WO2002018295A1 - Verfahren zur herstellung eines keramischen silber niobium tantalat körpers - Google Patents
Verfahren zur herstellung eines keramischen silber niobium tantalat körpers Download PDFInfo
- Publication number
- WO2002018295A1 WO2002018295A1 PCT/DE2001/003107 DE0103107W WO0218295A1 WO 2002018295 A1 WO2002018295 A1 WO 2002018295A1 DE 0103107 W DE0103107 W DE 0103107W WO 0218295 A1 WO0218295 A1 WO 0218295A1
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- WO
- WIPO (PCT)
- Prior art keywords
- particles
- producing
- suspension
- mixture
- produced
- Prior art date
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/495—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates
Definitions
- the invention relates to a method for producing a ceramic body, the composition of which is based on a mixture of silver oxide, niobium oxide and tantalum oxide, a pressing being sintered.
- a method for producing a ceramic body based on silver oxide, niobium oxide and tantalum oxide, hereinafter referred to as ANT, is known from the publication WO 98/03446, these oxides and possibly other oxides being mixed with one another in small amounts and in the form of a calcined powder with a Particle size between 1 and 2 ⁇ m is prepared. This calcined powder is pressed and then sintered at a temperature between 1150 ° C and 1250 ° C.
- the known method for producing a ceramic body has the disadvantage that it does not allow the production of a dense phase-heterogeneous ceramic, where two different components are present as separate phases. Due to the small size of the grains mixed with one another, a phase equilibrium can occur during sintering of the ceramic, which then contains the various components of the ANT ceramic as a "solid solution". In particular, it is not possible to produce a dense phase-heterogeneous ceramic, the individual phases having different compositions of ANT.
- phase-heterogeneous ceramic which is based on silver, niobium and tantalum, would be desirable, for example, in order to compensate for the temperature coefficient of the dielectric constant ⁇ of a phase A with a temperature coefficient of a phase B different therefrom, which has a different composition than phase A .
- the aim of the present invention is therefore to provide a method for producing a ceramic body based on ANT, which allows the production of a dense phase-heterogeneous ceramic.
- the invention specifies a method for producing a ceramic body, particles being produced in a first step and having an expansion of at least 5 ⁇ m.
- the particles comprise a ceramic material that is based on a mixture of silver oxide, niobium oxide and tantalum oxide.
- Particles of a type A and a type B are produced, each having a composition A or B of their ceramic materials, the compositions A and B being different from one another.
- the different types of particles are mixed together, whereby a particle mixture is produced.
- pressing is carried out by pressing the particle mixture. The pressure is then sintered, which creates a ceramic body from the particle mixture.
- the process according to the invention has the advantage that the use of large particles, each corresponding to either only composition A or only composition B, results in the formation of a "solid solution" in which all components of composition A and B would be mixed while of sintering is prevented.
- the components of the particles diffuse, but only over lengths of a few ⁇ m. A large part of the interior of the particles is thus retained in its composition A or B. Therefore tiert from the inventive method, a ceramic body with a phase heterogeneous composition.
- the process according to the invention has the advantage that, owing to the involvement of silver oxide, niobium oxide and tantalum oxide, it allows the production of a ceramic body which has a high dielectric constant e> 300.
- the ceramic body produced by the method is therefore suitable for use in microwave components, the high dielectric constant, in particular, making it possible to miniaturize the external dimensions of the body to a great extent.
- compositions A and B are based on a mixture of silver oxide, niobium oxide and tantalum oxide, the use of the known powder with a size of 1 to 2 ⁇ m would definitely form a mixed ceramic during sintering as a state of equilibrium, which would have completely new dielectric properties.
- a ceramic body can be produced in which the dielectric properties result from averaging the dielectric properties of compositions A and B.
- the particles can be produced in a form which contains grains, the grains being held together by a binder.
- a binder Such particles are also known to the person skilled in the art as granules. This shape of the particles makes it possible to assemble them from a finer powder, as can easily be produced by methods customary in ceramic production.
- the particles can be produced particularly advantageously from a suspension by a process with the following steps: al) producing a calcine of composition A or B a2) producing grains with a grain size of up to 10 ⁇ m by grinding the calcined a3) producing a suspension by mixing the grains with water and a suitable binder and homogenizing the suspension.
- the particles can be produced from the suspension by a method with the following steps: a31) producing an agglomerated powder by removing the water from the suspension a32) pressing the agglomerated powder through a sieve.
- This method has the advantage that the mesh size of the sieve, which can be chosen to be 500 ⁇ m or larger, for example, allows the expansion of the particles to be predetermined.
- the particles can also be produced by atomizing the suspension by means of a suitable construction in a hot air stream.
- a suitable construction can be, for example, a nozzle or a hose that drips the suspension onto a rotating disc. This creates droplets, the size of which defines the size of the particles formed from the droplets.
- the water is removed from the suspension in a hot air stream, so that the grains connected by the binder remain in the individual particles.
- the calcine can be produced particularly advantageously in a two-stage process, with the following steps: all) Production of a precursor caicinate from a mixture of oxides which contains niobium and tantalum oxide by calcining at a temperature which is higher than the melting temperature of silver al2) mixing the precursor calcine with silver oxide al3) calcining the mixture.
- This two-stage process has the advantage that niobium and tantalum can be calcined at a temperature of 1300 ° C., as a result of which the tantalum / niobium mixture can be well caused to react.
- V O5 H 3 BO 3 , Li 2 0, W0 3 , Mn ⁇ 3 , Bi 2 0 3 , Ga ⁇ 3 or oxides of rare earths (SE), such as samarium, lanthanum, cerium, come in particular as further oxides , Praseodymium, Neodymium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium or Lutetium, in each case according to the formula SE 2 O 3 .
- SE rare earths
- compositions A and B in a suitable manner in such a way that the temperature coefficients of the dielectric constants and TK ⁇ ⁇ of the particles have different signs from one another in a temperature interval.
- Such a method has the advantage that it allows the production of a ceramic body, the temperature coefficient of which is largely compensated for by the dielectric constant.
- the figure shows an example of a ceramic body produced using the method according to the invention in a schematic cross section.
- the figure shows a ceramic body 1, which is composed of particles 2 of a type A and a type B. All particles 2 are based on a mixture of silver oxide, niobium oxide and tantalum oxide. The particles 2 of types A and B differ in their composition of the ceramic material.
- niobium oxide and tantalum oxide which are mixed together with any additional dopants in a suitable ratio
- deionized water is added to this oxide mixture, a suspension with a solids content of 40 to 60% being formed.
- This suspension is homogenized in a ball mill with a volume of 2 liters, using grinding balls with a diameter between 10 and 20 mm.
- the suspension is processed in the ball mill for a period of between 16 and 24 hours. After homogenization, the suspension is dried in a hot air oven for 24 hours at a temperature between 40 ° C and 90 ° C.
- the powder is then pressed through a metal sieve with a mesh size of 500 ⁇ m.
- the calcination is then carried out in a chamber furnace, using a corundum (AI2O 3 ) conversion capsule.
- Table 1 shows the data for the two stages of the two-stage temperature profile used for the calcination.
- the third column gives the after
- Heating reached temperature T The third column shows the holding time H.
- the fifth column shows the atmosphere used.
- Table 1 Temperature profile for the first calcination.
- the calcined powder is pressed again through the metal sieve and mixed with a suitable amount of silver oxide and possibly other additives in the desired ratio.
- Deionized water is then added to the oxide mixture again to produce a suspension with 40 to 60% solids.
- the suspension is homogenized and dried using the process already given above. Then it is pushed through the metal sieve again. A calcination then takes place which proceeds in four steps, which are shown in Table 2 in a manner corresponding to Table 1.
- Table 2 Temperature profile for the second calcination.
- the powder produced with the second calcination is crushed in a coarse mill, after which deionized water is added in an amount which leads to a suspension of 60 to 70% solids content.
- This suspension is ground in a ball mill with a volume of 0.5 1, zircon grinding balls with a diameter between 0.8 and 1.5 mm being used.
- Table 3 describes the values for the average particle size G of the ground powder or the specific surface 0 of the ground powder at various meal M.
- Table 3 Meal, particle size and specific surface.
- the powder produced by the last grinding is mixed with 22 to 27% by weight of an aqueous polyethylene glycol solution (PEG20000).
- Ethylene glycol acts as a binder.
- the powder is then granulated by pressing through a sieve and then drying. This creates granules with a size of at least 20 ⁇ m.
- the particles of the granules are produced by pressing the powder mixed with the binder through a sieve with a mesh size of 500 ⁇ m. This produces particles that are between 63 and 500 ⁇ m in size.
- the particles are dried at room temperature for a period of 24 hours.
- the particles with a composition A are then mixed with particles of a composition B.
- the particles are mixed in the dry state in a tumble mixer.
- Table 4 Temperature / atmosphere profile for the sintering of the particle mixture.
- a ceramic of composition A is prepared from a precursor with 46.9% by weight of Nb 2 ⁇ 5, 52.0% by weight of Ta 2 Ü 5 and 1.1% by weight of V 2 O5.
- the vanadium oxide is used as a sintering aid.
- the precursor starting materials are mixed in the specified ratio.
- so much deionized water is added that a suspension with 50% solids content is formed.
- This suspension is then homogenized in a ball mill with a volume of 2 l, using grinding balls with a diameter between 10 and 20 mm. The grinding takes 20 hours.
- After homogenization of the suspension it is dried in a forced air oven at 50 ° C for 24 hours.
- the resulting powder is pressed through a metal sieve with a mesh size of 500 ⁇ m and then calcined in a chamber furnace.
- Table 5 shows the temperature profile of the calcination.
- Table 5 Temperature profile for the first calcination of Example 1, composition A.
- the calcined powder is pressed again through the sieve already described above.
- a mixture is then produced from the powder and silver oxide in a weight ratio of 59.9% by weight of powder and 41.0% by weight of Ag2 ⁇ .
- Deionized water is then added to the mixture, so that a suspension with a solids content of 50% is formed.
- the suspension is homogenized in a ball mill. This is followed by the drying step specified for the precursor.
- a second calcination step takes place, the temperature or atmospheric profile of which can be seen in Table 6.
- the powder calcined in this way is comminuted in a coarse mill and then mixed with distilled water to produce a suspension with a solids content of 65%.
- the suspension is ground in a ball mill with a volume of 0.5 1, zircon grinding balls with a diameter of 1 mm being used.
- Table 7 shows this Result of this grinding process depending on the meal according to Table 3.
- Table 7 Meal M, particle size G and specific surface area 0 for example 1, composition A.
- the result of this grinding process is a ceramic of composition A.
- This powder is mixed with 24% by weight of aqueous polyethylene glycol solution, from which the particles are then produced by one of the methods described above.
- a ceramic of composition B is then produced, a mixture of oxides of the following composition being used for the precursor: 45.6% by weight of Nb2O5, 50.5% by weight of Ta 2 0 5 , 1.1% by weight. % V 2 0 5 and 2.8% by weight Ga 2 0 3 .
- the procedure for this precursor B is now the same as for the procedure for precursor A already described above.
- 59.0% by weight of the precursor is mixed with 37.9% by weight of Ag 0 and 3.1% by weight. -% Sm 2 0 3 mixed.
- This mixture B is subjected to the same process steps as mixture A.
- the first calcination again corresponds to that described in Table 5.
- the powder calcined in this way is again used in accordance with the process for composition A, the result of the grinding process, in particular, depending on the grinding time, being the same as that described in table 7.
- the production of the particles of the composition B also takes place in the same way as the production of the particles of the composition A, as has already been described above.
- the particles of types A and B thus produced are mixed with one another in a weight ratio of 42.5% component A to 57.5% component B and the particles thus produced
- the mixture is pressed and then sintered.
- the sintering conditions described in Table 9 are used.
- Table 9 Temperature / atmosphere profile for the sintering of the ceramic body from example 1, mixture B.
- a precursor composed of 45.4% by weight of Nb 2 ⁇ 5 and 54.6% by weight of Ta 2 ⁇ 5 is used for composition A.
- the following process steps are the same as in Example 1, with the Most calcination corresponds to Table 5.
- 58.9% by weight of the calcine are then mixed with 40.1% by weight of silver oxide and 1% by weight of H 3 BO 3 .
- the H 3 BO 3 has the function of a sintering aid.
- the further processing of this mixture down to the particles of type A from exemplary embodiment 2 again corresponds to example 1, the second calcination and the grinding process in particular being carried out in accordance with table 6 and table 7, respectively.
- a second precursor is produced which contains a mixture of 24.5% by weight of Nb 2 ⁇ 5 and 75.5% by weight of Ta2 ⁇ 5.
- the further process steps up to the first calcination correspond to those as are carried out for the composition B of exemplary embodiment 2.
- 61.5% by weight of the calcine are then mixed with 37.5% by weight of Ag 2 O and 1% by weight of H 3 BO 3 . This mixture is then processed further as indicated in Example 1.
- the particles of the types A and B are then mixed with one another, as already indicated above, and processed further to form a sintered body.
- the ceramic body produced according to Example 1 is outstandingly suitable as a base body for a microwave component due to the good compensation of the temperature coefficients of the dielectric constants of composition A and composition B and because of the low dielectric losses.
- To produce a microwave component through-holes can still be made in the body while the powder is being pressed.
- the ceramic body produced according to embodiment 2 has a high insulation resistance, due to the use of H 3 BO 3 as a sintering aid and due to the
- Example 2 Lack of other ingredients besides silver oxide, niobium oxide and tantalum oxide. As a result, the body produced according to Example 2 is particularly suitable as a dielectric for capacitors.
- the ceramic bodies produced according to Example 1 and Example 2 are provided with electrodes by electroplating so that electrical measurements can be carried out.
- Table 10 shows the results of the electrical measurements for the ceramic bodies according to Example 1 and Example 2.
- Table 10 Microwave properties of the ceramic bodies produced according to Examples 1 and 2.
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- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Compositions Of Oxide Ceramics (AREA)
Abstract
Description
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Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/363,075 US6843956B2 (en) | 2000-08-29 | 2001-08-14 | Method for producing a ceramic silver niobium tantalate body |
JP2002523419A JP2004507433A (ja) | 2000-08-29 | 2001-08-14 | 銀ニオブタンタル酸塩のセラミック体の製造方法 |
EP01969234A EP1313680A1 (de) | 2000-08-29 | 2001-08-14 | Verfahren zur herstellung eines keramischen silber niobium tantalat körpers |
AU2001289562A AU2001289562A1 (en) | 2000-08-29 | 2001-08-14 | Method for producing a ceramic silver niobium tantalate body |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10042349A DE10042349C1 (de) | 2000-08-29 | 2000-08-29 | Verfahren zur Herstellung eines keramischen Körpers |
DE10042349.3 | 2000-08-29 |
Publications (1)
Publication Number | Publication Date |
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WO2002018295A1 true WO2002018295A1 (de) | 2002-03-07 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/DE2001/003107 WO2002018295A1 (de) | 2000-08-29 | 2001-08-14 | Verfahren zur herstellung eines keramischen silber niobium tantalat körpers |
Country Status (7)
Country | Link |
---|---|
US (1) | US6843956B2 (de) |
EP (1) | EP1313680A1 (de) |
JP (1) | JP2004507433A (de) |
AU (1) | AU2001289562A1 (de) |
DE (1) | DE10042349C1 (de) |
TW (1) | TW572865B (de) |
WO (1) | WO2002018295A1 (de) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
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DE10145363A1 (de) * | 2001-09-14 | 2003-04-10 | Epcos Ag | Verfahren zur Herstellung eines keramischen Substrats und keramisches Substrat |
US7019391B2 (en) | 2004-04-06 | 2006-03-28 | Bao Tran | NANO IC packaging |
US7895223B2 (en) * | 2005-11-29 | 2011-02-22 | Cisco Technology, Inc. | Generating search results based on determined relationships between data objects and user connections to identified destinations |
CN113372115B (zh) * | 2021-07-12 | 2023-04-07 | 昆明理工大学 | 一种离心式喷雾造粒法制备钽酸盐(Y/Al/RE)3TaO7空心球粉体的方法 |
CN116422224B (zh) * | 2023-04-14 | 2024-03-12 | 北京华圻生态科技有限公司 | 一种球形空心粉体及其制备方法和应用 |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1998003446A1 (en) | 1996-07-19 | 1998-01-29 | Ins^¿Titut Joz^¿Ef Stefan | Microwave dielectric ceramics based on silver, niobium and tantalum oxides |
EP0916632A2 (de) * | 1997-11-17 | 1999-05-19 | Lucent Technologies Inc. | Binäre Oxide von Calciumniobat und Calciumtantalat enthaltendes dielektrisches Material mit niedrigem Temperaturkoeffizienten |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2864713A (en) * | 1955-09-09 | 1958-12-16 | Gen Electric Co Ltd | Ceramic dielectric compositions |
JPS62183608A (ja) | 1986-02-07 | 1987-08-12 | Murata Mfg Co Ltd | 誘電体共振器の製造方法 |
JPH01234358A (ja) | 1988-03-15 | 1989-09-19 | Matsushita Electric Ind Co Ltd | 誘電体磁器組成物 |
JP2731940B2 (ja) | 1989-03-10 | 1998-03-25 | 日本セメント株式会社 | マイクロ波用誘電体セラミックス |
-
2000
- 2000-08-29 DE DE10042349A patent/DE10042349C1/de not_active Expired - Fee Related
-
2001
- 2001-08-10 TW TW90119653A patent/TW572865B/zh not_active IP Right Cessation
- 2001-08-14 AU AU2001289562A patent/AU2001289562A1/en not_active Abandoned
- 2001-08-14 US US10/363,075 patent/US6843956B2/en not_active Expired - Fee Related
- 2001-08-14 WO PCT/DE2001/003107 patent/WO2002018295A1/de not_active Application Discontinuation
- 2001-08-14 JP JP2002523419A patent/JP2004507433A/ja not_active Withdrawn
- 2001-08-14 EP EP01969234A patent/EP1313680A1/de not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1998003446A1 (en) | 1996-07-19 | 1998-01-29 | Ins^¿Titut Joz^¿Ef Stefan | Microwave dielectric ceramics based on silver, niobium and tantalum oxides |
EP0916632A2 (de) * | 1997-11-17 | 1999-05-19 | Lucent Technologies Inc. | Binäre Oxide von Calciumniobat und Calciumtantalat enthaltendes dielektrisches Material mit niedrigem Temperaturkoeffizienten |
Non-Patent Citations (1)
Title |
---|
VALANT M ET AL: "New high-permittivity AgNb/sub 1-x/Ta/sub x/O/sub 3/ microwave ceramics. I. Crystal structures and phase-decomposition relations", JOURNAL OF THE AMERICAN CERAMIC SOCIETY, JAN. 1999, AMERICAN CERAMIC SOC, USA, vol. 82, no. 1, pages 81 - 87, XP002186343, ISSN: 0002-7820 * |
Also Published As
Publication number | Publication date |
---|---|
DE10042349C1 (de) | 2001-11-15 |
US6843956B2 (en) | 2005-01-18 |
US20040029708A1 (en) | 2004-02-12 |
AU2001289562A1 (en) | 2002-03-13 |
JP2004507433A (ja) | 2004-03-11 |
EP1313680A1 (de) | 2003-05-28 |
TW572865B (en) | 2004-01-21 |
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