JPH0773082B2 - Method for producing zinc oxide varistor - Google Patents
Method for producing zinc oxide varistorInfo
- Publication number
- JPH0773082B2 JPH0773082B2 JP61289208A JP28920886A JPH0773082B2 JP H0773082 B2 JPH0773082 B2 JP H0773082B2 JP 61289208 A JP61289208 A JP 61289208A JP 28920886 A JP28920886 A JP 28920886A JP H0773082 B2 JPH0773082 B2 JP H0773082B2
- Authority
- JP
- Japan
- Prior art keywords
- zinc oxide
- silicon
- slurry
- varistor
- oxide
- 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
Links
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Apparatuses And Processes For Manufacturing Resistors (AREA)
- Thermistors And Varistors (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は酸化亜鉛を主成分とする酸化亜鉛形バリスタの
製造方法に関するものである。Description: TECHNICAL FIELD The present invention relates to a method for producing a zinc oxide varistor containing zinc oxide as a main component.
従来の技術 酸化亜鉛形バリスタ素子は、大きなサージ電流耐量と優
れた電圧非直線性を持ち、低圧タイプの素子はサージア
ブソーバとして、高圧タイプの素子はギャップレスアレ
スタ素子として広く利用されている。2. Description of the Related Art Zinc oxide varistor elements have a large surge current withstanding capability and excellent voltage nonlinearity, and low-voltage type elements are widely used as surge absorbers, and high-voltage type elements are widely used as gapless arrester elements.
従来、酸化亜鉛形バリスタ素子は主成分の酸化亜鉛(Zn
O)に酸化ビスマス(Bi2O3),酸化アンチモン(Sb
2O3),酸化コバルト(Co2O3),酸化マンガン(Mn
O2),酸化珪素(SiO2)などを添加し、適当なバインダ
ーを加え、ボールミルなどで湿式粉砕ののち、造粒,成
形,焼結工程を経て製造されている。アレスタ用の酸化
亜鉛形バリスタを製造する場合、一般に単位厚み当りの
バリスタ電圧(V1mA/mm)が200V以上の材料が、素子の
小形化,低価格化のために必要である。前記添加物の中
で特に酸化珪素(SiO2)は、酸化亜鉛の粒成長を抑制
し、合わせて温度特性,課電寿命特性を向上させる物質
として知られ、高圧タイプのアレスタ素子用の材料には
不可欠の成分となっている。X線マイクロアナライザ
ー,X線回折による分析の結果、酸化珪素は焼結体中にお
いて、酸化アンチモンと同様に酸化亜鉛グレイン間の三
重点付近に偏析し、珪酸亜鉛(Zn2SiO4)として存在し
ている事が確認された。Conventionally, zinc oxide type varistor elements are mainly composed of zinc oxide (Zn
O) to bismuth oxide (Bi 2 O 3 ) and antimony oxide (Sb
2 O 3 ), cobalt oxide (Co 2 O 3 ), manganese oxide (Mn
O 2 ), silicon oxide (SiO 2 ), etc. are added, an appropriate binder is added, and wet pulverization is performed with a ball mill or the like, followed by granulation, molding and sintering processes. When manufacturing a zinc oxide varistor for an arrester, generally, a material with a varistor voltage per unit thickness (V 1mA / mm) of 200V or more is required for downsizing and cost reduction of the element. Among the above additives, silicon oxide (SiO 2 ) is known as a substance that suppresses the grain growth of zinc oxide, and also improves the temperature characteristics and the voltage life characteristics, and is a material for high pressure type arrester elements. Is an essential ingredient. As a result of analysis by X-ray microanalyzer and X-ray diffraction, silicon oxide was segregated in the vicinity of triple points between zinc oxide grains in the sintered body in the same manner as antimony oxide, and was present as zinc silicate (Zn 2 SiO 4 ). Was confirmed.
発明が解決しようとする問題点 しかしながら酸化亜鉛形バリスタの出発原料に酸化珪素
(SiO2)を用いた場合、他の添加物に比べ嵩比重が著し
く軽く、沈降性の材料を用いても充分粉砕されず、この
結果、焼結体中にボイドが発生し、酸化亜鉛形バリスタ
の最も重要な特性の一つであるサージ耐量(2ms)の矩
形波電流印加試験が低いという問題点を有していた。ま
た、材料の高圧化を図るため酸化珪素(SiO2)を1モル
%以上添加すると、粉砕した原料スラリーの粘度が著し
く増加し、造粒が困難になる問題点も同時に有してい
た。Problems to be Solved by the Invention However, when silicon oxide (SiO 2 ) is used as a starting material for a zinc oxide type varistor, its bulk specific gravity is significantly lighter than other additives, and even if a sedimentable material is used, it is sufficiently crushed. As a result, voids are generated in the sintered body, and there is a problem that the rectangular wave current application test of surge withstand (2 ms), which is one of the most important characteristics of zinc oxide varistor, is low. It was In addition, when silicon oxide (SiO 2 ) is added in an amount of 1 mol% or more in order to increase the pressure of the material, the viscosity of the pulverized raw material slurry remarkably increases, making it difficult to granulate.
本発明は、このような従来の問題点を解決するもので、
酸化亜鉛形バリスタの高性能化、特にサージ耐量の大幅
な向上を主目的とし、合わせてスラリーのゲル化のない
酸化亜鉛形バリスタの製造方法の提供を目的とするもの
である。The present invention solves such conventional problems,
The main purpose of the present invention is to improve the performance of a zinc oxide varistor, in particular, to greatly improve the surge withstand capability, and also to provide a method for producing a zinc oxide varistor without gelling of a slurry.
問題点を解決するための手段 この目的を達成するために、本発明は酸化亜鉛を主成分
とし、副成分として少なくとも1.0〜10モル%の粉末状
珪素を添加した原料粉末に水とバインダーを添加、粉砕
してスラリーを得る工程と、このスラリーをスプレード
ライヤーにて乾燥・造粒して造粒粉を得る工程と、この
造粒粉を成形して空気中で焼成する工程とを備えたもの
である。Means for Solving the Problems In order to achieve this object, the present invention adds water and a binder to a raw material powder containing zinc oxide as a main component and at least 1.0 to 10 mol% of powdered silicon as an accessory component. A step of pulverizing to obtain a slurry, a step of drying and granulating the slurry with a spray dryer to obtain a granulated powder, and a step of molding the granulated powder and firing in air Is.
作用 上記方法によると、粉末珪素を用いているためスラリー
のゲル化を防止し、スプレードライヤーによる造粒が可
能となるため、大量の原料処理ができ安定して量産が可
能となる。Action According to the above method, since powdered silicon is used, gelation of the slurry can be prevented and granulation can be performed by a spray dryer, so that a large amount of raw material can be processed and stable mass production can be performed.
また、粉砕工程において、珪素の粉砕が速やかにかつ均
一に進むため、焼結体内部の欠陥(ボイドなど)が発生
しにくくなり、極めて高いサージ耐量を有し、特性バラ
ツキの少ない酸化亜鉛形バリスタを得ることができる。Further, in the crushing process, since the crushing of silicon proceeds rapidly and uniformly, defects (voids etc.) inside the sintered body are less likely to occur, the surge resistance is extremely high, and the zinc oxide type varistor with few characteristic variations. Can be obtained.
実施例 以下、本発明の製造方法およびそれにより得られた酸化
亜鉛形バリスタについて実施例に基づき詳細に説明す
る。Examples Hereinafter, the manufacturing method of the present invention and the zinc oxide type varistor obtained thereby will be described in detail based on Examples.
まず、酸化亜鉛の粉末に、合計量に対し酸化ビスマス0.
5モル%,酸化アンチモン1.0モル%,酸化コバルト0.5
モル%,酸化マンガン0.5モル%に0.5〜20.0モル%の粉
末状珪素を加えた原料粉末に、固形分比率が約60重量%
となるよう純水を加え、バインダーとしてPVA(ポリビ
ニルアルコール)を固形分に対し0.5重量%添加し、全
体をジルコニア玉石とともにボールミルに入れ、30時間
粉砕しスラリーを得た。このスラリーをスプレードライ
ヤーにて乾燥,造粒して原料粉を作成した。原料粉は直
径40mm,厚さ30mmの大きさに圧縮成形し、空気中におい
て1200℃で焼結させた。このようにして得られた焼結体
の両端面を研磨し、アルミニウムの溶射電極を形成し
た。スラリーの粘度は回転粘度計にて測定した。また比
較のため、出発原料に酸化珪素を用いた系も同様に製造
工程により作成した。図にスラリー粘度の時間変化を示
す。出発原料として1モル%の酸化珪素を用いた場合、
約5時間で粘度が500cpsを越え、スプレードライヤーで
造粒を行うのは不可能となる。さらに5モル%の酸化珪
素を用いた場合、初期粘度が既に500cpsを越えているこ
とが確認された。一方、出発原料として1モル%の粉末
珪素を用いた場合、スラリーの増粘現象はほとんど見ら
れないことがわかる。また10モル%の珪素を用いた場合
にも同様に増粘現象は見られなかった。従って、粉末珪
素の添加方式により長時間に渡りスプレードライヤーに
よる造粒が可能となり、大量の原料処理にも究めて好都
合となることがわかる。First, zinc oxide powder, bismuth oxide 0.
5 mol%, antimony oxide 1.0 mol%, cobalt oxide 0.5
Mol%, manganese oxide 0.5 mol% with 0.5 to 20.0 mol% of powdered silicon added to the raw material powder, solid content ratio of about 60 wt%
Pure water was added so that PVA (polyvinyl alcohol) was added as a binder in an amount of 0.5% by weight based on the solid content, and the whole was put in a ball mill together with zirconia boulders and pulverized for 30 hours to obtain a slurry. This slurry was dried with a spray dryer and granulated to prepare raw material powder. The raw material powder was compression-molded to a size of 40 mm in diameter and 30 mm in thickness, and sintered in air at 1200 ° C. Both end surfaces of the thus obtained sintered body were polished to form a sprayed aluminum electrode. The viscosity of the slurry was measured with a rotary viscometer. Also, for comparison, a system using silicon oxide as a starting material was similarly prepared by the manufacturing process. The figure shows the change in slurry viscosity over time. When 1 mol% of silicon oxide is used as a starting material,
The viscosity exceeds 500 cps in about 5 hours, making it impossible to granulate with a spray dryer. Further, when 5 mol% of silicon oxide was used, it was confirmed that the initial viscosity was already over 500 cps. On the other hand, when 1 mol% of powdered silicon was used as the starting material, it was found that the thickening phenomenon of the slurry was hardly seen. Similarly, no thickening phenomenon was observed when 10 mol% of silicon was used. Therefore, it can be seen that the addition method of powdered silicon enables granulation by a spray dryer for a long time, which is convenient for processing a large amount of raw material.
次に焼結体に電極を形成した試料の初期特性を第1表に
示す。V1mA,V10μAは直流定電流電源を用いて測定し
た。また制限電圧特性は電流波高値5000A,波形8/20μs
のインパルスを用いて測定した。初期特性は、スラリー
の増粘現象を除けば、酸化珪素添加方式と粉末珪素添加
方式の差はほとんど無いことがわかる。さらに粉末珪素
添加方式を採用することにより1〜10モル%以上の多量
添加が可能となり、素子の小形化,低価格化を容易に実
現することができる。また、粉末珪素を添加した焼結体
について材料解析を実施した結果、酸化珪素を添加した
場合と全く同様に、酸化亜鉛間の三重点付近に珪酸亜鉛
として存在していることが確認された。Next, Table 1 shows the initial characteristics of the sample in which the electrode was formed on the sintered body. V 1mA and V 10μA were measured using a DC constant current power supply. Also, the limiting voltage characteristics are: current peak value 5000A, waveform 8 / 20μs
The impulse was used for measurement. Regarding the initial characteristics, it can be seen that there is almost no difference between the method of adding silicon oxide and the method of adding powdered silicon, except for the thickening phenomenon of the slurry. Further, by adopting the powdered silicon addition method, it is possible to add a large amount of 1 to 10 mol% or more, and it is possible to easily realize the downsizing and cost reduction of the device. Further, as a result of material analysis of the sintered body to which powdered silicon was added, it was confirmed that zinc silicate was present in the vicinity of the triple point between zinc oxides, just as in the case of adding silicon oxide.
次に上記の試料についてサージ耐量試験を実施した。試
験条件は2ms,300Aの矩形波電流を同一方向に5分間イン
ターバルで素子が破壊に至るまで繰返し印加した。この
結果を第2表に示す。表中の値は、素子が破壊せずに耐
えた矩形波電流の印加回数を試料数各5個の平均値、お
よび分布範囲(最高値−最低値)で示した。 Next, a surge withstand test was performed on the above sample. The test condition was that a rectangular wave current of 300 A for 2 ms was repeatedly applied in the same direction at intervals of 5 minutes until the device was broken. The results are shown in Table 2. The values in the table represent the number of times a rectangular wave current was applied without breaking the element, the average value of 5 samples, and the distribution range (maximum value-minimum value).
第2表より、出発原料を酸化珪素から珪素に変えること
によってサージ耐量が約2倍になり、著しく高性能化し
ていることがわかる。また、分布範囲も、平均値に比べ
狭くなり素子の信頼性も向上していることがわかる。こ
れは、出発原料として珪素を用いた場合は酸化珪素を用
いた場合に比べ、粉砕が速やかに、かつ均一に進むた
め、焼結体内部にボイドの発生が減少し、合わせて珪酸
亜鉛の均一分布により電流分布が均一化したためと考え
られる。また珪素添加量が増加するのに反してサージ耐
量が徐々に低下するのは、珪素添加により単位厚み当り
のバリスタ電圧(V1mA/mm)が上昇し、単位体積当りに
かかるエネルギーが上昇し、熱ストレスにより破壊し易
くなるものと考えられるが、従来の試料と比較すれば性
能的にも、素子の小形低価格化といった面からも大きな
効果がある。 From Table 2, it can be seen that by changing the starting material from silicon oxide to silicon, the surge resistance doubles and the performance is remarkably improved. Further, it can be seen that the distribution range is narrower than the average value and the reliability of the element is improved. This is because, when silicon is used as the starting material, crushing progresses more quickly and uniformly than when silicon oxide is used, so that the occurrence of voids inside the sintered body is reduced and the zinc silicate is evenly distributed. It is considered that the current distribution was made uniform by the distribution. Moreover, the surge withstand amount gradually decreases in contrast to the increase in the amount of silicon added, because the addition of silicon increases the varistor voltage per unit thickness (V 1mA / mm), which increases the energy applied per unit volume. Although it is considered that the sample is easily destroyed by thermal stress, it has a great effect in terms of performance and size and cost reduction of the device as compared with the conventional sample.
発明の効果 以上本発明によると、少なくとも1.0〜10モル%の粉末
珪素を用いているためスラリーのゲル化を防止し、スプ
レードライヤーによる造粒が可能となるため、大量の原
料処理ができ安定して量産が可能となる。Effects of the Invention According to the present invention, since at least 1.0 to 10 mol% of powdered silicon is used, gelation of the slurry is prevented, and granulation by a spray dryer is possible, so that a large amount of raw material can be processed and stable. Mass production is possible.
また、粉砕工程において、珪素の粉砕が速やかにかつ均
一に進むため、焼結体内部の欠陥(ボイドなど)が発生
しにくくなり、極めて高いサージ耐量を有し、特性バラ
ツキの少ない酸化亜鉛形バリスタを得ることができる。Further, in the crushing process, since the crushing of silicon proceeds rapidly and uniformly, defects (voids etc.) inside the sintered body are less likely to occur, the surge resistance is extremely high, and the zinc oxide type varistor with few characteristic variations. Can be obtained.
図は本発明および従来の製造方法により得られた原料ス
ラリーの粘度の経時変化を示す図である。The figure is a diagram showing changes with time in viscosity of raw material slurries obtained by the present invention and the conventional manufacturing method.
Claims (1)
タにおいて、酸化亜鉛を主成分とし、副成分として少な
くとも1.0〜10モル%の粉末状珪素を添加した原料粉末
に水とバインダーを添加、粉砕してスラリーを得る工程
と、このスラリーをスプレードライヤーにて乾燥・造粒
して造粒粉を得る工程と、この造粒粉を成形して空気中
で焼成する工程とを備えた酸化亜鉛形バリスタの製造方
法。1. A zinc oxide varistor containing zinc silicate in a sintered body, wherein water and a binder are added to a raw material powder containing zinc oxide as a main component and at least 1.0 to 10 mol% of powdery silicon as an accessory component. Oxidation comprising a step of pulverizing to obtain a slurry, a step of drying and granulating the slurry with a spray dryer to obtain a granulated powder, and a step of molding the granulated powder and firing it in air. Manufacturing method of zinc varistor.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61289208A JPH0773082B2 (en) | 1986-12-04 | 1986-12-04 | Method for producing zinc oxide varistor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61289208A JPH0773082B2 (en) | 1986-12-04 | 1986-12-04 | Method for producing zinc oxide varistor |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS63142603A JPS63142603A (en) | 1988-06-15 |
JPH0773082B2 true JPH0773082B2 (en) | 1995-08-02 |
Family
ID=17740175
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP61289208A Expired - Lifetime JPH0773082B2 (en) | 1986-12-04 | 1986-12-04 | Method for producing zinc oxide varistor |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0773082B2 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2940486B2 (en) * | 1996-04-23 | 1999-08-25 | 三菱電機株式会社 | Voltage nonlinear resistor, method for manufacturing voltage nonlinear resistor, and lightning arrester |
CN114644339B (en) * | 2022-04-29 | 2023-04-25 | 成都理工大学 | Method for removing impurities in silicon by adopting inorganic zinc salt |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3928242A (en) * | 1973-11-19 | 1975-12-23 | Gen Electric | Metal oxide varistor with discrete bodies of metallic material therein and method for the manufacture thereof |
-
1986
- 1986-12-04 JP JP61289208A patent/JPH0773082B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPS63142603A (en) | 1988-06-15 |
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Legal Events
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EXPY | Cancellation because of completion of term |