Methods for manufacturing dielectric powders

• US 6,585,951 B1
• Filed: 10/30/2000
• Issued: 07/01/2003
• Est. Priority Date: 10/30/2000
• Status: Expired due to Term

• Current Assignee: Emw Co., Ltd., Idaho Research Foundation, Inc.
• Original Assignee: Idaho Research Foundation, Inc.
• Inventors: Park, Mun-Hyoun, Hong, Yang-Ki
• Primary Examiner(s): BOS, STEVEN J
• Application Number:
  US09/702,281
• Time in Patent Office: 974 Days
• Field of Search: 423/598, 423/DIG.12, 423/594, 423/593, 423/592, 501/10, 501/136, 501/137
• US Class Current: 423/598
• CPC Class Codes: C01G 23/006 Alkaline earth titanates
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C09C 1/36 Compounds of titanium C09C1/0009, C09C1/0015, C09C1/0078 take precedence

Abstract

Methods for manufacturing a powder of a dielectric compound include mixing particle components that are combinable to form the dielectric compound with matrix components. The mixture is melted, and the molten mixture is quenched to produce a solid material. The dielectric power is extracted from the solid material. A molar ratio of particle components to matrix components can be selected so that the solid material produced by quenching is amorphous. Particle components can be selected to produce Ba_1−xSr_xTiO₃ powder, wherein 0≦x≦1. Matrix components consist essentially of Na₂O·2B₂O₃ and Na₂O·SiO₂·9H₂O or can be selected from a group consisting of zinc oxide, zinc carbonate, and zinc hydroxide.

Claims

1. A method, of manufacturing a powder of a dielectric compound, comprising:

selecting particle components combinable to form the dielectric compound;

selecting matrix components that consist essentially of Na₂O·

SiO₂·

9H₂O, Na₂O·

2B₂O₃, and Na₂CO₃;

mixing the particle and matrix components to form a mixture;

melting the mixture;

combining the molten mixture with a quenching liquid to produce a sold material; and

extracting the powder of the dielectric compound from the solid material.

2. The method of claim 1, further comprising:

annealing the solid material; and

extracting the powder from the annealed solid material.

3. The method of claim 2, further comprising selecting a molar ratio of particle components to matrix components so that the solid material is amorphous.

4. The method of claim 3, wherein the particle components are selected to produce Ba₁₋

xSr_xTiO₃ powder, wherein 0≦

x≦

1, and the molar ratio is selected based on a value of x.

5. The method of claim 2, wherein the powder is extracted from the annealed solid material by exposing the solid material to an acidic solution that removes a glassy matrix portion of the solid material.

6. The method of claim 5, further comprising selecting a molar ratio of particle components to matrix components so that the solid material is amorphous.

7. The method of claim 6, further comprising extracting the powder of the dielectric compound from the solution that removes the glassy matrix.

8. The method of claim 7, wherein the powder comprises nanometer-sized particles of the dielectric compound.

9. The method of claim 8, wherein the nanometer-sized particles of the dielectric compound are substantially spherical.

10. The method of claim 2, wherein annealing the solid material includes a first annealing at a first temperature and a second annealing at a second temperature, wherein the second temperature is greater than the first temperature.

11. The method of claim 2, wherein the mixture of the particle components and matrix components is melted by exposing the mixture to a temperature in the range of about 1,100°

C. to 1,700°

C.

12. The method of claim 1, wherein the dielectric compound is BaTiO₃.

13. The method of claim 1, wherein the dielectric compound is Ba₁₋

xSr_xTiO₃, wherein 0≦

x≦

1.

14. The method of claim 1, wherein the particle components are selected from the group consisting of oxides, hydroxides, and carbonates of Da, Sr, and Ti.

15. The method of claim 1, wherein the particle components are selected from the group consisting of barium titanate (BaTiO₃), strontium titanate (SrTiO₃), barium carbonate (BaCO₃), strontium carbonate (SrCO₃), and titanium dioxide (TiO₂).

16. The method of claim 1, wherein a molar ratio of the particle components to the matrix components is between about 0.40 and 1.60.

17. The method of claim 1, wherein a molar ratio of the particle components to the matrix components is between about 0.40 and 1.60.

18. The method of claim 17, wherein the molar ratio is between about 0.8 and 1.2.

25. The method of claim 1, wherein the quenching includes immersing the molten mixture in water.

26. The method of claim 4, wherein the particles components are selected so that 0.3≦

x≦

0.7.

19. A method of manufacturing a powder of a dielectric compound, comprising:

selecting particle components combinable to form the dielectric compound;

selecting matrix components that consist essentially of 1.34 parts by mole Na₂O·

2B₂O₃, 1.13 parts by mole Na₂CO₃, and 1.0 parts by mole Na₂O·

SiO₂·

9H₂O;

mixing the particle and matrix components to form a mixture;

melting the mixture;

quenching the molten mixture to produce a solid material; and

extracting the powder of the dielectric compound from the solid material.

20. A method of manufacturing a powder of a dielectric compound, comprising:

selecting particle components combinable to form the dielectric compound;

selecting matrix components from the group consisting of zinc oxide, zinc carbonate, and zinc hydroxide;

mixing the particle and matrix components to form a mixture;

melting the mixture;

quenching the molten mixture to produce a solid material; and

extracting the powder of the dielectric compound from the solid material.

21. A method of producing a dielectric powder, comprising:

mixing powder components and matrix components to form a mixture;

melting the mixture;

cooling the molten mixture to form a glassy material;

forming particles of the dielectric powder in the glassy material by annealing the glassy material at a first temperature and then annealing the glassy material at a second temperature, wherein the second temperature is greater than the first temperature; and

extracting the dielectric powder from the annealed glassy material.

22. A method of producing a dielectric powder, comprising:

mixing powder components and matrix components to form a mixture, wherein the powder components consist essentially of compounds of Ba, Sr, and Ti and the matrix components consist essentially of Na₂O·

2B₂O₃, Na₂CO₃, and Na₂O·

SiO₂·

9H₂O;

melting the mixture;

cooling the molten mixture to form a glassy material;

forming particles of the dielectric powder in the glassy material by annealing the glassy material at a first temperature and then annealing the glassy material at a second temperature, wherein the second temperature is greater than the first temperature; and

extracting the dielectric powder from the annealed glassy material.

23. The method of claim 22, wherein the first temperature is in a range of about 400°

C. to 550°

C. and the second temperature is in a range of about 550°

C. to 700°

C.

24. The method of claim 22, wherein a molar ratio of the particle components to the matrix components is selected so that the glassy material includes an amorphous material formed by the matrix components.