US5133129A
Expired / Lapsed
US
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Methods of producing microwave device
Assignee: Nokia Bell Labs
•
Filing: 1990-07-16
•
Granted: 1992-07-28
•
Expires: 2010-07-16
Abstract
Abstract This invention concerns with microwave devices including resonant elements made from dielectric materials represented by the nominal formulas Ba2Ti9O20, BaTi4O9, ZrTiO4 (Sn) and the like. The resonant element is produced conventionally by a process including numerous steps of mixing, drying, screening, calcining, ball milling, drying, screening or remilling and spray drying, forming and sintering. These steps may take 72 hours or more, prior to the forming step, and are labor and energy consuming. The improvement resides in the use of a reduced number of steps which include mixing precursor powders with addition of water and dispersants, spray drying or flocculating and drying the mixed formulation, forming and reactively sintering, so as to reduce the total processing time, prior to the forming step, to form about 8 to 24 hours. The sintering step is conducted in an oxygen-enriched atmosphere and may be followed by soaking and annealing to enhance the Q characteristics of the element. Resultant product characteristics, e.g. Q's, are superior or at least comparable to those of the conventionally produced product.
Inventors
- 👤 John Thomson, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:09
CPC Classifications
H; H01; H01P; H01P11/00; H01P11/008; H01P7/00; H01P7/10; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49016
Claims Analysis
Total Claims: 58
Claim 1
Independent Claim
329 words
A method of fabricating a microwave device, comprising the steps of preparing a body of dielectric material selected from the group consisting of dielectric materials having the nominal formula Ba 2 Ti 9 O 20 , BaTi 4 O 9 , and ZrTiO 4 , and assembling said microwave device which comprises body of dielectric material, a means for introducing microwave electrical energy to the dielectric material, and a conducting member to contain the microwave electrical energy in the device, in which said body of dielectric material is prepared by the steps consisting essentially of mixing a slurry comprising oxidic precursor powders of said dielectric material, water and a dispersant, the amount of such precursor powders being sufficient to result upon sintering in a material with said nominal formula, said dispersant resulting in the reduction of the volume of water being used in the slurry and in improving the blending of the powers, said mixing being conducted for a period sufficient to result in blending of precursor powders, drying the mixture, said drying being selected from a) spray-drying the mixed slurry preceded by an inclusion into the slurry of organic materials including binders, plasticizers, lubricants and anti-foaming agents; and b) adding to the mixed slurry a dilute acid as a flocculating agent in an amount sufficient to neutralize effects of the dispersant, oven drying the flocculated slurry and screening the dried mixture, forming the dried mixture into a green form body, and sintering the formed body in an oxygen atmosphere, said sintering including heating the formed body at a rate of less than 200° C. per hour to a temperature sufficient to simultaneously react and sinter the precursor powders into said dielectric material body, soaking the body at said temperature for a period of up to 24 hours, and, optionally annealing the sintered body in an oxygen atmosphere for a period of up to 100 hours, the so-processed body having Q values (low microwave losses) in excess of 9000.
Claim 2
Independent Claim
329 words
A method of fabricating a microwave device, comprising the steps of preparing a body of dielectric material selected from the group consisting of dielectric materials having the nominal formula Ba 2 Ti 9 O 20 , BaTi 4 O 9 , and ZrTiO 4 , and assembling said microwave device which comprises body of dielectric material, a means for introducing microwave electrical energy to the dielectric material, and a conducting member to contain the microwave electrical energy in the device, in which said body of dielectric material is prepared by the steps consisting essentially of mixing a slurry comprising oxidic precursor powders of said dielectric material, water and a dispersant, the amount of such precursor powders being sufficient to result upon sintering in a material with said nominal formula, said dispersant resulting in the reduction of the volume of water being used in the slurry and in improving the blending of the powers, said mixing being conducted for a period sufficient to result in blending of precursor powders, drying the mixture, said drying being selected from a) spray-drying the mixed slurry preceded by an inclusion into the slurry of organic materials including binders, plasticizers, lubricants and anti-foaming agents; and b) adding to the mixed slurry a dilute acid as a flocculating agent in an amount sufficient to neutralize effects of the dispersant, oven drying the flocculated slurry and screening the dried mixture, forming the dried mixture into a green form body, and sintering the formed body in an oxygen atmosphere, said sintering including heating the formed body at a rate of less than 200° C. per hour to a temperature sufficient to simultaneously react and sinter the precursor powders into said dielectric material body, soaking the body at said temperature for a period of up to 24 hours, and, optionally annealing the sintered body in an oxygen atmosphere for a period of up to 100 hours, the so-processed body having Q values (low microwave losses) in excess of 9000.
Claim 3
Dependent Claim
25 words
The method of claim 1 in which said dispersant is selected from the group consisting of complex glassy phosphates, condensed arylsulfonic acids and ammoniated polyacrylates.
Claim 4
Dependent Claim
32 words
The method of claim 2 in which said dispersant is an ammoniated polyacrylate added in an amount of from 0.7 to 1.2 wt. percent based on the weight of dry precursor powders.
Claim 5
Dependent Claim
27 words
The method of claim 3 in which said dispersant is added in an amount of about 0.9 wt. percent based on the weight of dry precursor powders.
Claim 6
Dependent Claim
21 words
The method of claim 1 in which the said flocculating agent is acetic acid added as a 25-75 volume percent solution.
Claim 7
Dependent Claim
32 words
The method of claim 5 in which said acetic acid is added in an amount of about 10-20 ml. of a 50 volume percent solution per 1 kg of dry precursor powders.
Claim 8
Dependent Claim
15 words
The method of claim 1 in which said mixing is conducted for about 6 hours.
Claim 9
Dependent Claim
24 words
The method of claim 1 in which said mixing prior to the spray-drying step is conducted for a period of up to 6 hours.
Claim 10
Dependent Claim
43 words
The method of claim 1 in which one of said precursor powders is TiO 2 , and the amount of TiO 2 being added is reduced relatively to a required stoichiometric amount by an amount sufficient to avoid microcracking of the sintered body.
Claim 11
Dependent Claim
21 words
The method of claim 9 wherein the amount of TiO 2 powder is reduced by from 1.5 to 3 wt. percent.
Claim 12
Dependent Claim
18 words
The method of claim 10 in which the said reduction preferably ranges from 1.75 to 2.75 wt. percent.
Claim 13
Dependent Claim
17 words
The method of claim 1 in which said sintering temperature ranges from 1350° C. to 1420° C.
Claim 14
Dependent Claim
35 words
The method of claim 1 in which the sintered body is optionally annealed in an oxygen atmosphere at a temperature ranging from 900° C. to 1400° C. for a period of up to 100 hours.
Claim 15
Independent Claim
278 words
A method of fabricating a microwave device, comprising the steps of preparing a body of dielectric material selected from the group consisting of dielectric materials having the nominal formula Ba 2 Ti 9 O 20 , BaTi 4 O 9 , and ZrTiO 4 and assembling said microwave device which comprises a body of dielectric material, a means for introducing microwave electrical energy to the dielectric material, and a conducting member to contain the microwave electrical energy in the device, in which said body of dielectric material is prepared by the steps consisting essentially of, preparing a slurry comprising precursor powders of said dielectric material, water, dispersant, and organic ingredients including binders, plasticizers, lubricants and anti-foaming agents, the amount of such precursor powders being sufficient to result upon sintering in a material with said nominal formula, said dispersant resulting in the reduction of the volume of water being used in the slurry and in improving the blending of the powders, mixing said slurry for a period sufficient to result in blending of the precursor powders, spray-drying the mixture, forming the dried mixture into a desired green form body, and sintering the green form body in an oxygen atmosphere, said sintering including heating the formed body at a rate of less than 200 degree C. per hour to am temperature sufficient to react and sinter the precursor powders into said dielectric material body, and soaking the body at said temperature for a period of up to 24 hours, and optionally, annealing the sintered body in an oxygen atmosphere for a period of up to 100 hours, the so-processed body having Q values (low microwave losses) in excess of 9000.
Claim 16
Independent Claim
278 words
A method of fabricating a microwave device, comprising the steps of preparing a body of dielectric material selected from the group consisting of dielectric materials having the nominal formula Ba 2 Ti 9 O 20 , BaTi 4 O 9 , and ZrTiO 4 and assembling said microwave device which comprises a body of dielectric material, a means for introducing microwave electrical energy to the dielectric material, and a conducting member to contain the microwave electrical energy in the device, in which said body of dielectric material is prepared by the steps consisting essentially of, preparing a slurry comprising precursor powders of said dielectric material, water, dispersant, and organic ingredients including binders, plasticizers, lubricants and anti-foaming agents, the amount of such precursor powders being sufficient to result upon sintering in a material with said nominal formula, said dispersant resulting in the reduction of the volume of water being used in the slurry and in improving the blending of the powders, mixing said slurry for a period sufficient to result in blending of the precursor powders, spray-drying the mixture, forming the dried mixture into a desired green form body, and sintering the green form body in an oxygen atmosphere, said sintering including heating the formed body at a rate of less than 200 degree C. per hour to am temperature sufficient to react and sinter the precursor powders into said dielectric material body, and soaking the body at said temperature for a period of up to 24 hours, and optionally, annealing the sintered body in an oxygen atmosphere for a period of up to 100 hours, the so-processed body having Q values (low microwave losses) in excess of 9000.
Claim 17
Dependent Claim
21 words
The method of claim 14 in which the oxidic ingredients comprise BaTiO 3 and an anatase form of TiO 2 .
Claim 18
Dependent Claim
41 words
The method of claim 14 wherein an excess of Ba is provided by reducing from 1.5 to 3 wt. percent the amount of TiO 2 powder needed to produce a desired weight of stoichiometric Ba 2 Ti 9 O 20 .
Claim 19
Dependent Claim
18 words
The method of claim 16 in which the said reduction preferably ranges from 1.75 to 2.75 wt. percent.
Claim 20
Dependent Claim
25 words
The method of claim 14 in which said dispersant is selected from the group consisting of complex glassy phosphates, condensed arylsulfonic acids and ammoniated polyacrylates.
Claim 21
Dependent Claim
29 words
The method of claim 18 in which said dispersant is an ammoniated polyacrylate added in an amount of from 0.7 to 1.2 wt. percent based on dry precursor powders.
Claim 22
Dependent Claim
24 words
The method of claim 19 in which said dispersant is added in an amount of about 0.9 wt. percent based on dry precursor powders.
Claim 23
Dependent Claim
17 words
The method of claim 14 in which said sintering temperature ranges from 1350° C. to 1420° C.
Claim 24
Dependent Claim
21 words
The method of claim 16 in which said mixing prior to the spray drying is conducted for up to 6 hours.
Claim 25
Dependent Claim
21 words
The method of claim 14 in which the green formed body is heated at a rate of up to 100° C./hr.
Claim 26
Dependent Claim
30 words
The method of claim 23 in which said body is heated to a temperature of about 1410° C. and soaked at said temperature for a period of about 12 hours.
Claim 27
Dependent Claim
22 words
The method of claim 14 in which the said annealing is conducted at a temperature ranging from 900° C. to 1400° C.
Claim 28
Independent Claim
297 words
A method of fabricating a microwave device, comprising the steps of preparing a body of dielectric material selected from the group consisting of dielectric materials having the nominal formula Ba 2 Ti 9 O 20 , BaTi 4 O 9 , and ZrTiO 4 , and assembling said microwave device which comprises a body of dielectric material, a means for introducing microwave electrical energy to the dielectric material and a conducting member to contain the microwave electrical energy in the device, in which said body of dielectric material is prepared by the steps consisting essentially of preparing a slurry comprising oxidic precursor powders of dielectric material, water and a dispersant, the amount of such precursor powders being sufficient to result upon sintering in a material with said nominal formula, said dispersant resulting in the reduction of the volume of water being used in the slurry and in improving the blending of the powders, mixing said slurry for a period sufficient to result in blending of the precursor powders, adding to said mixture a dilute acid as a flocculating agent in an amount sufficient to neutralize effects of the dispersant, drying the mixture followed by screening of the dried material, forming the screened dried mixture into a green form body, and sintering the formed body in an oxygen atmosphere, said sintering including heating the formed body at a rate of less than 200° C. per hour to a temperature sufficient to simultaneously react and sinter the precursor powders into said dielectric material body, soaking the body at said temperature for a period of up to 24 hours, and, optionally annealing the sintered body in an oxygen atmosphere for a period of up to 100 hours, the so-processed body having Q values (low microwave losses) in excess of 9000.
Claim 29
Independent Claim
297 words
A method of fabricating a microwave device, comprising the steps of preparing a body of dielectric material selected from the group consisting of dielectric materials having the nominal formula Ba 2 Ti 9 O 20 , BaTi 4 O 9 , and ZrTiO 4 , and assembling said microwave device which comprises a body of dielectric material, a means for introducing microwave electrical energy to the dielectric material and a conducting member to contain the microwave electrical energy in the device, in which said body of dielectric material is prepared by the steps consisting essentially of preparing a slurry comprising oxidic precursor powders of dielectric material, water and a dispersant, the amount of such precursor powders being sufficient to result upon sintering in a material with said nominal formula, said dispersant resulting in the reduction of the volume of water being used in the slurry and in improving the blending of the powders, mixing said slurry for a period sufficient to result in blending of the precursor powders, adding to said mixture a dilute acid as a flocculating agent in an amount sufficient to neutralize effects of the dispersant, drying the mixture followed by screening of the dried material, forming the screened dried mixture into a green form body, and sintering the formed body in an oxygen atmosphere, said sintering including heating the formed body at a rate of less than 200° C. per hour to a temperature sufficient to simultaneously react and sinter the precursor powders into said dielectric material body, soaking the body at said temperature for a period of up to 24 hours, and, optionally annealing the sintered body in an oxygen atmosphere for a period of up to 100 hours, the so-processed body having Q values (low microwave losses) in excess of 9000.
Claim 30
Dependent Claim
25 words
The method of claim 26 in which said dispersant is selected from the group consisting of complex glassy phosphates, condensed arylsulfonic acids and ammoniated polyacrylates.
Claim 31
Dependent Claim
32 words
The method of claim 3 in which said dispersant is an ammoniated polyacrylate added in an amount of from 0.7 to 1.2 wt. percent based on the weight of dry precursor powders.
Claim 32
Dependent Claim
27 words
The method of claim 28 in which said dispersant is added in an amount of about 0.9 wt. percent based on the weight of dry precursor powders.
Claim 33
Dependent Claim
21 words
The method of claim 26 in which the said flocculating agent is acetic acid added as a 25-75 volume percent solution.
Claim 34
Dependent Claim
32 words
The method of claim 30 in which said acetic acid is added in an amount of about 10-20 ml. of a 50 volume percent solution per 1 kg of dry precursor powders.
Claim 35
Dependent Claim
15 words
The method of claim 26 in which said mixing is conducted for about 6 hours.
Claim 36
Dependent Claim
43 words
The method of claim 26 in which one of said precursor powders is TiO 2 , and the amount of TiO 2 being added is reduced relatively to a required stoichiometric amount by an amount sufficient to avoid microcracking of the sintered body.
Claim 37
Dependent Claim
22 words
The method of claim 33 in which the amount of TiO 2 powder is reduced by from 1.5 to 3 wt. percent.
Claim 38
Dependent Claim
18 words
The method of claim 34 in which the said reduction preferably ranges from 1.75 to 2.75 wt. percent.
Claim 39
Dependent Claim
17 words
The method of claim 26 in which said sintering temperature ranges from 1350° C. to 1420° C.
Claim 40
Dependent Claim
35 words
The method of claim 26 in which the sintered body is optionally annealed in an oxygen atmosphere at a temperature ranging from 900° C. to 1400° C. for a period of up to 100 hours.
Claim 41
Independent Claim
255 words
A method of fabricating a body of dielectric material by the steps consisting essentially of preparing a slurry comprising precursor powders including oxidic ingredients of Ba and Ti, water and a dispersant, the amount of such ingredients being sufficient to result in a material with a nominal formula Ba 2 Ti 9 O 20 , said dispersant resulting in the reduction of the volume of water being used in the slurry and in improving the blending of the powders, mixing said slurry for a period sufficient to result in blending of the precursor powders, drying the mixture, said drying being selected from a) spray-drying the mixed slurry preceded by an inclusion into the slurry of organic materials including binders, plasticizers, lubricants and anti-foaming agents; and b) adding to the mixed slurry a dilute acid as a flocculating agent in an amount sufficient to neutralize effects of the dispersant, oven drying the flocculated slurry and screening the dried mixture, forming the dried mixture into a green form body, and sintering the formed body in an oxygen atmosphere, said sintering including heating the formed body at a rate of less than 200° C. per hour to a temperature sufficient to simultaneously react and sinter the precursor powders into said dielectric material body, soaking the body at said temperature for a period of up to 24 hours, and, optionally annealing the sintered body in an oxygen atmosphere for a period of up to 100 hours, the so-processed body having Q values (low microwave losses) in excess of 9000.
Claim 42
Independent Claim
255 words
A method of fabricating a body of dielectric material by the steps consisting essentially of preparing a slurry comprising precursor powders including oxidic ingredients of Ba and Ti, water and a dispersant, the amount of such ingredients being sufficient to result in a material with a nominal formula Ba 2 Ti 9 O 20 , said dispersant resulting in the reduction of the volume of water being used in the slurry and in improving the blending of the powders, mixing said slurry for a period sufficient to result in blending of the precursor powders, drying the mixture, said drying being selected from a) spray-drying the mixed slurry preceded by an inclusion into the slurry of organic materials including binders, plasticizers, lubricants and anti-foaming agents; and b) adding to the mixed slurry a dilute acid as a flocculating agent in an amount sufficient to neutralize effects of the dispersant, oven drying the flocculated slurry and screening the dried mixture, forming the dried mixture into a green form body, and sintering the formed body in an oxygen atmosphere, said sintering including heating the formed body at a rate of less than 200° C. per hour to a temperature sufficient to simultaneously react and sinter the precursor powders into said dielectric material body, soaking the body at said temperature for a period of up to 24 hours, and, optionally annealing the sintered body in an oxygen atmosphere for a period of up to 100 hours, the so-processed body having Q values (low microwave losses) in excess of 9000.
Claim 43
Dependent Claim
21 words
The method of claim 38 in which the oxidic ingredients comprise BaTiO 3 and an anatase form of TiO 2 .
Claim 44
Dependent Claim
41 words
The method of claim 38 wherein an excess of Ba is provided by reducing from 1.5 to 3 wt. percent the amount of TiO 2 powder needed to produce a desired weight of stoichiometric Ba 2 Ti 9 O 20 .
Claim 45
Dependent Claim
18 words
The method of claim 40 in which the said reduction preferably ranges from 1.75 to 2.75 wt. percent.
Claim 46
Dependent Claim
25 words
The method of claim 38 in which said dispersant is selected from the group consisting of complex glassy phosphates, condensed arylsulfonic acids and ammoniated polyacrylates.
Claim 47
Dependent Claim
29 words
The method of claim 42 in which said dispersant is an ammoniated polyacrylate added in an amount of from 0.7 to 1.2 wt. percent based on dry precursor powders.
Claim 48
Dependent Claim
24 words
The method of claim 43 in which said dispersant is added in an amount of about 0.9 wt. percent based on dry precursor powders.
Claim 49
Dependent Claim
21 words
The method of claim 38 in which said flocculating agent is acetic acid added as a 25-75 volume percent aqueous solution.
Claim 50
Dependent Claim
33 words
The method of claim 45 in which said acetic acid is added in an amount of about 10-20 ml. of a 50 volume percent aqueous solution per 1 kg. of dry precursor powders.
Claim 51
Dependent Claim
14 words
The method of claim 38, in which said mixing is conducted for 6 hours.
Claim 52
Dependent Claim
21 words
The method of claim 38 in which said mixing prior to the spray drying is conducted for up to 6 hours.
Claim 53
Dependent Claim
21 words
The method of claim 38 in which the green formed body is heated at a rate of up to 100° C./hr.
Claim 54
Dependent Claim
30 words
The method of claim 49 in which said body is heated to a temperature of about 1410° C. and soaked at said temperature for a period of about 12 hours.
Claim 55
Dependent Claim
22 words
The method of claim 38 in which the said annealing is conducted at a temperature ranging from 900° C. to 1400° C.
Claim 56
Dependent Claim
20 words
The method of claim 1, in which said dielectric material has nominal formula Ba 2 Ti 9 O 20 .
Claim 57
Dependent Claim
20 words
The method of claim 14, in which said dielectric material has nominal formula Ba 2 Ti 9 O 20 .
Claim 58
Dependent Claim
20 words
The method of claim 26, in which said dielectric material has nominal formula Ba 2 Ti 9 O 20 .
References Cited (Backward Citations)
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