JPH0510762B2 - - Google Patents
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- Publication number
- JPH0510762B2 JPH0510762B2 JP59219379A JP21937984A JPH0510762B2 JP H0510762 B2 JPH0510762 B2 JP H0510762B2 JP 59219379 A JP59219379 A JP 59219379A JP 21937984 A JP21937984 A JP 21937984A JP H0510762 B2 JPH0510762 B2 JP H0510762B2
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- Japan
- Prior art keywords
- oxide
- weight
- dielectric constant
- temperature
- composition
- Prior art date
- 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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- Compositions Of Oxide Ceramics (AREA)
- Inorganic Insulating Materials (AREA)
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、磁器組成物、特に1200℃程度の低温
で焼結でき、広い温度範囲にわたつて誘電率の変
化率が小さく、誘電率が大きく、かつ誘電損失の
少ない優れた誘電体磁器組成物に関するものであ
る。
（従来の技術）
従来、誘電率が高く、誘電率の温度変化の小さ
な磁器組成物として、BaTiO3にNb2O5−MnOを
添加したもの（特公昭57−41042）、Nb2O5−CoO
等を添加したもの（Electrocomponent Science
and Tec.，1976，Vol.2，P.241〜247）、Nb2O5
−MgOを添加したもの（特開昭48−53297）、
Nb2O5−MgO−CaTiO3を添加したもの（特公昭
57−23366）、NiNb2O6−Sm2O3を添加したもの
（特開昭57−88611）など多くのものが知られてい
た。
しかしながら、それらの組成物を焼結する温度
は、いずれも1350〜1400℃の高温である。そのた
め、これを積層形コンデンサーに利用する場合、
内部電極材料として、この高温の焼結温度に耐え
得る白金、パラジウム等の高価な貴金属を使うこ
とが必要であり、コストアツプの最大の原因にな
つていた。それ故、積層形コンデンを安価に製造
するには、銀を主成分とする安価な金属を内部電
極に使用できるような、1200℃程度の低温で焼結
できる磁器組成物が望まれてきている。
現在までに低温で焼結できる磁器組成物とし
て、BaTiO3にビスマス化合物を添加した組成物
が知られているが、それらは焼成時に成分の蒸発
が著しく安定した性能が得られにくいこと、さら
に、高周波特性における誘電損失が大きいこと等
の欠点があり、積層形コンデンサー用の磁器組成
物として未だ満足できるものではない。
また、ビスマス化合物を含有せずに比較的低温
で焼結できる組成物として、BaTiO3にNd2O3，
Nb2O5，SiO2、MnO2，CoOを添加したものが知
られている（特開昭57−92575）。しかし、該組成
物の焼結温度は1250℃であり、さらに、得られる
磁器の誘電損失（tanδ）の値は１％と大きく、特
性的にも満足できるものではない。
（発明が解決しようとする問題点）
本発明者らは、ビスマス化合物を含有すること
なく低温で焼結でき、なおかつ誘電率が高く、誘
電率の温度変化率が、JISの特級ＹのＢ特あるい
はEIAのX7R特性のように小さく、誘電損失の小
さい誘電体磁器組成物を得ることを目的とし、以
下の発明に至つた。
（問題点を解決するための手段）
BaTiO3にNb2O5／MgOのモル比を2.3〜４の
範囲になるようにNb2O5とMgOを加え、これに
希土類を0.1〜0.5重量％添加した組成物が特公昭
55−19007に示され、実施例において、焼結の温
度は1200〜1380℃と記載されている。しかし、該
発明の組成を用いても、1200℃では焼結は不十分
で、絶縁抵抗値も小さいものであつた。該発明の
組成で希土類酸化物を0.5重量％以上に増やすこ
とにより、1200℃で十分焼結し、絶縁抵抗値も大
きくなる。しかし、誘電率の温度変化率は大きく
なり、望ましい温度特性のものは得られない。
そこで、本発明者らは、低温焼結性を保ち、な
おかつ高い誘電率と良好な温度特性、低いtanδ値
を持つ組成について鋭意研究を重ねた結果、本発
明の組成物を見出した。すなわち、本発明の磁器
組成物は、チタン酸バリウム95.20〜98.58重量
％、酸化プラセオジウム、酸化ネオジム、酸化サ
マリウム、酸化ジスプロシウムのうち少なくとも
１種を0.52〜1.50重量％、酸化ニオブ0.85〜3.00
重量％、酸化マグネシウム0.05〜0.35重量％を含
み、かつ酸化マグネシウムに対する酸化ニオブの
モル比が１：0.4ないし１：2.2の範囲にあること
を特徴とする。
本発明の組成範囲および組成比のものは、1200
℃程度の低温で焼結が可能となり、比誘電率も
2000程度と高く、広い温度範囲で誘電率の温度変
化率も小さい。さらに驚くべきことには、誘電損
失（tanδ）も0.7％以下と小さく、従来報告され
ているものに比べ著しく改善されたものである。
積層コンデンサーの場合には、tanδのとくに小さ
い組成物が望まれており、その点においても、本
発明の磁器組成物は工業的価値の大きいものであ
る。
本発明で使用されるチタン酸バリウムは、固相
法、液相法、蓚酸塩法、アルコキシド法等のいず
れの製法より得られるものでもよい。平均粒径が
0.07〜0.5μmで粒径のそろつたものを用いた場合、
均一な微構造の磁器が得られ、絶縁抵抗値がさら
に大きくなり、その値のばらつきも小さいものに
なる。また、本発明では、酸化プラセオジウム、
酸化ネオジム、酸化サマリウム、酸化ジスプロシ
ウム、酸化ニオブ、酸化マグネシウムとして酸化
物をそのまま用いることができるが、水酸化物、
炭酸塩、硝酸塩、蓚酸塩、アルコキシド等、焼結
温度以下で分解し酸化物となるものであれば、い
ずれのものも使用できる。酸化物となつた時の平
均粒径が3μm以下であるものが、より好適に使用
できる。
本発明における磁器組成物中のチタン酸バリウ
ムの割合は、BaTiO3として95.20〜98.58重量％
であり、その割合が98.58重量％を超えると焼結
困難で、さらに、誘電率の温度変化率も大きくな
る。95.20重量％未満では誘電率が小さく、実用
的でない。酸化プラセオジウム、酸化ネオジム、
酸化サマリウム、酸化ジスプロシウムの割合は、
Pr6O11，Nd2O3，Sm2O3，Dy2O3として合計0.52
〜1.50重量％であり、その割合が0.52重量％未満
では焼結困難で、絶縁抵抗値が低くなる。1.50重
量％を超えると誘電率の温度変化率が大きくな
る。酸化ニオブの割合は、Nb2O5として0.85〜
3.00重量％であり、その割合が0.85重量％未満で
は焼結結困難となり、3.00重量％を超えると誘電
率が小さく、温度変化率も大きくなる。酸化マグ
ネシウムの割合は、MgOとして0.05〜0.35重量％
であり、その割合が0.05重量％未満では温度変化
率が大きく、0.35重量％を超えると誘電率が小さ
い。MgOとNb2O5のモル比は0.4〜2.2の範囲であ
り、そのモル比が0.4未満では誘電率が小さく、
2.2を超えると誘電率の温度変化率が大きく、
tanδも大きくなる。また、Pr6O11，Nd2O3，Sm2
O3，Dy2O3の合計当量とMgOの当量の比が４／
３〜４／５の場合、得られる磁器組成物は高誘電
率で、温度特性も良好になり好ましい。
（実施例）
以下、本発明を実施例によつて詳細に説明す
る。
出発原料として、SEM粒径の平均粒径が0.2〜
0.3μmで、比表面積が５〜８m2／ｇであるチタン
酸バリウムに、酸化プラセオジウム、酸化ネオジ
ム、酸化サマリウム、酸化ジスプロシウムから選
ばれた少なくとも１種、酸化ニオブ、および酸化
マグネシウムを第１表の割合で添加し、純水を加
え混合する。混合物を乾燥した後に、粘結剤とし
てポリビニルアルコールを適当量加え、2t／cm2の
成形圧力で直径15mm、厚さ0.6mmの円板状成形物
を作成した。次に、これを1220℃で５時間焼結し
た。焼結した円板の両端面に10mmφの銀電極を
740℃で焼付け、それぞれの電気特性を評価した。
ここで、誘電率と誘電損失（tanδ）をLCRメー
ターを用いて1kHzで測定した。絶縁抵抗値は高
絶縁抵抗値を用い、500Vの電圧を印加した場合
の読み取り値である。誘電率の変化率％は20℃を
基準とした。
第１表において、試料No.１，７，８，11，12は
本発明の範囲外のものである。
第１表より明らかなように、本発明の範囲内の
ものは1220℃で焼結可能で、その磁器特性も比誘
電率が2000程度と高い値を示し、誘電率の変化率
も小さく、かつ誘電損失が小さいことがわかる。
（発明の効果）
以下のように、本発明により次の効果が見出さ
れた。
(1) ビスマス化合物を含まず、1200℃程度の低温
焼結が可能である。
(2) 特性面において比誘電率が2000以上と高く、
しかも、その温度による変化率が小さい。
(3) 誘電損失が小さい。
したがつて、本発明の磁器組成物は、電気特性
的にもきわめて優れており、コスト面からもきわ
めて有利であるので、工業上価値の大きいもので
ある。
【表】Detailed Description of the Invention (Field of Industrial Application) The present invention provides ceramic compositions that can be sintered at a low temperature of about 1200°C, have a small rate of change in dielectric constant over a wide temperature range, and have a low dielectric constant. The present invention relates to an excellent dielectric ceramic composition that is large and has low dielectric loss. (Prior art) Conventionally, as a ceramic composition with a high dielectric constant and a small temperature change in dielectric constant, BaTiO 3 with Nb 2 O 5 −MnO added (Japanese Patent Publication No. 57-41042), Nb 2 O 5 − CoO
(Electrocomponent Science
and Tec., 1976, Vol. 2, P. 241-247), Nb 2 O 5
- Added MgO (Japanese Patent Application Laid-Open No. 1983-53297),
Added Nb 2 O 5 −MgO−CaTiO 3 (Tokukosho
57-23366), and one containing NiNb 2 O 6 -Sm 2 O 3 (Japanese Patent Application Laid-open No. 57-88611). However, the temperature at which these compositions are sintered is a high temperature of 1350 to 1400°C. Therefore, when using this for multilayer capacitors,
As the internal electrode material, it is necessary to use expensive noble metals such as platinum and palladium that can withstand this high sintering temperature, which is the biggest cause of cost increase. Therefore, in order to manufacture laminated capacitors at low cost, there is a need for a porcelain composition that can be sintered at a low temperature of around 1200°C, which would allow the use of inexpensive metals mainly composed of silver for the internal electrodes. . To date, compositions in which a bismuth compound is added to BaTiO 3 are known as porcelain compositions that can be sintered at low temperatures. It has drawbacks such as large dielectric loss in high frequency characteristics, and is not yet satisfactory as a ceramic composition for multilayer capacitors. In addition, as a composition that does not contain bismuth compounds and can be sintered at relatively low temperatures, BaTiO 3 and Nd 2 O 3 ,
It is known that Nb 2 O 5 , SiO 2 , MnO 2 , and CoO are added (Japanese Patent Laid-Open No. 57-92575). However, the sintering temperature of this composition is 1250° C., and the dielectric loss (tan δ) of the obtained ceramic is as large as 1%, which is not satisfactory in terms of characteristics. (Problems to be Solved by the Invention) The present inventors have discovered an object that can be sintered at low temperatures without containing a bismuth compound, has a high dielectric constant, and has a temperature change rate of dielectric constant of B characteristic of JIS special grade Y. Alternatively, with the aim of obtaining a dielectric ceramic composition having a small dielectric loss similar to the X7R characteristic of EIA, the following invention was achieved. (Means for solving the problem) Nb 2 O 5 and MgO are added to BaTiO 3 so that the molar ratio of Nb 2 O 5 /MgO is in the range of 2.3 to 4, and 0.1 to 0.5% by weight of rare earths are added to this. The added composition is
55-19007, and in the examples, the sintering temperature is described as 1200 to 1380°C. However, even when the composition of the invention was used, sintering was insufficient at 1200°C and the insulation resistance value was low. By increasing the rare earth oxide to 0.5% by weight or more in the composition of the invention, sufficient sintering can be achieved at 1200°C, and the insulation resistance value can also be increased. However, the temperature change rate of the dielectric constant becomes large, and desirable temperature characteristics cannot be obtained. Therefore, the present inventors conducted extensive research on a composition that maintains low-temperature sinterability, has a high dielectric constant, good temperature characteristics, and a low tan δ value, and as a result, discovered the composition of the present invention. That is, the porcelain composition of the present invention contains 95.20 to 98.58% by weight of barium titanate, 0.52 to 1.50% by weight of at least one of praseodymium oxide, neodymium oxide, samarium oxide, and dysprosium oxide, and 0.85 to 3.00% by weight of niobium oxide.
% by weight, 0.05 to 0.35% by weight of magnesium oxide, and the molar ratio of niobium oxide to magnesium oxide is in the range of 1:0.4 to 1:2.2. The composition range and composition ratio of the present invention is 1200
Sintering can be performed at temperatures as low as ℃, and the relative permittivity is also low.
It has a high value of about 2000, and the rate of change in dielectric constant with temperature is small over a wide temperature range. What is even more surprising is that the dielectric loss (tan δ) is as small as 0.7% or less, which is a significant improvement compared to what has been previously reported.
In the case of multilayer capacitors, compositions with particularly small tan δ are desired, and in this respect as well, the ceramic composition of the present invention has great industrial value. The barium titanate used in the present invention may be obtained by any production method such as a solid phase method, a liquid phase method, an oxalate method, or an alkoxide method. The average particle size is
When using particles with a uniform particle size of 0.07 to 0.5 μm,
Porcelain with a uniform microstructure is obtained, and the insulation resistance value is further increased, and the variation in the value is also reduced. In addition, in the present invention, praseodymium oxide,
Oxides can be used as they are, such as neodymium oxide, samarium oxide, dysprosium oxide, niobium oxide, and magnesium oxide, but hydroxide,
Any substance, such as carbonate, nitrate, oxalate, alkoxide, etc., can be used as long as it decomposes to form an oxide below the sintering temperature. Those having an average particle size of 3 μm or less when converted into oxides can be used more preferably. The proportion of barium titanate in the porcelain composition in the present invention is 95.20 to 98.58% by weight as BaTiO3
If the proportion exceeds 98.58% by weight, sintering becomes difficult and the rate of change in dielectric constant with temperature increases. If it is less than 95.20% by weight, the dielectric constant is too small to be practical. praseodymium oxide, neodymium oxide,
The ratio of samarium oxide and dysprosium oxide is
Total 0.52 as Pr 6 O 11 , Nd 2 O 3 , Sm 2 O 3 , Dy 2 O 3
~1.50% by weight, and if the proportion is less than 0.52% by weight, sintering becomes difficult and the insulation resistance value becomes low. If it exceeds 1.50% by weight, the rate of change in dielectric constant with temperature increases. The proportion of niobium oxide is from 0.85 as Nb 2 O 5
If the proportion is less than 0.85% by weight, sintering becomes difficult, and if it exceeds 3.00% by weight, the dielectric constant will be small and the temperature change rate will be large. The proportion of magnesium oxide is 0.05-0.35% by weight as MgO
When the proportion is less than 0.05% by weight, the temperature change rate is large, and when it exceeds 0.35% by weight, the dielectric constant is small. The molar ratio of MgO and Nb 2 O 5 is in the range of 0.4 to 2.2, and when the molar ratio is less than 0.4, the dielectric constant is small;
If it exceeds 2.2, the rate of change in dielectric constant with temperature is large;
tanδ also increases. Also, Pr 6 O 11 , Nd 2 O 3 , Sm 2
The ratio of the total equivalent of O 3 , Dy 2 O 3 and the equivalent of MgO is 4/
When the ratio is 3 to 4/5, the resulting ceramic composition has a high dielectric constant and good temperature characteristics, which is preferable. (Examples) Hereinafter, the present invention will be explained in detail by way of examples. As a starting material, the average particle size of SEM particle size is 0.2 ~
At least one selected from praseodymium oxide, neodymium oxide, samarium oxide, dysprosium oxide, niobium oxide, and magnesium oxide as shown in Table 1 are added to barium titanate having a particle size of 0.3 μm and a specific surface area of 5 to 8 m 2 /g. Add pure water and mix. After drying the mixture, an appropriate amount of polyvinyl alcohol was added as a binder, and a disc-shaped molded product with a diameter of 15 mm and a thickness of 0.6 mm was produced at a molding pressure of 2 t/cm 2 . Next, this was sintered at 1220°C for 5 hours. Silver electrodes with a diameter of 10 mm are placed on both end surfaces of the sintered disk.
They were baked at 740°C and their electrical properties were evaluated.
Here, the dielectric constant and dielectric loss (tan δ) were measured at 1 kHz using an LCR meter. The insulation resistance value is the value read when using a high insulation resistance value and applying a voltage of 500V. The rate of change in dielectric constant (%) was based on 20°C. In Table 1, Samples Nos. 1, 7, 8, 11, and 12 are outside the scope of the present invention. As is clear from Table 1, products within the scope of the present invention can be sintered at 1220°C, and their porcelain properties show a high dielectric constant of about 2000, and the rate of change in dielectric constant is small. It can be seen that the dielectric loss is small. (Effects of the Invention) As described below, the following effects were found by the present invention. (1) It does not contain bismuth compounds and can be sintered at a low temperature of about 1200℃. (2) In terms of characteristics, the dielectric constant is high at over 2000.
Furthermore, the rate of change due to temperature is small. (3) Low dielectric loss. Therefore, the ceramic composition of the present invention has extremely excellent electrical properties and is extremely advantageous in terms of cost, so it is of great industrial value. 【table】
Claims (1)
プラセオジウム、酸化ネオジム、酸化サマリウ
ム、酸化ジスプロシウムのうち少なくとも１種を
0.52〜1.50重量％、酸化ニオブ0.85〜3.00重量％、
酸化マグネシウム0.05〜0.35重量％を含み、かつ
酸化マグネシウムに対する酸化ニオブのモル比が
１：0.4ないし１：2.2の範囲にあることを特徴と
する磁器誘電体組成物。1 Barium titanate 95.20 to 98.58% by weight, at least one of praseodymium oxide, neodymium oxide, samarium oxide, dysprosium oxide
0.52-1.50% by weight, niobium oxide 0.85-3.00% by weight,
A porcelain dielectric composition containing 0.05 to 0.35% by weight of magnesium oxide, and characterized in that the molar ratio of niobium oxide to magnesium oxide is in the range of 1:0.4 to 1:2.2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59219379A JPS6199210A (en) | 1984-10-20 | 1984-10-20 | Ceramic dielectric composition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59219379A JPS6199210A (en) | 1984-10-20 | 1984-10-20 | Ceramic dielectric composition |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6199210A JPS6199210A (en) | 1986-05-17 |
| JPH0510762B2 true JPH0510762B2 (en) | 1993-02-10 |
Family
ID=16734493
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59219379A Granted JPS6199210A (en) | 1984-10-20 | 1984-10-20 | Ceramic dielectric composition |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6199210A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01278474A (en) * | 1988-04-29 | 1989-11-08 | Tdk Corp | Porcelain composition of high dielectric constant system |
| JPH02267166A (en) * | 1989-04-07 | 1990-10-31 | Matsushita Electric Ind Co Ltd | Dielectric porcelain composition |
| KR102815914B1 (en) | 2019-06-14 | 2025-06-02 | 삼성전기주식회사 | Dielectric ceramic composition and multilayer ceramic capacitor comprising the same |
-
1984
- 1984-10-20 JP JP59219379A patent/JPS6199210A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6199210A (en) | 1986-05-17 |
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