JPH08124720A - Varistor and its manufacture - Google Patents
Varistor and its manufactureInfo
- Publication number
- JPH08124720A JPH08124720A JP6265237A JP26523794A JPH08124720A JP H08124720 A JPH08124720 A JP H08124720A JP 6265237 A JP6265237 A JP 6265237A JP 26523794 A JP26523794 A JP 26523794A JP H08124720 A JPH08124720 A JP H08124720A
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- JP
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- Prior art keywords
- resistance layer
- varistor element
- varistor
- high resistance
- electrode
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はバリスタとその製造方法
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a varistor and its manufacturing method.
【０００２】[0002]
【従来の技術】従来より、チップ部品は半田付け時に半
田により、Ａｇ外部電極が、侵されてしまうため、Ａｇ
外部電極の上にＮｉメッキ等を施し、この上からさら
に、半田付け性向上のため半田メッキを施している。し
かし、ＺｎＯバリスタは、半導体であるため電解メッキ
を行うと、セラミック素子表面もメッキされてしまうの
で、これを防ぐために、セラミック素子表面にＳｉ，
Ｂ，Ｂｉ，Ｐｂ，Ｃａ等からなるガラスをディップし
て、高抵抗層を形成していた。2. Description of the Related Art Conventionally, when a chip component is soldered, Ag external electrodes are attacked by the solder.
Ni plating or the like is applied to the external electrodes, and then solder plating is applied to improve the solderability. However, since the ZnO varistor is a semiconductor, if electrolytic plating is performed, the surface of the ceramic element is also plated. To prevent this, Si,
A high resistance layer was formed by dipping glass made of B, Bi, Pb, Ca or the like.
【０００３】[0003]
【発明が解決しようとする課題】しかし、ガラスによる
高抵抗層は選択的にセラミック素子表面だけに形成する
ことができず、また均一な厚さにすることが困難であっ
た。このため、メッキをするときメッキ流れをおこして
ショートしたり、水分等がセラミック素子内部に浸入し
てバリスタ特性を劣化させたりするという問題点を有し
ていた。However, the high resistance layer made of glass cannot be selectively formed only on the surface of the ceramic element, and it is difficult to make the thickness uniform. Therefore, there is a problem that when plating is performed, a flow of plating is caused to cause a short circuit, or moisture or the like enters the inside of the ceramic element to deteriorate the varistor characteristics.
【０００４】そこで本発明は、緻密で均一な厚みを有
し、選択的にセラミック素子表面に高抵抗層を形成し、
耐メッキ性、耐湿性に優れたバリスタを提供することを
目的とするものである。Therefore, the present invention has a dense and uniform thickness and selectively forms a high resistance layer on the surface of a ceramic element,
It is intended to provide a varistor having excellent plating resistance and moisture resistance.
【０００５】[0005]
【課題を解決するための手段】この目的を達成するため
に、本発明はバリスタ素子の表面に電極を形成し、次に
バリスタ素子の表面にＸの酸化物（Ｘ＝Ｆｅ，Ｓｂ，Ｔ
ｉ，Ａｌのうち少なくとも一種類）を主成分とする混合
物を配し、その後焼成し、バリスタ素子表面の少なくと
も電極に覆われていない部分に主成分がＺｎ−Ｘ−Ｏ系
の物質である高抵抗層を形成するものである。In order to achieve this object, the present invention forms an electrode on the surface of a varistor element and then forms an oxide of X (X = Fe, Sb, T) on the surface of the varistor element.
A mixture containing at least one of i and Al as a main component is arranged and then fired, and at least a portion of the surface of the varistor element which is not covered with the electrode has a Zn--X--O-based substance as a main component. It forms a resistance layer.
【０００６】[0006]
【作用】この構成により、バリスタ素子表面のＺｎＯ成
分がＸの酸化物と反応し、バリスタ素子表面に主成分が
Ｚｎ−Ｘ−Ｏ系の物質である高抵抗層が形成される。し
かし、バリスタ素子表面に設けられた電極とＸの酸化物
は反応しないので選択的に電極形成部分を除く、バリス
タ素子表面に、高抵抗層が形成され、前記電極上にメッ
キすることができる。前記高抵抗層は、酸、アルカリに
浸されないので、素子が酸、アルカリ溶液にエッチング
されるのを防ぎ、また、緻密で均一な厚みを有するの
で、メッキ流れや余分な水分などが浸入するのを防ぐこ
とができるので、耐湿性、耐メッキ性に優れたバリスタ
を得ることができる。With this structure, the ZnO component on the surface of the varistor element reacts with the oxide of X, and a high resistance layer whose main component is a Zn—X—O type substance is formed on the surface of the varistor element. However, since the electrode provided on the surface of the varistor element and the oxide of X do not react with each other, a high resistance layer is selectively formed on the surface of the varistor element except the electrode forming portion, and the electrode can be plated. Since the high resistance layer is not soaked in acid or alkali, it prevents the device from being etched by acid or alkali solution, and has a dense and uniform thickness, so that the plating flow or excess water can get in. Therefore, it is possible to obtain a varistor excellent in moisture resistance and plating resistance.
【０００７】さらに、積層型のバリスタの場合、外部電
極とバリスタ素子の間にも、高抵抗層が形成されるの
で、内部電極の遊端と、対向する外部電極の距離を短く
することができる。すなわち、内部電極の面積を大きく
することができるので、サージ耐量の大きなバリスタを
得ることができる。Further, in the case of a laminated varistor, since the high resistance layer is formed between the external electrode and the varistor element, the distance between the free end of the internal electrode and the opposing external electrode can be shortened. . That is, since the area of the internal electrodes can be increased, it is possible to obtain a varistor having a large surge resistance.
【０００８】なお外部電極のバリスタ素子側面に高抵抗
層が形成される理由は、現時点で明確になっていない
が、バリスタ素子の成分とＸの酸化物とが反応して液相
化し、界面から液相化した高抵抗成分が素子内に浸入す
るためであると思われる。The reason why the high resistance layer is formed on the side surface of the varistor element of the external electrode is not clear at this point, but the components of the varistor element react with the oxide of X to form a liquid phase, and from the interface. It is considered that this is because the liquid phase high resistance component penetrates into the element.
【０００９】[0009]
（実施例１）図１において、１はバリスタ素子で、その
内部にはＡｇ製の内部電極２が複数設けられている。こ
れらの内部電極２には、交互にバリスタ素子１の両端に
引き出され、その両端において、外部電極３と電気的に
接続されている。(Embodiment 1) In FIG. 1, reference numeral 1 is a varistor element, and a plurality of Ag internal electrodes 2 are provided therein. The internal electrodes 2 are alternately drawn out to both ends of the varistor element 1 and electrically connected to the external electrodes 3 at both ends thereof.
【００１０】また、内部電極２間、及びその外側に積層
されたセラミックシート１ａは、ＺｎＯを主成分とし、
副成分としてＢｉ2Ｏ3，Ｃｏ2Ｏ3，ＭｎＯ2，Ｓｂ
2Ｏ3，Ｂ2Ｏ3等を含んでいる。Further, the ceramic sheets 1a laminated between the internal electrodes 2 and on the outside thereof are mainly composed of ZnO,
Bi 2 O 3 , Co 2 O 3 , MnO 2 and Sb as auxiliary components
It contains 2 O 3 , B 2 O 3 and the like.
【００１１】図２は製造工程を示し、セラミックシート
１ａは図２において（５）で示すごとく原料の混合、粉
砕、スラリー化、シート成形により作製した。次にこの
セラミックシート１ａと、内部電極２とを積層（６）
し、それを切断（７）し、９３０℃で３０分間焼成
（８）後、シェーカーで１時間、バリスタ素子１の表面
の面取（９）をした。FIG. 2 shows the manufacturing process, and the ceramic sheet 1a was prepared by mixing the raw materials, pulverizing, slurrying, and sheet forming as shown by (5) in FIG. Next, the ceramic sheet 1a and the internal electrodes 2 are laminated (6).
Then, it was cut (7), baked at 930 ° C. for 30 minutes (8), and then the surface of the varistor element 1 was chamfered (9) with a shaker for 1 hour.
【００１２】次に、バリスタ素子１の両端面にＡｇ電極
ペーストを塗布（１０）し、６００℃〜９６０℃でＡｇ
電極焼付（１１）し、その後、図３に示すごとくＦｅ2
Ｏ3を主成分とする混合物１５にバリスタ素子１を埋没
させ、空気中あるいは酸素雰囲気中で６００℃〜９６０
℃で５分〜１０時間、焼成した（図２の１２）。Next, Ag electrode paste is applied (10) to both end faces of the varistor element 1, and Ag is applied at 600 ° C. to 960 ° C.
The electrode was baked (11) and then Fe 2 as shown in FIG.
The varistor element 1 is embedded in the mixture 15 containing O 3 as a main component, and the temperature is set to 600 ° C. to 960 in the air or the oxygen atmosphere.
It was baked at 5 ° C. for 5 minutes to 10 hours (12 in FIG. 2).
【００１３】この焼成により、バリスタ素子１の主成分
ＺｎＯと、Ｆｅ2Ｏ3が反応して、主にＺｎ−Ｆｅ−Ｏ系
の高抵抗層４ａが前記バリスタ素子１表面上に形成され
る。また、バリスタ素子１に副成分として、Ｂｉ2Ｏ3を
添加した場合、Ｂｉ2Ｏ3がＦｅ2Ｏ3と反応して、主にＺ
ｎ−Ｆｅ−Ｏ系の高抵抗層４ａと、この高抵抗層４ａの
上に、主にＢｉ−Ｆｅ−Ｏ系の高抵抗層４ｂとがバリス
タ素子１の表面上に形成される。By this firing, the main component ZnO of the varistor element 1 reacts with Fe 2 O 3 to form the Zn—Fe—O-based high resistance layer 4 a on the surface of the varistor element 1. Further, as a sub-component in the varistor element 1, the case of adding Bi 2 O 3, Bi 2 O 3 reacts with Fe 2 O 3, mostly Z
An n-Fe-O-based high resistance layer 4a and a Bi-Fe-O-based high resistance layer 4b, which is mainly a Bi-Fe-O-based high resistance layer 4a, are formed on the surface of the varistor element 1.
【００１４】また、バリスタ素子１の副成分としてＢ2
Ｏ3を添加した場合、Ｂ2Ｏ3がＦｅ2Ｏ3と反応して、主
にＺｎ−Ｆｅ−Ｏ系の高抵抗層４ａと、この上に、主に
Ｂ−Ｆｅ−Ｏ系の高抵抗層４ｂとがバリスタ素子１の表
面上に形成される。Further, B 2 is added as an auxiliary component of the varistor element 1.
When O 3 is added, B 2 O 3 reacts with Fe 2 O 3 to mainly form the Zn—Fe—O based high resistance layer 4a, and on top of this, mainly B—Fe—O based high resistance layer 4a. The resistance layer 4b is formed on the surface of the varistor element 1.
【００１５】さらに、バリスタ素子１に、副成分とし
て、Ｂｉ2Ｏ3とを添加した場合、Ｂｉ 2Ｏ3とＢ2Ｏ3とが
Ｆｅ2Ｏ3と反応して、主にＺｎ−Ｆｅ−Ｏ系の高抵抗層
４ａと、この上に、主にＢｉ−Ｆｅ−Ｏ系とＢ−Ｆｅ−
Ｏ系とからなる高抵抗層４ｂとがバリスタ素子１の表面
上に形成される。これら反応により生じた物質は、バリ
スタの特性への悪影響は生じず、バリスタとして極めて
特性の優れたものが得られる。ここで重要なことは、図
３に示すごとく個々のバリスタ素子１を全てＦｅ 2Ｏ3を
主成分とする混合物１５に埋没させておくことである。
そのために、まずアルミナのるつぼ１６の中に所定の厚
さでＦｅ2Ｏ3を主成分とする混合物１５を敷きつめ、そ
の上に、バリスタ素子１を隣接するものと接触しないよ
うに並べ、その状態でＦｅ2Ｏ3を主成分とする混合物１
５を充分に覆いかぶせた。この状態で焼成を行った後
に、バリスタ素子１表面と、外部電極３表面のＦｅ2Ｏ3
を主成分とする混合物１５を取り除いた。この除去は例
えば容器内にＳｉＣの玉石と純水とバリスタ素子１とを
入れて攪拌したり、エアーガンで複数のバリスタ素子１
を容器内で揺動させたりして行った。その後、外部電極
３表面に２Ａ，３０minで電解Ｎｉメッキ、その上に
０．６Ａ，３０minで半田メッキ（図２の１４）を行
い、バリスタを得た。Further, the varistor element 1 has a sub-component
Bi2O3When and are added, Bi 2O3And B2O3And
Fe2O3Zn--Fe--O-based high resistance layer
4a, and on top of this, mainly Bi-Fe-O system and B-Fe-
The high resistance layer 4b made of O-based material is the surface of the varistor element 1.
Formed on. The substances produced by these reactions are
As a varistor, it does not adversely affect the characteristics of the
A product with excellent characteristics can be obtained. The important thing here is the figure
As shown in 3, all individual varistor elements 1 are Fe 2O3To
It is to be buried in the mixture 15 containing the main component.
For that purpose, first, in an alumina crucible 16,
Then Fe2O3Spread the mixture 15 consisting mainly of
On top of it, do not touch the varistor element 1 with its neighbors.
Arranged in line and Fe in that state2O3Mixture 1 based on
Covered 5 well. After firing in this state
And Fe on the surface of the varistor element 1 and the surface of the external electrode 32O3
The mixture 15 containing as a main component was removed. This removal is an example
For example, put SiC boulders, pure water, and varistor element 1 in the container.
Put and stir, or use an air gun for multiple varistor elements 1
Was rocked in the container. Then the external electrode
Electrolytic Ni plating on 3 surface at 2A for 30min,
Solder plating (14 in Fig. 2) at 0.6A for 30 minutes
I got a barista.
【００１６】得られたバリスタの断面から、メッキの厚
みは、Ｎｉメッキが１．２μｍ、半田メッキは１．３μ
ｍであった。From the cross section of the obtained varistor, the plating thickness is 1.2 μm for Ni plating and 1.3 μ for solder plating.
It was m.
【００１７】また、耐メッキ性を調べ（表１）に示し
た。Also, the plating resistance was investigated and shown in Table 1.
【００１８】[0018]
【表１】 [Table 1]
【００１９】（表１）に示すように、高抵抗層４ａ，４
ｂを有していないバリスタ素子１にメッキを行うと、外
部電極３の形成部分以外のバリスタ素子１の表面積の１
００％がメッキされてしまう。As shown in (Table 1), the high resistance layers 4a, 4
When plating is applied to the varistor element 1 not having b, the surface area of the varistor element 1 other than the portion where the external electrode 3 is formed is 1
00% will be plated.
【００２０】また、従来のように、バリスタ素子１の表
面にガラスによる高抵抗層を形成したものは、７〜８％
メッキされた。しかし、本実施例によるものは、バリス
タ素子１の外部電極３の形成部分以外は全くメッキされ
なかった。Further, as in the conventional case, the high resistance layer made of glass is formed on the surface of the varistor element 1 to 7 to 8%.
Plated However, in the case of this example, no plating was applied to the varistor element 1 except for the portion where the external electrode 3 was formed.
【００２１】また、本発明のバリスタは、メッキ時も、
メッキ液による、バリスタ素子１の腐食が起きないの
で、優れた特性を有するものである。Further, the varistor of the present invention, even during plating,
Since the varistor element 1 is not corroded by the plating solution, it has excellent characteristics.
【００２２】なお、本実施例においてはＦｅ2Ｏ3のみを
用いたが、Ｆｅ，Ｓｂ，Ｔｉ，Ａｌの酸化物のうち少な
くとも一種類以上をどのような組合せで用いても同様の
効果が得られる。Although only Fe 2 O 3 is used in this embodiment, the same effect can be obtained by using at least one kind of oxides of Fe, Sb, Ti and Al in any combination. To be
【００２３】（実施例２）実施例１と同様にして、外部
電極３塗布（１０）後のバリスタ素子１を、図３に示す
ごとく、Ｆｅ2Ｏ3を主成分とする混合物１５に、埋没さ
せ、この状態で、６００〜９６０℃で５分〜１０時間焼
成した。その後、外部電極３上に、さらにＡｇ電極ペー
ストを塗布し、６００〜９６０℃で１０〜６０分間Ａｇ
電極焼付を行い、次にメッキ（１４）を行ってバリスタ
を得た。(Example 2) In the same manner as in Example 1, the varistor element 1 after the application (10) of the external electrode 3 was buried in a mixture 15 containing Fe 2 O 3 as a main component, as shown in FIG. Then, in this state, baking was performed at 600 to 960 ° C. for 5 minutes to 10 hours. Then, the Ag electrode paste is further applied onto the external electrode 3 and Ag is applied at 600 to 960 ° C. for 10 to 60 minutes.
Electrodes were baked and then plated (14) to obtain a varistor.
【００２４】また、実施例２においてＦｅ2Ｏ3を主成分
とする混合物１５にバリスタ素子１を埋没させて反応さ
せた後、外部電極３上についたＦｅ2Ｏ3の反応物は実施
例１と同様に除去してから、さらに外部電極３の上にＡ
ｇを塗布して焼付てもよい。Further, after the varistor element 1 was buried in the mixture 15 containing Fe 2 O 3 as a main component in Example 2 and reacted, the reaction product of Fe 2 O 3 on the external electrode 3 was obtained as in Example 1. After removing it in the same manner as above,
g may be applied and baked.
【００２５】実施例１と同様に、実施例２においても、
バリスタ素子１の主成分ＺｎＯとＦｅ2Ｏ3とが反応し
て、主にＺｎ−Ｆｅ−Ｏ系の高抵抗層４ａが前記バリス
タ素子１表面上に形成される。また、バリスタ素子１に
副成分として、Ｂｉ2Ｏ3を添加した場合、Ｂｉ2Ｏ3がＦ
ｅ2Ｏ3と反応して、主にＺｎ−Ｆｅ−Ｏ系の高抵抗層４
ａと、この高抵抗層４ａの上に、主にＢｉ−Ｆｅ−Ｏ系
の高抵抗層４ｂとがバリスタ素子１の表面上に形成され
る。Similar to the first embodiment, in the second embodiment as well,
The main component ZnO of the varistor element 1 reacts with Fe 2 O 3 to form a Zn—Fe—O-based high resistance layer 4 a on the surface of the varistor element 1. Further, when Bi 2 O 3 is added to the varistor element 1 as a sub ingredient, Bi 2 O 3 becomes F
reacts with e 2 O 3, mostly Zn-Fe-O-based high-resistance layer 4
a and a Bi-Fe-O-based high resistance layer 4b mainly on the high resistance layer 4a are formed on the surface of the varistor element 1.
【００２６】また、バリスタ素子１の副成分としてＢ2
Ｏ3を添加した場合、Ｂ2Ｏ3がＦｅ2Ｏ3と反応して、主
にＺｎ−Ｆｅ−Ｏ系の高抵抗層４ａと、この上に、主に
Ｂ−Ｆｅ−Ｏ系の高抵抗層４ｂとがバリスタ素子１の表
面上に形成される。Further, B 2 is added as an auxiliary component of the varistor element 1.
When O 3 is added, B 2 O 3 reacts with Fe 2 O 3 to mainly form the Zn—Fe—O based high resistance layer 4a, and on top of this, mainly B—Fe—O based high resistance layer 4a. The resistance layer 4b is formed on the surface of the varistor element 1.
【００２７】さらに、バリスタ素子１に、副成分とし
て、Ｂｉ2Ｏ3とＢ2Ｏ3を添加した場合、Ｂｉ2Ｏ3とＢ2
Ｏ3とがＦｅ2Ｏ3と反応して、主にＺｎ−Ｆｅ−Ｏ系の
高抵抗層４ａと、この上に、主にＢｉ−Ｆｅ−Ｏ系とＢ
ｉ−Ｆｅ−Ｏ系とからなる高抵抗層４ｂとがバリスタ素
子１の表面上に形成される。これら反応により生じた物
質は、バリスタの特性への悪影響は生じず、バリスタと
して、極めて優れた特性を有するものが得られる。Furthermore, the varistor element 1, if the secondary component, was added Bi 2 O 3 and B 2 O 3, Bi 2 O 3 and B 2
O 3 reacts with Fe 2 O 3 to form a Zn—Fe—O-based high resistance layer 4 a, and on top of this, a Bi—Fe—O-based high resistance layer 4 a.
A high resistance layer 4b made of i-Fe-O system is formed on the surface of the varistor element 1. The substances produced by these reactions do not adversely affect the characteristics of the varistor, and a varistor having extremely excellent characteristics can be obtained.
【００２８】なお、本実施例においても、Ｆｅ2Ｏ3のみ
の例を示したが、Ｆｅ2Ｏ3だけでなく、Ｆｅ，Ｔｉ，Ａ
ｌの酸化物を用いてもよいし、これらの中から少なくと
も一種類以上を、どのように組合せて用いたとしても同
様の効果が得られる。Although only Fe 2 O 3 is used in this embodiment, not only Fe 2 O 3 but also Fe, Ti and A are used.
The oxide of 1 may be used, and at least one kind of them may be used in any combination to obtain the same effect.
【００２９】（実施例３）実施例１と同様にして、面取
（９）後、図３に示すごとく、Ｆｅ2Ｏ3を主成分とする
混合物１５にバリスタ素子１を埋没させ、この状態で６
００℃〜９６０℃で５分〜１０時間、加熱する。加熱
後、外部電極３を塗布（１０）し、６００℃〜９６０
℃、１０〜６０分でＡｇ電極焼付、メッキ（１４）を行
う。(Example 3) In the same manner as in Example 1, after chamfering (9), as shown in FIG. 3, the varistor element 1 was immersed in a mixture 15 containing Fe 2 O 3 as a main component, and this state was set. In 6
Heat at 00 ° C to 960 ° C for 5 minutes to 10 hours. After heating, the external electrode 3 is applied (10), and 600 ° C to 960
Ag electrode baking and plating (14) are carried out at a temperature of 10 to 60 minutes.
【００３０】実施例１と同様に、実施例３においても、
バリスタ素子１の主成分ＺｎＯとＦｅ2Ｏ3とが反応し
て、主にＺｎ−Ｆｅ−Ｏ系の高抵抗層４ａが前記バリス
タ素子１表面上に形成される。また、バリスタ素子１に
副成分として、Ｂｉ2Ｏ3を添加した場合、Ｂｉ2Ｏ3がＦ
ｅ2Ｏ3と反応して、主にＺｎ−Ｆｅ−Ｏ系の高抵抗層４
ａと、この高抵抗層４ａの上に、主にＢｉ−Ｆｅ−Ｏ系
の高抵抗層４ｂとがバリスタ素子１の表面上に形成され
る。Similar to the first embodiment, in the third embodiment as well,
The main component ZnO of the varistor element 1 reacts with Fe 2 O 3 to form a Zn—Fe—O-based high resistance layer 4 a on the surface of the varistor element 1. Further, when Bi 2 O 3 is added to the varistor element 1 as a sub ingredient, Bi 2 O 3 becomes F
reacts with e 2 O 3, mostly Zn-Fe-O-based high-resistance layer 4
a and a Bi-Fe-O-based high resistance layer 4b mainly on the high resistance layer 4a are formed on the surface of the varistor element 1.
【００３１】また、バリスタ素子１の副成分としてＢ2
Ｏ3を添加した場合、Ｂ2Ｏ3がＦｅ2Ｏ3と反応して、主
にＺｎ−Ｆｅ−Ｏ系の高抵抗層４ａと、この上に、主に
Ｂ−Ｆｅ−Ｏ系の高抵抗層４ｂとがバリスタ素子１の表
面上に形成される。Further, B 2 is added as a sub ingredient of the varistor element 1.
When O 3 is added, B 2 O 3 reacts with Fe 2 O 3 to mainly form the Zn—Fe—O based high resistance layer 4a, and on top of this, mainly B—Fe—O based high resistance layer 4a. The resistance layer 4b is formed on the surface of the varistor element 1.
【００３２】さらに、バリスタ素子１に、副成分とし
て、Ｂｉ2Ｏ3とを添加した場合、Ｂｉ 2Ｏ3とＢ2Ｏ3とが
Ｆｅ2Ｏ3と反応して、主にＺｎ−Ｆｅ−Ｏ系の高抵抗層
４ａと、この上に、主にＢｉ−Ｆｅ−Ｏ系とＢ−Ｆｅ−
Ｏ系とからなる高抵抗層４ｂとがバリスタ素子１の表面
上に形成される。これら反応により生じた物質は、バリ
スタの特性への悪影響は生じず、バリスタとして、極め
て優れた特性を有するものが得られる。Further, the varistor element 1 has a sub-component
Bi2O3When and are added, Bi 2O3And B2O3And
Fe2O3Zn--Fe--O-based high resistance layer
4a, and on top of this, mainly Bi-Fe-O system and B-Fe-
The high resistance layer 4b made of O-based material is the surface of the varistor element 1.
Formed on. The substances produced by these reactions are
As a varistor, it does not adversely affect the characteristics of the
And excellent characteristics are obtained.
【００３３】なお、本実施例においても、Ｆｅ2Ｏ3のみ
の場合について示したが、Ｆｅ，Ｓｂ，Ｔｉ，Ａｌの酸
化物のうちの少なくとも一種類以上を、どのような組合
せで用いたとしても同様の効果が得られる。In the present embodiment, the case of only Fe 2 O 3 was shown, but it is assumed that at least one kind of oxides of Fe, Sb, Ti and Al is used in any combination. Also has the same effect.
【００３４】（実施例４）実施例１と同様にして、セラ
ミック素子１を得た後、Ｆｅの有機化合物を含む液体
に、セラミック素子１を浸漬させ、その後、空気中ある
いは酸素雰囲気中で、６００〜９６０℃で５分〜１０時
間焼成して高抵抗層４ａ，４ｂを形成した。このように
バリスタ素子１を上記液体に浸漬することにより、この
液体が、バリスタ素子の表面に入り込み、接触面積が広
くなり、反応性が良くなると共に均一な厚さの膜が得ら
れる。(Example 4) After obtaining the ceramic element 1 in the same manner as in Example 1, the ceramic element 1 is immersed in a liquid containing an organic compound of Fe, and then, in air or in an oxygen atmosphere. The high resistance layers 4a and 4b were formed by firing at 600 to 960 ° C. for 5 minutes to 10 hours. By immersing the varistor element 1 in the liquid as described above, the liquid enters the surface of the varistor element, the contact area is increased, the reactivity is improved, and a film having a uniform thickness is obtained.
【００３５】本実施例においても、実施例１と同様にバ
リスタ素子１の主成分ＺｎＯとＦｅ 2Ｏ3が反応して、主
にＺｎ−Ｆｅ−Ｏ系の高抵抗層４ａが前記バリスタ素子
１表面上に形成される。また、バリスタ素子１に副成分
として、Ｂｉ2Ｏ3を添加した場合、Ｂｉ2Ｏ3がＦｅ2Ｏ3
と反応して、主にＺｎ−Ｆｅ−Ｏ系の高抵抗層４ａと、
この高抵抗層４ａの上に、主にＢｉ−Ｆｅ−Ｏ系の高抵
抗層４ｂとがバリスタ素子１の表面上に形成される。Also in this embodiment, as in the first embodiment,
Main components of Lister element 1 ZnO and Fe 2O3Reacts, Lord
The Zn-Fe-O-based high resistance layer 4a is formed on the varistor element.
1 is formed on the surface. In addition, the varistor element 1 has a sub-component
As Bi2O3When added, Bi2O3Is Fe2O3
To react mainly with the Zn—Fe—O-based high resistance layer 4a,
On this high resistance layer 4a, a Bi--Fe--O-based high resistance layer is mainly formed.
The anti-layer 4b is formed on the surface of the varistor element 1.
【００３６】また、バリスタ素子１の副成分としてＢ2
Ｏ3を添加した場合、Ｂ2Ｏ3がＦｅ2Ｏ3と反応して、主
にＺｎ−Ｆｅ−Ｏ系の高抵抗層４ａと、この上に、主に
Ｂ−Ｆｅ−Ｏ系の高抵抗層４ｂとがバリスタ素子１の表
面上に形成される。Further, B 2 is added as a sub ingredient of the varistor element 1.
When O 3 is added, B 2 O 3 reacts with Fe 2 O 3 to mainly form the Zn—Fe—O based high resistance layer 4a, and on top of this, mainly B—Fe—O based high resistance layer 4a. The resistance layer 4b is formed on the surface of the varistor element 1.
【００３７】さらに、バリスタ素子１に、副成分とし
て、Ｂｉ2Ｏ3とＢ2Ｏ3とを添加した場合、Ｂｉ2Ｏ3とＢ
2Ｏ3とがＦｅ2Ｏ3と反応して、主にＺｎ−Ｆｅ−Ｏ系の
高抵抗層４ａと、この上に、主にＢｉ−Ｆｅ−Ｏ系とＢ
−Ｆｅ−Ｏ系とからなる高抵抗層４ｂとがバリスタ素子
１の表面上に形成される。これら反応により生じた物質
は、バリスタの特性への悪影響は生じず、バリスタとし
て、極めて優れた特性を有するものが得られる。Furthermore, the varistor element 1, as a sub-component, in the case of adding and Bi 2 O 3 and B 2 O 3, Bi 2 O 3 and B
2 O 3 reacts with Fe 2 O 3 to form a Zn-Fe-O-based high resistance layer 4a, and on top of this, a Bi-Fe-O-based high resistance layer 4a.
A high resistance layer 4 b made of —Fe—O system is formed on the surface of the varistor element 1. The substances produced by these reactions do not adversely affect the characteristics of the varistor, and a varistor having extremely excellent characteristics can be obtained.
【００３８】また、本実施例においても、Ｆｅ2Ｏ3のみ
の場合を示したが、Ｆｅ，Ｓｂ，Ｔｉ，Ａｌの酸化物の
うち少なくとも一種類以上をどのような組合せで用いた
としても、同様の効果を得ることができる。Also, in the present embodiment, the case of only Fe 2 O 3 is shown, but even if any combination of at least one kind of oxides of Fe, Sb, Ti and Al is used, The same effect can be obtained.
【００３９】なお実施例１〜４においてＦｅ，Ｓｂ，Ｔ
ｉ，Ａｌの酸化物のうち少なくとも一種類を主成分とす
る混合物１５にバリスタ素子１を埋没させる場合、図４
のように埋め込むだけでも高抵抗層は形成されるが、反
応性を考えた場合、図３のようにアルミナのるつぼ１６
中で反応させ、さらにおもしなどをして、圧力をかけて
Ｆｅ，Ｓｂ，Ｔｉ，Ａｌの酸化物のうち少なくとも一種
類を主成分とする混合物１５とバリスタ素子１との密着
性を上げた方がよい。また、ニッケル製あるいは磁器製
等のバリスタ素子１と反応しない材料でできた容器内に
ニッケルあるいはジルコニア等のバリスタ素子１と反応
しない玉石と、バリスタ素子１とＦｅ，Ｓｂ，Ｔｉ，Ａ
ｌの酸化物のうち少なくとも一種類を主成分とする混合
物１５とを入れ、回転させながら攪拌して反応を行う
と、より均一に反応させることができると思われる。In Examples 1 to 4, Fe, Sb, T
When the varistor element 1 is immersed in the mixture 15 containing at least one of i and Al oxides as a main component,
Although the high resistance layer is formed only by burying as shown in Fig. 3, considering the reactivity, the alumina crucible 16 as shown in Fig. 3 is formed.
The mixture was reacted in the atmosphere, and then a weight was applied to apply pressure to improve the adhesion between the varistor element 1 and the mixture 15 containing at least one of Fe, Sb, Ti, and Al oxides as a main component. Better. Further, in a container made of a material which does not react with the varistor element 1 such as nickel or porcelain, cobblestone which does not react with the varistor element 1 such as nickel or zirconia, and varistor element 1 and Fe, Sb, Ti, A
It is considered that a more uniform reaction can be achieved by adding the mixture 15 containing at least one of the oxides of 1 as the main component and stirring and rotating the mixture to carry out the reaction.
【００４０】また、液体に浸漬したバリスタ素子１を実
施例１〜３と同様に、混合物１５に埋没させて、高抵抗
層４ａ，４ｂを形成するとさらに均一な厚さを有する緻
密なものが形成できる。Further, by immersing the varistor element 1 immersed in a liquid in the mixture 15 to form the high resistance layers 4a and 4b as in the first to third embodiments, a dense element having a more uniform thickness is formed. it can.
【００４１】さらに、玉石は、バリスタ素子１よりも小
さいものを用いることが好ましい。また混合物１５はＦ
ｅ，Ｓｂ，Ｔｉ，Ａｌの酸化物のうち少なくとも一種類
を主成分とする粉体であるが、バリスタ素子１との反応
性を良くするために、粒径を２μｍ以下にすることが望
ましい。そして、混合物１５に用いる粉体として、マン
ガン、ジルコニア等の酸化物が望ましい。Further, it is preferable to use the boulders smaller than the varistor element 1. Also, the mixture 15 is F
Although it is a powder containing at least one of e, Sb, Ti, and Al oxides as a main component, in order to improve the reactivity with the varistor element 1, it is desirable that the particle size be 2 μm or less. As the powder used in the mixture 15, oxides such as manganese and zirconia are desirable.
【００４２】本実験は内部電極、外部電極にＡｇを用い
たため、９６０℃以下での焼成という制約をうけたが、
Ａｇを用いていなければ６００〜１３００℃で焼成、高
抵抗層形成を行ってもよい。In this experiment, since Ag was used for the internal electrode and the external electrode, there was a restriction of firing at 960 ° C. or lower.
If Ag is not used, the high resistance layer may be formed by firing at 600 to 1300 ° C.
【００４３】そして昇温を一気に行うことにより、バリ
スタ素子１の成分が蒸発して、ポアになるのを防ぐこと
ができる。これに対して降温は、特に５００〜８００℃
の間は、５０℃／ｈで降温させることが望ましい。これ
により、バリスタ素子１の内部に酸素が十分に供給さ
れ、低電流領域でのバリスタ特性が向上する。By raising the temperature all at once, it is possible to prevent the components of the varistor element 1 from evaporating and becoming pores. On the other hand, the temperature decrease is especially 500 to 800 ° C.
During this period, it is desirable to lower the temperature at 50 ° C./h. As a result, oxygen is sufficiently supplied to the inside of the varistor element 1, and the varistor characteristics in the low current region are improved.
【００４４】また、本発明のバリスタと従来のバリスタ
の湿中負荷試験を行い、その結果を図５に示した。Further, the varistor of the present invention and the conventional varistor were subjected to a wet and medium load test, and the results are shown in FIG.
【００４５】図５を見るとわかるように、従来のバリス
タは１００時間を過ぎるとAs can be seen from FIG. 5, the conventional varistor has a time of 100 hours.
【００４６】[0046]
【外１】 [Outside 1]
【００４７】が大きく変化するが、本発明のバリスタ
は、ほとんど変化していない。このように、本発明のバ
リスタは従来のものと比較すると非常に耐湿性に優れて
いることがわかる。Is greatly changed, but the varistor of the present invention is hardly changed. Thus, it can be seen that the varistor of the present invention is extremely excellent in moisture resistance as compared with the conventional one.
【００４８】また、（表２）に、サージ耐量に対する必
要な無効層厚みを示している。Further, (Table 2) shows the necessary ineffective layer thickness with respect to the surge resistance.
【００４９】[0049]
【表２】 [Table 2]
【００５０】（表２）によると、従来のバリスタは、も
れ電流を防ぐため、サージ耐量が５００Ａのバリスタで
は、無効層の厚みを有効層一層の厚みの２倍に、また２
００Ａのバリスタでは、無効層の厚みを有効層一層の厚
みと同じに最低限しなければならなかった。しかし、本
発明のバリスタは、サージ耐量が１０００Ａのバリスタ
でも、無効層の厚みを有効層一層の厚みの０．２倍にし
ても、外部電極３とバリスタ素子１の間に高抵抗層４
ａ，４ｂが介在しているので、もれ電流を防ぐことがで
きる。According to (Table 2), in the conventional varistor, in order to prevent leakage current, in the varistor having a surge withstand capacity of 500 A, the thickness of the ineffective layer is set to twice the thickness of the effective layer,
In the 00A varistor, the thickness of the ineffective layer had to be the same as the thickness of the effective layer. However, the varistor of the present invention has a high resistance layer 4 between the external electrode 3 and the varistor element 1 even if the varistor having a surge resistance of 1000 A is used, even if the thickness of the ineffective layer is 0.2 times the thickness of the effective layer.
Since a and 4b are interposed, the leakage current can be prevented.
【００５１】さらに、図１に示した積層型のバリスタの
場合、外部電極３とバリスタ素子１の間にも、高抵抗層
３ａが形成されるので、内部電極２の遊端２ａと、対向
する外部電極３の距離を短くすることができる。すなわ
ち、内部電極２の面積を大きくすることができるので、
サージ耐量の大きなバリスタを得ることができる。Further, in the case of the laminated type varistor shown in FIG. 1, since the high resistance layer 3a is formed between the external electrode 3 and the varistor element 1, it faces the free end 2a of the internal electrode 2. The distance between the external electrodes 3 can be shortened. That is, since the area of the internal electrode 2 can be increased,
A varistor with a large surge resistance can be obtained.
【００５２】なお外部電極３の内面側にも高抵抗層３ａ
が形成される理由は現時点で十分判明していないが、バ
リスタ素子の成分とＦｅ，Ｓｂ，Ｔｉ，Ａｌの酸化物の
うち少なくとも一種類とが、反応して液相化し、界面か
ら液相化した高抵抗成分が素子内に浸入するためである
と思われる。The high resistance layer 3a is formed on the inner surface of the external electrode 3 as well.
Although the reason for the formation of Al is not clear at this point, the components of the varistor element and at least one of the oxides of Fe, Sb, Ti, and Al react to form a liquid phase, and form a liquid phase from the interface. It is considered that this is because the high resistance component that has penetrated into the device penetrates.
【００５３】[0053]
【発明の効果】以上のように、本発明はバリスタ素子表
面の電極に覆われていない部分に、主成分がＺｎ−Ｘ−
Ｏ系（Ｘ＝Ｆｅ，Ｓｂ，Ｔｉ，Ａｌのうち少なくとも一
種類以上）である高抵抗層を形成するものである。As described above, according to the present invention, the main component is Zn--X-- in the portion of the surface of the varistor element which is not covered with the electrodes.
A high resistance layer of O type (at least one of X = Fe, Sb, Ti, and Al) is formed.
【００５４】この高抵抗層は、緻密で均一な厚さを有す
るので不要な水分などがバリスタ素子内に浸入して、バ
リスタ特性を劣化させることがない。また、メッキ時
も、メッキ流れを起こしショート不良が発生するのを防
ぐことができる。さらに、無効層の厚みを従来よりも薄
くすることができるので、小型化を図ることができる。
このように、本発明の高抵抗層は耐薬品性、耐湿性に優
れているので、優れた特性を有するバリスタを得ること
ができる。Since this high resistance layer is dense and has a uniform thickness, unnecessary moisture or the like does not enter the varistor element and does not deteriorate the varistor characteristics. Also, during plating, it is possible to prevent a flow of plating and a short circuit from occurring. Furthermore, since the thickness of the ineffective layer can be made thinner than before, the size can be reduced.
As described above, since the high resistance layer of the present invention has excellent chemical resistance and moisture resistance, it is possible to obtain a varistor having excellent characteristics.
【００５５】さらに、積層型のバリスタの場合、外部電
極とバリスタ素子の間にも、高抵抗層が形成されるの
で、内部電極の遊端と、対向する外部電極の距離を短く
することができる。すなわち、内部電極の面積を大きく
することができるので、サージ耐量の大きなバリスタを
得ることができる。Further, in the case of the laminated varistor, since the high resistance layer is formed between the external electrode and the varistor element, the distance between the free end of the internal electrode and the opposing external electrode can be shortened. . That is, since the area of the internal electrodes can be increased, it is possible to obtain a varistor having a large surge resistance.
【図１】本発明の一実施例におけるバリスタの断面図FIG. 1 is a sectional view of a varistor according to an embodiment of the present invention.
【図２】本発明の一実施例におけるバリスタの製造工程
図FIG. 2 is a manufacturing process diagram of a varistor according to an embodiment of the present invention.
【図３】本発明の一実施例における焼成工程の説明図FIG. 3 is an explanatory diagram of a firing process in an example of the present invention.
【図４】本発明の一実施例における焼成工程の説明図FIG. 4 is an explanatory diagram of a firing process in an example of the present invention.
【図５】本発明の一実施例におけるバリスタの耐湿性を
示す特性曲線図FIG. 5 is a characteristic curve diagram showing the humidity resistance of the varistor in one embodiment of the present invention.
１ バリスタ素子 ２ 内部電極 ２ａ 遊端 ３ 外部電極 ３ａ 高抵抗層 ４ａ 高抵抗層 ４ｂ 高抵抗層 1 Varistor Element 2 Internal Electrode 2a Free End 3 External Electrode 3a High Resistance Layer 4a High Resistance Layer 4b High Resistance Layer
Claims (9)
前記バリスタ素子の表面に設けた電極と、前記バリスタ
素子表面の少なくとも前記電極に覆われていない部分に
設けた高抵抗層とを備え、前記高抵抗層はＺｎ−Ｘ−Ｏ
系（Ｘ＝Ｆｅ，Ｓｂ，Ｔｉ，Ａｌのうち少なくとも一種
類）の物質を主成分とするバリスタ。1. A varistor element containing ZnO as a main component,
An electrode provided on the surface of the varistor element and a high resistance layer provided on at least a portion of the varistor element surface not covered by the electrode, the high resistance layer being Zn—X—O.
A varistor whose main component is a material of the system (X = Fe, Sb, Ti, or at least one of Al).
面に設けた電極と、前記バリスタ素子表面の少なくとも
前記電極に覆われていない部分に設けた第１の高抵抗層
と、前記第１の高抵抗層の上に設けた第２の高抵抗層と
を備え、前記バリスタ素子はＺｎＯを主成分とし、副成
分として少なくともＢｉを含有し、前記第１の高抵抗層
はＺｎ−Ｘ−Ｏ系（Ｘ＝Ｆｅ，Ｓｂ，Ｔｉ，Ａｌのうち
少なくとも一種類）の物質を主成分とし、前記第２の高
抵抗層はＢｉ−Ｘ−Ｏ系の物質を主成分とするバリス
タ。2. A varistor element, an electrode provided on the surface of the varistor element, a first high resistance layer provided on at least a portion of the varistor element surface not covered with the electrode, and the first high resistance layer. A second high resistance layer provided on the resistance layer, wherein the varistor element contains ZnO as a main component and at least Bi as a sub-component, and the first high resistance layer is a Zn—X—O system. A varistor containing a substance of (at least one of X = Fe, Sb, Ti, and Al) as a main component, and the second high resistance layer having a Bi—X—O-based substance as a main component.
面に設けた電極と、前記バリスタ素子表面の少なくとも
前記電極に覆われていない部分に設けた第１の高抵抗層
と、前記第１の高抵抗層の上に設けた第２の高抵抗層と
を備え、前記バリスタ素子はＺｎＯを主成分とし、副成
分として少なくともＢを含有し、前記第１の高抵抗層は
Ｚｎ−Ｘ−Ｏ系（Ｘ＝Ｆｅ，Ｓｂ，Ｔｉ，Ａｌのうち少
なくとも一種類）の物質を主成分とし、前記第２の高抵
抗層はＢ−Ｘ−Ｏ系の物質を主成分とするバリスタ。3. A varistor element, an electrode provided on the surface of the varistor element, a first high resistance layer provided on at least a portion of the surface of the varistor element that is not covered by the electrode, and the first high resistance layer. A second high resistance layer provided on the resistance layer, wherein the varistor element contains ZnO as a main component and at least B as a sub-component, and the first high resistance layer is a Zn—X—O system. A varistor whose main component is a substance (at least one of X = Fe, Sb, Ti, and Al), and the second high resistance layer is a main component of a B—X—O type substance.
面に設けた電極と、前記バリスタ素子表面の少なくとも
前記電極に覆われていない部分に設けた第１の高抵抗層
と、前記第１の高抵抗層の上に設けた第２の高抵抗層と
を備え、前記バリスタ素子はＺｎＯを主成分とし、副成
分として少なくともＢｉ，Ｂを含有し、前記第１の高抵
抗層はＺｎ−Ｘ−Ｏ系（Ｘ＝Ｆｅ，Ｓｂ，Ｔｉ，Ａｌの
うち少なくとも一種類）の物質を主成分とし、前記第２
の高抵抗層はＢｉ−Ｘ−Ｏ系の物質と、Ｂ−Ｘ−Ｏ系の
物質とを主成分とするバリスタ。4. A varistor element, an electrode provided on the surface of the varistor element, a first high resistance layer provided on at least a portion of the surface of the varistor element not covered by the electrode, and the first high resistance layer. A second high resistance layer provided on the resistance layer, wherein the varistor element contains ZnO as a main component and at least Bi and B as sub-components, and the first high resistance layer is Zn-X-. The O-based (X = at least one of Fe, Sb, Ti, and Al) substance as a main component, and the second
The high resistance layer is a varistor whose main component is a Bi-X-O type substance and a B-X-O type substance.
部に設けた内部電極と、前記バリスタ素子の両端面に、
前記内部電極と電気的に接続するように設けた外部電極
と、前記バリスタ素子表面の少なくとも前記電極で覆わ
れていない部分に設けたＺｎ−Ｘ−Ｏ系（Ｘ＝Ｆｅ，Ｓ
ｂ，Ｔｉ，Ａｌのうち少なくとも一種類）の高抵抗層と
を備え、前記内部電極の遊端に対向する前記外部電極の
前記バリスタ素子側面に高抵抗層を設けたバリスタ。5. A varistor element, an internal electrode provided inside the varistor element, and both end faces of the varistor element,
An external electrode provided so as to be electrically connected to the internal electrode, and a Zn—X—O system (X = Fe, S provided on at least a portion of the surface of the varistor element which is not covered with the electrode.
a high resistance layer of at least one of b, Ti, and Al), and a high resistance layer is provided on the side surface of the varistor element of the external electrode facing the free end of the internal electrode.
バリスタ素子を得、次に前記バリスタ素子表面に電極を
形成し、次に前記バリスタ素子の表面にＸの酸化物（Ｘ
＝Ｆｅ，Ｓｂ，Ｔｉ，Ａｌのうち少なくとも一種類）を
主成分とする混合物を配して焼成し、前記バリスタ素子
の表面に高抵抗層を形成するバリスタの製造方法。6. A raw material containing ZnO as a main component is molded to obtain a varistor element, an electrode is formed on the surface of the varistor element, and then an oxide of X (X) is formed on the surface of the varistor element.
= At least one of Fe, Sb, Ti, and Al) is disposed and fired to form a high resistance layer on the surface of the varistor element.
バリスタ素子を得、次に前記バリスタ素子の表面に第１
の電極を形成し、次に前記バリスタ素子の表面にＸの酸
化物（Ｘ＝Ｆｅ，Ｓｂ，Ｔｉ，Ａｌのうち少なくとも一
種類）を主成分とする混合物を配して焼成し、前記バリ
スタ素子表面に高抵抗層を形成後、前記第１の電極上に
第２の電極を形成するバリスタの製造方法。7. A varistor element is obtained by molding a raw material containing ZnO as a main component, and then a first varistor element is formed on the surface of the varistor element.
Electrode is formed, and then a mixture containing an oxide of X (at least one of X = Fe, Sb, Ti, and Al) as a main component is arranged on the surface of the varistor element, and the mixture is fired. A method of manufacturing a varistor, comprising forming a second electrode on the first electrode after forming a high resistance layer on the surface.
バリスタ素子を得、次に前記バリスタ素子の表面にＸの
酸化物（Ｘ＝Ｆｅ，Ｓｂ，Ｔｉ，Ａｌのうち一種類）を
主成分とする混合物を配して焼成して前記素子表面に高
抵抗層を形成し、次に前記バリスタ素子の表面に電極を
形成するバリスタの製造方法。8. A varistor element is obtained by molding a raw material containing ZnO as a main component, and an oxide of X (X = Fe, Sb, Ti, or Al) is mainly formed on the surface of the varistor element. A method of manufacturing a varistor, which comprises arranging and firing a mixture of components to form a high resistance layer on the surface of the element, and then forming an electrode on the surface of the varistor element.
バリスタ素子を得、次に前記バリスタ素子を、Ｘ（Ｘ＝
Ｆｅ，Ｓｂ，Ｔｉ，Ａｌの有機金属化合物のうち少なく
とも一種類）を含む液体に浸漬し、その後、前記バリス
タ素子を焼成して、前記バリスタ素子の表面に高抵抗層
を形成するバリスタの製造方法。9. A varistor element is obtained by molding a raw material containing ZnO as a main component.
A method of manufacturing a varistor in which a high resistance layer is formed on the surface of the varistor element by immersing the varistor element in a liquid containing at least one of organometallic compounds of Fe, Sb, Ti, and Al, and then firing the varistor element. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26523794A JP3396973B2 (en) | 1994-10-28 | 1994-10-28 | Manufacturing method of multilayer varistor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26523794A JP3396973B2 (en) | 1994-10-28 | 1994-10-28 | Manufacturing method of multilayer varistor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08124720A true JPH08124720A (en) | 1996-05-17 |
| JP3396973B2 JP3396973B2 (en) | 2003-04-14 |
Family
ID=17414433
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26523794A Expired - Fee Related JP3396973B2 (en) | 1994-10-28 | 1994-10-28 | Manufacturing method of multilayer varistor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3396973B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1288971A1 (en) * | 2001-08-29 | 2003-03-05 | Matsushita Electric Industrial Co., Ltd. | Zinc oxide varistor and method of manufacturing same |
| US6749891B2 (en) | 2001-08-30 | 2004-06-15 | Matsushita Electric Industrial Co., Ltd. | Zinc oxide varistor and method of manufacturing same |
| JP2005294670A (en) * | 2004-04-02 | 2005-10-20 | Murata Mfg Co Ltd | Laminated positive characteristic thermistor |
-
1994
- 1994-10-28 JP JP26523794A patent/JP3396973B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1288971A1 (en) * | 2001-08-29 | 2003-03-05 | Matsushita Electric Industrial Co., Ltd. | Zinc oxide varistor and method of manufacturing same |
| US6749891B2 (en) | 2001-08-30 | 2004-06-15 | Matsushita Electric Industrial Co., Ltd. | Zinc oxide varistor and method of manufacturing same |
| JP2005294670A (en) * | 2004-04-02 | 2005-10-20 | Murata Mfg Co Ltd | Laminated positive characteristic thermistor |
| JP4492187B2 (en) * | 2004-04-02 | 2010-06-30 | 株式会社村田製作所 | Multilayer positive temperature coefficient thermistor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3396973B2 (en) | 2003-04-14 |
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