JP2004119840A - Nonlinear resistor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonlinear resistor at a low cost and to provide a method for manufacturing the same. <P>SOLUTION: The nonlinear resistor comprises a zinc oxide (ZnO) as a main component and also comprises as additives 0.66-0.8 mol% of a bismuth oxide (Bi<SB>2</SB>O<SB>3</SB>), 0.05-0.2 mol% of an antimony oxide (Sb<SB>2</SB>O<SB>3</SB>), 0.033-0.67 mol% each of a cobalt oxide (Co<SB>3</SB>O<SB>4</SB>) and a manganese oxide (Mn<SB>3</SB>O<SB>4</SB>), 0.01-0.5 mol% of a chromium oxide (Cr<SB>2</SB>O<SB>3</SB>), 0.4-2 mol% of a boric acid (H<SB>3</SB>BO<SB>3</SB>), and 0.001-0.01 mol% of an aluminum nitrate (Al(NO<SB>3</SB>)<SB>3</SB>-9H<SB>2</SB>O). The method for manufacturing the nonlinear resistor comprises steps for forming an element assembly 1 in which the total of the main component and the additives is 100 mol%, burning an electrode surface at a temperature of 950-1,050°C without being in contact with a burn table, forming a high resistance layer 2 on side faces of the assembly 1 at a thickness of 50-100μm by providing glass which has been obtained by vitrifying low melting glass at a temperature of 500-600°C, and thereafter forming an electrode 3 throughout the entire electrode-forming surface without polishing the same. Thus, since burning can be carried out at a lower temperature comparing with a conventional process in which burning is carried out at a high temperature of 1,200°C, the nonlinear resistor can be manufactured at a low cost. <P>COPYRIGHT: (C)2004,JPO

Description

【００１７】
表１は従来品と実施の形態１に示す発明品との電気特性について示した表である。表１において、従来品および発明品の試料をそれぞれ１０個について、小電流域平坦性および大電流域平坦性について測定し、その平均値を、従来品を１００として表したものである。
【００１８】
表１に示すように、発明品は従来品より小電流域平坦性および大電流域平坦性が小さくなっている。これは、発明品は従来品より常時における漏れ電流が小さく、雷時の電圧抑制効果が大きいことを示している。従って、本発明は従来品に比べて優れた電気特性を示していることが分かる。
【００１９】
このように、側面高抵抗層２をエポキシ系樹脂材料で形成し、９５０〜１０５０℃、一回で素体１の焼成を可能とし、焼成時および側面高抵抗層２形成時において電極面の処理台への接触および異物の付着を防止したので、電極３形成前に行なっていた研磨および洗浄工程を省略することができる。従って、非直線抵抗体の製造において従来技術よりも低い温度で一回焼成にて素子を緻密に焼き固めることができるとともに工程数を削減することができ、非直線抵抗体を安価に製造することができる。
【００２０】
実施の形態２．
上記実施の形態１において、少ない工程数で良好な電気特性を有する非直線抵抗体の製造方法について説明したが、ここではさらに、耐量性能の良好な非直線抵抗体の得られる製造方法について説明する。
【００２１】
上記実施の形態１と同様にして非直線抵抗体を形成する。但し、試料１は側面高抵抗層２の厚みを３０μｍとしたもの、試料２は側面高抵抗層２の厚みを６０μｍとしたものを作成した。耐量性能試験は、従来品と試料１と試料２とをそれぞれ１０個ずつ準備し、１５０Ａ，２ｍｓの方形波を１０回通電して異常がないことを確認する方法で行なった。表２は耐量試験後、素子に異常が認められないものを合格品としてその割合を示した表である。
【００２２】
【表２】

【００２３】
表２より、従来品と試料２とは同等に良好な性能を有することがわかる。さらに、発明者の実験によれば、実施の形態１に示す非直線抵抗体の製造方法において、側面高抵抗層２を５０〜１００μｍ程度形成すれば、方形波耐量性能が良好で従来品に劣ることのない非直線抵抗体を簡単に、安価に形成することができる。
【００２４】
実施の形態３．
上記実施の形態１および２では側面高抵抗層をエポキシ樹脂で形成したものについて説明を行なったが、ここでは側面高抵抗層を低融点ガラスで形成した場合について説明する。
【００２５】
上記実施の形態１と同様にして非直線抵抗体を形成する。但し、側面高抵抗層２として、素体１に影響を及ぼさない温度である５００〜６００℃でガラス化できる低融点ガラスを素体１側面に厚さ５０〜１００μｍ程度形成する。その後、上記実施の形態１とほぼ同様に、素体１の両底面に電極３を形成する。
表３は、側面高抵抗層２である低融点ガラスの厚みは同じ５０〜１００μｍであるが、電極の形成範囲を変えて形成した試料を用いて行なった耐量性能試験の結果を示したものである。
【００２６】
【表３】

【００２７】
表３において、試料３はマスクを用いずに素体１周辺から０ｍｍ内側まで電極３（全面電極）を形成したもの、試料４はマスクを用いて素体１周辺から１ｍｍ内側まで電極３を形成したもの、試料５はマスクを用いて素体１周辺から２ｍｍ内側まで電極３を形成したものをそれぞれ１０個ずつ準備し、１５０Ａ，２ｍｓの方形波を１０回通電して異常がないことを確認する方法で行なった。
【００２８】
表３から分かるように、側面高抵抗層として低融点ガラスを用いた場合、厚みが５０〜１００μｍのものについては、電極３の大きさが素体１周辺から０〜２ｍｍの範囲では良好な耐量性能が得られた。特に、側面高抵抗層として低融点ガラスを用いた場合、厚みが５０〜１００μｍのものについては、全面電極を形成しても従来品に劣ることのない良好な非直線抵抗体を得ることができた。
これは、低融点ガラスが上記実施の形態１で用いた樹脂に比べてカバレッジが良く、素体１周辺部の凹みはガラスにより被覆することができることによると思われる。
【００２９】
また、表４は側面高抵抗層２である低融点ガラスの厚みを変えて形成した試料を用いて行なった耐量性能試験の結果を示したものである。
【００３０】
【表４】

【００３１】
表４において、試料３は全面電極で、側面高抵抗層２である低融点ガラスの厚みを５０〜１００μｍとしたもので表３で用いたものと同じである。さらに、試料６は全面電極で、低融点ガラスの厚みを３０μｍとしたものである。それぞれ１０個ずつ準備し、１５０Ａ，２ｍｓの方形波を１０回通電して異常がないことを確認する方法で行なった。
【００３２】
表４から分かるように、側面高抵抗層として厚みが５０〜１００μｍの低融点ガラスを用いた場合、全面電極を形成しても良好な非直線抵抗体を得ることができる。
【００３３】
つまり、側面高抵抗層として厚みが５０〜１００μｍの低融点ガラスを用い、全面電極を形成すれば、非直線抵抗体の製造方法における電極形成工程時のマスクの形成も削除することができ、より簡単に安価に非直線抵抗体を製造することができる。
【００３４】
実施の形態４．
上記実施の形態１ないし３で説明を行なった本発明の製造方法を用いて作成された直線抵抗体を用いた避雷器素子のバリスタ電圧について説明する。
表５は本発明の製造方法で作成された素子において、１ｍｍ厚み当たりのバリスタ電圧を変化させた試料を用いて行なった耐量性能試験の結果を示したものである。
【００３５】
【表５】

【００３６】
表５において、試料７はバリスタ電圧が１００Ｖ／ｍｍ，試料８はバリスタ電圧が１５０Ｖ／ｍｍ，試料９はバリスタ電圧が２５０Ｖ／ｍｍ，試料１０はバリスタ電圧が４００Ｖ／ｍｍ，のものをそれぞれ１０個ずつ準備し、１５０Ａ，２ｍｓの方形波を１０回通電して異常がないことを確認する方法で行なった。試料７〜１０はすべて、ＺｎＯを主成分とした素体１を一回焼成した後、側面高抵抗層２としてガラスを厚み５０〜１００μｍ形成し、研磨せずに全面電極を形成したものである。
【００３７】
表５から分かるように、バリスタ電圧が２５０Ｖ／ｍｍまでのものについては良好な耐量性能を有することがわかる。但し、試料７の１００Ｖ／ｍｍのものは耐量性能は良いが、実際に避雷器として使用する際には、使用枚数が多く必要となる。従って、避雷器が大きくなってしまい、避雷器としての価格は高くなってしまう。
【００３８】
また、試料１０のバリスタ電圧が４００Ｖ／ｍｍのものについては、耐量性能に問題がある。１５０Ａ通電時に電解が大きくなり過ぎて素体１の側面端部の凹みへの電解集中が大きくなり破壊するものと考えられる。
【００３９】
従って、バリスタ電圧１５０〜２５０Ｖ／ｍｍの非直線抵抗体を簡単で安価な工程を用いて得ることができ、避雷器を簡単で安価に提供することができる。
【００４０】
【発明の効果】
以上のようにこの発明によれば、素体は、主成分を酸化亜鉛（ＺｎＯ）とし、添加物として酸化ビスマス（Ｂｉ_２Ｏ_３）を０．６６〜０．８モル％、酸化アンチモン（Ｓｂ_２Ｏ_３）を０．０５〜０．２モル％、酸化コバルト（Ｃｏ_３Ｏ_４）と酸化マンガン（Ｍｎ_３Ｏ_４）とをそれぞれ０．０３３〜０．６７モル％、酸化クロム（Ｃｒ_２Ｏ_３）を０．０１〜０．５モル％、ほう酸（Ｈ_３ＢＯ_３）を０．４〜２モル％、硝酸アルミニウム（Ａｌ（ＮＯ_３）_３・９Ｈ_２Ｏ）を０．００１〜０．０１モル％の割合とし、上記主成分と添加物との総和を１００モル％としたので、従来行なっていた１２００℃程度の高温の焼成工程を従来より低い９５０〜１０５０℃の温度で行え、非直線抵抗体を安価に製造することができる。
【図面の簡単な説明】
【図１】この発明の非直線高抵抗体を示す断面図である。
【符号の説明】
１　素体、２　側面高抵抗層、３　電極。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a nonlinear resistor, and more particularly to a lightning arrester element containing zinc oxide as a main component and a method for manufacturing the same.
[0002]
[Prior art]
Conventional non-linear resistors include, in the ZnO powder, 0.5 mol% of Bi ₂ O _3, 0.5 mol% of Co ₂ O _3, 0.5 mol% of MnO ₂ , and Sb ₂ O with respect to the total amount. ₃ 1.0 _mol%, Cr ₂ O 3 0.5 mol%, _SiO 2 0.5 mol% was added, pure water, a binder, thoroughly mixed in with the dispersion劑for example, a ball mill, was ground, the spray dryer The mixture was dried and granulated to obtain a raw material powder. This raw material powder was compression-molded to a size of 40 mm in diameter and 30 mm in thickness, and degreased under a temperature condition of 500 ° C. or more. Then, it was fired in a temperature range of 1100 to 1250 ° C to obtain a sintered body.
[0003]
Next, the glass paste for coating was printed on the side surface of the sintered body by using, for example, a screen of 125 to 250 mesh using a curved screen printer. Thereafter, the coating glass paste was baked under a temperature condition of 350 to 700 ° C. to form a side surface high resistance layer on the sintered body. Next, both end surfaces of the sintered body were polished to form an aluminum metallikon electrode, and a zinc oxide varistor was obtained (for example, see Patent Document 1).
[0004]
Further, conventional non-linear resistor element body, as a blending, a zinc oxide (ZnO) as a main component, respectively 0.1 to 2 mole% of bismuth oxide as an additive _{(Bi 2 O} 3), antimony oxide (Sb ₂ O ₃ ), cobalt oxide (CoO), manganese oxide (MnO), chromium oxide (Cr ₂ O ₃ ), silicon oxide (SiO ₂ ), and 0.001 to 0.01 mol% of boric acid (H ₃ BO) ₃ ) and aluminum nitrate (Al (NO ₃ ) ₃ .9H ₂ O) were selected, pulverized, mixed, granulated and molded, and then fired at 1200 ° C. (for example, see Patent Document 2).
[0005]
[Patent Document 1]
JP-A-9-162016 ([0010] [0016] [0017], FIG. 1)
[Patent Document 2]
Japanese Patent Publication No. 5-22362 (page 2)
[0006]
[Problems to be solved by the invention]
The conventional method for manufacturing a nonlinear resistor is as described above.
(1) Molding.
(2) Degreasing firing (500 ° C. or higher).
(3) firing (1100 ° C to 1250 ° C);
(4) Material application and baking of the side high resistance layer.
(5) Polishing of both end faces.
(6) Metallicon electrode formation.
In order to manufacture a non-linear resistor, a number of steps including firing at a high temperature are required. For this reason, there is a problem that the manufacturing cost of the non-linear resistor becomes very expensive.
[0007]
The present invention has been made to solve the above problems, and has as its object to provide an inexpensive nonlinear resistor and a method of manufacturing the same.
[0008]
[Means for Solving the Problems]
Nonlinear resistor of the invention, element body, and the main component zinc oxide (ZnO), from 0.66 to 0.8 mol% of bismuth oxide _(Bi 2 _{O 3)} as an additive, antimony oxide (Sb ₂ O ₃ ) in an amount of 0.05 to 0.2 mol%, cobalt oxide (Co ₃ O ₄ ) and manganese oxide (Mn ₃ O ₄ ) in an amount of 0.033 to 0.67 mol%, and chromium oxide (Cr ₂ O). ₃₎ 0.01 to 0.5 mol%, boric acid _(H 3 BO ₃₎ and 0.4 to 2 mol%, aluminum nitrate _{(Al (NO} 3) the 3 · _9H 2 O) 0.001~0. The ratio is 01 mol%, and the total of the main component and the additive is 100 mol%.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a sectional view showing a nonlinear resistor according to the present invention. As shown in the figure, the non-linear resistor is a columnar element 1 that absorbs energy, a side high-resistance layer 2 provided on the side of the columnar element to prevent edge discharge, and a columnar element. And electrodes 3 for supplying a uniform electric current to the element body 1.
[0010]
Next, a method of manufacturing the non-linear resistor according to the present invention will be described. First, as a principal component zinc oxide as the material of the element body 1 (ZnO), as an additive, 0.66 to 0.8 mol% of bismuth oxide _(Bi 2 _{O 3),} an antimony oxide _(Sb 2 _{O 3)} 0.05 to 0.2 mol%, cobalt oxide (Co ₃ O ₄ ) and manganese oxide (Mn ₃ O ₄ ) are 0.033 to 0.67 mol%, respectively, and chromium oxide (Cr ₂ O ₃ ) is 0. .01～0.5 mol%, boric acid _(H 3 BO ₃₎ and 0.4 to 2 mol%, aluminum nitrate _{(Al (NO 3) 3 ·} 9H 2 O) of 0.001-0.01 mole% And the total of the main component and the additive was 100 mol%. Further, nickel oxide (NiO) or the like may be added to make the total amount 100 mol%.
[0011]
The mixing of the additive material for forming the element body 1 is limited to a slightly smaller amount of bismuth oxide (Bi ₂ O ₃ ) of 0.66 to 0.8 mol% than that described in the related art. Then, antimony oxide (Sb ₂ O ₃ ) was less, cobalt oxide (Co ₃ O ₄ ) and manganese oxide (Mn ₃ O ₄ ) were the same, chromium oxide (Cr ₂ O ₃ ) was less, and boric acid was used. _{(H 3} BO 3) is significantly more, aluminum nitrate _{(Al (NO 3) 3 ·} 9H 2 O) is the same amount, silicon oxide (SiO ₂₎ and nickel oxide (NiO) was not added.
[0012]
A small amount of water and polyvinyl alcohol (PVA) for a binder is added to a mixture of the crushed additive and zinc oxide, mixed well to form a slurry, and then granulated to form a granulated powder. Thus, a columnar element body 1 is formed.
Next, the element body 1 is placed on a firing table and fired at a first temperature of 950 to 1050 ° C., and the element is fired while removing the binder. Although this is a lower temperature than the above-mentioned conventional technique, it is possible to sinter sufficiently and densely even at a low temperature by using the composition of the material of the element body 1 of the first embodiment.
[0013]
Further, the columnar element body 1 is formed, for example, by forming a groove such as a V-shaped notch as a fixing portion on a firing table and fixing the curved surface of the element body 1 with the groove. Instead, it is fixed on the firing table on the side and fired. Therefore, firing can be performed without bringing the electrode surface into contact with the firing table.
[0014]
Next, an epoxy-modified silicone, which is a resin material, diluted with a thinner is applied to the side surface of the element body 1 to form the side surface high-resistance layer 2. At this time, the electrode surface is covered, and the side surface high-resistance layer material does not drip on the electrode surface. In addition, the resin material can be baked by a heat treatment at 100 to 200 ° C., which is a second temperature lower than the first temperature, and the sintering temperature after the formation of the side surface high-resistance layer 2 conventionally performed can be further reduced. .
[0015]
Next, a metallikon operation is performed using a mask from the periphery of the body 1 to 1 mm inside, and electrodes 3 are formed on both bottom surfaces of the body 1. This mask is for avoiding a dent of about 0.5 mm in the peripheral portion of the element body 1 formed during the molding of the element body 1.
At this time, at the time of firing, both bottom surfaces of the element body 1 are not in contact with the firing table, and the electrode forming surfaces are also covered at the time of forming the side surface high-resistance layer 2. The electrode 3 can be attached without polishing.
[0016]
[Table 1]

[0017]
Table 1 is a table showing electrical characteristics of the conventional product and the invention product described in the first embodiment. In Table 1, the flatness of the small current region and the flatness of the large current region were measured for ten samples each of the conventional product and the invention product, and the average value was represented as 100 for the conventional product.
[0018]
As shown in Table 1, the invention product has smaller small current region flatness and large current region flatness than the conventional product. This indicates that the invention product has a smaller leakage current at all times than the conventional product and has a greater voltage suppression effect during lightning. Therefore, it can be seen that the present invention shows superior electrical characteristics as compared with the conventional product.
[0019]
As described above, the side surface high-resistance layer 2 is formed of the epoxy-based resin material, and the element body 1 can be fired at 950 to 1050 ° C. once, and the electrode surface is treated during firing and when the side surface high-resistance layer 2 is formed. Since the contact with the table and the attachment of foreign matter are prevented, the polishing and cleaning steps performed before the formation of the electrode 3 can be omitted. Therefore, in the production of a non-linear resistor, the element can be densely hardened by a single firing at a lower temperature than the conventional technology, the number of steps can be reduced, and the non-linear resistor can be manufactured at low cost. Can be.
[0020]
Embodiment 2 FIG.
In the first embodiment, a method of manufacturing a non-linear resistor having good electric characteristics with a small number of steps has been described. Here, a method of manufacturing a non-linear resistor having good withstand performance will be further described. .
[0021]
A non-linear resistor is formed in the same manner as in the first embodiment. However, sample 1 was prepared with the side high-resistance layer 2 having a thickness of 30 μm, and sample 2 was prepared with the side high-resistance layer 2 having a thickness of 60 μm. The tolerance test was performed by preparing 10 pieces each of a conventional product, sample 1 and sample 2, and applying a square wave of 150 A and 2 ms 10 times to confirm that there was no abnormality. Table 2 is a table showing the ratios of those having no abnormality in the devices after the proof test as acceptable products.
[0022]
[Table 2]

[0023]
From Table 2, it can be seen that the conventional product and Sample 2 have equally good performance. Further, according to an experiment conducted by the inventor, in the method of manufacturing the nonlinear resistor shown in the first embodiment, if the side high-resistance layer 2 is formed to have a thickness of about 50 to 100 μm, the square wave withstand capability is good and the conventional product is inferior. A non-linear resistor without any problem can be formed easily and inexpensively.
[0024]
Embodiment 3 FIG.
In the first and second embodiments, the case where the side surface high resistance layer is formed of epoxy resin has been described. Here, the case where the side surface high resistance layer is formed of low melting point glass will be described.
[0025]
A non-linear resistor is formed in the same manner as in the first embodiment. However, low-melting-point glass that can be vitrified at a temperature that does not affect the element 1 at 500 to 600 ° C. is formed on the side of the element 1 as the side surface high-resistance layer 2 with a thickness of about 50 to 100 μm. Thereafter, the electrodes 3 are formed on both bottom surfaces of the element body 1 in substantially the same manner as in the first embodiment.
Table 3 shows the results of a proof test performed using a sample formed by changing the electrode formation range while the thickness of the low melting point glass as the side surface high resistance layer 2 is the same of 50 to 100 μm. is there.
[0026]
[Table 3]

[0027]
In Table 3, Sample 3 was formed by forming an electrode 3 (entire electrode) from the periphery of the body 1 to 0 mm inside without using a mask, and Sample 4 was formed by using a mask to form the electrode 3 from the periphery of the body 1 to 1 mm inside. The sample 5 was prepared by forming 10 electrodes 3 each from the periphery of the element body 1 to 2 mm inside from the periphery of the element body 1 using a mask, and a square wave of 150 A, 2 ms was supplied 10 times to confirm that there was no abnormality. Was performed in the following manner.
[0028]
As can be seen from Table 3, when the low-melting glass is used as the side surface high-resistance layer, when the electrode 3 has a thickness of 50 to 100 μm and the electrode 3 has a size of 0 to 2 mm from the periphery of the element body 1, it has a good resistance. Performance was obtained. In particular, when a low-melting glass is used as the side high-resistance layer, when the thickness is 50 to 100 μm, a good non-linear resistor that is not inferior to the conventional product can be obtained even if the entire surface electrode is formed. Was.
This is presumably because the low-melting glass has better coverage than the resin used in the first embodiment, and the depression around the element body 1 can be covered with the glass.
[0029]
Table 4 shows the results of a proof test performed using samples formed by changing the thickness of the low-melting glass, which is the side surface high-resistance layer 2.
[0030]
[Table 4]

[0031]
In Table 4, Sample 3 is a full-surface electrode, in which the thickness of the low-melting glass, which is the side surface high-resistance layer 2, is 50 to 100 μm, which is the same as that used in Table 3. Sample 6 is a full-surface electrode in which the thickness of the low-melting glass is 30 μm. Ten pieces each were prepared, and a square wave of 150 A, 2 ms was supplied 10 times to confirm that there was no abnormality.
[0032]
As can be seen from Table 4, when a low-melting glass having a thickness of 50 to 100 μm is used as the side high-resistance layer, a good non-linear resistor can be obtained even if the entire surface electrode is formed.
[0033]
That is, if low-melting-point glass having a thickness of 50 to 100 μm is used as the side surface high-resistance layer and the entire surface electrode is formed, the formation of a mask in the electrode forming step in the method for manufacturing a non-linear resistor can be eliminated. A non-linear resistor can be easily and inexpensively manufactured.
[0034]
Embodiment 4 FIG.
A varistor voltage of a lightning arrester element using a linear resistor produced by using the manufacturing method of the present invention described in the first to third embodiments will be described.
Table 5 shows the results of a proof performance test performed on a device manufactured by the manufacturing method of the present invention, using a sample in which the varistor voltage per 1 mm thickness was changed.
[0035]
[Table 5]

[0036]
In Table 5, Sample 7 has a varistor voltage of 100 V / mm, Sample 8 has a varistor voltage of 150 V / mm, Sample 9 has a varistor voltage of 250 V / mm, and Sample 10 has 10 varistor voltages of 400 V / mm. Each was prepared, and a square wave of 150 A, 2 ms was applied 10 times to confirm that there was no abnormality. In all of Samples 7 to 10, after firing the element body 1 containing ZnO as a main component once, a glass having a thickness of 50 to 100 μm was formed as the side high-resistance layer 2 and the entire surface electrode was formed without polishing. .
[0037]
As can be seen from Table 5, those having a varistor voltage up to 250 V / mm have good withstand performance. However, the sample 7 having 100 V / mm has good withstand capability, but when actually used as a lightning arrester, a large number of sheets must be used. Therefore, the surge arrester becomes large, and the price as the surge arrester increases.
[0038]
Further, when the varistor voltage of the sample 10 is 400 V / mm, there is a problem in the withstand capacity performance. It is conceivable that the electrolysis becomes too large when the current of 150 A is applied, so that the concentration of the electrolysis in the dent at the side end of the element body 1 increases and the element 1 is broken.
[0039]
Therefore, a non-linear resistor having a varistor voltage of 150 to 250 V / mm can be obtained using a simple and inexpensive process, and a lightning arrester can be provided simply and inexpensively.
[0040]
【The invention's effect】
According to the invention, as described above, the element body has a main component of zinc oxide (ZnO), from .66 to 0.8 mol% of bismuth oxide _(Bi 2 _{O 3)} as an additive, antimony oxide (Sb ₂ O ₃ ) of 0.05 to 0.2 mol%, cobalt oxide (Co ₃ O ₄ ) and manganese oxide (Mn ₃ O ₄ ) of 0.033 to 0.67 mol%, and chromium oxide (Cr ₂ O ₃₎ 0.01 to 0.5 mol%, boric acid _(H 3 BO ₃₎ and 0.4 to 2 mol%, aluminum nitrate _{(Al (NO} 3) the 3 · _9H 2 O) 0.001~0 0.01 mol%, and the sum of the main component and the additive was 100 mol%, so that the conventional high-temperature baking process of about 1200 ° C. can be performed at a lower temperature of 950 to 1050 ° C. Non-linear resistors can be manufactured at low cost.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a non-linear high-resistance body of the present invention.
[Explanation of symbols]
1 body, 2 side high resistance layer, 3 electrodes.

Claims (9)

In a columnar element, a side-surface high-resistance layer provided on a side surface of the element, and a nonlinear resistor composed of electrodes provided on both bottom surfaces of the element,
The element body, and the main component zinc oxide (ZnO), from 0.66 to 0.8 mol% of bismuth oxide _(Bi 2 _{O 3)} as an additive, 0.05 to antimony oxide _(Sb 2 _{O 3)} 0.2 mol%, cobalt oxide (Co ₃ O ₄ ) and manganese oxide (Mn ₃ O ₄ ) are 0.033 to 0.67 mol%, respectively, and chromium oxide (Cr ₂ O ₃ ) is 0.01 to 0 mol%. .5 mol%, boric acid _(H 3 BO ₃₎ and 0.4 to 2 mol%, aluminum nitrate _{(Al (NO 3) 3 ·} 9H 2 O) and a ratio of 0.001 to 0.01 mol%, the A non-linear resistor, wherein the total sum of a main component and the additive is 100 mol%. The non-linear resistor according to claim 1, wherein the side surface high resistance layer is made of an epoxy resin or a low melting point glass. 3. The non-linear resistor according to claim 1, wherein the thickness of the side high resistance layer is 50 to 100 [mu] m. A step of firing the columnar element at a first temperature, and applying a side surface high-resistance layer to a side surface of the fired element body, and then applying the side surface high-resistance layer to a second temperature lower than the first temperature. Baking at a temperature, and a method of manufacturing a nonlinear resistor comprising a step of forming electrodes on both bottom surfaces of the element body,
Firing said body at said first temperature, the material of the element body, the main component and zinc oxide (ZnO), bismuth oxide as an additive of _(Bi 2 _{O 3)} 0.66~0. 8 mol%, 0.05 to 0.2 mol% of antimony oxide _(Sb 2 _{O 3),} and cobalt oxide _(Co 3 _{O 4)} manganese oxide _(Mn 3 _{O 4)} and respectively 0.033 to 0.67 mole%, 0.01 to 0.5 mole% of chromium oxide _(Cr 2 _{O 3),} boric acid _{(H 3} BO 3) _0.4~2 mol%, aluminum nitrate _{(Al (NO 3) 3 ·} 9H 2 O) in a ratio of 0.001 to 0.01 mol%, the total of the main component and the additive is 100 mol%, and the first temperature is 950 to 1050 ° C. for firing. A method for manufacturing a non-linear resistor. After applying the side surface high resistance layer to the fired body, in the step of baking the side surface high resistance layer at a second temperature lower than the first temperature, the side surface high resistance layer is made of an epoxy resin. 5. The method according to claim 4, wherein the second temperature is set to 100 to 200 [deg.] C. for baking. After applying the side surface high-resistance layer to the fired body, in the step of baking the side surface high-resistance layer at a second temperature lower than the first temperature, the side surface high-resistance layer is made of low-melting glass. 5. The method for manufacturing a nonlinear resistor according to claim 4, wherein the second temperature is set at 500 to 600 [deg.] C. for baking. The method for manufacturing a non-linear resistor according to any one of claims 4 to 6, wherein the thickness of the side surface high resistance layer is 50 to 100 µm. A fixing unit for fixing a surface other than the electrode surface of the element body is provided on a firing table on which the element body is placed and fired, and the surface other than the electrode surface of the element body is fixed by the fixing unit. A method for manufacturing a non-linear resistor, characterized by firing an elementary body. In the eighth aspect, when the side surface high-resistance layer is a low-melting glass, the step of forming an electrode on the electrode surface of the element is a step of forming the electrode on the entire surface without polishing the electrode surface. A method for producing a non-linear resistor.

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