010
• Est. Priority Date: 08/02/2006
• Status: Active Grant

• Current Assignee: Eestor Inc. (FuelPositive Corp.)
• Original Assignee: Eestor Inc. (FuelPositive Corp.)
• Inventors: Nelson, Carl W., Weir, Richard D.
• Granted Patent: US 8,853,116 B2
• Time in Patent Office: Days
• US Class Current: 501/138
• CPC Class Codes: C01B 13/185 Preparing mixtures of oxides
• CPC Class Codes: C01B 13/363 Mixtures of oxides or hydroxides by precipitation
• CPC Class Codes: C01G 1/02 Oxides
• CPC Class Codes: C01G 23/003 Titanates C01G23/001 takes precedence
• CPC Class Codes: C01G 23/006 Alkaline earth titanates
• CPC Class Codes: C01P 2002/34 perovskite-type (ABO3)
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/51 Particles with a specific particle size distribution
• CPC Class Codes: C01P 2004/53 bimodal size distribution
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: C01P 2006/80 Compositional purity
• CPC Class Codes: C01P 2006/90 Other properties not specified above
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• 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 2235/3244 Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3262 : Manganese oxides, manganates, rhenium oxides or oxide-forming salts thereof, e.g. MnO
• CPC Class Codes: C04B 2235/441 : Alkoxides, e.g. methoxide, tert-butoxide
• CPC Class Codes: C04B 2235/449 : Organic acids, e.g. EDTA, citrate, acetate, oxalate
• CPC Class Codes: C04B 2235/5436 : micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5445 : submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/5472 : Bimodal, multi-modal or multi-fraction
• CPC Class Codes: C04B 2235/5481 : Monomodal
• CPC Class Codes: C04B 2235/762 : Cubic symmetry, e.g. beta-SiC
• CPC Class Codes: C04B 35/4682 : based on BaTiO3 perovskite phase
• CPC Class Codes: C04B 35/49 : containing also titanium oxides or titanates
• CPC Class Codes: C04B 35/62655 : Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
• CPC Class Codes: C04B 40/0082 : making use of a rise in temperature, e.g. caused by an exothermic reaction

Abstract

A method of forming composition-modified barium titanate ceramic particulate includes mixing a plurality of precursor materials and a precipitant solution to form an aqueous suspension. The plurality of precursors include barium nitrate, titanium chelate, and a metal or oxometal chelate. The precipitant solution includes tetraalkylammonium hydroxide and tetraalkylammonium oxalate. The method further includes treating the aqueous suspension at a temperature of at least 150° C. and a pressure of at least 200 psi, and separating particulate from the aqueous suspension after treating.

Claims

1. A method for preparing a ceramic powder, the method comprising:

providing a plurality of precursor materials in solution, wherein each of the plurality of precursor materials in solution further comprises at least one constituent ionic species of a ceramic powder, a first precursor material including a barium source, a second precursor including a titanium source, and a third precursor comprising a metal ion or oxometal ion and a chelating agent, the chelating agent being 2-hydroxypropanoic acid or an alpha-hydroxycarboxylic acid selected from the group consisting of 2-hydroxyethanoic acid, 2-hydroxybutanedioic acid, 2,3-dihydroxybutanedioic acid, 2-hydroxy-1,2,3-propanetricarboxylic acid, 2-hydroxybutanoic acid, 2-hydroxypentanoic acid, and 2-hydroxyhexanoic acid;

combining the plurality of precursor materials in solution with a precipitant solution including an oxalate compound and tetraalkylammonium hydroxide to cause co-precipitation of the ceramic powder in a combined solution; and

separating the ceramic powder from the combined solution.

2. The method of claim 1, wherein the oxalate compound includes ammonium oxalate.

3. The method of claim 1, wherein the barium source includes barium nitrate.

4. The method of claim 1, wherein the titanium source includes a titanium chelate.

5. The method of claim 1, wherein the metal ion or oxometal ion of the metal chelate comprises at least one of:

Nd, Zr, Mn, La, Y, Pr, Sm, Gd, Dy, Er, Ho, Yb, Ga, Ag, Dy, Er, Ho, Nb, and Mo.

6. The method of claim 1, further comprising:

preparing the third precursor using a chelating agent, the chelating agent being one of the 2-hydroxypropanoic acid or the alpha-hydroxycarboxylic acid.

7. The method of claim 6, further comprising:

reacting a metal alkyl oxide with the chelating agent and a weak base solution.

8. The method of claim 6, further comprising:

reacting at least one of a metal-ion carbonate, a metal-ion nitrate, and an oxometal-ion nitrate with the chelating agent and a weak base solution.

9. The method of claim 1, wherein the plurality of precursor materials further include Ca(NO₃)₂.

10. The method of claim 1, wherein the combining further comprises:

mixing the plurality of precursor materials in solution and the precipitant solution in a fluid jet column.

11. The method of claim 10, further comprising:

introducing the plurality of precursor materials in solution in a first stream; and

introducing the precipitant solution in a second stream.

12. The method of claim 1, further comprising:

drying the separated ceramic powder; and

calcining the separated ceramic powder.

13. The method of claim 12, wherein the ceramic powder includes a cubic perovskite composition modified barium titanate.

14. A method for preparing a ceramic powder, the method comprising:

providing a plurality of precursor materials in solution, wherein each of the plurality of precursor materials in solution further comprises at least one constituent ionic species of a ceramic powder, a first precursor material including barium nitrate, a second precursor including a titanium chelate, and a third precursor comprising a metal ion or oxometal ion and a chelating agent, the chelating agent being 2-hydroxypropanoic acid or an alpha-hydroxycarboxylic acid selected from the group consisting of 2-hydroxyethanoic acid, 2-hydroxybutanedioic acid, 2,3-dihydroxybutanedioic acid, 2-hydroxy-1,2,3-propanetricarboxylic acid, 2-hydroxybutanoic acid, 2-hydroxypentanoic acid, and 2-hydroxyhexanoic acid;

combining the plurality of precursor materials in solution with a precipitant solution including an oxalate compound and tetraalkylammonium hydroxide to cause co-precipitation of the ceramic powder in a combined solution; and

separating the ceramic powder from the combined solution.

15. The method of claim 14, wherein the oxalate compound includes ammonium oxalate.

16. The method of claim 14, wherein the metal ion or oxometal ion of the metal chelate comprises at least one of:

Nd, Zr, Mn, La, Y, Pr, Sm, Gd, Dy, Er, Ho, Yb, Ga, Ag, Dy, Er, Ho, Nb, and Mo.

17. The method of claim 14, wherein the plurality of precursor materials further include Ca(NO₃)₂.

18. The method of claim 14, further comprising:

drying the separated ceramic powder; and

calcining the separated ceramic powder.

19. The method of claim 18, wherein the ceramic powder includes a cubic perovskite composition modified barium titanate.

20. A method for preparing a ceramic powder, the method comprising:

providing a plurality of precursor materials in solution, wherein each of the plurality of precursor materials in solution further comprises at least one constituent ionic species of a ceramic powder, a first precursor material including barium nitrate, a second precursor including a titanium chelate, and a third precursor comprising a metal ion or oxometal ion and a chelating agent, the chelating agent being 2-hydroxypropanoic acid or an alpha-hydroxycarboxylic acid selected from the group consisting of 2-hydroxyethanoic acid, 2-hydroxybutanedioic acid, 2,3-dihydroxybutanedioic acid, 2-hydroxy-1,2,3-propanetricarboxylic acid, 2-hydroxybutanoic acid, 2-hydroxypentanoic acid, and 2-hydroxyhexanoic acid;

combining the plurality of precursor materials in solution with a precipitant solution including ammonium oxalate and tetraalkylammonium hydroxide to cause co-precipitation of the ceramic powder in a combined solution;

separating the ceramic powder from the combined solution;

drying the separated ceramic powder; and

calcining the separated ceramic powder to form a ceramic powder including cubic perovskite composition-modified barium titanate.

21. The method of claim 20, wherein the metal ion or oxometal ion of the metal chelate comprises at least one of:

Nd, Zr, Mn, La, Y, Pr, Sm, Gd, Dy, Er, Ho, Yb, Ga, Ag, Dy, Er, Ho, Nb, and Mo.

22. The method of claim 20, wherein the plurality of precursor materials further include Ca(NO₃)₂.