JPH03150827A - Manufacture of aluminum electrode for electrolytic capacitor - Google Patents
Manufacture of aluminum electrode for electrolytic capacitorInfo
- Publication number
- JPH03150827A JPH03150827A JP28955889A JP28955889A JPH03150827A JP H03150827 A JPH03150827 A JP H03150827A JP 28955889 A JP28955889 A JP 28955889A JP 28955889 A JP28955889 A JP 28955889A JP H03150827 A JPH03150827 A JP H03150827A
- Authority
- JP
- Japan
- Prior art keywords
- aluminum
- deposited
- nitride
- electrode
- electrolytic capacitor
- 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.)
- Pending
Links
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 40
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 40
- 239000003990 capacitor Substances 0.000 title claims description 29
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 21
- 238000001704 evaporation Methods 0.000 claims description 16
- CFJRGWXELQQLSA-UHFFFAOYSA-N azanylidyneniobium Chemical compound [Nb]#N CFJRGWXELQQLSA-UHFFFAOYSA-N 0.000 claims description 15
- 238000007740 vapor deposition Methods 0.000 claims description 11
- 230000008020 evaporation Effects 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 25
- 229910052751 metal Inorganic materials 0.000 abstract description 15
- 239000002184 metal Substances 0.000 abstract description 15
- 150000004767 nitrides Chemical class 0.000 abstract description 8
- 229910021645 metal ion Inorganic materials 0.000 abstract description 7
- 229910052758 niobium Inorganic materials 0.000 abstract description 7
- 239000010955 niobium Substances 0.000 abstract description 7
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 abstract description 7
- 238000006243 chemical reaction Methods 0.000 abstract description 6
- 230000006866 deterioration Effects 0.000 abstract description 5
- 229910001873 dinitrogen Inorganic materials 0.000 abstract description 5
- 238000000151 deposition Methods 0.000 abstract description 4
- 239000013077 target material Substances 0.000 abstract description 4
- 230000001070 adhesive effect Effects 0.000 abstract 2
- 230000008021 deposition Effects 0.000 abstract 1
- 239000010408 film Substances 0.000 description 16
- 239000010409 thin film Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 150000002500 ions Chemical class 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 239000008151 electrolyte solution Substances 0.000 description 4
- 239000011888 foil Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- 238000000541 cathodic arc deposition Methods 0.000 description 3
- 238000010891 electric arc Methods 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 239000001307 helium Substances 0.000 description 3
- 229910052734 helium Inorganic materials 0.000 description 3
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 3
- 238000005121 nitriding Methods 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 239000010405 anode material Substances 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005422 blasting Methods 0.000 description 2
- 239000010406 cathode material Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052754 neon Inorganic materials 0.000 description 2
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- FLDCSPABIQBYKP-UHFFFAOYSA-N 5-chloro-1,2-dimethylbenzimidazole Chemical compound ClC1=CC=C2N(C)C(C)=NC2=C1 FLDCSPABIQBYKP-UHFFFAOYSA-N 0.000 description 1
- 239000001741 Ammonium adipate Substances 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 235000019293 ammonium adipate Nutrition 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 238000010849 ion bombardment Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000000053 physical method Methods 0.000 description 1
- 238000005268 plasma chemical vapour deposition Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 238000005019 vapor deposition process Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Landscapes
- Physical Vapour Deposition (AREA)
Abstract
Description
この発明は電解コンデンサに用いられるアルミニウム電
極の製造方法に関し、さらに詳しくは表面に誘電体層が
形成された陰極用電極に用いられる高純度アルミニウム
電極の製造方法に関する。The present invention relates to a method of manufacturing an aluminum electrode used in an electrolytic capacitor, and more particularly to a method of manufacturing a high-purity aluminum electrode used as a cathode electrode having a dielectric layer formed on the surface.
電解コンデンサは、小型、大容量、安価で整流出力の平
滑用などの用途に優れた特性を示し、各種の電気・電子
機器の重要な構成要素の一つである。
電解コンデンサは、一般にアルミニウム等の絶縁性酸化
皮膜が形成され得る、いわゆる弁金属を陽極に用い、前
記絶縁性酸化皮膜を誘電体層として用い、集電用の陰極
電極との間に電解液を介在させてコンデンサ素子が作成
され、この素子を外装容器内に収納し、電極と外部との
電気的接続を得るためのリード線を設けた構造を有する
。
陽極材料は前述したように、アルミニウムをはじめ、タ
ンタル、ニオブ、チタンなどが使用される。また集電の
ための陰極電極材料には、通常陽極材料と同種の金属が
用いられる。
ところが、弁金属は一般に自然酸化による酸化皮膜層が
表面に形成される。この傾向はアルミニウムにおいて特
に顕著である。そしてこの自然酸化皮膜は極めて薄い絶
縁層のため、陰極側にも静電容量が形成され、電解コン
デンサは陽極側の静電容量および、陰極側の静電容量が
直列に接続された合成容量となり、所望の静電容量が得
られなくなる。また所望の静電容量を得ようとすれば、
陽極側の静電容量を必要以上に大きくする必要がある。
この影響を少なくするためには、陽極側の静電容量値に
比べて陰極側の静電容量値を著しく高くすれば、陰極側
の静電容量による影響は殆ど無視できることになるが、
低電圧用の電解コンデンサの陽極側の静電容量は相当に
高く、これをより高くするのは困難で、合成容量による
静電容量値の低下は免れ得ない。
そこで陰極側の電極の静電容量値をより高くするために
、陰極電極表面をエツチング処理して表面積を拡大する
方法がある。しかしこの表面積を拡大する技術は、現在
では高度に洗練されているが、この技術のみによって電
解コンデンサの静電容量を飛曜的に増加させるのは次第
に困難になりつつある。
むしろ陰極との合成容量による静電容量の低下の問題の
解決のためには、陰極の表面部に静電容量値を持つ自然
酸化皮膜が形成されないか、あるいは形成されてもその
自然酸化皮膜が極めて薄く、高容量のまま保持できる形
態をとるのが望ましい。
このために、陰極材料の少な（との表面に弁金属以外の
金属を用いれば、絶縁性の酸化皮膜が形成されない。
そこでこれを解決する手段として、例えば特開昭６０−
１８２６号公報のように、アルミニウムの表面に各種の
導電性の金属を真空蒸着することが知られている。また
薄膜を形成するためには、前記の真空蒸着によるものの
ほか、イオンブレーティング法、スパッタリング法また
はプラズマＣＶＤ法なのような各種の物理的方法がある
。
しかし、電解コンデンサは内部に電解液が含浸されてお
り、電解液との反応によって腐食等の不具合が発生する
ことから、陰極材料として弁金属以外に問題なく使用で
きるものは、白金、金等の安定性の高い貴金属に限られ
る。しかしこれらの貴金属を集電用の陰極として用いる
ことは、経済的な理由ゆえまず不可能である。
しかも前記した方法では、アルミニウム表面における金
属の蒸着膜の密着性は必ずしも充分でなく、特に被蒸着
物の選択と、蒸着技術を改良してより優れた電解コンデ
ンサ用アルミニウム陰極電極を製造する余地が残されて
いた。
また前記した既存の蒸着技術では、処理時間が長くかか
るため、生産効率の点でも不十分であった。Electrolytic capacitors are small, large-capacitance, inexpensive, and have excellent characteristics for applications such as smoothing rectified output, and are one of the important components of various electrical and electronic devices. Electrolytic capacitors generally use a so-called valve metal such as aluminum on which an insulating oxide film can be formed as an anode, the insulating oxide film is used as a dielectric layer, and an electrolyte is placed between the cathode electrode for current collection. It has a structure in which a capacitor element is created by interposing it, this element is housed in an outer container, and lead wires are provided for electrically connecting the electrodes to the outside. As mentioned above, the anode materials used include aluminum, tantalum, niobium, and titanium. Further, the same type of metal as the anode material is usually used as the cathode electrode material for current collection. However, valve metals generally have an oxide film layer formed on their surfaces due to natural oxidation. This tendency is particularly noticeable in aluminum. Since this natural oxide film is an extremely thin insulating layer, capacitance is also formed on the cathode side, and an electrolytic capacitor is a composite capacitance in which the capacitance on the anode side and the capacitance on the cathode side are connected in series. , the desired capacitance cannot be obtained. Also, if you want to obtain the desired capacitance,
It is necessary to increase the capacitance on the anode side more than necessary. In order to reduce this effect, if the capacitance value on the cathode side is made significantly higher than the capacitance value on the anode side, the effect of the capacitance on the cathode side can be almost ignored.
The electrostatic capacitance on the anode side of a low-voltage electrolytic capacitor is quite high, and it is difficult to increase it even higher, and it is inevitable that the capacitance value will decrease due to the combined capacitance. Therefore, in order to increase the capacitance value of the cathode side electrode, there is a method of enlarging the surface area by etching the surface of the cathode electrode. However, although this technique of increasing surface area is now highly sophisticated, it is becoming increasingly difficult to dramatically increase the capacitance of electrolytic capacitors using this technique alone. Rather, in order to solve the problem of the decrease in capacitance due to the combined capacitance with the cathode, it is necessary to either prevent the formation of a natural oxide film with a capacitance value on the surface of the cathode, or to prevent the natural oxide film from forming on the surface of the cathode. It is desirable to have a form that is extremely thin and can maintain a high capacity. For this reason, if a metal other than the valve metal is used on the surface of the cathode material, an insulating oxide film will not be formed.
As disclosed in Japanese Patent No. 1826, it is known that various conductive metals are vacuum-deposited on the surface of aluminum. Further, in order to form a thin film, in addition to the above-mentioned method of vacuum evaporation, there are various physical methods such as an ion blasting method, a sputtering method, or a plasma CVD method. However, electrolytic capacitors are impregnated with an electrolytic solution, and problems such as corrosion can occur due to reactions with the electrolytic solution. Therefore, materials other than valve metal that can be used without problems as cathode materials include platinum, gold, etc. Limited to highly stable precious metals. However, it is almost impossible to use these noble metals as a current collecting cathode due to economic reasons. Moreover, with the above-mentioned method, the adhesion of the metal vapor deposited film to the aluminum surface is not necessarily sufficient, and there is room to manufacture better aluminum cathode electrodes for electrolytic capacitors by improving the selection of the material to be vaporized and the vapor deposition technology. It was left behind. Furthermore, the existing vapor deposition techniques described above are insufficient in terms of production efficiency because of the long processing time.
この発明は、電解コンデンサ用アルミニウム電極を製造
するに際し、高純度アルミニウム表面に、窒素を含んだ
全圧が１×１０−’〜Ｉ Ｘｌ０−４Ｔｏｒｒの雰囲気
中で、ニオブの窒化物からなる蒸着層を陰極アーク蒸着
法によって形成することを特徴とする電解コンデンサ用
アルミニウム電極の製造方法である。
またこの発明では、被処理材である高純度アルミニウム
を２００”Ｃないし４５０℃に加熱することも特徴とし
ている。
陰極アーク蒸着法は、ターゲット側を陰極とした陰極ア
ーク放電現象を利用して、ターゲット材料を局所的に溶
融蒸発させ、被処理材料表面に蒸着を行うもので、陰極
アーク放電の特性として、陰極側（ターゲット）に非常
に小さな陰極輝点を生じ、大きなアーク電流がこの小さ
い点に流れ込むことから、陰極点の近傍は極めて高温に
熱せられて、ニオブ等の高融点材料も瞬時に溶融蒸発さ
せる。
通常の陰極アーク蒸着法によれば、蒸着処理を行うチャ
ンバ内は、ヘリウム、アルゴン、ネオン等の不活性ガス
が僅かに存在する雰囲気中で蒸着を行うが、この発明に
おいてはニオブを窒化させ、窒化物として蒸着膜を形成
する必要があることから、チャンバ内に微量の窒素ガス
を存在させて、蒸着処理を行うものである。
そして溶融蒸発したターゲツト材は、同時に金属イオン
となり真空中に放出される。この際蒸着を行うチャンバ
内を窒素ガスを含む所定の圧力の雰囲気にしてお（こと
によって、バイアス電圧を被処理材料に印加することに
より、この金属イオンは、加速された反応ガス粒子と共
に被処理材料の表面に窒化物として蒸着され、緻密な薄
膜を生成する。
この発明によれば、被処理材料としては、通常の電解コ
ンデンサの陰極に用いる高純度の箔状あるいは板状のア
ルミニウムを用いることができる。
このアルミニウム表面は、あらかじめ脱脂処理等にをよ
り表面を清浄化しておくことが望ましい。
またアルミニウム表面は、エツチング処理を施しても良
いし、ブレーンのままであっても良い。
この発明における、陰極アーク蒸着の好ましい条件とし
ては、チャンバ内の窒素ガスの量は、窒化反応が充分行
われ、しかも遊離した金属イオンが被処理材表面に蒸着
形成されるのを妨げない範囲で選択されるべきで、その
範囲は窒素を含む全圧でｌ Ｘｌ０−’〜Ｉ Ｘｌ０−
４Ｔｏｒｒの範囲である。また上記範囲において圧力の
調整のため窒素以外に不活性ガスとしてアルゴン、ヘリ
ウム、ネオン等のガスを混合できる。
またこの発明では、蒸着されるニオブが被処理材である
高純度アルミニウム表面での窒化反応が円滑に行われる
ために、被処理材を加熱し、蒸着面での酸化反応を促進
させることも好ましいことである。この温度は窒化反応
促進の見地から言えば、比較的高い温度が良いが、被処
理材が高純度のアルミニウムであることから、その範囲
は２００゛Ｃから４５０″Ｃで行うことが好ましい。When manufacturing aluminum electrodes for electrolytic capacitors, this invention involves depositing a vapor-deposited layer of niobium nitride on the surface of high-purity aluminum in an atmosphere containing nitrogen and having a total pressure of 1 x 10-' to I Xl0-4 Torr. This is a method for producing an aluminum electrode for an electrolytic capacitor, characterized in that the aluminum electrode is formed by cathodic arc evaporation. This invention is also characterized by heating high-purity aluminum, which is the material to be treated, to 200"C to 450°C. The cathodic arc evaporation method utilizes the cathodic arc discharge phenomenon with the target side as the cathode. The target material is melted and evaporated locally and deposited on the surface of the material to be treated.As a characteristic of cathodic arc discharge, a very small cathode bright spot is generated on the cathode side (target), and a large arc current is applied to this small point. The area near the cathode spot is heated to an extremely high temperature, and high-melting point materials such as niobium are instantly melted and evaporated.According to the normal cathodic arc evaporation method, the chamber in which the evaporation process is performed uses helium, helium, Vapor deposition is performed in an atmosphere containing a small amount of inert gas such as argon or neon, but in this invention it is necessary to nitride niobium and form a deposited film as a nitride, so a trace amount of nitrogen is present in the chamber. The vapor deposition process is carried out in the presence of a gas.The melted and vaporized target material simultaneously turns into metal ions and is released into vacuum.At this time, the inside of the chamber where the vapor deposition is performed is set to a predetermined pressure atmosphere containing nitrogen gas. By applying a bias voltage to the material to be treated, the metal ions are deposited as nitrides on the surface of the material to be treated together with the accelerated reactive gas particles, producing a dense thin film. According to the present invention, the material to be treated can be high-purity foil-like or plate-like aluminum used for the cathode of ordinary electrolytic capacitors. It is desirable to keep the aluminum surface clean. Also, the aluminum surface may be etched or left blank. In this invention, the preferred conditions for cathodic arc evaporation are as follows: The amount should be selected within a range that allows the nitriding reaction to occur sufficiently and does not prevent free metal ions from being deposited on the surface of the material to be treated. ~I Xl0-
It is in the range of 4 Torr. Further, within the above range, in addition to nitrogen, gases such as argon, helium, and neon can be mixed as an inert gas in order to adjust the pressure. In addition, in this invention, in order for the nitriding reaction of niobium to be vapor-deposited to occur smoothly on the surface of high-purity aluminum, which is the material to be treated, it is also preferable to heat the material to be treated to promote the oxidation reaction on the surface of the vapor-deposited material. That's true. From the standpoint of promoting the nitriding reaction, a relatively high temperature is preferable, but since the material to be treated is high-purity aluminum, it is preferably carried out within a range of 200°C to 450°C.
【作 用］
この発明の陰極アーク蒸着法により、窒化ニオブの蒸着
薄膜が高純度アルミニウムの表面に形成できる。
窒化ニオブは、比抵抗値が２００μΩ・ｃｍと低い抵抗
値を有する硬質な化合物で、アルミニウムとの反応性も
良好なことから、アルミニウム表面に低比抵抗の緻密な
薄膜が形成される。
この結果、アルミニウム電極は表面に形成された高静電
容量の極めて薄い自然酸化皮膜か、あるいは特定の微小
部分については、自然酸化皮膜が殆ど生成されない電導
度の高い金属アルミニウムの表面がそのまま窒化ニオブ
薄膜によって安定して保護されることになり、電極全体
として高い静電容量が得られるものと思われる。
また窒化ニオブは、電解液との反応が起きにくく、電解
コンデンサの電気的特性を長期にわたって安定して維持
させる。
さらにこの発明の方法によれば、粒子のイオン化率が高
いため、イオンボンバード効果が強いこと、またコーテ
ィング中のバイアス効果も強いことなどの特徴があり、
窒化ニオブがアルミニウムとの反応性が良いことと相ま
って被処理材との密着性が極めて高い皮膜となる。
二の発明の陰極アーク蒸着法と、従来のイオンブレーテ
ィング法およびスパッタリング法について、−船釣な金
属の被処理材上のイオン化率および粒子エネルギーを比
較したものを、以下の第１表に示す。
（第 １ 表）
このように、陰極アーク蒸着法によれば、イオン化率が
他の方法に比べて著しく大きく、高イオンエネルギーで
あるため、反応効率が向上し、アルミニウム電極と蒸着
金属の窒化物との密着性ならびに緻密性を顕著に向上さ
せることができる。
また処理時間についても、この発明の陰極アーク蒸着法
によれば長くとも１０分程度で処理が終わるのに対し、
イオンブレーティング法では２０分程度、スパッタリン
グ法によれば５０分程度と、何れもこの発明の方法に比
べ相当の時間を要する。
【実 施 例】
以下実施例に基づいて、この発明を説明する。
図面は、陰極アーク蒸着に使用する装置の概略を説明し
たものである。この発明は図面の装置により、ニオブか
らなる金属ターゲット（蒸発源）１０を陰極としてアー
ク放電を起こすと、アークはターゲット１０の表面にア
ークスポットを形成し、アークスポットに集中するアー
ク電流のエネルギーにより、ターゲツト材■０は瞬時に
溶融蒸発すると同時に金属イオン１２となり、真空中に
放出される。
この際、高純度のアルミニウムからなる被処理材１４に
対しバイアス電圧を印加することにより、この金属イオ
ン１２は、加速された反応ガス粒子１６と共に被処理材
１４の表面に密着し、緻密な膜を生成する。なお、図面
中で、１８および２０はアーク電源、２２はバイアス電
源、２４は回転テーブル、２６はガス人口、２８はガス
出口、３０は真空チャンバである。
そして図面の陰極アーク薄着装置を用いて、以下の実施
例の電解コンデンサ用電極を作成した。
−災施孤一
交流による電気化学的なエツチング処理が施された高純
度のアルミニウム箔（純度９９．９５％）を５０Ｘ １
００ｍｍに切断したものを被処理材として使用し、この
表面に窒化ニオブを蒸着した。
実施例では、被処理材のアルミニウムを２００℃に加熱
しておき、窒素ガスを含むチャンバ内の全圧を５ Ｘ
１Ｏ−３Ｔｏｒｒの範囲に設定し、蒸発距離２００印、
アーク電源の電流値を１００Ａ、蒸発速度０．０５μｍ
／分とし、４分間陰極アーク蒸着を行い、０．２μｍの
膜厚の窒化ニオブ蒸着膜を形成した。
−比較■土−
被処理材の高純度アルミニウムは、実施例と同じものを
使用し、ニオブを蒸発源として、窒素ガスを含む全圧が
２ Ｘｌ０−４Ｔｏｒｒの雰囲気中で、蒸発距離２００
＋ｎｍ、形成速度０．０１ ｐ ｍ ７分で２０分間イ
オンブレーティング法による窒化ニオブ蒸着を行い、０
．２μｍの膜厚の窒化ニオブ蒸着膜を形成した。
−上ＪＪ[Function] By the cathodic arc deposition method of the present invention, a thin film of niobium nitride can be formed on the surface of high-purity aluminum. Niobium nitride is a hard compound with a low resistivity of 200 μΩ·cm and has good reactivity with aluminum, so a dense thin film with low resistivity is formed on the aluminum surface. As a result, the aluminum electrode has an extremely thin natural oxide film with high capacitance formed on its surface, or in certain microscopic areas, the surface of highly conductive metal aluminum, on which almost no natural oxide film is formed, remains as it is with niobium nitride. It is thought that the thin film provides stable protection and that a high capacitance can be obtained as a whole electrode. In addition, niobium nitride is less likely to react with the electrolytic solution and maintains the electrical characteristics of the electrolytic capacitor stably over a long period of time. Furthermore, according to the method of this invention, since the ionization rate of particles is high, the ion bombardment effect is strong, and the bias effect during coating is also strong.
Combined with the fact that niobium nitride has good reactivity with aluminum, the result is a film with extremely high adhesion to the treated material. Table 1 below shows a comparison of the ionization rate and particle energy of the cathodic arc evaporation method of the second invention and the conventional ion blating method and sputtering method on the metal to be treated. . (Table 1) As described above, according to the cathodic arc evaporation method, the ionization rate is significantly higher than that of other methods, and the ion energy is high, so the reaction efficiency is improved and the nitride of the aluminum electrode and the deposited metal are It is possible to significantly improve the adhesion and density of the material. Regarding the processing time, according to the cathodic arc evaporation method of the present invention, the processing can be completed in about 10 minutes at the most.
The ion blasting method takes about 20 minutes, and the sputtering method takes about 50 minutes, both of which take a considerable amount of time compared to the method of the present invention. [Examples] The present invention will be described below based on Examples. The drawings schematically illustrate an apparatus used for cathodic arc deposition. This invention uses the device shown in the drawings to cause arc discharge using a metal target (evaporation source) 10 made of niobium as a cathode, the arc forms an arc spot on the surface of the target 10, and the energy of the arc current concentrated on the arc spot causes the arc to discharge. The target material 10 instantaneously melts and evaporates, turning into metal ions 12 and being released into the vacuum. At this time, by applying a bias voltage to the material to be processed 14 made of high-purity aluminum, the metal ions 12, together with the accelerated reaction gas particles 16, adhere to the surface of the material to be processed 14, forming a dense film. generate. In the drawings, 18 and 20 are arc power sources, 22 is a bias power source, 24 is a rotary table, 26 is a gas port, 28 is a gas outlet, and 30 is a vacuum chamber. Then, electrodes for electrolytic capacitors according to the following examples were created using the cathodic arc thinning apparatus shown in the drawings. - High purity aluminum foil (purity 99.95%) that has been electrochemically etched using alternating current (50x1)
A piece cut into 00 mm was used as a material to be treated, and niobium nitride was vapor-deposited on the surface. In the example, aluminum as the material to be treated is heated to 200°C, and the total pressure inside the chamber containing nitrogen gas is increased to 5
Set to 1O-3Torr range, evaporation distance 200 mark,
The current value of the arc power source is 100A, and the evaporation rate is 0.05μm.
/min, and cathodic arc deposition was performed for 4 minutes to form a niobium nitride evaporated film with a thickness of 0.2 μm. - Comparison ■ Soil - The same high-purity aluminum as the material to be treated was used as in the example, and the evaporation distance was 200 in an atmosphere containing nitrogen gas with a total pressure of 2 Xl0-4 Torr using niobium as the evaporation source.
+nm, formation rate 0.01 pm Niobium nitride evaporation was performed by ion blating method for 7 minutes for 20 minutes, and 0.
．． A niobium nitride vapor deposited film with a thickness of 2 μm was formed. -Upper JJ
【Ｌ−
被処理材の高純度アルミニウムは、実施例と同一のもの
を用いた。従ってこの処理材では、表面が交流による電
気化学的なエツチング処理が施されたのみである。
これら実施例および比較例のうち、蒸着処理をしたもの
について、蒸着された窒化ニオブの付着力を測定し、密
着性を調べたところ、実施例のものは、付着力が３．１
Ｋｇｍ５であったのに対し、比較例１のものは２．４Ｋ
ｇｍ５であり、この発明の陰極アーク蒸着法による薄膜
の密着性の良いことがわかる。
次に、これらの実施例および比較例の、単位面積あたり
の静電容量値を測定した結果を第２表に示す。
（第 ２ 表）
この結果かられかるように、従来のアルミニウム電極表
面をエツチング処理したのみの電極の静電容量は、蒸着
により窒化ニオブ層を設けたものに比べて著しく静電容
量値が低いことがわかる。
また蒸着法により窒化ニオブ薄膜を形成したものは、い
ずれも高い静電容量値を示すが、この発明の陰極アーク
蒸着によるものは、比較例１の従来の方法に比べて短時
間でほぼ同等の厚さの薄膜を得ることができ、製造効率
に優れることがわかる。
次に形成された薄膜の安定性を調べるために、これらの
被処理材を実際の陰極として電解コンデンサを作成し、
寿命試験を行い特性の変化を調べた。
作成した電解コンデンサは、リード線同一方向型の電解
コンデンサで、箔状の電極をセパレータと共に巻回した
素子に電解液を含浸し、金属ケースに収納し、開口部を
封口ゴムで密閉したものである。電解コンデンサを構成
する材料は、陰極箔として、上記の実施例および比較例
のものを用いた以外は全て共通のものを用いた。また組
立方法についても全て同じである。
電解コンデンサの定格は、定格電圧６．３■、定格静電
容量４７μＦ、外形寸法が直径５ ｍｍ、長さ７柵であ
る。使用した電解液の組成は、エチレングリコール７８
重量％、アジピン酸アンモニウム１０重量％、水１２重
量％の組成からなるもので、通常用いられる電解液に比
べて、水の含有量を多くしである。これは、水による電
極箔の水和劣化の発生が顕著になるようにしたためであ
る。
この電解コンデンサに定格電圧を印加し、１１０℃で５
００時間寿命試験を行った後の静電容量値と、初期の静
電容量値との変化率を調べた。この結果を第３表に示す
。
（第
表）
この結果かられかるように、この発明のアルミニウム電
極は、エツチング処理のみが行われたものはもとより、
他の蒸着法を用いたものに比べても表面の劣化や経時変
化が少なく、長期にわたって特性が安定していることが
わかる。
【発明の効果】
以上述べたようにこの発明によれば、電解コンデンサ用
の電極として、単位面積あたりの静電容量値を高めるこ
とができるので、特に低圧領域において、電解コンデン
サを小型化できるとともに、大容量の電解コンデンサが
得られる。
また電極表面が窒化ニオブによって保護されるので、長
期にわたって安定した電気特性が維持でき、電解コンデ
ンサの信頬性が向上する。
さらに電極の処理時間が短時間で済むことから、生産効
率が良いという利点がある。[L- The same high-purity aluminum as in the example was used as the material to be treated. Therefore, in this treated material, the surface was only subjected to electrochemical etching treatment using alternating current. Among these Examples and Comparative Examples, the adhesion force of the vapor-deposited niobium nitride was measured for those subjected to vapor deposition treatment, and the adhesion was investigated.
Kgm5, whereas that of Comparative Example 1 was 2.4K.
gm5, which indicates that the thin film obtained by the cathodic arc evaporation method of the present invention has good adhesion. Next, Table 2 shows the results of measuring the capacitance values per unit area of these Examples and Comparative Examples. (Table 2) As can be seen from these results, the capacitance of a conventional aluminum electrode with only an etched surface is significantly lower than that of an electrode with a niobium nitride layer formed by vapor deposition. I understand that. In addition, all of the niobium nitride thin films formed by the vapor deposition method show high capacitance values, but the one formed by the cathodic arc vapor deposition method of this invention achieves almost the same capacitance value in a shorter time than the conventional method of Comparative Example 1. It can be seen that a thin film can be obtained and the manufacturing efficiency is excellent. Next, in order to investigate the stability of the formed thin film, we created an electrolytic capacitor using these treated materials as actual cathodes.
A lifespan test was conducted to examine changes in characteristics. The electrolytic capacitor we created is an electrolytic capacitor with lead wires in the same direction.The element is made by winding foil electrodes together with a separator and is impregnated with electrolyte.The electrolytic capacitor is housed in a metal case, and the opening is sealed with a rubber seal. be. All of the materials constituting the electrolytic capacitors were common, except that the cathode foil used in the above examples and comparative examples was used. The assembly method is also the same. The electrolytic capacitor has a rated voltage of 6.3 mm, a rated capacitance of 47 μF, and an external dimension of 5 mm in diameter and 7 bars in length. The composition of the electrolyte used was ethylene glycol 78
It has a composition of 10% by weight of ammonium adipate and 12% by weight of water, which has a higher water content than a commonly used electrolytic solution. This is to make the occurrence of hydration deterioration of the electrode foil due to water more noticeable. Apply the rated voltage to this electrolytic capacitor, and
The rate of change between the capacitance value after the 00 hour life test and the initial capacitance value was investigated. The results are shown in Table 3. (Table) As can be seen from the results, the aluminum electrodes of the present invention include those that have only been subjected to etching treatment, as well as
It can be seen that compared to those using other vapor deposition methods, there is less surface deterioration and change over time, and the characteristics are stable over a long period of time. [Effects of the Invention] As described above, according to the present invention, as an electrode for an electrolytic capacitor, it is possible to increase the capacitance value per unit area, so it is possible to downsize the electrolytic capacitor, especially in the low voltage region. , a large capacity electrolytic capacitor can be obtained. Furthermore, since the electrode surface is protected by niobium nitride, stable electrical characteristics can be maintained over a long period of time, improving the reliability of the electrolytic capacitor. Furthermore, since the processing time for the electrodes is short, it has the advantage of high production efficiency.
図面は、この発明で用いる陰極アーク薄着装置の概略を
表した説明図である。The drawing is an explanatory diagram schematically showing a cathodic arc thinning apparatus used in the present invention.
Claims (2)
１×１０＾−＾１〜１×１０＾−＾４Ｔｏｒｒの雰囲気
中で、ニオブの窒化物からなる蒸着層を陰極アーク蒸着
法によって形成することを特徴とする電解コンデンサ用
アルミニウム電極の製造方法。(1) A vapor deposited layer of niobium nitride is formed on the surface of high-purity aluminum by cathodic arc evaporation in an atmosphere containing nitrogen with a total pressure of 1 x 10^-^1 to 1 x 10^-^4 Torr. A method for manufacturing an aluminum electrode for an electrolytic capacitor, characterized by:
℃に加熱して蒸着を行う請求項１記載の電解コンデンサ
用アルミニウム電極の製造方法。(2) High-purity aluminum to be treated at 200°C to 450°C
The method for manufacturing an aluminum electrode for an electrolytic capacitor according to claim 1, wherein the vapor deposition is performed by heating to a temperature of .degree.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28955889A JPH03150827A (en) | 1989-11-07 | 1989-11-07 | Manufacture of aluminum electrode for electrolytic capacitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28955889A JPH03150827A (en) | 1989-11-07 | 1989-11-07 | Manufacture of aluminum electrode for electrolytic capacitor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03150827A true JPH03150827A (en) | 1991-06-27 |
Family
ID=17744792
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28955889A Pending JPH03150827A (en) | 1989-11-07 | 1989-11-07 | Manufacture of aluminum electrode for electrolytic capacitor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03150827A (en) |
-
1989
- 1989-11-07 JP JP28955889A patent/JPH03150827A/en active Pending
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