JP4362938B2 - Dielectric porcelain composition - Google Patents
Dielectric porcelain composition Download PDFInfo
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- JP4362938B2 JP4362938B2 JP2000126928A JP2000126928A JP4362938B2 JP 4362938 B2 JP4362938 B2 JP 4362938B2 JP 2000126928 A JP2000126928 A JP 2000126928A JP 2000126928 A JP2000126928 A JP 2000126928A JP 4362938 B2 JP4362938 B2 JP 4362938B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、誘電体共振器材料として好適なカルシウム、チタン、アルミニウム、タンタルおよび酸素からなる誘電体磁器組成物に関するものである。
本発明の誘電体磁器組成物は、誘電体共振器材料のほかに、例えばマイクロ波ＩＣ用基板、誘電体調整棒等にも利用できる。
【０００２】
【従来の技術】
近年、マイクロ波回路の集積化に伴い、小型で高性能の誘電体共振器が求められている。このような誘電体共振器に使用される誘電体磁器組成物には、比誘電率εｒが大きいこと、また、共振周波数の温度係数τｆの安定度および共振周波数の温度特性の直線性が優れ、無負荷Ｑが大きいこと等の特性が要求されている。
【０００３】
【発明が解決しようとする課題】
このような誘電体磁器組成として従来、ＴｉＯ2、ＢａＯ−ＴｉＯ2等を主成分とするものが知られていたが、温度係数が大きかったり、マイクロ波帯域での誘電損失が大きかったりして実用化するには困難な面がある。
【０００４】
更に、Ｂａ（Ｍｇ1/3Ｔａ2/3）Ｏ3系、Ｂａ（Ｚｎ1/3Ｔａ2/3）Ｏ3系、Ｂａ（Ｚｎ1/3Ｎｂ2/3）Ｏ3系等のペロブスカイト型構造を有する誘電体磁器組成物も知られているが、これらは誘電率が小さいために、例えば０．１〜５ＧＨｚ帯では共振器が大きくなりすぎるという難点がある。
【０００５】
本発明の目的は、誘電体共振器材料、特に０．１〜５ＧＨｚ帯で使用される誘電体共振器材料として好適な誘電体磁器組成物を提供することにある。
また、本発明の目的は、高誘電率で、Ｑ値が大きく、εｒの安定性がよい誘電体磁器組成物を提供することにある。
【０００６】
【課題を解決するための手段】
本発明者らは、誘電体磁器組成物に使用されている多数の成分元素の中で、カルシウム、チタン、アルミニウム、タンタルおよび酸素の組み合わせからなる特定の磁器組成物によって前記目的を達成できることを知見した。本発明は、組成式ａＣａＯ・ｂＴｉＯ2・ｃＡｌ2Ｏ3・ｄＴａ2Ｏ5（式中、ａ＋ｂ＋ｃ＋ｄ＝１、０．５７５≦ａ≦０．６０６、０．１８２≦ｂ≦０．２７６、０．０７４７≦ｃ≦０．１０６、０．０７４７≦ｄ≦０．１０６）で表わされる、カルシウム、チタン、アルミニウム、タンタルおよび酸素からなることを特徴とする誘電体磁器組成物に関するものである。
【０００７】
【発明の実施の形態】
本発明の誘電体磁器組成物は、比誘電率が大きいために、共振器の小型化が図られ、無負荷Ｑも大きくなる。更に共振周波数の温度係数τｆが小さい。
【０００８】
本発明の誘電体磁器組成物は、金属元素としてＣａ、Ｔｉ、Ａｌ、Ｔａを含む複合酸化物であるが、これらの組成を上記の範囲に限定した理由は以下の通りである。
【０００９】
０．５７５≦ａ≦０．６０６としたのは、ａが過度に小さいとτfが正に大きくなり５０ｐｐｍ／℃を超えてしまうからである。ａが過度に大きいと誘電率が低下し、τfが負に大きくなり−７０ｐｐｍ／℃を超えてしまうからである。
【００１０】
０．１８２≦ｂ≦０．２７６としたのは、ｂが過度に大きいとτfが正に大きくなり５０ｐｐｍ／℃を超えてしまうからである。ｂが過度に小さいと誘電率が低下し、τfが負に大きくなり−７０ｐｐｍ／℃を超えてしまうからである。
【００１１】
０．０７４７≦ｃ≦０．１０６としたのは、ｃが過度に小さいとτfが正に大きくなり５０ｐｐｍ／℃を超えてしまうからである。ｃが過度に大きいと誘電率が低下し、τfが負に大きくなり−７０ｐｐｍ／℃を超えてしまうからである。
【００１２】
０．０７４７≦ｄ≦０．１０６としたのは、ｄが過度に小さいとτfが正に大きくなり５０ｐｐｍ／℃を超えてしまうからである。ｄが過度に大きいと誘電率が低下し、τfが負に大きくなり−７０ｐｐｍ／℃を超えてしまうからである。
【００１３】
本発明の誘電体磁器組成物の好適な製造法の一例を次に説明する。
炭酸カルシウム、酸化チタン、酸化アルミニウム、酸化タンタルの出発原料を所定量ずつ、水、アルコール等の溶媒と共に湿式混合する。続いて、水、アルコール等を除去した後、粉砕し、酸素含有ガス雰囲気（例えば空気雰囲気）下に１０００〜１３００℃で約２〜１０時間程度仮焼する。これによって形成された仮焼物を粉砕し、ポリビニルアルコールの如き有機バインダと共に混合して均質にし、乾燥、粉砕して、加圧成型（圧力１００〜１０００Ｋｇ／ｃｍ2）する。そして、この成型物を空気の如き酸素含有ガス雰囲気下に１３５０〜１６５０℃で焼成すれば、上記組成式で表わされる誘電体磁器組成物が得られる。
【００１４】
こうして得られた誘電体磁器組成物は、そのまま、または必要に応じて、適当な形状およびサイズに加工することで、誘電体共振器、マイクロ波ＩＣ用誘電体基板、誘電体調整棒等の材料として使用することができ、特に０．１〜５ＧＨｚ帯で使用される誘電体共振器としたときに優れた効果が表れる。
【００１５】
なお、カルシウム、チタン、アルミニウム、タンタルの原料としては、ＣａＣＯ3、ＴｉＯ2、Ａｌ2Ｏ3、Ｔａ2Ｏ5等の他に、焼成時に酸化物となる炭酸塩、水酸化物等を使用することができる。
【００１６】
【実施例】
以下に実施例を示し、本発明を更に具体的に説明する。
実施例１
〔試料Ｎｏ．１〕
炭酸カルシウム（ＣａＣＯ3）粉末、酸化チタン（ＴｉＯ2）粉末、酸化アルミニウム（Ａｌ2Ｏ3）粉末、酸化タンタル（Ｔａ2Ｏ5）粉末をエタノールと共にボールミルに入れて、１２時間湿式混合した。この混合物から溶媒のエタノールを除去し、らいかい機で１時間粉砕し、０．５５６ＣａＯ−０．３３３ＴｉＯ2−０．０５６Ａｌ2Ｏ3−０．０５６Ｔａ2Ｏ5なる仮焼粉を得た。
【００１７】
次いで、この仮焼粉に適量のポリビニルアルコール溶液を加えて均一に混合した後、直径１０ｍｍφ、厚み４ｍｍｔのペレットに成型して空気雰囲気下１５００℃で２時間焼成、焼結して本発明の誘電体磁器組成物を得た。
こうして得られた磁器組成物を適当な大きさにカットした後、誘電体共振法によって測定し、共振周波数ｆ0（４〜６ＧＨｚ）における無負荷Ｑおよび比誘電率εｒを求めた。
また、共振周波数の温度依存性については、−４０〜８０℃の範囲で測定し、温度係数τｆを求めた。その結果を表１に示す。
【００１８】
〔試料Ｎｏ．２〜Ｎｏ．１３〕
前記試料Ｎｏ．１の炭酸カルシウム、酸化チタン、酸化アルミニウム、酸化タンタルの混合割合を表１記載のようにかえた他は、試料Ｎｏ．１と同様にして誘電体磁器組成物を製造し、同様に特性を測定した。
その結果を表１に示す。表において＊印を付したものは、本発明の範囲外の比較例である。
【００１９】
表１からも明らかなように、本発明で得られた誘電体は比誘電率が３０以上、ｆ0×Ｑ値が４８０００以上、τfが−７０〜＋５０ｐｐｍ／℃以内の優れた誘電体特性が得られた。一方、本発明の範囲外の誘電体では、誘電率またはｆ0×Ｑ値が低いか、τfの絶対値が５０を超えている。
【００２０】
【発明の効果】
本発明によれば、高誘電率で、Ｑ値が大きく、しかもτｆの安定性がよい誘電体磁器組成物が得られる。
【００２１】
【表１】
BACKGROUND OF THE INVENTION
The present invention relates to a dielectric ceramic composition composed of calcium, titanium, aluminum, tantalum and oxygen suitable as a dielectric resonator material.
In addition to the dielectric resonator material, the dielectric ceramic composition of the present invention can be used for a microwave IC substrate, a dielectric adjustment rod, and the like.
[0002]
[Prior art]
In recent years, with the integration of microwave circuits, small and high performance dielectric resonators are required. The dielectric ceramic composition used in such a dielectric resonator has a large relative dielectric constant εr, excellent stability of the resonance frequency temperature coefficient τf, and excellent linearity of the resonance frequency temperature characteristics, Characteristics such as a large no-load Q are required.
[0003]
[Problems to be solved by the invention]
Conventionally, such a dielectric porcelain composition having TiO 2 , BaO—TiO 2 or the like as a main component has been known, but it has a large temperature coefficient and a large dielectric loss in the microwave band. It is difficult to make it easier.
[0004]
Further, perovskite types such as Ba (Mg 1/3 Ta 2/3 ) O 3 , Ba (Zn 1/3 Ta 2/3 ) O 3 , Ba (Zn 1/3 Nb 2/3 ) O 3, etc. Dielectric porcelain compositions having a structure are also known, but since these have a low dielectric constant, there is a problem that the resonator becomes too large, for example, in the 0.1 to 5 GHz band.
[0005]
An object of the present invention is to provide a dielectric ceramic composition suitable as a dielectric resonator material, particularly as a dielectric resonator material used in the 0.1 to 5 GHz band.
Another object of the present invention is to provide a dielectric ceramic composition having a high dielectric constant, a large Q value, and good stability of εr.
[0006]
[Means for Solving the Problems]
The present inventors have found that the above object can be achieved by a specific porcelain composition comprising a combination of calcium, titanium, aluminum, tantalum and oxygen among a number of constituent elements used in dielectric ceramic compositions. did. The present invention has a composition formula aCaO · bTiO 2 · cAl 2 O 3 · dTa 2 O 5 (where a + b + c + d = 1, 0.575 ≦ a ≦ 0.606, 0.182 ≦ b ≦ 0.276, 0. 0747 ≦ c ≦ 0.106, 0.0747 ≦ d ≦ 0.106 ), and relates to a dielectric ceramic composition comprising calcium, titanium, aluminum, tantalum, and oxygen.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Since the dielectric ceramic composition of the present invention has a large relative dielectric constant, the resonator can be miniaturized and the unloaded Q also becomes large. Furthermore, the temperature coefficient τf of the resonance frequency is small.
[0008]
The dielectric ceramic composition of the present invention is a complex oxide containing Ca, Ti, Al, and Ta as metal elements. The reason why these compositions are limited to the above range is as follows.
[0009]
The reason for setting 0.575 ≦ a ≦ 0.606 is that if a is excessively small, τf becomes positively large and exceeds 50 ppm / ° C. This is because if a is excessively large, the dielectric constant decreases, and τf becomes negatively large and exceeds −70 ppm / ° C.
[0010]
The reason why 0.182 ≦ b ≦ 0.276 is set is that if b is excessively large, τf increases positively and exceeds 50 ppm / ° C. This is because if b is excessively small, the dielectric constant decreases, and τf becomes negatively large and exceeds −70 ppm / ° C.
[0011]
The reason why 0.0747 ≦ c ≦ 0.106 is set is that if c is excessively small, τf increases positively and exceeds 50 ppm / ° C. This is because if c is excessively large, the dielectric constant decreases, and τf increases negatively and exceeds −70 ppm / ° C.
[0012]
The reason why 0.0747 ≦ d ≦ 0.106 is set is that if d is excessively small, τf increases positively and exceeds 50 ppm / ° C. This is because if d is excessively large, the dielectric constant decreases, and τf becomes negatively large and exceeds −70 ppm / ° C.
[0013]
Next, an example of a preferred method for producing the dielectric ceramic composition of the present invention will be described.
A predetermined amount of starting materials of calcium carbonate, titanium oxide, aluminum oxide, and tantalum oxide are wet-mixed together with a solvent such as water and alcohol. Subsequently, after removing water, alcohol, and the like, it is pulverized and calcined at 1000 to 1300 ° C. for about 2 to 10 hours in an oxygen-containing gas atmosphere (for example, air atmosphere). The calcined material thus formed is pulverized, mixed with an organic binder such as polyvinyl alcohol, homogenized, dried, pulverized, and pressure-molded (pressure 100 to 1000 Kg / cm 2 ). And if this molding is baked at 1350-1650 degreeC in oxygen-containing gas atmosphere like air, the dielectric material ceramic composition represented by the said compositional formula will be obtained.
[0014]
The dielectric ceramic composition thus obtained can be processed into an appropriate shape and size as it is, or as necessary, to obtain materials for dielectric resonators, dielectric substrates for microwave ICs, dielectric adjustment bars, etc. In particular, when a dielectric resonator used in the 0.1 to 5 GHz band is used, an excellent effect appears.
[0015]
As raw materials for calcium, titanium, aluminum, and tantalum, carbonates, hydroxides, and the like that become oxides during firing are used in addition to CaCO 3 , TiO 2 , Al 2 O 3 , Ta 2 O 5, and the like. be able to.
[0016]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1
[Sample No. 1]
Calcium carbonate (CaCO 3 ) powder, titanium oxide (TiO 2 ) powder, aluminum oxide (Al 2 O 3 ) powder, and tantalum oxide (Ta 2 O 5 ) powder were placed in a ball mill together with ethanol and wet mixed for 12 hours. Ethanol as a solvent was removed from this mixture, and the mixture was pulverized for 1 hour with a coarse machine to obtain a calcined powder of 0.556CaO-0.333TiO 2 -0.056Al 2 O 3 -0.056Ta 2 O 5 .
[0017]
Next, after adding an appropriate amount of polyvinyl alcohol solution to the calcined powder and mixing it uniformly, it is molded into a pellet having a diameter of 10 mmφ and a thickness of 4 mmt, and is fired and sintered at 1500 ° C. for 2 hours in an air atmosphere. A body porcelain composition was obtained.
The porcelain composition thus obtained was cut to an appropriate size and then measured by the dielectric resonance method to determine the no-load Q and the relative dielectric constant εr at the resonance frequency f 0 (4 to 6 GHz).
Further, the temperature dependence of the resonance frequency was measured in the range of −40 to 80 ° C., and the temperature coefficient τf was obtained. The results are shown in Table 1.
[0018]
[Sample No. 2-No. 13]
Sample No. 1 except that the mixing ratio of calcium carbonate, titanium oxide, aluminum oxide and tantalum oxide was changed as shown in Table 1. A dielectric ceramic composition was produced in the same manner as in Example 1, and the characteristics were measured in the same manner.
The results are shown in Table 1. Those marked with * in the table are comparative examples outside the scope of the present invention.
[0019]
As is clear from Table 1, the dielectric obtained by the present invention has excellent dielectric properties with a relative dielectric constant of 30 or more, f 0 × Q value of 48000 or more, and τf within −70 to +50 ppm / ° C. Obtained. On the other hand, dielectrics outside the scope of the present invention have a low dielectric constant or f 0 × Q value, or the absolute value of τf exceeds 50.
[0020]
【The invention's effect】
According to the present invention, a dielectric ceramic composition having a high dielectric constant, a large Q value, and a good stability of τf can be obtained.
[0021]
[Table 1]
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000126928A JP4362938B2 (en) | 2000-04-27 | 2000-04-27 | Dielectric porcelain composition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000126928A JP4362938B2 (en) | 2000-04-27 | 2000-04-27 | Dielectric porcelain composition |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001302332A JP2001302332A (en) | 2001-10-31 |
| JP4362938B2 true JP4362938B2 (en) | 2009-11-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000126928A Expired - Lifetime JP4362938B2 (en) | 2000-04-27 | 2000-04-27 | Dielectric porcelain composition |
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| Country | Link |
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| JP (1) | JP4362938B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP4870920B2 (en) * | 2004-09-30 | 2012-02-08 | 日本特殊陶業株式会社 | Dielectric ceramic composition and electronic component |
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| JP2001302332A (en) | 2001-10-31 |
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Free format text: JAPANESE INTERMEDIATE CODE: R250 |
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| EXPY | Cancellation because of completion of term |