US3419496A - Garnet compositions - Google Patents
Garnet compositions Download PDFInfo
- Publication number
- US3419496A US3419496A US444437A US44443765A US3419496A US 3419496 A US3419496 A US 3419496A US 444437 A US444437 A US 444437A US 44443765 A US44443765 A US 44443765A US 3419496 A US3419496 A US 3419496A
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- US
- United States
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- mixture
- compositions
- garnet
- hours
- garnets
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- 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
- C04B35/26—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 ferrites
- C04B35/2608—Compositions containing one or more ferrites of the group comprising manganese, zinc, nickel, copper or cobalt and one or more ferrites of the group comprising rare earth metals, alkali metals, alkaline earth metals or lead
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
- H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
- H01B3/025—Other inorganic material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/32—Non-reciprocal transmission devices
Definitions
- the present invention relates to garnet compositions. More particularly it relates to garnet compositions for use in non-reciprocal devices such as isolators, phase shifters or circulators for ultra-high frequency waves.
- the invention provides a resistivity gain by a factor which may easily exceed 1000.
- the invention alter concegns a method of preparation of such garnets which is remarkable in that it includes thermal treatment in an oxygen atmosphere at a temperature between 1365 and 1385 C.
- the raw materials used have to have a high degree of purity preferably higher than 99%.
- Oxides Y O and Gd O in particular have to be free of any impurity of the type Eu O H0 0 Dy O This precaution is necessary to ensure narrow resonance lines. 7
- the raw materials taken in proportion defined by the above formula, are crushed in steel jars containing steel balls, in the presence of distilled water, for 24 hours.
- the resulting mixture is dried out and is then presintered over 1000 C. for two hours, preferably at 1200 C.
- the product After crushing as above, but for 48 hours, followed by drying and mixing with a 15% polyvinyl alcohol solution in water (10% solution), the product is converted to a fine granulate.
- the latter is pressed in steel moulds to the desired shape and is sintered in oxygen atmosphere at 1380 C. for 2 hours, followed by cooling down at the rate of 50 C. to C. per hour.
- the resistivity p of the resulting garnets, expressed in megohm-centimetres was measured on discs about 20 mm. in diameter and 2 mm. thick. The two sides of the discs were ground and silvered and the measurement effected by means of a megohm-meter.
- the width of the resonance line AH was measured at about 9500 mc./s. in a resonant cavity on samples in the form of spheres 1.5 mm. in diameter, placed 'at a node of an ultra-high frequency magnetic field.
- a method for preparing garnets comprising the following steps: presintering at above 1000 C. for about 2 hours a mixture of compounds defined by the formula:
- x is between 0.3 and 0.6, e is between 0.005 and 0.002 and y is between 0.1 and l in mole proportion to obtain a pre-sintered mixture; crushing said pre-sintered mixture and shaping it by pressing to obtain a pressed mixture; sintering said pressed mixture in oxygen atmosphere at temperatures between 1365 and 1385 C. for about 2 hours; and cooling said pressed mixture at a rate of 50 to 150 C. per hour.
- a method for preparing a garnet composition for use with ultra-high frequency waves comprising the steps of pre-sintering at about 1200 C. for about 2 hours a mixture of compound defined by the formula:
- x is between 0.3 and 0.6, e is between 0.005 and 0.20 and y is between 0.1 and 1 in mole proportion to ob- 4 tain a pre-sintered mixture, crushing said pre-sintered' mixture and shaping it by pressing to obtain a pressed mixture, sintering said pressed mixture in oxygen atmosphere at temperatures between 1365 and 1385 C. for about 2 hours and cooling said pressed mixture at a rate of 50 to 150 C. per hour.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Soft Magnetic Materials (AREA)
- Compounds Of Iron (AREA)
Description
3,419,496 atented Dec. 31, 1968 GARNET COMPOSITIONS Avnir Vassiliev, Jean Nicolas, and Mieczyslaw Hildebrandt, Paris, France, assignors to CSF-Compagnie Generale de Telegraphie. Sans Fil, a corporation of France No Drawing. Filed Mar. 31, 1965, Ser. No. 444,437 Claims priority, application France, Apr. 22, 1964,
4 Claims. (Cl. 252-6257) ABSTRACT OF THE DISCLOSURE Garnet compositions having a resistivity higher than in known materials of this kind thus reducing considerably the dielectric losses. In these compositions are introduced paramagnetic ions Fe and Mn, in molecular proportions defined by the general formula where in mole proportion. These garnet compositions are used in non-reciprocal devices such as i solators, phase shifters, or circulators for ultra-high frequency electromagnetic waves.
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The present invention relates to garnet compositions. More particularly it relates to garnet compositions for use in non-reciprocal devices such as isolators, phase shifters or circulators for ultra-high frequency waves.
It is an object of the invention to provide a garnet composition providing a resistivity higher than in known materials of this kind, thus considerably reducing dielectric loss which usually limits the performance of such devices.
It is another object of the invention to provide a method for preparing such compositions.
With the other performances remaining comparable the invention provides a resistivity gain by a factor which may easily exceed 1000.
This is most important, in particular for the design of circulators such as the so-called Y type circulators (because they are provided with three channels) intended, in particular, for multiplex radars, especially when combined with masers.
It is known to use in this kind of application yttrium garnets and garnets containing some other trivalent ions, such as 6d and sometimes Al+++. In the case of these garnets great care was taken to avoid introducing, for example, any foreign paramagnetic ion, for fear of prohibitively widening the resonance line, the latter being relatively narrow when these materials are pure and properly prepared.
According to the invention, on the contrary, there are introduced in garnets of this type paramagnetic ions Fe and Mn, in molecular proportions defined by the general formula:
where 0.3 x 0.6 0.0Q5 e 0.020 0.1 y 1 in mole proportion.
The invention alter concegns a method of preparation of such garnets which is remarkable in that it includes thermal treatment in an oxygen atmosphere at a temperature between 1365 and 1385 C.
. The invention will be better understood by means of the following description.
The raw materials used have to have a high degree of purity preferably higher than 99%. Oxides Y O and Gd O in particular have to be free of any impurity of the type Eu O H0 0 Dy O This precaution is necessary to ensure narrow resonance lines. 7
The raw materials, taken in proportion defined by the above formula, are crushed in steel jars containing steel balls, in the presence of distilled water, for 24 hours.
The resulting mixture is dried out and is then presintered over 1000 C. for two hours, preferably at 1200 C.
After crushing as above, but for 48 hours, followed by drying and mixing with a 15% polyvinyl alcohol solution in water (10% solution), the product is converted to a fine granulate. The latter is pressed in steel moulds to the desired shape and is sintered in oxygen atmosphere at 1380 C. for 2 hours, followed by cooling down at the rate of 50 C. to C. per hour.
The following table shows a number of examples of compositions, in which:
x=0.5 and 5:0.015
The resistivity p of the resulting garnets, expressed in megohm-centimetres was measured on discs about 20 mm. in diameter and 2 mm. thick. The two sides of the discs were ground and silvered and the measurement effected by means of a megohm-meter.
The width of the resonance line AH was measured at about 9500 mc./s. in a resonant cavity on samples in the form of spheres 1.5 mm. in diameter, placed 'at a node of an ultra-high frequency magnetic field.
y in mole percentage pMt'Zcm. A 11.0.,
It will be noted that for values of y greater than 1 p decreases. while AH is hardly altered, this being a surprising and quite remarkable result.
It is to be understood that the details of the method of preparation may be varied without departing from the spirit and scope of the invention.
What is claimed is: 1. A garnet composition defined by the general for- 'mula:
3 [1x)Y O; X Gd203] I-G) Fe O yMnO where:
x is between 0.3 and 0.6 e is between 0.005 and 0.020 y is between 0.1 and 1 in mole proportion 3. A method for preparing garnets comprising the following steps: presintering at above 1000 C. for about 2 hours a mixture of compounds defined by the formula:
al i
where x is between 0.3 and 0.6, e is between 0.005 and 0.002 and y is between 0.1 and l in mole proportion to obtain a pre-sintered mixture; crushing said pre-sintered mixture and shaping it by pressing to obtain a pressed mixture; sintering said pressed mixture in oxygen atmosphere at temperatures between 1365 and 1385 C. for about 2 hours; and cooling said pressed mixture at a rate of 50 to 150 C. per hour.
4. A method for preparing a garnet composition for use with ultra-high frequency waves comprising the steps of pre-sintering at about 1200 C. for about 2 hours a mixture of compound defined by the formula:
where x is between 0.3 and 0.6, e is between 0.005 and 0.20 and y is between 0.1 and 1 in mole proportion to ob- 4 tain a pre-sintered mixture, crushing said pre-sintered' mixture and shaping it by pressing to obtain a pressed mixture, sintering said pressed mixture in oxygen atmosphere at temperatures between 1365 and 1385 C. for about 2 hours and cooling said pressed mixture at a rate of 50 to 150 C. per hour.
References Cited UNITED STATES PATENTS 3,007,874 11/1961' Peyssou et 'al 25262.56 3,038,861 12/1962 Van Uitert 25262.57 3,232,877 2/1966 Vassiliev et a1 25262.56
TOBIAS E. LEVOW, Primary Examiner.
R. D. EDMONDS, Assistant Examiner.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR971828A FR1405866A (en) | 1964-04-22 | 1964-04-22 | Composition of garnets intended for the production of devices for transmitting electromagnetic waves at ultra high frequency |
Publications (1)
Publication Number | Publication Date |
---|---|
US3419496A true US3419496A (en) | 1968-12-31 |
Family
ID=8828365
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US444437A Expired - Lifetime US3419496A (en) | 1964-04-22 | 1965-03-31 | Garnet compositions |
Country Status (4)
Country | Link |
---|---|
US (1) | US3419496A (en) |
FR (1) | FR1405866A (en) |
GB (1) | GB1045260A (en) |
NL (1) | NL6505150A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3751663A (en) * | 1969-12-06 | 1973-08-07 | Philips Corp | Magnetisable material for detecting and/or recording electromagnetic radiation and electrons |
US5055214A (en) * | 1989-06-15 | 1991-10-08 | Murata Mfg. Co., Ltd. | Magnetic material for microwave and millimeter wave frequencies |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3007874A (en) * | 1957-05-09 | 1961-11-07 | Steatite Res Corp | Process of manufacturing ternary ferrites containing manganese and zinc |
US3038861A (en) * | 1957-12-27 | 1962-06-12 | Bell Telephone Labor Inc | Polycrystalline garnet materials |
US3232877A (en) * | 1960-12-06 | 1966-02-01 | Csf | Nickel ferrite containing cobalt and manganese |
-
1964
- 1964-04-22 FR FR971828A patent/FR1405866A/en not_active Expired
-
1965
- 1965-03-31 US US444437A patent/US3419496A/en not_active Expired - Lifetime
- 1965-04-01 GB GB13945/65A patent/GB1045260A/en not_active Expired
- 1965-04-22 NL NL6505150A patent/NL6505150A/xx unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3007874A (en) * | 1957-05-09 | 1961-11-07 | Steatite Res Corp | Process of manufacturing ternary ferrites containing manganese and zinc |
US3038861A (en) * | 1957-12-27 | 1962-06-12 | Bell Telephone Labor Inc | Polycrystalline garnet materials |
US3232877A (en) * | 1960-12-06 | 1966-02-01 | Csf | Nickel ferrite containing cobalt and manganese |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3751663A (en) * | 1969-12-06 | 1973-08-07 | Philips Corp | Magnetisable material for detecting and/or recording electromagnetic radiation and electrons |
US5055214A (en) * | 1989-06-15 | 1991-10-08 | Murata Mfg. Co., Ltd. | Magnetic material for microwave and millimeter wave frequencies |
Also Published As
Publication number | Publication date |
---|---|
FR1405866A (en) | 1965-07-16 |
NL6505150A (en) | 1965-10-25 |
GB1045260A (en) | 1966-10-12 |
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