JP3840917B2 - Voltage-dependent nonlinear resistor - Google Patents

Description

【００５９】
Ａサイト成分のモル比は、バリスタの電気的特性、特にバリスタ電圧Ｅ_１０の温度特性に大きな影響を与える。Ｅ_１０温度特性は、−０．０５〜＋０．０５［％／℃］の範囲にあることが望ましい。従って、試料１５〜１８は好ましい範囲のものではない。
【００６０】
Ｅ_１０温度特性が良好であっても、バリスタ電圧Ｅ_１０が高いものは本発明の趣旨から外れている。試料８、１０及び１９はＣａが多すぎるためバリスタ電圧Ｅ_１０がかなり高く、これは採用できない。バリスタ電圧Ｅ_１０としては、１５Ｖ以下であることが望まれており、従って、試料９、１１及び１８は好ましい範囲のものではない。
【００６１】
さらに、非直線係数αは、３．０以上であることが望まれるため、試料１２〜１７も望ましい範囲のものではない。
【００６２】
従って、Ｅ_１０温度特性が−０．０５〜＋０．０５［％／℃］の範囲にあり、バリスタ電圧Ｅ_１０が１５Ｖ以下であり、かつ非直線係数αが３．０以上である試料１〜７が、本発明の好ましい範囲といえる。これは、請求項１に規定したＡサイトモル比に対応する。この範囲では、半田コテ温度が３６０℃、４００℃及び４５０℃のサーマルクラック試験においてクラックが発生しなかった。
【００６３】
特に、試料４は、バリスタ電圧Ｅ_１０、Ｅ_１０温度特性及び非直線係数αのバランスが最良であり、この周辺のＡサイト成分のモル比が本発明の最も好ましい範囲である。
【００６４】
実施例２
この実施例２は、半導体化剤の量を変えた試料による比較である。
【００６５】
Ａサイトモル比、半導体化剤の種類、トータルＡ／Ｂ、ＳｉＯ_２のモル％並びにＣｏＯ_４／３のモル％等の他のパラメータを一定にし、半導体化剤のモル％を表２に示されるものとしたこと以外は実施例１の場合と同様にして試料を作製し、これらについても実施例１の場合と同様な測定を行った。結果を表２に示す。
【００６６】
【表２】

【００６７】
半導体化剤の量は、バリスタ磁器の耐サーマルクラック性に影響を与える。試料２０及び２５は、半導体化剤がそれぞれ少なすぎる及び多すぎるため、半田コテ温度が３６０℃の試験でサーマルクラックが発生するため、好ましくない。従って、半田コテ温度が３６０℃の試験でサーマルクラックが発生しない試料４及び２１〜２４が本発明の好ましい範囲である。これは、請求項１に規定した半導体化剤のモル％に対応する。
【００６８】
さらに、試料２４は半田コテ温度が４００℃及び４５０℃の試験においてサーマルクラックが発生するため、この４００℃及び４５０℃のサーマルクラック試験でクラックが発生しない試料４及び２１〜２３が本発明のより好ましい範囲となる。これは、請求項３に規定した半導体化剤のモル％に対応する。なお、試料４の周辺の半導体化剤のモル％が本発明の最も好ましい範囲である。
【００６９】
実施例３
この実施例３は、半導体化剤の種類を変えた試料による比較である。
【００７０】
Ａサイトモル比、半導体化剤のモル％、トータルＡ／Ｂ、ＳｉＯ_２のモル％並びにＣｏＯ_４／３のモル％等の他のパラメータを一定にし、半導体化剤の種類を表３に示されるものとしたこと以外は実施例１の場合と同様にして試料を作製し、これらについても実施例１の場合と同様な測定を行った。結果を表３に示す。
【００７１】
【表３】

【００７２】
試料４及び２６〜４２のいずれも半田コテ温度が３６０℃の試験及び４００℃の試験においてサーマルクラックが発生しないため、半導体化剤としてＮｂＯ_５／２、ＴａＯ_５／２、ＹＯ_３／２、ＬａＯ_３／２、ＣｅＯ_２、ＰｒＯ_１１／６、ＮｄＯ_３／２、ＳｍＯ_３／２、ＥｕＯ_３／２、ＧｄＯ_３／２、ＴｂＯ_７／４、ＤｙＯ_３／２、ＨｏＯ_３／２、ＥｒＯ_３／２、ＴｍＯ_３／２、ＹｂＯ_３／２、ＬｕＯ_３／２又はＮｂＯ_５／２＋ＹＯ_３／２（等モル数）を用いることは本発明の好ましい範囲である。これは、請求項１に規定した半導体化剤の種類に対応する。
【００７３】
実施例４
この実施例４は、トータルＡ／Ｂを変えた試料による比較である。
【００７４】
Ａサイトモル比、半導体化剤のモル％及び種類、ＳｉＯ_２のモル％並びにＣｏＯ_４／３のモル％等の他のパラメータを一定にし、トータルＡ／Ｂを表４に示されるものとしたこと以外は実施例１の場合と同様にして試料を作製し、これらについても実施例１の場合と同様な測定を行った。結果を表４に示す。
【００７５】
【表４】

【００７６】
トータルＡ／Ｂの値は、磁器の焼結性に影響を与える。試料４３及び４９は、トータルＡ／Ｂがそれぞれ小さすぎる及び大きすぎるため、緻密な磁器を焼結することができず、再酸化処理により全体が絶縁化されてしまったためバリスタとして動作しない。さらに、サーマルクラックも半田コテ温度が３６０℃で発生している。
【００７７】
表４から分かるように、ＳｉＯ_２の量が少なくかつ半導体化剤が多く添加される領域においては、耐サーマルクラック性を維持するために、トータルＡ／Ｂの特に上限を制御することが不可欠となる。トータルＡ／Ｂが１．１６を越えると３６０℃でサーマルクラックが発生するようになり、トータルＡ／Ｂが１．０１を越えると４００℃及び４５０℃でサーマルクラックが発生するようになる。
【００７８】
試料４８は半田コテ温度が３６０℃でサーマルクラックが発生していないが、バリスタ電圧Ｅ_１０が１５Ｖを大幅に越えてしまっている。従って、試料４及び４４〜４７が、本発明の好ましい範囲である。これは、請求項１に規定したトータルＡ／Ｂの範囲に対応する。
【００７９】
さらに、試料４及び４５〜４７は、半田コテ温度が４００℃及び４５０℃の試験においてもサーマルクラックが発生せず、またバリスタ電圧Ｅ_１０も１５Ｖ以下であるため、本発明のより好ましい範囲となる。これは、請求項３に規定したトータルＡ／Ｂの範囲に対応する。これは、請求項２に規定したトータルＡ／Ｂの範囲に対応する。なお、試料４のごとくＢサイト成分がややリッチなトータルＡ／Ｂ近辺が本発明の最も好ましい範囲である。
【００８０】
実施例５
この実施例５は、ＳｉＯ_２のモル％を変えた試料による比較である。
【００８１】
Ａサイトモル比、半導体化剤のモル％及び種類、トータルＡ／Ｂ並びにＣｏＯ_４／３のモル％等の他のパラメータを一定にし、ＳｉＯ_２のモル％を表５に示されるものとしたこと以外は実施例１の場合と同様にして試料を作製し、これらについて実施例１の場合と同様な測定を行った。結果を表５に示す。
【００８２】
【表５】

【００８３】
ＳｉＯ_２は焼結助剤として添加され、これが含まれると組成が変動しても安定に焼成することができるが、その量が増えると、サーマルクラックが発生し易くなる。
【００８４】
試料５４及び５５は、ＳｉＯ_２が多すぎるため、半田コテ温度が３６０℃の試験でもサーマルクラックが発生するため好ましくない。従って、半田コテ温度が３６０℃の試験及び４００℃の試験においてもサーマルクラックが発生しない試料４及び５０〜５３が本発明の好ましい範囲である。これは、請求項１に規定したＳｉＯ_２のモル％に対応する。なお、試料５０は、ＳｉＯ_２の添加量が０の場合であるが、実際には、各原料に不純物としてＳｉＯ_２が含まれているため、試料５０のＳｉＯ_２含有量は０とはならない。
【００８５】
さらに、試料５３は半田コテ温度が４５０℃の試験においてサーマルクラックが発生するため、半田コテ温度が４５０℃の試験においてもサーマルクラックが発生しない試料４及び５０〜５２が本発明のより好ましい範囲となる。これは、請求項４に規定したＳｉＯ_２のモル％に対応する。なお、試料４の周辺のＳｉＯ_２のモル％が本発明の最も好ましい範囲である。
実施例６
この実施例６は、ＣｏＯ_４／３のモル％を変えた試料による比較である。
【００８６】
Ａサイトモル比、半導体化剤のモル％及び種類、トータルＡ／Ｂ並びにＳｉＯ_２のモル％等の他のパラメータを一定にし、ＣｏＯ_４／３のモル％を表６に示されるものとしたこと以外は実施例１の場合と同様にして試料を作製し、これらについて実施例１の場合と同様な測定を行った。結果を表６に示す。
【００８７】
【表６】

【００８８】
ＣｏＯ_４／３を添加することにより、バリスタ電圧Ｅ_１０が小さくなる。しかしながら、この添加量が多すぎると、焼結過剰となりサーマルクラックが発生し易くなる。
【００８９】
試料５６はＣｏＯ_４／３が含まれていない比較例として示されている。この試料５６はバリスタ電圧Ｅ_１０が１５Ｖを越えてしまっている。試料６２は、ＣｏＯ_４／３が多すぎるため、半田コテ温度が３６０℃の試験でもサーマルクラックが発生するため好ましくない。従って、半田コテ温度が３６０℃の試験及び４００℃の試験においてもサーマルクラックが発生しない試料４及び５７〜６１が本発明の好ましい範囲である。これは、請求項１に規定したＣｏＯ_４／３のモル％に対応する。
【００９０】
さらに、試料６１は半田コテ温度が４５０℃の試験においてサーマルクラックが発生するため、半田コテ温度が４５０℃の試験においてもサーマルクラックが発生しない試料４及び５７〜６０が本発明のより好ましい範囲となる。これは、請求項５に規定したＣｏＯ_４／３のモル％に対応する。なお、試料４の周辺のＣｏＯ_４／３のモル％が本発明の最も好ましい範囲である。
【００９１】
実施例７
この実施例７は、付加添加物の種類及び量を変えた試料による比較である。
【００９２】
Ａサイトモル比、半導体化剤のモル％及び種類、トータルＡ／Ｂ、ＳｉＯ_２のモル％並びにＣｏＯ_４／３のモル％等の他のパラメータを一定にし、付加添加物の種類及び量を表７に示されるものとしたこと以外は実施例１の場合と同様にして試料を作製し、これらについても実施例１の場合と同様な測定を行った。結果を表７に示す。
【００９３】
【表７】

【００９４】
付加添加物はバリスタ電圧Ｅ_１０及び非直線係数α等の電気的特性を調整する作用がある。Ｍｎは非直線係数αを大きくする。表７には示されていないが、その他のＬｉ、Ｎａ、Ｎｉ、Ｃｕ、Ｚｎ、Ｓｃ、Ｆｅ、Ｇａ及びＩｎにも同様の作用が認められる。
【００９５】
試料６６は、添加量が多すぎたため、バリスタ電圧Ｅ_１０が１５Ｖを越えている。従って主成分に対するモル％が０．１０以下である試料６３〜６５が本発明の好ましい範囲である。これは、請求項６に規定した付加添加物の種類及びモル％に含まれている。
【００９６】
以上述べた実施形態及び実施例は全て本発明を例示的に示すものであって限定的に示すものではなく、本発明は他の種々の変形態様及び変更態様で実施することができる。従って本発明の範囲は特許請求の範囲及びその均等範囲によってのみ規定されるものである。
【００９７】
【発明の効果】
以上詳細に説明したように本発明によれば、ＣｏＯ_４／３を添加することにより、バリスタ電圧Ｅ_１０を小さくしている。ただし、この添加量が多すぎると、焼結過剰となりサーマルクラックが発生し易くなるから、添加量には上限がある。さらに、これらとＡサイトモル比及び半導体化剤の量及び種類をバランスよく適切に選ぶことによって、バリスタの電気的特性の向上を図ることができる。即ち、このような適切な量のＣｏＯ_４／３を上述した組成に添加することによって、再酸化後の素地強度が大きく、かつ半田こてによる熱衝撃試験でのサーマルクラック発生頻度が低いバリスタにおいて、３〜１５Ｖという比較的低いバリスタ電圧を得ることができる。
【図面の簡単な説明】
【図１】本発明の一実施形態として、リングバリスタの構造を示す平面図及びそのＡ−Ａ線断面図である。
【図２】電極材料にＣｕ及びＡｇをそれぞれ使用した場合の半田温度に対する残存電極面積の割合を示す特性図である。
【図３】Ｅ_１及びＥ_１０の測定回路を示す回路図である。
【符号の説明】
１０ バリスタ磁器
１０ａ 半導体部分
１０ｂ 絶縁層
１１ 電極
３０ 電流計
３１ バリスタ
３２ 直流定電流源
３３ 電圧計[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a voltage-dependent non-linear resistor (varistor), and in particular, (Sr, Ba, Ca) TiO.₃The present invention relates to a varistor including a composite perovskite ceramic having the following composition.
[0002]
[Prior art]
A varistor is a resistance element whose resistance value changes non-linearly in response to changes in the applied voltage. Specifically, it is a resistance element whose resistance value rapidly decreases when a voltage exceeding a certain voltage value is applied. is there.
[0003]
As the porcelain mainly constituting the varistor, there are various types of porcelain. (Sr, Ba, Ca) TiO₃The composite perovskite porcelain having the composition of the above has both the non-linearity of its resistance value and the capacitance function, so it absorbs surge voltage generated in electronic devices and eliminates noise. It is very suitable to do. For example, it is applied to a ring varistor for a DC micromotor.
[0004]
The varistor provided with this composite perovskite ceramic can control the temperature dependence of the varistor voltage by selecting the A site ratio, that is, the molar ratio of Sr, Ba and Ca. That is, the varistor voltage (the voltage at which the resistance value suddenly decreases) decreases as the temperature rises during operation, and the temperature dependence is reduced to around zero to prevent excessive current from flowing through the varistor and causing thermal runaway. Can be adjusted. In Japanese Patent Publication No. 8-28287 (Japanese Patent Laid-Open No. 2-146702), Japanese Patent Laid-Open No. 3-45559 and Japanese Patent No. 2944697 (Japanese Patent Laid-Open No. 3-237057), the temperature dependence of the varistor voltage is thus described. A varistor with adjusted properties is described.
[0005]
[Problems to be solved by the invention]
In recent years, in mounting electronic devices such as varistors, the soldering operation has been speeded up, and high-temperature solder or lead-free solder has been used, so the soldering temperature has been increasing. For this reason, the varistor is subjected to severe soldering conditions, and thermal cracks based on local thermal shock are likely to occur. Furthermore, an Ag (silver) electrode is generally used as the electrode of the varistor, but the Ag component of this electrode elutes into the solder due to the high temperature of soldering, and at least a part of the electrode disappears. As a result, the function as a varistor may be impaired.
[0006]
For the purpose of obtaining such a varistor resistant to thermal shock, Japanese Patent Laid-Open No. 63-276201 discloses TiO 2.₂A ring varistor using a system porcelain is described, but no specific data is described. Moreover, such TiO₂The system varistor porcelain cannot be employed because it is considerably inferior to the composite perovskite system varistor porcelain in terms of electric characteristics relating to capacitance and varistor voltage controllability.
[0007]
In order to obtain a varistor resistant to thermal shock, the applicant of the present application is a first component comprising at least one selected from a first component consisting of oxides of Sr, Ba, Ca and Ti and an oxide of R (Y and lanthanoid). A composite perovskite semiconductor ceramic containing at least one of a third component selected from two components and an oxide of M (Nb and Ta) and a fourth component formed from an oxide of Si The composition is 0.10 ≦ a / (a + b + c) ≦ 0.40, 0.30 ≦ b / (a + b + c) ≦ 0.50, 0.20 <c / (a + b + c) ≦ 0.50, 0.84 ≦ ( a + b + c + e) / (d + f) ≦ 1.16, 1.0 ≦ (e + f) /d×100≦10.0, g / d × 100 ≦ 0.6 (where a is Sr of the first component converted to SrO) The number of moles, b is the first component B a is the number of moles in terms of BaO, c is the number of moles in which the first component Ca is converted to CaO, and d is the first component Ti in TiO₂The number of moles converted to, e is R of the second component YO_3/2, CeO₂, PrO_11/6, TbO_7/4, RO_3/2The number of moles converted to (other lanthanoid), f is the third component M is NbO_5/2, TaO_5/2The number of moles converted in terms of g, g is the fourth component Si into SiO.₂The varistor has been previously proposed (Japanese Patent Application No. 2000-347896).
[0008]
However, in the varistor previously proposed by the present applicant, it was very difficult to obtain a relatively low varistor voltage of 3 to 15 V under manufacturing conditions considering heat resistance.
[0009]
Accordingly, an object of the present invention is to provide a composite perovskite varistor which has excellent electrical characteristics and does not impair its function even when high-temperature soldering is performed.
[0010]
Another object of the present invention is to provide a composite perovskite varistor having a relatively low varistor voltage.
[0011]
[Means for Solving the Problems]
According to the present invention, a first component composed of oxides of Sr, Ba, Ca and Ti, a second component composed of at least one selected from oxides of R (Y and lanthanoid), and M (Nb and Ta A composite perovskite system comprising at least one component of at least one third component selected from oxides of (4), a fourth component of Si oxide, and a fifth component of Co oxide. The composition of the semiconductor ceramic is 0.30 ≦ a / (a + b + c) ≦ 0.40, 0.30 ≦ b / (a + b + c) ≦ 0.40, 0.25 ≦ c / (a + b + c) ≦ 0.35,. 84 ≦ (a + b + c + e) / (d + f) ≦ 1.01, 1.0 ≦ (e + f) /d×100≦10.0, g / d × 100 ≦ 0.6, 0.01 ≦ h / d × 100 ≦ 1.50 (where a is the first component Sr replaced with SrO The number of moles, b is the number of moles in terms of Ba of the first component in BaO, c is the number of moles in terms of Ca of the first component in CaO, d is TiO a Ti of the first component₂The number of moles converted to, e is R of the second component YO_3/2, CeO₂, PrO_11/6, TbO_7/4, RO_3/2The number of moles converted to (other lanthanoid), f is the third component M is NbO_5/2, TaO_5/2The number of moles converted in terms of g, g is the fourth component Si into SiO.₂The number of moles converted to, h is the fifth component of CoO_4/3Is a varistor).
[0012]
CoO_4/3Is added to the varistor voltage E.₁₀Is made smaller. However, if the addition amount is too large, sintering is excessive and thermal cracks are likely to occur, so the addition amount has an upper limit. Such an appropriate amount of CoO_4/3Is added to the above-described composition to obtain a relatively low varistor voltage of 3 to 15 V in a varistor having a high substrate strength after reoxidation and a low frequency of thermal cracks in a thermal shock test using a soldering iron. Can do.
[0013]
SiO used as sintering aid₂As much as possible, the varistor's resistance to thermal shock is increased, and the occurrence of thermal cracks due to local thermal shock due to severe soldering conditions is suppressed.₂Total A / B represented by (a + b + c + e) / (d + f) as a decrease in sinterability caused by a decrease in the amount (A site component including other elements that can enter the lattice of the A site component from the relationship of the ion radius) And the ratio of the total number of moles of the B site component including other elements that can enter the lattice of the B site component). Furthermore, the electrical characteristics of the varistor can be improved by appropriately selecting the A site molar ratio and the amount and type of the semiconducting agent in a balanced manner.
[0014]
In the present invention, the perovskite structure is not a simple A / B which is the ratio of the number of moles of the A site component composed solely of Sr, Ba and Ca and the number of moles of the B site component composed solely of Ti, but also includes additives. A parameter of total A / B, which is the molar ratio of ions, is introduced. That is, it is considered that such a total A / B is not a simple A / B that really contributes to sinterability. In particular, the semiconducting agent among the additives is an important solid solution ion, and in the case of the present invention having a large amount of addition, the error increases when using a simple A / B, and the total A / B is used. For the first time, accurate control becomes possible, and a varistor without characteristic variations can be provided.
[0015]
Thus, in the above-described composition range of the present invention, in a varistor having a high substrate strength after reoxidation and a low frequency of occurrence of cracks (thermal cracks) in a thermal shock test by a soldering iron, it is as low as 3 to 15 V. A varistor voltage can be obtained.
[0016]
The composition of the first component and at least one of the second component and the third component is preferably 0.96 ≦ (a + b + c + e) / (d + f) ≦ 1.01. Moreover, it is also preferable that the composition of at least one of the second component and the third component is 1.0 ≦ (e + f) /d×100≦4.0. Furthermore, it is also preferable that the composition of the fourth component is g / d × 100 ≦ 0.3. Furthermore, it is also preferable that the composition of the fifth component is 0.01 ≦ h / d × 100 ≦ 1.00.
[0017]
The porcelain further contains a sixth component made of at least one selected from oxides of Li, Na, Mn, Ni, Cu, Zn, Sc, Fe, Ga, In, Mo and W, and 0 < i / d × 100 ≦ 0.1 (where i is the sixth component of Li, Na, Mn, Ni, Cu, Zn, Sc, Fe, Ga, In, Mo, W and LiO)_1/2, NaO_1/2, MnO, NiO, CuO, ZnO, ScO_3/2, FeO_3/2, GaO_3/2, InO_3/2, MoO₃, WO₃It is also preferred that the number of moles converted to
[0018]
By adding this sixth component, the varistor voltage E₁₀And electrical characteristics such as non-linear coefficient α can be adjusted. For example, Mn has the effect of increasing the nonlinear coefficient α. Various components other than those listed here can be used. If too much is added, the varistor voltage E₁₀Becomes 15V or more.
[0019]
It is also preferable that an electrode formed on the surface of the porcelain is provided, and this electrode is made of Cu or a material mainly containing Cu. In the latter case, the electrode is more preferably made of Cu containing Cu alloy or glass frit.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a plan view showing a structure of a ring varistor and a cross-sectional view taken along line AA, as an embodiment of the present invention.
[0021]
In the figure, 10 is a varistor porcelain formed in a ring shape, and 11 is an electrode formed on one surface thereof. In this embodiment, five electrodes 11 are provided at equal angles. As shown in FIG. 2B, the varistor ceramic 10 is composed of an internal semiconductor portion 10a and an insulating layer 10b formed near the entire surface thereof.
[0022]
Hereinafter, the composition of the varistor ceramic 10 will be described.
[0023]
The varistor porcelain 10 includes a first component of a composite perovskite composed of oxides of Sr, Ba, Ca and Ti, and R (Y and lanthanoids (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho , Er, Tm, Yb, and Lu)) at least one selected from oxides and at least one selected from M (Nb and Ta) oxides. And a fourth component made of Si oxide and a fifth component made of Co oxide. a is the number of moles converted from Sr of the first component to SrO, b is the number of moles converted from Ba of the first component to BaO, c is the number of moles converted from Ca of the first component to CaO, and d is the first component. Ti of TiO₂The number of moles converted to, e is R of the second component YO_3/2, CeO₂, PrO_11/6, TbO_7/4, RO_3/2The number of moles converted to (other lanthanoid), f is the third component M is NbO_5/2, TaO_5/2The number of moles converted in terms of g, g is the fourth component Si into SiO.₂Number of moles converted to, h is Co is CoO_4/3Assuming that the number of moles is converted to, the composition of this varistor porcelain is 0.30 ≦ a / (a + b + c) ≦ 0.40, 0.30 ≦ b / (a + b + c) ≦ 0.40, 0.25 ≦ c. /(A+b+c)≦0.35, 0.84 ≦ (a + b + c + e) / (d + f) ≦ 1.01, 1.0 ≦ (e + f) /d×100≦10.0, g / d × 100 ≦ 0.6 0.01 ≦ h / d × 100 ≦ 1.50. This composition is more preferably 0.96 ≦ (a + b + c + e) / (d + f) ≦ 1.01, 1.0 ≦ (e + f) /d×100≦4.0, g / d × 100 ≦ 0.3, 0.01 ≦ h / d × 100 ≦ 1.00.
[0024]
The first component is the main component of the varistor porcelain 10. In the composite perovskite, the first component is composed of an A site component made of Sr, Ba and Ca and a B site component made of Ti. The second component and the third component are metal oxides that contribute to semiconductorization, and the fourth component is added mainly for improving the sinterability. Furthermore, the fifth component is added to reduce the varistor voltage.
[0025]
The electrical characteristics of the varistor are mainly varistor voltage E₁₀Is expressed by the temperature characteristic and the nonlinear coefficient α. Varistor voltage E₁₀Represents an applied voltage value when a current of 10 mA flows through the varistor, and the nonlinear coefficient α is generally α = 1 / log (E₁₀/ E₁). However, E₁Is the applied voltage value when a current of 1 mA flows through the varistor.
[0026]
The molar ratio of Sr, Ba and Ca which are A site components is such that Sr is 0.30 or more and 0.40 or less, Ba is 0.30 or more and 0.40 or less, Ca is 0.25 or more and 0.35 or less. By setting so that the varistor voltage E₁₀Controllability, E₁₀Electrical characteristics such as temperature characteristics and nonlinear coefficient α can be improved, and the thermal shock resistance of the varistor can be improved. That is, if there is too much Sr, E₁₀If the temperature characteristic becomes negative and is too low, the varistor voltage E₁₀Becomes higher. Also, if there is too much Ba, the varistor voltage E₁₀Becomes higher or the non-linear coefficient α becomes too small.₁₀The temperature characteristic becomes negative. Furthermore, the varistor voltage E can be used regardless of whether Ca is too much or too little.₁₀As a result, the non-linear coefficient α becomes smaller. In addition, if there is too much Ca, the varistor voltage E₁₀Becomes extremely large and control becomes difficult.₁₀The temperature characteristic becomes negative.
[0027]
Main component (TiO₂) So that the mol% (calculated by the number of moles of metal ions) of the semiconducting agent (second and / or third component) is 1.0 or more and 10.0 or less, more preferably 1.0 or more and 4. By setting it to be 0 or less, the thermal shock resistance of the varistor can be enhanced. That is, thermal cracks are likely to occur if there is too much or too little semiconducting agent.
[0028]
By setting so that the total A / B is 0.84 or more and 1.01 or less, more preferably 0.96 or more and 1.01 or less, the fourth component ( SiO₂The sinterability can also be improved when the amount of) is reduced. That is, if the total A / B is too large or too small, sintering is inhibited, and the base is insulated by reoxidation. Also, if the total A / B is too large or too small, the strength decreases and thermal cracks are likely to occur. SiO₂In a region where a small amount of the semiconducting agent is added as described above, the upper limit of total A / B is controlled to 1.01 or less in order to maintain thermal crack resistance.
[0029]
Main component (TiO₂) The fourth component (SiO₂), The thermal shock resistance of the varistor can be greatly improved. That is, SiO₂Is added as a sintering aid, and if it is included, it can be fired stably even if the composition fluctuates. However, if the amount increases, thermal cracks are likely to occur.
[0030]
Main component (TiO₂) To the fifth component (CoO_4/3) Is set to be 0.01 or more and 1.50 or less, more preferably 0.01 or more and 1.00 or less.₁₀Can be reduced. That is, CoO_4/3Is included, the varistor voltage E₁₀However, if the amount of addition is too large, sintering is excessive and thermal cracks are likely to occur.
[0031]
By substantially not containing Mg, the thermal shock resistance of the varistor can be enhanced. That is, if Mg is contained in the porcelain, thermal cracks are likely to occur. “Substantially free” means that the content is generally less than 0.001 mol%.
[0032]
The varistor porcelain 10 further includes a sixth component (additive additive) made of at least one selected from oxides of Li, Na, Mn, Ni, Cu, Zn, Sc, Fe, Ga, In, Mo, and W. You may contain. Its content is Li, Na, Mn, Ni, Cu, Zn, Sc, Fe, Ga, In, Mo, W, LiO._1/2, NaO_1/2, MnO, NiO, CuO, ZnO, ScO_3/2, FeO_3/2, GaO_3/2, InO_3/2, MoO₃, WO₃If it is the number of moles converted to, it is preferable that 0 <i / d × 100 ≦ 0.1. As a result, the varistor voltage E₁₀And electrical characteristics such as non-linear coefficient α can be adjusted. For example, Mn can increase the nonlinear coefficient α, but if the amount added is too large, the varistor voltage E₁₀Becomes higher than 15V.
[0033]
The varistor ceramic 10 may contain other elements such as P, S, K, Al, and Zr as inevitable impurities in addition to such additives. Such elements are usually present as oxides.
[0034]
As described above, the varistor porcelain 10 is a polycrystalline body composed of a perovskite crystal. Each component is partly dissolved in the crystal grains and enters the perovskite crystal, and part is present as an oxide or composite oxide at the crystal grain boundary. For example, Ba, Ca, Sr, Ti, Nb, Ta, Y, lanthanoids, and the like are present in the crystal grains, and Mo, W, Mn, Si, and the like are present in the crystal grain boundaries.
[0035]
The average crystal grain size of the varistor ceramic 10 is usually about 0.5 to 10 μm, particularly about 1 to 6 μm.
[0036]
The electrode 11 is formed of Cu or a material mainly containing Cu. When the electrode is made of Ag, the Ag component of the electrode is eluted in the solder due to the high temperature of soldering, and at least a part of the electrode disappears. The electrode 11 is less susceptible to corrosion even at high temperatures and can withstand high temperature soldering operations.
[0037]
The material containing Cu as a main component is a Cu alloy such as Cr, Zr, Ag, Ti, Be, Zn, Sn, Ni, Al or Si, or Li, Na, K, Sr, Ba, Mn, Cu, Zn. Cu containing glass frit with oxides such as B, Si, Al, Bi or Pb.
[0038]
FIG. 2 is a characteristic diagram showing the ratio of the remaining electrode area to the solder temperature when Cu and Ag are used as electrode materials, respectively.
[0039]
After applying a flux to a sample ring varistor and preheating it, it is immersed in a solder bath of eutectic solder at each temperature for 5 seconds.
[0040]
As is clear from the figure, when the solder temperature is 400 ° C., the Ag electrode is eroded and the remaining electrode area is about 55.5%, whereas the Cu electrode is not eroded at all. The remaining electrode area is 100%.
[0041]
Next, a method for manufacturing the varistor ceramic 10 will be briefly described.
[0042]
The varistor porcelain 10 is obtained by processing the raw material powder in the order of mixing, calcination, pulverization, molding, binder removal, reduction firing, and reoxidation.
[0043]
As the raw material powder, a powder of a compound of each constituent element of porcelain is usually used. As the raw material powder, an oxide or a compound that becomes an oxide by firing, such as a carbonate or a hydroxide, can be used. For example, taking Ba as an example, the raw material is BaCO.₃, BaSiO₃, BaO, BaCl₂, Ba (OH)₂, Ba (NO₃)₂Alkoxides (eg (CH₃O)₂At least one barium compound such as Ba) can be used. The average particle diameter of the raw material powder is usually about 0.2 to 5 μm.
[0044]
First, the raw material powder is weighed so that the final composition becomes the composition described above, and usually wet mixed. Next, after dehydration, it is dried and pre-baked at about 1080 to 1250 ° C. for about 2 to 4 hours. Next, after pulverizing the temporarily fired product, an organic binder is added, and water, a pH adjuster, a moisturizing agent, and the like are further added and mixed. Next, the mixture is molded and treated to remove the binder, and then fired in a reducing atmosphere at about 1250 to 1400 ° C. for about 2 to 4 hours to obtain a semiconductor ceramic.
[0045]
In addition, about each raw material powder, such as Nb, Ta, Y, a lanthanoid, Mo, W, Mn, Si, you may add the oxide in the case of mixing after temporary baking. Co may be mixed with other raw materials at one time before calcination, or CoO after calcination._4/3May be added.
[0046]
The thus obtained semiconductor ceramic is subjected to heat treatment (reoxidation treatment) at a temperature of, for example, about 800 to 1000 ° C. in an oxidizing atmosphere such as air so that an appropriate varistor voltage corresponding to the purpose can be obtained. Apply. By this heat treatment, the insulating layer 10b is formed in the surface layer portion. Varistor characteristics are manifested by the presence of this insulating layer. If this insulating layer is thick, the nonlinear coefficient α and the varistor voltage increase, and if it is thin, the nonlinear coefficient α and the varistor voltage decrease, so that the insulating layer has an appropriate thickness according to the characteristics required for the product. What is necessary is just to select the heat processing conditions suitably.
[0047]
After the re-oxidation treatment, an electrode is formed on one surface of the varistor porcelain with Cu or a material mainly containing Cu to form a varistor.
[0048]
【Example】
Hereinafter, the present invention will be described in more detail with reference to specific examples.
[0049]
Example 1
In Example 1, the mol% and type of semiconducting agent, total A / B, SiO 2₂Mol% and CoO_4/3This is a comparison using a sample in which other parameters such as mol% of A are constant and the molar ratio of the A site component is changed.
[0050]
First, SrCO as a raw material₃, BaCO₃, CaCO₃TiO₂, NbO_5/2, SiO₂CoO_4/3Each was converted and weighed so as to have the composition shown in Table 1 and blended, then mixed for 10 to 20 hours using a wet media mill, dehydrated and dried.
[0051]
The obtained mixture was calcined at 1150 ° C. using a tunnel furnace, coarsely pulverized, mixed again by a wet media mill for 10 to 20 hours, dehydrated and dried. Next, 1.0 to 1.5% by weight of polyvinyl alcohol is mixed as an organic binder and granulated, and the molding pressure is 2 t / cm.²To form a molded body having an outer diameter of 12 mm, an inner diameter of 9 mm, and a thickness of 1.0 mm.
[0052]
After removing the binder from the molded body in an air atmosphere at about 1000 ° C., N₂(95% by volume) + H₂In a reducing atmosphere of (5% by volume), firing was performed at about 1300 ° C. for 4 hours to obtain a semiconductor ceramic. Next, the semiconductor porcelain was reoxidized in air at 900 ° C. for 4 hours to obtain a varistor porcelain.
[0053]
Next, as shown in FIG. 1, a Cu paste is applied to one surface of the varistor porcelain 10 and baked at 750 ° C. in a neutral atmosphere to form a 5-electrode Cu electrode 11 as shown in FIG. A varistor sample was prepared.
[0054]
Then, E of each sample at 20 ° C.₁And E₁₀And measured E₁And E₁₀Using α = 1 / log (E₁₀/ E₁) To determine the nonlinear coefficient α. Furthermore, the varistor voltage E₁₀The temperature characteristics (temperature coefficient) were also obtained. Furthermore, a thermal crack test of each sample was performed.
[0055]
E₁And E₁₀The measurement of was performed using the measurement circuit shown in FIG. In this measurement circuit, an ammeter 30 is connected in series between a varistor 31 and a DC constant current source 32, and a voltmeter 33 is connected in parallel to the varistor 31. E₁And E₁₀Measured the voltage value between the two terminals of the varistor 31 when currents of 1 mA and 10 mA flowed through the varistor 31 using the ammeter 30 and the voltmeter 33, respectively.
[0056]
Varistor voltage E₁₀Temperature characteristics (temperature coefficient) ΔE_10TIs ΔE for each sample._10T= {E₁₀(85) -E₁₀(20)} / {E₁₀(20) × (85-20)} × 100 [% / ° C.] E₁₀(20) and E₁₀(85) is the varistor voltage E at temperatures of 20 ° C. and 85 ° C., respectively.₁₀It is. These were measured using a thermostat.
[0057]
In the thermal crack test, a soldering iron whose temperature was set in advance was brought into contact with the electrode surface of the sample left at room temperature for 3 seconds while supplying eutectic solder. As the temperature of the soldering iron, three temperatures of 360 ° C., 400 ° C. and 450 ° C. were used. The number of samples was 100, and the presence or absence of cracks was visually determined using alcohol. The results are shown in Table 1.
[0058]
[Table 1]

[0059]
The molar ratio of the A site component depends on the electrical characteristics of the varistor, in particular,₁₀This greatly affects the temperature characteristics. E₁₀The temperature characteristics are desirably in the range of −0.05 to +0.05 [% / ° C.]. Therefore, samples 15 to 18 are not in the preferred range.
[0060]
E₁₀Even if the temperature characteristics are good, the varistor voltage E₁₀Higher values are not within the spirit of the present invention. Samples 8, 10 and 19 have too much Ca, so varistor voltage E₁₀Is quite expensive and cannot be adopted. Varistor voltage E₁₀Therefore, it is desired that the voltage is 15 V or less, and therefore, Samples 9, 11 and 18 are not in a preferable range.
[0061]
Furthermore, since it is desired that the non-linear coefficient α is 3.0 or more, the samples 12 to 17 are not in a desirable range.
[0062]
Therefore, E₁₀The temperature characteristics are in the range of −0.05 to +0.05 [% / ° C.], and the varistor voltage E₁₀Samples 1 to 7 having a non-linear coefficient α of 3.0 or more can be said to be a preferred range of the present invention. This corresponds to the A site molar ratio defined in claim 1. In this range, no crack was generated in the thermal crack test at a soldering iron temperature of 360 ° C., 400 ° C., and 450 ° C.
[0063]
In particular, sample 4 has a varistor voltage E.₁₀, E₁₀The balance between temperature characteristics and nonlinear coefficient α is the best, and the molar ratio of the surrounding A site components is the most preferred range of the present invention.
[0064]
Example 2
This Example 2 is a comparison using samples with different amounts of semiconducting agent.
[0065]
A site molar ratio, type of semiconducting agent, total A / B, SiO₂Mol% and CoO_4/3Samples were prepared in the same manner as in Example 1 except that the other parameters such as mol% were constant and the mol% of the semiconducting agent was as shown in Table 2. Measurements similar to the above were performed. The results are shown in Table 2.
[0066]
[Table 2]

[0067]
The amount of semiconducting agent affects the thermal crack resistance of the varistor porcelain. Samples 20 and 25 are not preferable because the amount of the semiconducting agent is too small and too large, and thermal cracks occur in a test at a soldering iron temperature of 360 ° C. Therefore, samples 4 and 21 to 24 in which thermal cracks do not occur in a test with a soldering iron temperature of 360 ° C. are within the preferred range of the present invention. This corresponds to the mol% of the semiconducting agent as defined in claim 1.
[0068]
Furthermore, since the sample 24 generates thermal cracks in the test where the soldering iron temperature is 400 ° C. and 450 ° C., the samples 4 and 21 to 23 in which cracks do not occur in the 400 ° C. and 450 ° C. thermal crack test This is a preferred range. This corresponds to the mol% of the semiconducting agent as defined in claim 3. Note that the mol% of the semiconducting agent around the sample 4 is the most preferable range of the present invention.
[0069]
Example 3
This Example 3 is a comparison using samples with different types of semiconducting agents.
[0070]
A site molar ratio, mol% of semiconducting agent, total A / B, SiO₂Mol% and CoO_4/3Samples were prepared in the same manner as in Example 1 except that the other parameters such as mol% were constant and the type of semiconducting agent was as shown in Table 3. The same measurement as in the case was performed. The results are shown in Table 3.
[0071]
[Table 3]

[0072]
In both the samples 4 and 26 to 42, thermal cracks do not occur in the test where the soldering iron temperature is 360 ° C and the test where the temperature is 400 ° C._5/2, TaO_5/2, YO_3/2, LaO_3/2, CeO₂, PrO_11/6, NdO_3/2, SmO_3/2, EuO_3/2, GdO_3/2, TbO_7/4, DyO_3/2, HoO_3/2, ErO_3/2, TmO_3/2, YbO_3/2, LuO_3/2Or NbO_5/2+ YO_3/2The use of (equal mole number) is a preferred range of the present invention. This corresponds to the type of semiconducting agent defined in claim 1.
[0073]
Example 4
Example 4 is a comparison using samples with different total A / B.
[0074]
A site molar ratio, mol% and type of semiconducting agent, SiO₂Mol% and CoO_4/3Samples were prepared in the same manner as in Example 1 except that other parameters such as mol% were constant and the total A / B was as shown in Table 4. The same measurement was performed. The results are shown in Table 4.
[0075]
[Table 4]

[0076]
The total A / B value affects the sinterability of the porcelain. Samples 43 and 49 do not operate as varistors because the total A / B is too small and too large, respectively, so that the dense porcelain cannot be sintered and the whole is insulated by the re-oxidation treatment. Furthermore, thermal cracks also occur at a soldering iron temperature of 360 ° C.
[0077]
As can be seen from Table 4, SiO₂In a region where a small amount of the semiconducting agent is added, it is essential to control the upper limit of the total A / B in order to maintain the thermal crack resistance. When the total A / B exceeds 1.16, thermal cracks occur at 360 ° C., and when the total A / B exceeds 1.01, thermal cracks occur at 400 ° C. and 450 ° C.
[0078]
Sample 48 had a soldering iron temperature of 360 ° C. and no thermal cracks, but varistor voltage E₁₀Has significantly exceeded 15V. Therefore, samples 4 and 44 to 47 are the preferred range of the present invention. This corresponds to the total A / B range defined in claim 1.
[0079]
Further, Samples 4 and 45 to 47 did not cause thermal cracks even in tests with soldering iron temperatures of 400 ° C. and 450 ° C., and varistor voltage E₁₀Since it is 15V or less, it becomes the more preferable range of the present invention. This corresponds to the total A / B range defined in claim 3. This corresponds to the total A / B range defined in claim 2. The most preferable range of the present invention is the vicinity of the total A / B where the B-site component is slightly rich like the sample 4.
[0080]
Example 5
In Example 5, SiO 2₂It is the comparison by the sample which changed mol% of.
[0081]
A site molar ratio, mol% and type of semiconducting agent, total A / B and CoO_4/3Other parameters such as mol% of₂Samples were prepared in the same manner as in Example 1 except that the mol% of those shown in Table 5 was used, and the same measurements as in Example 1 were performed. The results are shown in Table 5.
[0082]
[Table 5]

[0083]
SiO₂Is added as a sintering aid, and if it is included, it can be fired stably even if the composition fluctuates. However, if the amount increases, thermal cracks tend to occur.
[0084]
Samples 54 and 55 are SiO₂Therefore, it is not preferable because a thermal crack occurs even in a test where the soldering iron temperature is 360 ° C. Accordingly, Samples 4 and 50 to 53 in which thermal cracks do not occur in the test where the soldering iron temperature is 360 ° C. and the test where the temperature is 400 ° C. are within the preferable range of the present invention. This is the SiO as defined in claim 1.₂Corresponds to the mole percent of Sample 50 is made of SiO.₂However, in practice, SiO2 as an impurity is included in each raw material.₂Since SiO is contained in Sample 50,₂The content is not zero.
[0085]
Furthermore, since the sample 53 causes thermal cracks in the test where the soldering iron temperature is 450 ° C., samples 4 and 50 to 52 in which thermal cracking does not occur even in the test where the soldering iron temperature is 450 ° C. are more preferable ranges of the present invention. Become. This is the SiO as defined in claim 4.₂Corresponds to the mole percent of In addition, SiO around sample 4₂Is the most preferred range of the present invention.
Example 6
In this example 6, CoO_4/3It is the comparison by the sample which changed mol% of.
[0086]
A site molar ratio, mol% and type of semiconducting agent, total A / B and SiO₂Other parameters such as mol% of_4/3Samples were prepared in the same manner as in Example 1 except that the mol% of those shown in Table 6 was used, and the same measurements as in Example 1 were performed. The results are shown in Table 6.
[0087]
[Table 6]

[0088]
CoO_4/3Is added to the varistor voltage E.₁₀Becomes smaller. However, when this addition amount is too large, sintering becomes excessive and thermal cracks are likely to occur.
[0089]
Sample 56 is CoO_4/3It is shown as a comparative example that does not contain. This sample 56 has a varistor voltage E.₁₀Has exceeded 15V. Sample 62 is CoO_4/3Therefore, it is not preferable because a thermal crack occurs even in a test where the soldering iron temperature is 360 ° C. Therefore, Samples 4 and 57 to 61 in which thermal cracks do not occur in the test where the soldering iron temperature is 360 ° C. and the test where the soldering iron temperature is 400 ° C. are within the preferable range of the present invention. This is the CoO as defined in claim 1_4/3Corresponds to the mole percent of
[0090]
Further, since the sample 61 generates thermal cracks in the test with the soldering iron temperature of 450 ° C., the samples 4 and 57 to 60 in which the thermal crack does not occur even in the test with the soldering iron temperature of 450 ° C. are more preferable ranges of the present invention. Become. This is a CoO as defined in claim 5_4/3Corresponds to the mole percent of In addition, CoO around sample 4_4/3Is the most preferred range of the present invention.
[0091]
Example 7
This Example 7 is a comparison using samples with different types and amounts of additive additives.
[0092]
A site molar ratio, mol% and type of semiconducting agent, total A / B, SiO₂Mol% and CoO_4/3Samples were prepared in the same manner as in Example 1 except that other parameters such as mol% were constant and the type and amount of additive were as shown in Table 7. The same measurement as in 1 was performed. The results are shown in Table 7.
[0093]
[Table 7]

[0094]
The additive is varistor voltage E₁₀And has an effect of adjusting electrical characteristics such as a non-linear coefficient α. Mn increases the nonlinear coefficient α. Although not shown in Table 7, other Li, Na, Ni, Cu, Zn, Sc, Fe, Ga, and In have similar effects.
[0095]
Sample 66 had too much added, so varistor voltage E₁₀Is over 15V. Therefore, the samples 63 to 65 having a mol% based on the main component of 0.10 or less are a preferable range of the present invention. This is included in the type and mol% of additive as defined in claim 6.
[0096]
The above-described embodiments and examples are all illustrative and do not limit the present invention, and the present invention can be implemented in various other modifications and changes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.
[0097]
【The invention's effect】
As described in detail above, according to the present invention, CoO_4/3Is added to the varistor voltage E.₁₀Is made smaller. However, if the addition amount is too large, sintering is excessive and thermal cracks are likely to occur, so the addition amount has an upper limit. Furthermore, the electrical characteristics of the varistor can be improved by appropriately selecting the A site molar ratio and the amount and type of the semiconducting agent in a balanced manner. That is, such an appropriate amount of CoO_4/3Is added to the above-described composition to obtain a relatively low varistor voltage of 3 to 15 V in a varistor having a high substrate strength after reoxidation and a low frequency of thermal cracks in a thermal shock test using a soldering iron. Can do.
[Brief description of the drawings]
FIG. 1 is a plan view showing a structure of a ring varistor and a cross-sectional view taken along line AA, as an embodiment of the present invention.
FIG. 2 is a characteristic diagram showing the ratio of the remaining electrode area to the solder temperature when Cu and Ag are used as electrode materials, respectively.
FIG. 3 E₁And E₁₀It is a circuit diagram which shows these measurement circuits.
[Explanation of symbols]
10 Varistor porcelain
10a Semiconductor part
10b Insulating layer
11 electrodes
30 Ammeter
31 Barista
32 DC constant current source
33 Voltmeter

Claims (9)

A first component composed of oxides of Sr, Ba, Ca and Ti, a second component composed of at least one selected from oxides of R (Y and lanthanoids), and an oxide of M (Nb and Ta) The composition of the composite perovskite semiconductor ceramic containing at least one of the third component consisting of at least one kind, the fourth component consisting of Si oxide, and the fifth component consisting of Co oxide is: 0.30 ≦ a / (a + b + c) ≦ 0.40, 0.30 ≦ b / (a + b + c) ≦ 0.40, 0.25 ≦ c / (a + b + c) ≦ 0.35, 0.84 ≦ (a + b + c + e) / (D + f) ≦ 1.01, 1.0 ≦ (e + f) /d×100≦10.0, g / d × 100 ≦ 0.6, 0.01 ≦ h / d × 100 ≦ 1.50 (however, a is the number of moles of Sr of the first component converted to SrO, b Moles in terms of Ba of the first component in BaO, c is the number of moles in terms of Ca of the first component in CaO, d is the number of moles in terms of Ti of the first component to TiO _2, e is the second component R is the number of moles converted to YO _3/2 , CeO ₂ , PrO _11/6 , _{TbO 7/4} , RO _3/2 (other lanthanoids), f is the third component M is NbO _5/2 , TaO _The number of moles converted to _5/2 , g is the number of moles of the fourth component Si converted to SiO ₂ , and h is the number of moles of the fifth component Co converted to CoO _4/3 ). Characteristic voltage-dependent non-linear resistor. The composition of the first component and at least one of the second component and the third component is 0.96 ≦ (a + b + c + e) / (d + f) ≦ 1.01. The voltage-dependent nonlinear resistor as described. 3. The voltage dependence according to claim 1, wherein the composition of at least one of the second component and the third component satisfies 1.0 ≦ (e + f) /d×100≦4.0. Non-linear resistor. 4. The voltage-dependent nonlinear resistor according to claim 1, wherein the composition of the fourth component is g / d × 100 ≦ 0.3. 5. 5. The voltage-dependent nonlinear resistor according to claim 1, wherein the composition of the fifth component is 0.01 ≦ h / d × 100 ≦ 1.00. The porcelain further contains a sixth component of at least one selected from oxides of Li, Na, Mn, Ni, Cu, Zn, Sc, Fe, Ga, In, Mo, and W; <I / d × 100 ≦ 0.1 (where i is the sixth component of Li, Na, Mn, Ni, Cu, Zn, Sc, Fe, Ga, In, Mo, W, LiO _1/2 , NaO _{1 / 2} , MnO, NiO, CuO, ZnO, ScO _3/2 , FeO _3/2 , GaO _3/2 , InO _3/2 , MoO ₃ , and WO ₃ ). The voltage-dependent nonlinear resistor according to claim 1, wherein The voltage-dependent non-dependency according to any one of claims 1 to 6, further comprising an electrode formed on a surface of the porcelain, wherein the electrode is made of Cu or a material mainly containing Cu. Linear resistor. The voltage-dependent nonlinear resistor according to claim 7, wherein the electrode is made of a Cu alloy. The voltage-dependent nonlinear resistor according to claim 7, wherein the electrode is made of Cu containing glass frit.

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