WO2005028370A1 - A process for the production of niobium oxide power for use in capacitors - Google Patents
A process for the production of niobium oxide power for use in capacitors Download PDFInfo
- Publication number
- WO2005028370A1 WO2005028370A1 PCT/BR2004/000003 BR2004000003W WO2005028370A1 WO 2005028370 A1 WO2005028370 A1 WO 2005028370A1 BR 2004000003 W BR2004000003 W BR 2004000003W WO 2005028370 A1 WO2005028370 A1 WO 2005028370A1
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- WO
- WIPO (PCT)
- Prior art keywords
- niobium
- production
- monoxide
- niobium monoxide
- powder
- Prior art date
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G33/00—Compounds of niobium
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/04—Electrodes or formation of dielectric layers thereon
- H01G9/048—Electrodes or formation of dielectric layers thereon characterised by their structure
- H01G9/052—Sintered electrodes
- H01G9/0525—Powder therefor
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/12—Surface area
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/14—Pore volume
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/40—Electric properties
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Definitions
- the present invention is related to a process for the production of niobium monoxide (NbO) powder characterized by two niobium pentoxide (Nb 2 0 5 ) reduction steps, the first step comprising reducing, by hydrogen, of the niobium pentoxide (Nb 2 0 5 ) to niobium dioxide (Nb0 2 ), and the second step comprising reducing the niobium dioxide (TSfb0 2 ) to niobium monoxide (NbO), by using an oxygen getter material and in a convenient atmosphere allowing the transfer of the oxygen atoms from the, niobium dioxide (Nb0 2 ) to the getter material, under adequate conditions of time and temperature to form the niobium monoxide (NbO).
- NbO niobium monoxide
- the oxygen getter material undergoes a lesser oxidation, rendering the process more efficient and controlled, and allowing the use of lesser quantities of getter material.
- the niobium monoxide (NbO) may be reduced in a controlled manner, yielding a powder of high purity, porous, with controlled morphology, with low apparent density and large specific surface area.
- Figure 1 A photograph of a scanning electron microscopy of a niobium dioxide (Nb0 2 ) agglomerate - Magnification of 5,000 times.
- Figure 2 A photograph of a scanning electron microscopy of a niobium dioxide (Nb0 2 ) agglomerate - Magnification of 10,000 times.
- Figure 3 A photograph of a scanning electron microscopy of a niobium monoxide (NbO) agglomerate - Magnification of 800 times.
- Figure 4 A photograph of a scanning electron microscopy of a niobium monoxide (NbO) agglomerate - Magnification of 6,000 times.
- NbO niobium monoxide
- the present invention is related to a process for the production of a powder of niobium monoxide (NbO) characterized by two niobium pentoxide
- niobium pentoxide Nb 2 0 5
- niobium dioxide Nb0 2
- a refractory metal or a reactive metal and/or hydrides thereof of high purity
- the reducing agent in the first step is hydrogen gas or any other gas or gaseous mixture with adequate reducing potential, such as for example, carbon monoxide, while in the second step the reducing agent, also named oxygen getter, is a refractory or reactive metal or metal alloy and/or a hydride of a refractory or reactive metal such as niobium, tantalum, zirconium, and preferably niobium or tantalum.
- the niobium pentoxide (Nb 2 0 5 ) used in the first reduction step may have any shape or size.
- the niobium pentoxide (Nb 2 0 5 ) may be in the form of powders or agglomerated particles. Examples of the types of powders that can be used include, but are not limited to these examples, flaked, rod-like, angular, nodular, sponge-like powder types and/or a mixture or variations thereof.
- the niobium pentoxide (Nb 2 0 5 ) should be in the form of a powder with adequate porosity that more effectively leads to the niobium dioxide (Nb0 2 ).
- the preferred niobium pentoxide (Nb 2 0 5 ) powders are those having mesh sizes from 2.0 millimeters to 0.04 millimeters (10 Mesh Tyler and 325 Mesh Tyler).
- the first reduction step takes place in an atmosphere of hydrogen gas or a combination of hydrogen gas with other inert gasses in various ratios, such as for example argon, helium, and nitrogen, or any gas or gaseous mixture having an adequate reducing potential, such as for example, the carbon monoxide.
- the pressure of the gasses during the process may vary from 13,3 to 266,6 kPa (100 to 2000 Torr) and preferably from 13,3 to 160 kPa (100 to 1200 Torr).
- the temperature and the time of the first reduction step should be adequate to warrant the reduction of the niobium pentoxide (Nb 2 0 5 ) to niobium dioxide (Nb0 2 ).
- the reaction may be conducted at a temperature between 700°C and 1500°C, and preferably between 800°C and 1200°C, for periods of time varying from 15 to 300 minutes, and preferably from 30 to 180 minutes.
- the product of the reaction is cooled in the process atmosphere until it reaches ambient temperature.
- the first reduction step may be conducted in muffle-type furnaces, retort-type furnaces, bogie-hearth furnaces, continuous conveyor belt hearth furnaces or any other type of equipment capable of achieving the required temperatures and of maintaining the reducing atmosphere required for the process.
- the product of the first reduction step consists in niobium dioxide (Nb0 2 ).
- the niobium dioxide (Nb0 2 ) produced has preferably a sponge-like morphology, with primary particles of 1 micron or less and binding "neck" between particles of adequate diameter. This product has a convenient porosity allowing to achieve high levels of capacitance when transformed into capacitor anodes.
- the scanning electron microscopy images of Figures 1 and 2 show the type of niobium (Nb0 2 ) of the present invention. As may be seen in these images, the niobium dioxide (Nb0 2 ) of the present invention has a large specific surface area and a porous structure with at least 50% porosity when measured by mercury porometry.
- the niobium dioxide (Nb0 2 ) of the present invention may be physically characterized as having a specific surface area of 0.5 to 20.0 m 2 /g, and preferably 0,8 to 12,0 m /g.
- the niobium dioxide (Nb0 2 ) obtained from the first reaction step is mixed with the oxygen getter material.
- the oxygen getter material may be any material capable of reducing the niobium dioxide (Nb0 2 ) specified in the process to niobium monoxide (NbO).
- the oxygen getter material consists in a refractory or reactive metal or metal alloy and/or hydrides thereof, there being preferred the use of niobium and/or tantalum, and niobium being the most preferred one.
- the niobium as used as the oxygen getter is any material containing metallic niobium capable of removing or reducing the oxygen present in the niobium dioxide (Nb0 2 ).
- the niobium used as the getter material may consist in an alloy or a material containing a mixture of niobium with other components.
- the getter niobium is predominantly, if not exclusively, comprised of metallic niobium.
- the purity of this niobium is not important, but preferentially there is used metallic niobium of high purity to avoid introducing other impurities during the process.
- the oxygen getter material may have any shape or size.
- the getter material is in the form of powder, in order to have sufficient surface area to function properly as an oxygen getter. Therefore, the getter material may consist in a powder with angular, flaked, rod-like, nodular or sponge-like shape, and/or a mixture or variations of these shapes.
- the getter material is a hydride of niobium and/or metallic niobium, in the form of granules that may be easily separated by sieving the niobium monoxide powder produced.
- a sufficient amount of getter material should be present to reduce the niobium dioxide (Nb0 2 ) to niobium monoxide (NbO). Preferentially, the amount of getter material present in the reaction with the niobium dioxide
- Nb0 2 is 1 to 6 times the stoichiometric quantity for fully reducing the niobium dioxide (Nb0 2 ) to niobium monoxide (NbO).
- the second reaction step is performed in furnaces or reactors commonly used for processing of niobium and/or tantalum, such as, for example, electric vacuum furnaces.
- the reaction of the niobium dioxide (Nb0 2 ) with the getter material is conducted at a temperature and for a time that are sufficient to allow the reduction of niobium dioxide to niobium monoxide (NbO) to occur.
- the temperature and the time duration of the process are dependent on several factors, such as, for example, the amount, the morphology and the particle-size distribution of the niobium dioxide and of the getter material loaded; and on the form of mixture of these materials.
- the temperature of the process may be between 1000°C and 1700°C, and preferably between 1200°C and 1600°C, for periods of time between 10 minutes and 720 minutes, and preferentially between 30 minutes .and 360 minutes.
- the second reduction step is conducted in an atmosphere that allows the transfer of the oxygen atoms of the niobium dioxide (Nb0 2 ) to the oxygen getter material.
- the reaction is conducted in an atmosphere containing hydrogen gas, and preferably consisting only in hydrogen gas.
- Other gasses may be present in addition to the hydrogen, such as nitrogen and/or argon and/or helium, provided that these gasses do not lower the reducing potential of the hydrogen.
- the pressure of the gasses during the second reducing step is preferably from 100 Torr to 2000 Torr, and most preferably from 500 Torr to 1500 Torr.
- the niobium monoxide (NbO) of the present invention exhibits an atomic rate of niobium to oxygen between 1:0.6 and 1:1.5 and preferably an atomic rate of niobium to oxygen between 1:0.7 and 1:1.1.
- the niobium monoxide has a formulation between NbO 0 .6 and NbO ⁇ . 5 and preferentially a formulation between NbO 0.7 and NbO u .
- the product of the second reduction step is niobium monoxide (NbO), with a morphology similar to the feed material, niobium dioxide (Nb0 2 ).
- NbO niobium monoxide
- niobium dioxide as a raw material for the 2 nd reduction step resides in that its melting temperature is substantially higher than the melting temperature of niobium pentoxide. This higher melting temperature of the niobium dioxide causes the morphology of the particles to remain practically unchanged during the final reduction reaction, which is conducted under high temperature.
- the niobium monoxide (NbO) produced has preferentially a sponge-like morphology, with primary particles of 1 micron or less and a binding "neck" between particles having an adequate diameter.
- This product has a convenient porosity allowing to achieve high levels of capacitance when used to make capacitor anodes.
- the scanning electron microscopy images of Figures 3 and 4 depict the type of niobium monoxide (NbO) of the present invention.
- the niobium monoxide (NbO) of the present invention has a large specific surface area and a porous structure with at least 50% porosity.
- the niobium monoxide (NbO) according to the present invention may be physically characterized as having a specific surface area of 0.5 to 20.0 m 2 /g, and preferably of 0.8 to 6.0 m 2 /g.
- the niobium monoxide (NbO) according to the present invention was also characterized by its electrical properties resulting from the manufacture thereof as a capacitor anode.
- the capacitor anode may be manufactured by pressing powders of niobium monoxide (NbO) to form anodes, and sintering those anodes at appropriate temperatures and anodizing the same to produce electrolytic capacitor anodes that may be tested as to their electrical properties.
- the anodes produced by pressing powders of niobium monoxide (NbO) according to the present invention had a mass of 100 mg. They were sintered in vacuum at about 6.7x 10 " Pa (5.0 x 10 " Torr), at a temperature of
- the anodizing voltage used was 30 Volts.
- the capacitance after anodizing was measured using a bridge LCR Agilent 4284A, the electrolyte used was a solution of H 2 S0 4 at 18% (by mass) and the frequency used was 120 Hz.
- the current leakage measurement was conducted in a solution of H 3 P0 4 at 0.1% (by mass), the voltage used corresponded to 70% of the anodizing voltage, that is, 21 Volts, and the current was monitored until 180 seconds after application of the voltage.
- Example 1 First reduction step: 200 grams of powdered niobium pentoxide were loaded into a tubular furnace. Hydrogen gas was admitted to the furnace chamber, and the furnace temperature was raised from ambient temperature to 800°C. The load was kept at this temperature for 300 minutes, whereupon the heating was turned off. The hydrogen atmosphere was maintained until the load reached ambient temperature, whereupon the furnace chamber was pressurized with nitrogen prior to removal of the load from the furnace.
- the product of this first reaction step had the following properties: X-Ray Diffraction: Nb0 2 Specific surface area, BET analysis method: 3.2 m 2 /g Porosity: 83.8%
- Second reduction step 6 grams of niobium dioxide, produced in the first reduction step, were loaded into a niobium crucible, together with 34g of powdered niobium hydride with particle size of less than 0.6 mm and greater than 0.3 mm.
- the crucible containing the mixture was loaded into the chamber of an electric vacuum furnace, the furnace chamber was evacuated and thereafter was pressurized with hydrogen gas to a pressure of 4 kPa (30 Torr) above atmospheric pressure. The temperature was raised from ambient temperature to a reaction temperature of 1200°C and kept at that level for 180 minutes.
- the furnace Upon there having elapsed the period of 180 minutes, the furnace was turned off and the furnace chamber was evacuated until there was reached a pressure of 0.067 Pa (5 x 10 "4 Torr). The furnace chamber was awaited to cool until ambient temperature prior to pressurizing the same with nitrogen. After the pressurization, the chamber was opened and the load was withdrawn from the furnace. The niobium monoxide powder was separated from the getter material powder by sieving using a screen with 0.2 mm mesh size.
- First reduction step were loaded into a tubular furnace. Hydrogen gas was admitted to the furnace chamber, and the furnace temperature was raised from ambient temperature to 800°C. The load was kept at this temperature for 150 minutes, whereupon the heating was turned off. The hydrogen atmosphere was maintained until the load reached ambient temperature, whereupon the furnace chamber was pressurized with nitrogen prior to removal of the load from the furnace.
- the product of this first reaction step had the following properties: X-Ray Diffraction: Nb0 2 Specific surface area, BET analysis method: 3.5 m 2 /g Porosity: 84.4%
- Second reduction step 180 grams of niobium dioxide, produced in the first reduction step, were loaded into a niobium crucible, together with 1000 g of powdered niobium hydride with particle size of less than 0.6 mm and greater than 0.3 mm.
- the crucible containing the mixture was loaded into the chamber of an electric vacuum furnace, the furnace chamber was evacuated and thereafter was pressurized with hydrogen gas to a pressure of 4 kPa (30 Torr) above atmospheric pressure. The temperature was raised from ambient temperature to a reaction temperature of 1200°C and kept at that level for 180 minutes.
- the furnace Upon there having elapsed the period of 180 minutes, the furnace was turned off and the furnace chamber was evacuated until there was reached a pressure of 0.067 Pa (5 x 10 "4 Torr). The furnace chamber was awaited to cool until ambient temperature prior to pressurizing the same with nitrogen. After the pressurization, the chamber was opened and the load was withdrawn from the furnace. The niobium monoxide powder was separated from the getter material powder by sieving using a screen with 0.2 mm mesh size.
- First reduction ste were loaded into a tubular furnace. Hydrogen gas was admitted to the furnace chamber, and the furnace temperature was raised from ambient temperature to 800°C. The load was kept at this temperature for 90 minutes, whereupon the heating was turned off. The hydrogen atmosphere was maintained until the load reached ambient temperature, whereupon the furnace chamber was pressurized with nitrogen prior to removal of the load from the furnace.
- the product of this first reaction step had the following properties: X-Ray Diffraction: Nb0 2 Specific surface area, BET analysis method: 7.0 m 2 /g Porosity: 80.4%
- Second reduction step 890 grams of niobium dioxide, produced in the first reduction step, were loaded into a niobium crucible, together with 5000 g of powdered niobium hydride with particle size of less than 0.6 mm and greater than 0.3 mm.
- the crucible containing the mixture was loaded into the chamber of an electric vacuum furnace, the furnace chamber was evacuated and thereafter was pressurized with hydrogen gas to a pressure of 4 kPa (30 Torr) above atmospheric pressure. The temperature was raised from ambient temperature to a reaction temperature of 1200°C and kept at that level for 360 minutes.
- the furnace Upon there having elapsed the period of 360 minutes, the furnace was turned off and the furnace chamber was evacuated until there was reached a pressure of 0.067 Pa (5 x 10 "4 Torr). The furnace chamber was awaited to cool until ambient temperature prior to pressurizing the same with nitrogen. After the pressurization, the chamber was opened and the load was withdrawn from the furnace. The niobium monoxide powder was separated from the getter material powder by sieving using a screen with 0.2 mm mesh size.
- First reduction step were loaded into a tubular furnace. Hydrogen gas was admitted to the furnace chamber, and the furnace temperature was raised from ambient temperature to 900°C. The load was kept at this temperature for 150 minutes, whereupon the heating was turned off. The hydrogen atmosphere was maintained until the load reached ambient temperature, whereupon the furnace chamber was pressurized with nitrogen prior to removal of the load from the furnace.
- the product of this first reaction step had the following properties: X-Ray Diffraction: Nb02 Specific surface area, BET analysis method: 1.6 m 2 /g Porosity: 77.0%
- Second reduction step 6 grams of niobium dioxide, produced in the first reduction step, were loaded into a niobium crucible, together with 34 g of powdered niobium hydride with particle size of less than 0.6 mm and greater than 0.3 mm.
- the crucible containing the mixture was loaded into the chamber of an electric vacuum furnace, the furnace chamber was evacuated and thereafter was pressurized with hydrogen gas to a pressure 4 kPa (30 Torr) above atmospheric pressure. The temperature was raised from ambient temperature to the reaction temperature of 1300°C and kept at that level for 180 minutes.
- the furnace Upon there having elapsed the period of 180 minutes, the furnace was turned off and the furnace chamber was evacuated until there was reached a pressure of 0.067 kPa (5 x 10 "4 Torr). The furnace chamber was awaited to cool until ambient temperature prior to pressurizing the same with nitrogen. After the pressurization, the chamber was opened and the load was withdrawn from the furnace. The niobium monoxide powder was separated from the getter material powder by sieving using a screen with 0.2 mm mesh size. The product was tested and the following results were obtained: X-Ray Diffraction: NbO Specific surface area, BET analysis method: 1.2 m 2 /g Capacitance: 91,600 CV/g Current Leakage: 0.3 nA/CV.
Abstract
Description
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Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2006527231A JP2007506634A (en) | 2003-09-25 | 2004-01-23 | Preparation of niobium oxide powder for use in capacitors |
DE112004001796T DE112004001796T5 (en) | 2003-09-25 | 2004-01-23 | A process for the production of niobium oxide powder for use in capacitors |
US10/573,293 US20060275204A1 (en) | 2003-05-05 | 2004-01-23 | Process for the production of niobium oxide powder for use in capacitors |
GB0605986A GB2421945A (en) | 2003-09-25 | 2004-01-23 | A process for the production of niobium oxide power for use in capacitors |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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BRPI0304252-9 | 2003-09-25 | ||
BR0304252A BR0304252B1 (en) | 2003-09-25 | 2003-09-25 | production process of niobium monoxide powder, niobium monoxide, and capacitor. |
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WO2005028370A1 true WO2005028370A1 (en) | 2005-03-31 |
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PCT/BR2004/000003 WO2005028370A1 (en) | 2003-05-05 | 2004-01-23 | A process for the production of niobium oxide power for use in capacitors |
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JP (1) | JP2007506634A (en) |
CN (1) | CN1856446A (en) |
BR (1) | BR0304252B1 (en) |
DE (1) | DE112004001796T5 (en) |
GB (1) | GB2421945A (en) |
WO (1) | WO2005028370A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2008001754A1 (en) * | 2006-06-26 | 2008-01-03 | Mitsui Mining & Smelting Co., Ltd. | Niobium monoxide |
WO2008001774A1 (en) * | 2006-06-26 | 2008-01-03 | Mitsui Mining & Smelting Co., Ltd. | Process for production of niobium oxides and niobium monoxide |
JP2008542174A (en) * | 2005-06-03 | 2008-11-27 | ハー.ツェー.スタルク ゲゼルシャフト ミット ベシュレンクテル ハフツング | Inorganic compounds |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009012124A2 (en) * | 2007-07-18 | 2009-01-22 | Cabot Corporation | Niobium suboxide- and niobium-tantalum-oxide-powders and capacitor anodes produced thereof |
CN100577574C (en) * | 2007-08-25 | 2010-01-06 | 宁夏东方钽业股份有限公司 | Method for preparing low chemical valence niobium oxide or niobium powder |
CN108046323B (en) * | 2017-12-20 | 2019-08-02 | 广东省稀有金属研究所 | A kind of preparation method of niobium oxide |
Citations (4)
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US6391275B1 (en) * | 1998-09-16 | 2002-05-21 | Cabot Corporation | Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides |
US6416730B1 (en) * | 1998-09-16 | 2002-07-09 | Cabot Corporation | Methods to partially reduce a niobium metal oxide oxygen reduced niobium oxides |
US20030104923A1 (en) * | 2001-05-15 | 2003-06-05 | Showa Denko K.K. | Niobium oxide powder, niobium oxide sintered body and capacitor using the sintered body |
WO2004042095A1 (en) * | 2002-11-04 | 2004-05-21 | Companhia Brasileira De Metalurgia E Mineração - Cbmm | A process for the production of niobium and/or tantalum powder with large surface area |
-
2003
- 2003-09-25 BR BR0304252A patent/BR0304252B1/en not_active IP Right Cessation
-
2004
- 2004-01-23 GB GB0605986A patent/GB2421945A/en not_active Withdrawn
- 2004-01-23 JP JP2006527231A patent/JP2007506634A/en active Pending
- 2004-01-23 CN CNA2004800277767A patent/CN1856446A/en active Pending
- 2004-01-23 DE DE112004001796T patent/DE112004001796T5/en not_active Withdrawn
- 2004-01-23 WO PCT/BR2004/000003 patent/WO2005028370A1/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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US6391275B1 (en) * | 1998-09-16 | 2002-05-21 | Cabot Corporation | Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides |
US6416730B1 (en) * | 1998-09-16 | 2002-07-09 | Cabot Corporation | Methods to partially reduce a niobium metal oxide oxygen reduced niobium oxides |
US20030104923A1 (en) * | 2001-05-15 | 2003-06-05 | Showa Denko K.K. | Niobium oxide powder, niobium oxide sintered body and capacitor using the sintered body |
WO2004042095A1 (en) * | 2002-11-04 | 2004-05-21 | Companhia Brasileira De Metalurgia E Mineração - Cbmm | A process for the production of niobium and/or tantalum powder with large surface area |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008542174A (en) * | 2005-06-03 | 2008-11-27 | ハー.ツェー.スタルク ゲゼルシャフト ミット ベシュレンクテル ハフツング | Inorganic compounds |
WO2008001754A1 (en) * | 2006-06-26 | 2008-01-03 | Mitsui Mining & Smelting Co., Ltd. | Niobium monoxide |
WO2008001774A1 (en) * | 2006-06-26 | 2008-01-03 | Mitsui Mining & Smelting Co., Ltd. | Process for production of niobium oxides and niobium monoxide |
JP2008001582A (en) * | 2006-06-26 | 2008-01-10 | Mitsui Mining & Smelting Co Ltd | Niobium monoxide |
JPWO2008001774A1 (en) * | 2006-06-26 | 2009-11-26 | 三井金属鉱業株式会社 | Niobium oxide production method and niobium monoxide |
US7988945B2 (en) | 2006-06-26 | 2011-08-02 | Mitsui Mining & Smelting Co., Ltd. | Niobium monoxide |
Also Published As
Publication number | Publication date |
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CN1856446A (en) | 2006-11-01 |
BR0304252B1 (en) | 2013-05-14 |
GB2421945A (en) | 2006-07-12 |
DE112004001796T5 (en) | 2006-09-07 |
GB0605986D0 (en) | 2006-05-03 |
JP2007506634A (en) | 2007-03-22 |
BR0304252A (en) | 2005-05-31 |
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