JPS6310561B2 - - Google Patents
Info
- Publication number
- JPS6310561B2 JPS6310561B2 JP54161145A JP16114579A JPS6310561B2 JP S6310561 B2 JPS6310561 B2 JP S6310561B2 JP 54161145 A JP54161145 A JP 54161145A JP 16114579 A JP16114579 A JP 16114579A JP S6310561 B2 JPS6310561 B2 JP S6310561B2
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- sintering
- manufacturing
- nonlinear resistor
- pressure
- 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
Links
- 238000005245 sintering Methods 0.000 claims description 20
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 19
- 238000004519 manufacturing process Methods 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 16
- 239000011230 binding agent Substances 0.000 claims description 14
- 238000000748 compression moulding Methods 0.000 claims description 12
- 239000000654 additive Substances 0.000 claims description 8
- 239000011787 zinc oxide Substances 0.000 claims description 8
- 230000000996 additive effect Effects 0.000 claims description 7
- 238000000465 moulding Methods 0.000 claims description 7
- 229910000416 bismuth oxide Inorganic materials 0.000 claims description 3
- 229910000428 cobalt oxide Inorganic materials 0.000 claims description 3
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 claims description 3
- TYIXMATWDRGMPF-UHFFFAOYSA-N dibismuth;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Bi+3].[Bi+3] TYIXMATWDRGMPF-UHFFFAOYSA-N 0.000 claims description 3
- 230000006835 compression Effects 0.000 claims description 2
- 238000007906 compression Methods 0.000 claims description 2
- 239000000615 nonconductor Substances 0.000 claims 2
- 238000010304 firing Methods 0.000 description 32
- 239000000203 mixture Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 239000011148 porous material Substances 0.000 description 4
- KAGOZRSGIYZEKW-UHFFFAOYSA-N cobalt(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Co+3].[Co+3] KAGOZRSGIYZEKW-UHFFFAOYSA-N 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 description 2
- 239000011812 mixed powder Substances 0.000 description 2
- 229910000480 nickel oxide Inorganic materials 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910015902 Bi 2 O 3 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910000410 antimony oxide Inorganic materials 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Chemical compound [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- VTRUBDSFZJNXHI-UHFFFAOYSA-N oxoantimony Chemical compound [Sb]=O VTRUBDSFZJNXHI-UHFFFAOYSA-N 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
- MMKQUGHLEMYQSG-UHFFFAOYSA-N oxygen(2-);praseodymium(3+) Chemical compound [O-2].[O-2].[O-2].[Pr+3].[Pr+3] MMKQUGHLEMYQSG-UHFFFAOYSA-N 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 229910003447 praseodymium oxide Inorganic materials 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
Landscapes
- Thermistors And Varistors (AREA)
Description
本発明は、酸化亜鉛を主体とする焼結体を使用
した電圧非直線抵抗器の製造方法に関するもので
ある。
近年、酸化亜鉛に各種添加物を加えて焼結した
バルク型の電圧非直線抵抗器の開発が活発に行な
われ、優れた電流−電圧特性をもち、さらにサー
ジ吸収特性に優れた素子が実用に供されるように
なつてきている。
本発明は、特に酸化亜鉛主体の焼結体を製造す
る際、混合、造粒粉体を予備圧縮成型し、予備圧
縮成型圧力以上の圧力を加えながら焼結させると
均一で気孔が少なく、耐湿性に優れ、制限電圧比
がよく、しかもサージエネルギー耐量の大きな電
圧非直線抵抗器を得ることができる。また本発明
の方法により得られる電圧非直線抵抗器の焼結体
は、均一で気孔が少なく、機械的強度が強いの
で、薄く機械加工することができるものである。
さらに再焼成することによつて、機械加工時のひ
ずみが除去され特性を改善することができる。
避雷器やサージ保護素子に適用するためには、
大電流における電圧と微少電流における電圧との
比、すなわち制限電圧比が小さいほどよい。また
サージに耐えられる能力を表わすサージエネルギ
ー耐量も大きいほどよい。サージエネルギー耐量
を大きくするには、基本的には素子の面積を大き
くすればよいが、実際には素子の面積を大きくし
ても、期待するほどサージエネルギー耐量は向上
しない。これは素子の均一性によるものであり、
とくに本発明の方法による電圧非直線抵抗器にお
いては電圧非直線性が著しいので、不均一性が何
倍にも拡大されて、電流の局部的な集中を招き、
サージエネルギー耐量を向上させることが困難で
あつた。また、制限電圧比を向上させるためにも
素子の面積を大きくするほどよく、同一面積の場
合にはサージエネルギー耐量を大きくするときと
同様に素子の均一性を向上させることが必要であ
る。また避雷器などとして応用する場合には、長
期間安定であることが必要であり、耐湿性のよい
ものが必要とされる。
本発明は、制限電圧電流特性、サージエネルギ
ー耐量特性および耐湿特性の面で優れた特性をも
つ酸化亜鉛焼結体電圧非直線抵抗器の製造方法を
提供するものであり、特に焼成段階において予備
圧縮成型時に加えた圧力より高い圧力で加圧焼成
することにより、制限電圧電流特性、サージエネ
ルギー耐量特性および耐湿特性のすべての面に優
れた特性を得ることができるものである。
本発明について説明するに先立つて、電圧非直
線抵抗器の電気特性について、あらかじめ説明
し、定義をしておく。非直線抵抗器の電流−電圧
特性は通常次の式で近似される。
Ｉ＝（Ｖ／Ｃ）〓
ここで、Ｉ、Ｖはそれぞれ電流および電圧を表
わし、Ｃとαは定数である。αは非直線性を表わ
す指数で、Ｃは電流の立ち上がり電圧を示す非直
線抵抗値である。α＝１のときオーム性となり、
そのときＣは通常の抵抗値を表わす。
実施例では、実用的な測定領域としてαは0.1
ｍＡ〜1.0ｍＡにおける値を示すこととし、また
Ｃの代りに１ｍＡのときＣの値をV1nAと示すこ
ととする。
また、制限電圧比とは８×20マイクロ秒の衝撃
電流で100A流れたときの端子電圧と直流１ｍＡ
流れたときの端子電圧との比をいう。
サージエネルギー耐量とは、１回のサージ印加
によつて生ずるバリスタ電圧の変化（ΔV1nA）が
−50％以内であるような衝撃電流（波形は２ミリ
秒矩形波）の最大エネルギーで示す。
以下、実施例をあげて本発明の製造方法につい
て説明する。
実施例 １
酸化亜鉛（ZnO）：95.397モル％
酸化ビスマス（Bi2O3）：1.0モル％
酸化コバルト（Co2O3）：0.5モル％
二酸化マンガン（MnO2）：0.5モル％
酸化アンチモン（Sb2O3）：1.0モル％
酸化クロム（Cr2O3）：0.1モル％
酸化ニツケル（NiO）：1.0モル％
酸化ケイ素（SiO2）：0.5モル％
酸化アルミニウム（Al2O3）：0.003モル％
よりなる混合粉体を直径3.5mm、厚さ15mmの円板
状に50〜500Kg／cm2で予備圧縮成型した。その200
〜800℃の温度でバインダ除去をおこなつた。こ
のようにして得た円板状成型体を200℃／時の昇
温速度で焼結温度まで加熱したのち、予備圧縮成
型時に加えた圧力よりも高い圧力を加え、２時間
保持した。その後圧力をぬき、200℃／時の降温
速度で冷却した。その後、このようにして円板状
焼結体の両面にアルミニウムの溶射電極を設け、
しかるのち電気特性を測定した。
第１表は予備圧縮成型圧力と焼成時圧力とを
種々変化させたときの各種電気特性に及ぼす効果
を示す。焼成条件は焼成温度1100℃、焼成時間２
時間一定とした。表においてV1nA/nnは電流１ｍ
Ａを流したときの単位厚さ当りの電圧である。こ
のような単位厚さ当りの電圧を使用しているの
は、酸化亜鉛を主体とする前記焼結がバルク非直
線特性を示すことによる。αは電圧非直線指数
で、電流0.1ｍＡ、１ｍＡを流したときの電極間
の電圧値を用い、先に示した電流、電圧の関係式
によつて求めている。また電圧変化率ΔV1nA（％）
は試験前後の電圧V1nAの変化を示すものである。
ここで試験条件は雰囲気の温度70℃で相対湿度95
％、印加電圧直流500V、および電圧印加時間
1000時間である。
The present invention relates to a method of manufacturing a voltage nonlinear resistor using a sintered body mainly composed of zinc oxide. In recent years, bulk type voltage nonlinear resistors made by sintering zinc oxide with various additives have been actively developed, and elements with excellent current-voltage characteristics and excellent surge absorption characteristics have been put into practical use. It is becoming increasingly available. In particular, when manufacturing a sintered body mainly consisting of zinc oxide, the mixed and granulated powder is pre-compression molded, and sintered while applying pressure higher than the pre-compression molding pressure. It is possible to obtain a voltage nonlinear resistor with excellent performance, good limiting voltage ratio, and large surge energy resistance. Furthermore, the sintered body of the voltage nonlinear resistor obtained by the method of the present invention is uniform, has few pores, and has strong mechanical strength, so that it can be machined into a thin body.
Further, by re-firing, the strain caused during machining can be removed and the properties can be improved. To apply to lightning arresters and surge protection elements,
The smaller the ratio between the voltage at a large current and the voltage at a minute current, that is, the limiting voltage ratio, the better. Also, the higher the surge energy resistance, which indicates the ability to withstand surges, the better. In order to increase the surge energy withstand capacity, it is basically necessary to increase the area of the element, but in reality, even if the area of the element is increased, the surge energy withstand capacity does not improve as much as expected. This is due to the uniformity of the element,
In particular, in the voltage nonlinear resistor according to the method of the present invention, the voltage nonlinearity is significant, so the nonuniformity is magnified many times, leading to local concentration of current.
It has been difficult to improve surge energy resistance. Further, in order to improve the limiting voltage ratio, it is better to increase the area of the element, and when the area is the same, it is necessary to improve the uniformity of the element in the same way as when increasing the surge energy withstand capacity. Furthermore, when used as a lightning arrester, etc., it is necessary to be stable for a long period of time, and a material with good moisture resistance is required. The present invention provides a method for manufacturing a zinc oxide sintered voltage nonlinear resistor that has excellent characteristics in terms of limited voltage and current characteristics, surge energy withstand characteristics, and moisture resistance characteristics. By performing pressurized firing at a pressure higher than the pressure applied during molding, it is possible to obtain excellent characteristics in all aspects, including limited voltage and current characteristics, surge energy withstand characteristics, and moisture resistance characteristics. Before explaining the present invention, the electrical characteristics of a voltage nonlinear resistor will be explained and defined in advance. The current-voltage characteristics of a nonlinear resistor are usually approximated by the following equation. I=(V/C) Here, I and V represent current and voltage, respectively, and C and α are constants. α is an index representing nonlinearity, and C is a nonlinear resistance value representing the rising voltage of the current. When α=1, it becomes ohmic,
C then represents the normal resistance value. In the example, α is 0.1 as a practical measurement range.
The value at mA to 1.0 mA will be shown, and instead of C, the value of C at 1 mA will be shown as V 1nA . Also, the limiting voltage ratio is the terminal voltage when 100A flows with an impact current of 8 x 20 microseconds and the DC 1mA.
This is the ratio to the terminal voltage when the current flows. The surge energy withstand capacity is defined as the maximum energy of an impact current (waveform is a 2 millisecond rectangular wave) such that the change in varistor voltage (ΔV 1nA ) caused by one surge application is within −50%. Hereinafter, the manufacturing method of the present invention will be explained with reference to Examples. Example 1 Zinc oxide (ZnO): 95.397 mol% Bismuth oxide (Bi 2 O 3 ): 1.0 mol% Cobalt oxide (Co 2 O 3 ): 0.5 mol% Manganese dioxide (MnO 2 ): 0.5 mol% Antimony oxide (Sb) 2 O 3 ): 1.0 mol% Chromium oxide (Cr 2 O 3 ): 0.1 mol% Nickel oxide (NiO): 1.0 mol% Silicon oxide (SiO 2 ): 0.5 mol% Aluminum oxide (Al 2 O 3 ): 0.003 mol % was preliminarily compressed into a disk shape with a diameter of 3.5 mm and a thickness of 15 mm at a pressure of 50 to 500 kg/cm 2 . Part 200
Binder removal was performed at a temperature of ~800°C. The disc-shaped molded body thus obtained was heated to the sintering temperature at a heating rate of 200° C./hour, then a pressure higher than that applied during preliminary compression molding was applied and maintained for 2 hours. Thereafter, the pressure was released, and the temperature was cooled at a rate of 200°C/hour. After that, sprayed aluminum electrodes were provided on both sides of the disk-shaped sintered body in this way,
After that, the electrical characteristics were measured. Table 1 shows the effects on various electrical properties when the precompression molding pressure and the firing pressure were varied. Firing conditions are firing temperature 1100℃, firing time 2
The time was set to be constant. In the table, V 1nA/nn is a current of 1m
This is the voltage per unit thickness when A is applied. The reason why such a voltage per unit thickness is used is that the sintered material mainly composed of zinc oxide exhibits bulk nonlinear characteristics. α is a voltage non-linearity index, which is obtained by using the voltage value between the electrodes when currents of 0.1 mA and 1 mA are passed, and from the relational expression between current and voltage shown above. Also, voltage change rate ΔV 1nA (%)
indicates the change in voltage V 1nA before and after the test.
Here, the test conditions are an ambient temperature of 70℃ and a relative humidity of 95℃.
%, applied voltage DC 500V, and voltage application time
It is 1000 hours.
【表】
第１表から明らかなように電圧V1nA/nnおよび
指数αには予備圧縮成型以上の圧力で焼成を行な
うことによる効果はあまり認められないが、制限
電圧比、エネルギー耐量および電圧V1nA/nnの変
化率ΔV1nAは焼成時の圧力に依存していることが
明らかである。すなわち、焼成時に予備圧縮成型
時よりも高い圧力で加圧焼成することにより、素
体中に残存している気泡が液相となつているBi
粒界相をつたつて外部におし出され、孔のない緻
密な焼結体を作つている。それは第１表に同時に
示した焼結体密度をもつてしても明らかである。
予備圧縮成型圧力が50Kg／cm2以下であれば成型
体強度が弱く、また逆に500Kg／cm2以上になると
焼結体の制限電圧比、およびエネルギー耐量はさ
ほどよくならない。これから予備圧縮成型圧力は
50〜500Kg／cm2が適当である。また、焼成時の圧
力は予備圧縮成型圧力より大きく100〜1000Kg／
cm2が適当である。それ以上の圧力をかけても特性
が飽和するだけで、特にその効果が見られない。
実施例 ２
次に上述した電圧非直線抵抗器の製造条件のう
ち予備圧縮成型圧力250Kg／cm2、焼成時圧力350
Kg／cm2、焼成時間２時間一定として、焼成温度の
影響を測定した。第１図および第２図に検討した
結果を示す。電気特性測定方法は前述したとおり
である。
第１図より明らかなように電圧V1nA/nnおよび
指数αは焼成時の加圧の差違による効果はない
が、第２図より明らかなように、制限電圧比およ
びエネルギー耐量は明らかに良好な効果が認めら
れる。焼成温度については、それが800℃より低
くなると焼結不十分で、磁器としての諸性質に劣
る。たとえば、機械的強度が小さくなつて、破損
しやすくなる。また焼成温度が1400℃を超えると
焼結が過度となり、電圧非直線性や寿命特性が悪
くなるという傾向にある。これから適当な温度範
囲は800〜1400℃である。さらに制限電圧比が最
小となるとともにサージエネルギー耐量が最大と
なる1000〜1100℃が最も良好な焼成温度といえ
る。
実施例 ３
次に、上述した電圧非直線抵抗器の製造方法の
うち予備圧縮成型後のバインダー除去のあり、な
しによる特性について調べた。上述の混合粉体を
250Kg／cm2の圧力で予備圧縮成型をおこない、一
方は大気中500℃、２時間の条件でバインダー除
去を行ない。他方はバインダー除去を行なわない
成型体をそれぞれ作製した。次に両方の成型体と
も昇温速度200℃／時間で1100℃まで加熱したの
ち、350Kg／cm2の圧力で加圧して２時間保持した。
その後圧力をぬき、200℃／時間の降温速度で冷
却した。その後この２種類の焼結体のそれぞれ両
面にアルミニウム溶射電極をつけ、しかるのち電
気特性を調べた。第２表にその結果を示す。[Table] As is clear from Table 1, there is not much effect on the voltage V 1nA/nn and the index α by firing at a pressure higher than that of precompression molding, but the limiting voltage ratio, energy withstand capacity, and voltage V It is clear that the rate of change ΔV 1nA of 1nA/nn depends on the pressure during firing. In other words, by performing pressure firing at a higher pressure than during pre-compression molding, the remaining air bubbles in the element body become a liquid phase.
It is expelled to the outside through the grain boundary phase, creating a dense sintered body with no pores. This is also clear from the sintered body density shown in Table 1. If the precompression molding pressure is less than 50 Kg/cm 2 , the strength of the molded product will be weak, and if it is more than 500 Kg/cm 2 , the limited voltage ratio and energy withstand capacity of the sintered product will not be so good. From this, the pre-compression molding pressure will be
50-500Kg/ cm2 is suitable. In addition, the pressure during firing is higher than the pre-compression molding pressure and is 100 to 1000 kg/
cm2 is appropriate. Even if more pressure is applied, the characteristics will simply become saturated and no particular effect will be observed. Example 2 Next, among the manufacturing conditions of the voltage nonlinear resistor described above, the precompression molding pressure is 250 Kg/cm 2 and the firing pressure is 350 Kg/cm 2
The influence of firing temperature was measured with Kg/cm 2 and firing time constant for 2 hours. Figures 1 and 2 show the results of the study. The method for measuring electrical characteristics was as described above. As is clear from Figure 1, the voltage V 1nA/nn and the index α have no effect due to the difference in pressure during firing, but as is clear from Figure 2, the limiting voltage ratio and energy withstand capacity are clearly good. The effect is recognized. Regarding the firing temperature, if the temperature is lower than 800°C, sintering will be insufficient and the properties of porcelain will be inferior. For example, mechanical strength decreases, making it easier to break. Furthermore, when the firing temperature exceeds 1400°C, sintering becomes excessive, and voltage nonlinearity and life characteristics tend to deteriorate. From this, a suitable temperature range is 800-1400°C. Furthermore, it can be said that the most favorable firing temperature is 1000 to 1100°C, at which the limiting voltage ratio is minimized and the surge energy withstand capacity is maximized. Example 3 Next, the characteristics of the above-described voltage nonlinear resistor manufacturing method with and without binder removal after preliminary compression molding were investigated. The above mixed powder
Preliminary compression molding was performed at a pressure of 250 Kg/cm 2 , and the binder was removed on the other hand at 500°C in the atmosphere for 2 hours. On the other hand, molded bodies were produced without removing the binder. Next, both molded bodies were heated to 1100°C at a temperature increase rate of 200°C/hour, then pressurized at a pressure of 350 kg/cm 2 and held for 2 hours.
Thereafter, the pressure was released and the mixture was cooled at a temperature decreasing rate of 200°C/hour. Thereafter, aluminum sprayed electrodes were attached to both sides of each of the two types of sintered bodies, and the electrical properties were then examined. Table 2 shows the results.
【表】
上表から明らかなように電圧V1nA/nn、指数α、
制限電圧比、エネルギー耐量、変化率ΔV1nAおよ
び密度のすべての面にわたり、バインダー除去を
しなかつたものは、除去したものに比べて特性が
おとつている。これは焼成時に有機バインダーが
酸化せず素体内部を還元雰囲気としていることに
起因している。このため加圧焼成する前にバイン
ダー除去することが必要である。その条件は200
〜800℃の範囲が適当である。なぜなら、200℃よ
りも低い温度であれば有機バインダーがとばずに
成型体内に残存し、また800℃よりも高くなると
焼結が進むからである。
実施例 ４
次に上述した配合組成の混合粉体を直径35mm、
厚さ15mmの円板状に250Kg／cm2で予備圧縮成型し
た。その後500℃、２時間の条件でバインダー除
去を行なつた。しかるのち昇温速度200℃／時で
1100℃まで加熱し、1100℃で２時間保持した。そ
のとき350Kg／cm2の圧力を加えた。このようにし
て得られた焼結体を0.5mmの厚さに切り出し、両
面に銀電極を設けて、電気特性を測定した。その
結果電気特性は良好な値を示した。又0.5mmより
さらに薄く切り出した。比較のため、焼成時に加
圧しなかつた焼結体についても同様の検討を行な
つた。その結果、焼成時に加圧していない焼結体
は0.5mm以下の厚さに切断しようとすると割れや、
焼結体のくずれが発生したのに対して焼成時に加
圧したものは0.3mm以下の厚さになつても十分な
強度をもち、もとの形状を保つていた。このよう
に加圧焼成を行なつた焼結体により、特性的に優
れた低電圧用の電圧非直線抵抗器が得られるよう
になつた。
実施例 ５
次に、実施例４で切り出した焼結体を、圧力を
加えながら焼結温度以上の温度で再焼成し、その
後両面に銀電極を設け、電気特性を測定した。そ
の結果を第３表に示す。[Table] As is clear from the above table, the voltage V 1nA/nn , the index α,
In all aspects of limiting voltage ratio, energy withstand capacity, rate of change ΔV 1nA , and density, the properties of the samples without binder removal are lower than those with binder removal. This is due to the fact that the organic binder does not oxidize during firing, creating a reducing atmosphere inside the element body. Therefore, it is necessary to remove the binder before pressure firing. The condition is 200
A range of ~800°C is suitable. This is because if the temperature is lower than 200°C, the organic binder will not be blown off and will remain in the molded body, and if the temperature is higher than 800°C, sintering will proceed. Example 4 Next, the mixed powder having the above-mentioned composition was prepared into a powder with a diameter of 35 mm.
Preliminary compression molding was performed at 250 kg/cm 2 into a disc shape with a thickness of 15 mm. Thereafter, the binder was removed at 500°C for 2 hours. After that, the heating rate was 200℃/hour.
It was heated to 1100°C and held at 1100°C for 2 hours. At that time, a pressure of 350 Kg/cm 2 was applied. The sintered body thus obtained was cut out to a thickness of 0.5 mm, silver electrodes were provided on both sides, and the electrical properties were measured. As a result, the electrical properties showed good values. It was also cut thinner than 0.5mm. For comparison, a similar study was conducted on a sintered body that was not pressurized during firing. As a result, when trying to cut a sintered body that is not pressurized during firing to a thickness of 0.5 mm or less, it may crack or
While the sintered body collapsed, the one that was pressurized during firing had sufficient strength and maintained its original shape even when the thickness was less than 0.3 mm. By using the sintered body subjected to pressure firing in this manner, it has become possible to obtain a voltage nonlinear resistor for low voltage with excellent characteristics. Example 5 Next, the sintered body cut out in Example 4 was re-fired at a temperature equal to or higher than the sintering temperature while applying pressure, and then silver electrodes were provided on both surfaces and the electrical properties were measured. The results are shown in Table 3.
【表】
上表から明らかなように、焼結した温度以上の
温度で再焼成するとすべての電気特性において特
性が向上する。これは焼成時の圧力によるひずみ
やスライスによる機械的ひずみが取り除かれるた
めではないかと考えられる。
なお、再焼成温度は過焼成とならない温度でな
ければならないことは言うまでもないことであ
る。
実施例 ６
次に前述した組成比以外に添加物としてBiの
ない組成、すなわち非オーム性を発現させる添加
物として酸化コバルトを含む材料組成について検
討した。
組成１
酸化亜鉛（ZnO） ：98.5モル％
酸化プラセオジウム（PrO5） ：0.5モル％
酸化コバルト（Co2O3） ：1.0モル％
組成２
酸化亜鉛（ZnO） ：99.0モル％
酸化バリウム（BaO） ：0.5モル％
酸化コバルト（Co2O3） ：0.5モル％
上記２種類の配合組成についても、前述と同様
な実験を行なつた結果、酸化ビスマスを用いた場
合と同じように、制限電圧比、サージエネルギー
耐量、耐湿特性のすべての面で改善の効果が見ら
れた。すなわち、酸化亜鉛を主成分とする、非オ
ーム性を発現させる添加物であれば、すべてにお
いて本発明による効果が得られる。
本発明における加圧焼成を行なわない場合、圧
縮成形時に粉体に一様な圧力がかからずできあが
つた成形体は圧力の不均一な成型体となり、ひい
ては焼結後もこの圧力の不均一性が残り、均一性
の悪い焼結体となる。これに比較して、加圧焼成
を行なうと成型時の圧力不均一性が焼結時に矯正
されて、均一性のよい焼結体となる。このことが
制限電圧比およびサージエネルギー耐量を向上さ
せることとなつている。次に加圧焼成することに
より、成型体内部に残存している気孔が焼成時に
粒界層を通つて外部に強制的に押し出されるた
め、気孔の少ない焼結体が得られる。これにより
焼結体に対する外部湿気の浸透が少なくなり、結
果的に耐湿性に優れた焼結体となる。よつて本発
明による電圧非直線抵抗器の製造方法は、従来よ
りも制限電圧比、サージエネルギー耐量、耐湿性
に優れた電圧非直線抵抗を得ることができる。[Table] As is clear from the table above, re-firing at a temperature higher than the sintering temperature improves all electrical properties. This is thought to be because strain caused by pressure during firing and mechanical strain caused by slicing are removed. It goes without saying that the re-firing temperature must be a temperature that does not cause over-firing. Example 6 Next, in addition to the above-mentioned composition ratio, a composition without Bi as an additive, that is, a material composition containing cobalt oxide as an additive to exhibit non-ohmic properties was investigated. Composition 1 Zinc oxide (ZnO): 98.5 mol% Praseodymium oxide (PrO 5 ): 0.5 mol% Cobalt oxide (Co 2 O 3 ): 1.0 mol% Composition 2 Zinc oxide (ZnO): 99.0 mol% Barium oxide (BaO): 0.5 mol% Cobalt oxide (Co 2 O 3 ): 0.5 mol% As a result of conducting the same experiment as above for the above two types of compounding compositions, the limiting voltage ratio, Improvements were seen in all aspects of surge energy resistance and moisture resistance. That is, the effects of the present invention can be obtained with any additive that has zinc oxide as its main component and exhibits non-ohmic properties. If pressure sintering in the present invention is not performed, the powder will not be subjected to uniform pressure during compression molding, resulting in a molded product with uneven pressure, and this pressure will not be uniform even after sintering. Uniformity remains, resulting in a sintered body with poor uniformity. In contrast, when pressure firing is performed, pressure nonuniformity during molding is corrected during sintering, resulting in a sintered body with good uniformity. This is supposed to improve the limiting voltage ratio and surge energy resistance. Next, by pressurizing and firing, the pores remaining inside the molded body are forcibly pushed out through the grain boundary layer during firing, so that a sintered body with fewer pores can be obtained. This reduces the penetration of external moisture into the sintered body, resulting in a sintered body with excellent moisture resistance. Therefore, the method for manufacturing a voltage non-linear resistor according to the present invention can provide a voltage non-linear resistor that is superior in limiting voltage ratio, surge energy withstand capacity, and moisture resistance compared to conventional resistors.
第１図は焼成温度をパラメータとしたときの
V1nA/nn、αの値について本発明の方法による電
圧非直線抵抗器と、従来法によるそれとを対比さ
せて示したものである。第２図は同様に焼成温度
をパラメータとしたときの制限電圧比とエネルギ
ー耐量を、本発明の方法による電圧非直線抵抗器
と、従来法によるそれとを対比させて示したもの
である。
Figure 1 shows the results when the firing temperature is used as a parameter.
The figure shows a comparison of the values of V 1nA/nn and α between the voltage nonlinear resistor according to the method of the present invention and that according to the conventional method. FIG. 2 similarly shows the limiting voltage ratio and energy withstand capacity when firing temperature is used as a parameter, comparing the voltage nonlinear resistor made by the method of the present invention and that made by the conventional method.
Claims (1)
焼結後に焼結体自身に非オーム性を発現させる添
加物を混合、造粒し、金型を用いて予備圧縮成型
した後、バインダーを除去し、予備圧縮成型時に
加えた圧力以上の圧力を加えながら焼結させるこ
とを特徴とする電圧非直線抵抗器の製造方法。 ２ 予備圧縮成型圧力が50〜500Kg／cm2であるこ
とを特徴とする特許請求の範囲第１項に記載の電
圧非直線抵抗器の製造方法。 ３ 焼結時に加える圧力が100〜1000Kg／cm2であ
ることを特徴とする特許請求の範囲第１項に記載
の電圧非直線抵抗器の製造方法。 ４ 焼結温度が800〜1400℃であることを特徴と
する特許請求の範囲第１項に記載の電圧非直線抵
抗器の製造方法。 ５ 焼結後に焼結体自身が非オーム性を発現させ
る添加物として酸化ビスマスおよび酸化コバルト
の少なくともいずれか一方を含ませてなることを
特徴とする特許請求の範囲第１項に記載の電圧非
直線抵抗器の製造方法。 ６ バインダーを除去する温度が200〜800℃であ
ることを特徴とする特許請求の範囲第１項に記載
の電圧非直線抵抗器。 ７ 主成分の酸化亜鉛と少なくとも１種以上の、
焼結後に焼結体自身に非オーム性を発現させる添
加物を混合、造粒し、金型を用いて予備圧縮成型
した後、バインダーを除去してから、焼結し、さ
らに得られた焼結体を切断し、この切り出された
焼結体を加圧しながら、焼結した温度以上であつ
て過焼成とならない温度で再焼成することを特徴
とする電圧非直線抵抗器の製造方法。 ８ 予備圧縮成型圧力が50〜500Kg／cm2であるこ
とを特徴とする特許請求の範囲第７項に記載の電
圧非直線抵抗器の製造方法。 ９ 焼結時に加える圧力が100〜1000Kg／cm2であ
ることを特徴とする特許請求の範囲第７項に記載
の電圧非直線抵抗器の製造方法。 １０ 焼結温度が800〜1400℃であることを特徴
とする特許請求の範囲第７項に記載の電圧非直線
抵抗器の製造方法。 １１ 焼結後に焼結体自身が非オーム性を発現さ
せる添加物として酸化ビスマスおよび酸化コバル
トの少なくともいずれか一方を含ませてなること
を特徴とする特許請求の範囲第７項に記載の電圧
非直線抵抗器の製造方法。 １２ バインダーを除去する温度が200〜800℃で
あることを特徴とする特許請求の範囲第７項に記
載の電圧非直線抵抗器の製造方法。[Claims] 1. Zinc oxide as a main component and at least one or more
After sintering, an additive that makes the sintered body itself non-ohmic is mixed and granulated, and after pre-compression molding using a mold, the binder is removed and a pressure higher than the pressure applied during pre-compression molding is applied. A method for manufacturing a voltage nonlinear resistor, characterized in that sintering is performed while adding. 2. The method for manufacturing a voltage nonlinear resistor according to claim 1, wherein the precompression molding pressure is 50 to 500 Kg/cm 2 . 3. The method for manufacturing a voltage nonlinear resistor according to claim 1, wherein the pressure applied during sintering is 100 to 1000 Kg/cm 2 . 4. The method for manufacturing a voltage nonlinear resistor according to claim 1, wherein the sintering temperature is 800 to 1400°C. 5. The voltage non-conductor according to claim 1, characterized in that the sintered body itself contains at least one of bismuth oxide and cobalt oxide as an additive to exhibit non-ohmic properties after sintering. How to make a linear resistor. 6. The voltage nonlinear resistor according to claim 1, wherein the temperature at which the binder is removed is 200 to 800°C. 7 Main component zinc oxide and at least one or more
After sintering, an additive that makes the sintered body itself non-ohmic is mixed and granulated, pre-compression molded using a mold, the binder is removed, and the resulting sintered body is sintered. A method for manufacturing a voltage nonlinear resistor, which comprises cutting a compact, and refiring the cut out sintered compact while pressurizing it at a temperature higher than the sintering temperature but not causing overfiring. 8. The method for manufacturing a voltage nonlinear resistor according to claim 7, wherein the pre-compression molding pressure is 50 to 500 Kg/cm 2 . 9. The method for manufacturing a voltage nonlinear resistor according to claim 7, wherein the pressure applied during sintering is 100 to 1000 Kg/cm 2 . 10. The method for manufacturing a voltage nonlinear resistor according to claim 7, wherein the sintering temperature is 800 to 1400°C. 11. The voltage non-conductor according to claim 7, characterized in that the sintered body itself contains at least one of bismuth oxide and cobalt oxide as an additive to exhibit non-ohmic properties after sintering. How to make a linear resistor. 12. The method for manufacturing a voltage nonlinear resistor according to claim 7, wherein the temperature at which the binder is removed is 200 to 800°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16114579A JPS5683005A (en) | 1979-12-11 | 1979-12-11 | Method of manufacturing voltage nonnlinear resistor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16114579A JPS5683005A (en) | 1979-12-11 | 1979-12-11 | Method of manufacturing voltage nonnlinear resistor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5683005A JPS5683005A (en) | 1981-07-07 |
| JPS6310561B2 true JPS6310561B2 (en) | 1988-03-08 |
Family
ID=15729440
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16114579A Granted JPS5683005A (en) | 1979-12-11 | 1979-12-11 | Method of manufacturing voltage nonnlinear resistor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5683005A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6188501A (en) * | 1984-10-05 | 1986-05-06 | 富士電機株式会社 | Manufacture of voltage non-linear resistance element |
| JP2572859B2 (en) * | 1989-10-26 | 1997-01-16 | 日本碍子株式会社 | Voltage non-linear resistor and surge arrester |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5941287A (en) * | 1982-08-31 | 1984-03-07 | Tokyo Electric Co Ltd | Label printer |
-
1979
- 1979-12-11 JP JP16114579A patent/JPS5683005A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5941287A (en) * | 1982-08-31 | 1984-03-07 | Tokyo Electric Co Ltd | Label printer |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5683005A (en) | 1981-07-07 |
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