JPH07204936A - Graphite electrode for electrochemical machining - Google Patents
Graphite electrode for electrochemical machiningInfo
- Publication number
- JPH07204936A JPH07204936A JP3407194A JP3407194A JPH07204936A JP H07204936 A JPH07204936 A JP H07204936A JP 3407194 A JP3407194 A JP 3407194A JP 3407194 A JP3407194 A JP 3407194A JP H07204936 A JPH07204936 A JP H07204936A
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- Japan
- Prior art keywords
- graphite
- electrode
- graphite material
- metal
- pore volume
- 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.)
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- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は電解加工用黒鉛電極に関
する。FIELD OF THE INVENTION The present invention relates to a graphite electrode for electrolytic processing.
【０００２】[0002]
【従来の技術】精密な金型をより短納期で納入するため
の対応策として、放電加工時において、荒加工は大電流
による高速加工とし、必要な面粗さに見合う電気条件で
仕上げ放電加工を行っている。しかしながら、例えば面
粗さが１０μｍＲｍａｘ以下の加工精度を要求される場
合には、電気条件を抑制する必要があり、そのため加工
時間がけた違いに長くなる。2. Description of the Related Art As a measure to deliver precision molds in a shorter delivery time, during electric discharge machining, rough machining is performed at high speed with a large current, and finish electric discharge machining is performed under electrical conditions suitable for the required surface roughness. It is carried out. However, for example, when the surface roughness is required to have a processing accuracy of 10 μmR max or less, it is necessary to suppress the electrical conditions, and therefore the processing time becomes erroneously long.
【０００３】電解加工法は、放電加工における仕上げ面
粗さを極めて短時間で良くする方法で、その原理は、電
解加工液（以下、電解液と略す）中で陰極となる電極と
陽極となる被加工物の間に、高密度の電流を通じて被加
工物を加工するものである。この方法で加工を行うと、
被加工物の表面は極めて平滑な加工面が得られる。The electrolytic machining method is a method of improving the finished surface roughness in electric discharge machining in an extremely short time, and its principle is to form an electrode and an anode which become cathodes in an electrolytic machining solution (hereinafter abbreviated as electrolytic solution). A workpiece is processed by passing a high-density electric current between the workpieces. When processed by this method,
An extremely smooth machined surface can be obtained on the surface of the workpiece.
【０００４】通常、電解加工に使用される電極は、製品
の形状に合わせた電極を別途製作することもあるが、被
加工物と電極との間のクリアランスを一定にすることが
困難であるので、より精密な金型を製作するためには、
専ら仕上げ放電加工に使用された電極が使用されてい
る。Usually, as an electrode used for electrolytic processing, an electrode matching the shape of the product may be separately manufactured, but it is difficult to make the clearance between the workpiece and the electrode constant. , To make a more precise mold,
The electrodes used exclusively for finishing electrical discharge machining are used.
【０００５】電解加工に使用される電極材料としては、
主に銅または黒鉛材料が使用されている。銅は気孔が存
在しない反面、電極を製作するために費やす時間が長
く、しかも密度が黒鉛の約５倍で、放電加工機及び電解
加工機への取り付け重量に制限があるため、大型の電極
は使用できなかった。また、重いため持ち運びが不便
で、作業性も悪かった。これに対し、黒鉛材料は機械加
工時の切削抵抗が金属の約１／１０であるので加工性が
良く、複雑な形状の電極であっても製作し易く、電極の
消耗も少ないという長所を有し、年々使用量が増加して
きている。As the electrode material used for electrolytic processing,
Copper or graphite materials are mainly used. Although copper has no pores, it takes a long time to manufacture an electrode, its density is about 5 times that of graphite, and the weight attached to an electric discharge machine or an electrolytic machine is limited. I couldn't use it. Moreover, since it is heavy, it is inconvenient to carry and workability is poor. On the other hand, the graphite material has a cutting resistance at the time of machining which is about 1/10 of that of the metal, so that it has good machinability, and it has the advantage that it is easy to manufacture even an electrode having a complicated shape and the consumption of the electrode is small. However, the usage is increasing year by year.
【０００６】ところが、電極に用いる人造黒鉛材料は、
炭素質骨材を結合剤と混練し、成形、焼成、黒鉛化して
得られる多孔質材料であるため多くの気孔を有し、電解
加工に使用すると、電解液が黒鉛電極表面の気孔から電
極内部に浸透し、電解液の結晶が気孔壁に析出し、再び
電極として使用するためには、水洗いしなければならな
いという欠点があった。However, the artificial graphite material used for the electrodes is
Since it is a porous material obtained by kneading a carbonaceous aggregate with a binder, molding, firing, and graphitizing, it has many pores.When it is used for electrolytic processing, the electrolytic solution causes the electrolyte from the pores on the surface of the graphite electrode to the inside of the electrode. However, there was a drawback in that crystals of the electrolytic solution were deposited on the pore walls and had to be washed with water in order to be used again as an electrode.
【０００７】そこで、上記黒鉛電極の持つ欠点を補うた
めに、例えば（１）特開平５−１６９３１９号公報に
は、黒鉛基材の表面に熱分解炭素あるいはガラス状カー
ボンの被膜を形成した黒鉛電極、（２）黒鉛基体に電気
めっきを施す等で電解液の浸透を防止する手段が提案さ
れている。Therefore, in order to make up for the drawbacks of the above graphite electrode, for example, (1) Japanese Patent Laid-Open No. 5-169319 discloses a graphite electrode in which a pyrolytic carbon or glassy carbon coating is formed on the surface of a graphite substrate. (2) A means for preventing the permeation of an electrolytic solution by applying electroplating to a graphite substrate has been proposed.
【０００８】また、用途及び使用条件は異なるが、
（３）特開昭６３−７４５２２号公報には、放電加工用
黒鉛電極に金属を含浸した電極、（４）特開平５−１８
２７３３号公報には、炭素基体の表面を無電解めっき法
で形成したカーボンブラシが開示されている。[0008] Further, although the use and use conditions are different,
(3) JP-A-63-74522 discloses an electrode in which a graphite electrode for electric discharge machining is impregnated with a metal, and (4) JP-A-5-18.
Japanese Patent No. 2733 discloses a carbon brush in which the surface of a carbon substrate is formed by electroless plating.
【０００９】[0009]
【発明が解決しようとする課題】ところが、（１）に開
示されるような電極を使用すると、電解加工を行ってい
る最中に、黒鉛基体と被膜の熱膨張係数の違いが原因と
考えられるクラックが被膜に発生するという欠点があっ
た。また、熱分解炭素あるいはガラス状カーボンを被覆
した電極は、電解加工時に電極が短絡によって損傷する
という問題点があった。However, when the electrode as disclosed in (1) is used, it is considered that the difference in the coefficient of thermal expansion between the graphite substrate and the coating film is caused during the electrolytic processing. There was a defect that cracks were generated in the coating. Further, the electrode coated with pyrolytic carbon or glassy carbon has a problem that the electrode is damaged by a short circuit during electrolytic processing.
【００１０】また、（２）のように黒鉛電極の表面に電
気めっきで金属の被膜を形成させると、黒鉛基体に金属
被膜が形成され難い（即ち、金属の、乗りが悪い）だけ
でなく、得られた電極を電解加工に使用すると、黒鉛電
極と金属被膜の接合部分の接合強度が弱いため、金属被
膜が剥離し、やはりその部分から電解液が電極内部に浸
透するという問題点があった。さらに（３）は放電加工
に使用する黒鉛電極に関し、電極消耗を減少させ且つ加
工面粗さを向上せる内容のものであり、（４）は電気機
械用ブラシに無電解めっきを施す内容のもので、共に電
解液の浸透を防止するというものでない。When a metal coating is formed on the surface of the graphite electrode by electroplating as in (2), not only is it difficult to form a metal coating on the graphite substrate (that is, the metal does not ride well), but When the obtained electrode was used for electrolytic processing, the joint strength between the graphite electrode and the metal coating was weak, so the metal coating peeled off, and the electrolytic solution also penetrated into the electrode from that portion. . Further, (3) relates to a graphite electrode used for electrical discharge machining, which is intended to reduce electrode consumption and improve the surface roughness, and (4) is intended to apply electroless plating to brushes for electric machines. However, neither is to prevent the permeation of the electrolytic solution.
【００１１】従って、本発明は黒鉛材料の持つ優れた点
を活かしながら上記問題点、即ちクラック及び剥離を防
止して電解液が浸透せず、しかも電解加工時に電極の損
傷がない電解加工用電極を提供することを目的とする。Therefore, the present invention makes use of the advantages of the graphite material while preventing the above-mentioned problems, that is, preventing cracks and peeling and preventing the electrolyte solution from penetrating, and that the electrode is not damaged during electrolytic processing. The purpose is to provide.
【００１２】[0012]
【課題を解決するための手段】そこで、本発明者らは上
記問題点を解決するために試験研究を重ねた結果、平均
気孔半径及び累積気孔容積を特定した黒鉛基体に金属被
膜を形成させると、電解加工時に金属被膜に剥離及びク
ラックが発生せず、その上、電解液の浸透も防止でき、
さらに都合の良いことに、電気伝導性の良い金属の被膜
を電極表面に形成させると、電解加工時に、電極が突発
的に大きな短絡を起こさずに電極の損傷を防止できるこ
とを見いだして本発明を完成するに到ったものである。
即ち、本発明は、平均気孔半径か０．１乃至３．０μｍ
であって且つ累積気孔容積が１０×１０−２・ｍ３／Ｍ
ｇ以下の黒鉛材料に、電気伝導性の良い金属の被膜を形
成させてなる電解加工用黒鉛電極を要旨とする。Accordingly, the inventors of the present invention have conducted repeated tests to solve the above-mentioned problems, and as a result, formed a metal coating on a graphite substrate having specified average pore radius and cumulative pore volume. No peeling or cracking of the metal coating during electrolytic processing, and in addition, it is possible to prevent penetration of the electrolytic solution.
More conveniently, it has been found that, by forming a metal coating having good electrical conductivity on the surface of the electrode, it is possible to prevent the electrode from being damaged during electrolysis without causing a sudden short circuit. It has been completed.
That is, the present invention has an average pore radius of 0.1 to 3.0 μm.
And the cumulative pore volume is 10 × 10 −2 · m 3 / M
The gist is a graphite electrode for electrolytic processing, which is formed by forming a metal coating having good electrical conductivity on a graphite material of g or less.
【００１３】[0013]
【発明の構成及び作用】本発明の電解加工用黒鉛電極素
材は、実質的に炭素のみからなる材料であり、ピッチ含
浸品、樹脂含浸品を包含する炭素化品や黒鉛化品等の各
種炭素材料を包含する。具体的には、石油系あるいは石
炭系のコークス、人造黒鉛、メソフェーズ炭素球晶、カ
ーボンブラック、炭素繊維等を所定の粒度に調整したも
のを炭素質骨材とし、必要に応じてコールタールピッチ
等を結合剤として混練し、二次粉砕後、押し出しあるい
は冷間静水圧加圧法または熱間静水圧加圧法等で成形
し、焼成、含浸、含浸焼成、黒鉛化して製造された高密
度等方性黒鉛や、高密度黒鉛等の黒鉛材料、焼成炭素材
料、炭素繊維強化炭素複合材料などがあげられ、これら
を電極の形状に加工して使用することができる。The graphite electrode material for electrolytic processing of the present invention is a material consisting essentially of carbon, and various carbons such as carbonized products including pitch-impregnated products and resin-impregnated products and graphitized products. Including materials. Specifically, petroleum-based or coal-based coke, artificial graphite, mesophase carbon spherulite, carbon black, carbon fiber, etc. adjusted to a predetermined particle size are used as a carbonaceous aggregate, and coal tar pitch, etc., if necessary. Is a high density isotropic material produced by firing, impregnation, impregnation firing, graphitization, or the like by extruding or molding by cold isostatic pressing or hot isostatic pressing after secondary pulverization. Examples thereof include graphite, graphite materials such as high-density graphite, calcined carbon materials, carbon fiber reinforced carbon composite materials, and the like, which can be processed into electrodes and used.
【００１４】電解加工は、大電流を流すので、室温での
電気抵抗が低い黒鉛材料とすることが望ましく、５０μ
Ω・ｍ以下、更には１５μΩ・ｍ以下の黒鉛材料を選択
することが望ましく、また放電加工に使用した電極を電
解加工に用いる場合も多々あるため、曲げ強度が５０Ｍ
Ｐａ以上の黒鉛材料を選択することが更に望ましい。そ
の中でも平均気孔半径が０．１乃至３．０μｍであって
且つ累積気孔容積が１０×１０−２・ｍ３／Ｍｇ以下の
黒鉛材料が一層望ましく、とりわけ等方性黒鉛材料を電
解加工用電極の素材とすることが最も望ましい。なお、
ここでいう等方性黒鉛材料とは、黒鉛材料における任意
に直角をなす方向に測った電気抵抗の比の平均値が０．
８乃至１．２の間の黒鉛材料をいうものとする。Since a large current is passed in the electrolytic processing, it is desirable to use a graphite material having a low electric resistance at room temperature.
It is desirable to select a graphite material of Ω · m or less, further 15 μΩ · m or less, and since the electrode used for electrical discharge machining is often used for electrolytic machining, the bending strength is 50M.
It is more desirable to select a graphite material having Pa or more. Among them, a graphite material having an average pore radius of 0.1 to 3.0 μm and a cumulative pore volume of 10 × 10 −2 · m 3 / Mg or less is more desirable, and an isotropic graphite material is particularly preferable for an electrode for electrolytic processing. It is most desirable to use this material. In addition,
The term "isotropic graphite material" as used herein means that the average value of the electrical resistance ratios of the graphite material measured in an arbitrary right angle direction is 0.
It refers to a graphite material between 8 and 1.2.
【００１５】ここで電極素材の物理特性を特定した理由
について若干説明する。平均気孔半径が０．１μｍより
も小さい黒鉛材料は製造が困難であり、平均気孔半径が
３．０μｍよりも大きな素材を使用すると、電極表面の
気孔を前記金属によって充分に封孔させることができ
ず、電解液が浸透する原因となるため望ましくない。ま
た、累積気孔容積が、１０×１０−２・ｍ３／Ｍｇより
も多い素材を用いた場合も同様に、前記金属によって気
孔を封孔することができないため望ましくない。Here, the reason why the physical characteristics of the electrode material are specified will be briefly described. It is difficult to manufacture a graphite material having an average pore radius smaller than 0.1 μm, and when a material having an average pore radius larger than 3.0 μm is used, the pores on the electrode surface can be sufficiently sealed by the metal. This is not desirable because it causes the electrolyte to permeate. Similarly, when a material having a cumulative pore volume of more than 10 × 10 −2 · m 3 / Mg is used, the pores cannot be sealed by the metal, which is also undesirable.
【００１６】なお、平均気孔半径及び累積気孔容積の測
定は水銀圧入法で行い、試料の大きさは直径１０ｍｍ、
長さ４０ｍｍの円柱形状とし、最大圧力１００ＭＰａま
で加圧したときの気孔量を累積気孔容積とし、累積気孔
容積の１／２の気孔容積に相当する値を平均気孔半径と
した。The average pore radius and the cumulative pore volume were measured by mercury porosimetry, and the sample size was 10 mm in diameter.
The columnar shape having a length of 40 mm was used as the cumulative pore volume when the maximum pressure was 100 MPa, and the value corresponding to 1/2 of the cumulative pore volume was defined as the average pore radius.
【００１７】本発明の電解加工用電極は、上記電極素材
に、例えば金属の無電解めっきを施すことによって製作
される。無電解めっきの方法自体は一般によく知られて
おり、例えば「無電解めっき」〔槙書店、神戸徳蔵著
（１９９０）〕及び「無電解めっきの応用」〔槙書店、
神戸徳蔵著（１９９１）］に詳述されており、任意に選
択することができる。The electrode for electrolytic processing of the present invention is manufactured by subjecting the above electrode material to electroless plating of metal, for example. The electroless plating method itself is generally well known, and includes, for example, "electroless plating" [Maki Shoten, Tokuzo Kobe (1990)] and "application of electroless plating" [Maki Shoten,
Tokuzo Kobe (1991)], and can be arbitrarily selected.
【００１８】なお、本発明でいう電気伝導性の良い金属
とは、室温での電気抵抗が０．５μΩ・ｍ以下の金属を
いい、その中でも黒鉛基体に容易に被膜を形成する金属
であることが更に望ましい。例えばニッケル（６．８４
×１０−２μΩ・ｍ）、コバルト（６．２４×１０−２
μΩ・ｍ）、銅（１．６７×１０−２μΩ・ｍ）、錫
（１１．０×１０−２μΩ・ｍ）、銀（１．５９×１０
−２μΩ・ｍ）、金（２．３５×１０−２μΩ・ｍ） またはこれらの金属の合金があげられる。中でも銅は電
気抵抗が低く安価であるのでもっとも使用に適している
が、本発明はこれらに限定されるものではない。The metal having good electric conductivity referred to in the present invention means a metal having an electric resistance of 0.5 μΩ · m or less at room temperature, and among them, a metal which easily forms a film on a graphite substrate. Is more desirable. For example, nickel (6.84
× 10 −2 μΩ · m), cobalt (6.24 × 10 −2)
μΩ · m), copper (1.67 × 10 −2 μΩ · m), tin (11.0 × 10 −2 μΩ · m), silver (1.59 × 10)
-2 μΩ · m), gold (2.35 × 10 −2 μΩ · m) or alloys of these metals. Among them, copper is most suitable for use because it has low electric resistance and is inexpensive, but the present invention is not limited to these.
【００１９】本発明の電解加工用電極は、例えば銅を例
示すると、銅塩水溶液に対して錯化剤として酒石酸アル
カリ塩、ＥＤＴＡ等を加え、弱アルカリ性下にて錯化状
態で安定化せしめ、還元剤としてはホルムアルデヒドや
ヒドラジン塩等を用いて、黒鉛電極基体上に銅被膜を析
出形成させるものである。その反応を式で示せば、下記
の化学反応式（１）の通りである。In the electrolytic processing electrode of the present invention, for example, when copper is used, an alkaline salt of tartrate, EDTA or the like is added as a complexing agent to an aqueous solution of a copper salt to stabilize it in a complexed state under weak alkaline, Forming agent, hydrazine salt or the like is used as the reducing agent to deposit and form a copper coating on the graphite electrode substrate. The reaction can be expressed by the following chemical reaction formula (1).
【００２０】[0020]
【化１】 [Chemical 1]
【００２１】電極の表面に形成させる金属の被膜は一層
または二層以上の複数層の構造とすることも可能であ
る。この場合、一層を複数の金属から構成する被膜とす
ることもでき、さらに、複数層の場合に、各々の層が一
種類または二種類以上の金属で構成されていても問題は
なく、任意に選択することができる。また、無電解めっ
きを施した後に電気めっきを行うと、電解液の浸透防止
及び電極の損傷を防止する上で一層効果的である。The metal coating formed on the surface of the electrode may have a structure of one layer or a plurality of layers of two or more layers. In this case, one layer may be a coating film composed of a plurality of metals, further, in the case of a plurality of layers, there is no problem even if each layer is composed of one kind or two or more kinds of metal, arbitrarily You can choose. In addition, electroplating after electroless plating is more effective in preventing permeation of the electrolytic solution and damage to the electrodes.
【００２２】金属被膜の膜厚は、２乃至３０μｍ程度で
あることが望ましい。被膜の膜厚が２μｍよりも薄い
と、電解液の浸透を防止することができないため望まし
くない。また３０μｍよりも被膜が厚くなると膜を形成
させるための時間が長くなるだけでなく、電解加工時に
金属被膜が剥離する可能性が生じるため、望ましくな
い。被膜の膜厚は５乃至１５μｍであることが望まし
い。The thickness of the metal coating is preferably about 2 to 30 μm. When the film thickness of the coating film is smaller than 2 μm, it is not desirable because the permeation of the electrolytic solution cannot be prevented. Further, if the coating film is thicker than 30 μm, not only the time for forming the film becomes longer, but also the metal coating film may peel off during the electrolytic processing, which is not desirable. The film thickness of the coating is preferably 5 to 15 μm.
【００２３】なお、金属の被膜は、常に黒鉛電極全面に
行う必要はなく、マスキング法等の手段で、必要に応じ
て一部分のみ、とりわけ被加工物と対抗する面のみ被膜
を形成させることも可能である。The metal coating does not always have to be formed on the entire surface of the graphite electrode, and it is possible to form a coating only on a part of the surface of the graphite electrode, especially on the surface facing the work piece, by a masking method or the like. Is.
【００２４】本発明の電解加工用黒鉛電極は、平均気孔
半径及び累積気孔容積をある特定の黒鉛基体としている
ので、該黒鉛基体に無電解メッキを施すことによって、
金属の被膜が黒鉛基体とアンカー効果で強固に接合して
いる。Since the graphite electrode for electrolytic processing of the present invention uses a specific graphite base having an average pore radius and a cumulative pore volume, electroless plating is applied to the graphite base to obtain
The metal coating is firmly bonded to the graphite substrate by the anchor effect.
【００２５】[0025]
【実施例】以下に本発明を実施例に基づき具体的に説明
するが、本発明はこれらの実施様態に限定されるもので
はない。EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited to these embodiments.
【００２６】実施例１ 平均気孔半径２．９μｍ、累積気孔容積９．８×１０
−２・ｍ３／Ｍｇで、電気抵抗が３０μΩ・ｍの黒鉛材
料を試作し、６０×６０×３０ｍｍの寸法に加工した。
この加工片に付着している切削粉を超音波洗浄で除去
し、３７３Ｋで乾燥した。一方、硫酸銅３４．６ｇを５
００ｍｌの水溶液（Ａ液）とした。また他方では水酸化
ナトリウム５０ｇと酒石酸ナトリウムカリウム１７３ｇ
を５００ｍｌの水溶液（Ｂ液）とした。Ａ液に同量のＢ
液を加えた後、全容量の１／５の容量のホルムアルデヒ
ドを加え良く攪拌し、加工片を浸漬して黒鉛基体の表面
に還元銅の被膜を形成させた。銅被膜の膜厚は断面を顕
微鏡で測定したところ７μｍであった。Example 1 Average pore radius 2.9 μm, cumulative pore volume 9.8 × 10
A graphite material having an electric resistance of −2 · m 3 / Mg and an electric resistance of 30 μΩ · m was prototyped and processed into a size of 60 × 60 × 30 mm.
Cutting powder adhering to this processed piece was removed by ultrasonic cleaning and dried at 373K. Meanwhile, 34.6 g of copper sulfate was added to 5
A 00 ml aqueous solution (Liquid A) was used. On the other hand, 50 g of sodium hydroxide and 173 g of sodium potassium tartrate.
Was used as a 500 ml aqueous solution (solution B). The same amount of B as liquid A
After adding the liquid, formaldehyde in a volume of 1/5 of the total volume was added and well stirred, and the processed piece was immersed to form a reduced copper film on the surface of the graphite substrate. The thickness of the copper coating was 7 μm when the cross section was measured with a microscope.
【００２７】実施例２ 平均気孔半径０．８μｍ、累積気孔容積６．０×１０
−２・ｍ３／Ｍｇで、電気抵抗が１５μΩ・ｍの等方性
黒鉛材料を試作し、６０×６０×３０ｍｍの寸法に加工
した。この加工片に付着している切削粉を超音波洗浄で
除去し、３７３Ｋで乾燥した。その後、実施例１と同様
にして等方性黒鉛基体からなる加工片の表面に還元銅の
被膜を形成させた。銅被膜の膜厚は７μｍであった。Example 2 Average pore radius 0.8 μm, cumulative pore volume 6.0 × 10
An isotropic graphite material having an electric resistance of −2 · m 3 / Mg and an electric resistance of 15 μΩ · m was prototyped and processed into a size of 60 × 60 × 30 mm. Cutting powder adhering to this processed piece was removed by ultrasonic cleaning and dried at 373K. Thereafter, in the same manner as in Example 1, a reduced copper film was formed on the surface of the processed piece made of an isotropic graphite substrate. The thickness of the copper coating was 7 μm.
【００２８】実施例３ 平均気孔半径０．２μｍ、累積気孔容積７．０×１０
−２・ｍ３／Ｍｇで、電気抵抗が１４．５μΩ・ｍの等
方性黒鉛材料を試作し、６０×６０×３０ｍｍの寸法に
加工した。この加工片に付着している切削粉を超音波洗
浄で除去し、３７３Ｋで乾燥した。一方、水６０ｍｌに
硝酸銀３．５ｇを溶解し、アンモニア水を加え、一旦生
じた沈澱が再溶解するまでアンモニア水を加え続けた。
この溶液に、水酸化ナトリウム２．５ｇを加え、清澄な
溶液となるまでアンモニア水を加えこれを銀液とした。
またこの溶液とは別に、グルコース４５ｇ、酒石酸４ｇ
を水１０００ｍｌに順次溶解し、１０分間煮沸し、常温
まで冷却後、アルコールを１００ｍｌ加えこれを還元液
とした。上記銀液と同量の還元液を混合し、この混合溶
液に加工片を浸漬し、銀の被膜を１０μｍ形成させた。Example 3 Average pore radius 0.2 μm, cumulative pore volume 7.0 × 10
An isotropic graphite material with an electric resistance of −2 · m 3 / Mg and an electric resistance of 14.5 μΩ · m was experimentally manufactured and processed into a size of 60 × 60 × 30 mm. Cutting powder adhering to this processed piece was removed by ultrasonic cleaning and dried at 373K. On the other hand, 3.5 g of silver nitrate was dissolved in 60 ml of water, aqueous ammonia was added, and the aqueous ammonia was continuously added until a precipitate that had once formed was redissolved.
To this solution, 2.5 g of sodium hydroxide was added, and aqueous ammonia was added until a clear solution was obtained, which was used as a silver solution.
Separately from this solution, glucose 45g, tartaric acid 4g
Was sequentially dissolved in 1000 ml of water, boiled for 10 minutes, cooled to room temperature, and 100 ml of alcohol was added to obtain a reducing solution. The same amount of the reducing solution as the silver solution was mixed, and the processed piece was dipped in this mixed solution to form a silver film of 10 μm.
【００２９】実施例４ 実施例２で得られた無電解銅めっき被膜を形成した加工
片に、実施例３の方法でさらに銀の被膜を５μｍ形成さ
せた２層構造とし、これを試験片とした。Example 4 The processed piece obtained in Example 2 on which the electroless copper plating film was formed was further formed with a silver film of 5 μm by the method of Example 3 to form a two-layer structure, which was used as a test piece. did.
【００３０】比較例１ 平均気孔半径３．５μｍ、累積気孔容積１２．２×１０
−２・ｍ３／Ｍｇで、電気抵抗が４０μΩ・ｍの市販黒
鉛材料を、６０×６０×３０ｍｍの寸法に加工した。こ
の試験片を超音波洗浄で試験片に付着している切削粉を
除去し、３７３Ｋで乾燥した。その後、実施例１の方法
で銅の被膜を５０μｍ形成させた。Comparative Example 1 Average pore radius 3.5 μm, cumulative pore volume 12.2 × 10
A commercial graphite material having a resistance of −2 · m 3 / Mg and an electric resistance of 40 μΩ · m was processed into a size of 60 × 60 × 30 mm. The test piece was subjected to ultrasonic cleaning to remove cutting powder adhering to the test piece, and dried at 373K. Then, a copper coating having a thickness of 50 μm was formed by the method of Example 1.
【００３１】比較例２ 実施例１で使用した黒鉛材料の加工片を用意し、ポリイ
ミド樹脂をＮ−メチル−２−ピロリドンに溶解した溶液
を吹き付けた。その後５２３Ｋで樹脂を硬化させた後、
１２７３Ｋで炭化した。顕微鏡で測定すると加工片の表
面にはガラス状炭素膜が１０μｍ形成されてた。Comparative Example 2 A processed piece of the graphite material used in Example 1 was prepared and sprayed with a solution prepared by dissolving a polyimide resin in N-methyl-2-pyrrolidone. After curing the resin at 523K,
Carbonized at 1273K. When measured with a microscope, a glassy carbon film was formed on the surface of the processed piece in a thickness of 10 μm.
【００３２】比較例３ 実施例１の黒鉛材料を用意した。Comparative Example 3 The graphite material of Example 1 was prepared.
【００３３】先ず、実施例１乃至４及び比較例１乃至３
で得られた各々の試験片の電気抵抗を図１に示す電圧降
下法で測定した。測定条件は、定電圧装置を介し、直流
２．５Ａを試験片に流した。スパン４ｃｍで電圧計を接
続し、その時の電圧降下から電気抵抗を求めた。電気抵
抗の測定結果を表１に示す。電気抵抗の計算式は下に示
す。First, Examples 1 to 4 and Comparative Examples 1 to 3
The electrical resistance of each test piece obtained in 1. was measured by the voltage drop method shown in FIG. As the measurement conditions, a direct current of 2.5 A was applied to the test piece through a constant voltage device. A voltmeter was connected with a span of 4 cm, and the electric resistance was calculated from the voltage drop at that time. Table 1 shows the measurement results of the electric resistance. The formula for calculating the electrical resistance is shown below.
【００３４】[0034]
【数１】 [Equation 1]
【００３５】［式中、ρ（単位はμΩ・ｍ）は固有抵抗
であり、Ｖ（単位はＶ）は電圧であり、Ｉ（単位はＡ）
は電流であり、Ｓ（単位はｃｍ２）は断面積であり、Ｌ
（単位はｃｍ）は電圧端子間距離である。］[Where ρ (unit: μΩ · m) is specific resistance, V (unit is V) is voltage, and I (unit is A))
Is current, S (unit: cm 2 ) is cross-sectional area, L
(Unit is cm) is the distance between the voltage terminals. ]
【００３６】また実施例１乃至４及び比較例１乃至３で
得られた試験片を用いて下記の条件で電解加工試験を行
った。 使用機械：ＣＯＴＡＣ−４１ 電気条件：電流密度４００ｋＡ／ｍ２ ワーク材：ＳＫＤ−６１ 加工液 ：硝酸ナトリウム水溶液 Ｇａｐ ：１００μｍ 加工面積：３．６×１０−３／ｍ２ Further, using the test pieces obtained in Examples 1 to 4 and Comparative Examples 1 to 3, an electrolytic processing test was conducted under the following conditions. Machine used: COTAC-41 Electric condition: Current density 400 kA / m 2 Work material: SKD-61 Working fluid: Sodium nitrate aqueous solution Gap: 100 μm Working area: 3.6 × 10 −3 / m 2
【００３６】上記電解加工試験を終えた材料についてク
ラック及び剥離の有無と、さらに電解液の浸透等につい
て調べた。その結果も併せて表１に示す。The materials that had been subjected to the electrolytic processing test were examined for cracks and peeling, and the penetration of the electrolytic solution. The results are also shown in Table 1.
【００３７】[0037]
【発明の効果】以上のように本発明では、ある特定の黒
鉛基体に電気伝導性の良い金属の被膜を形成しているの
で、金属被膜と黒鉛電極基体が強固に接合されており、
電解加工時に、被膜にクラック及び剥離が発生すること
がない。従って、電解液が黒鉛電極に浸透することがな
い。また電気伝導性の良い金属の被膜を形成しているの
で、突発的な短絡によって電極が損傷することもない。
さらに、電気伝導性の良い金属の被膜を黒鉛電極表面に
形成させることにより、黒鉛単味の電極の場合よりも加
工量が増加するという本発明に特有な効果を得ることも
できる。As described above, in the present invention, since a metal coating having good electric conductivity is formed on a specific graphite base, the metal coating and the graphite electrode base are firmly bonded,
No crack or peeling of the coating film occurs during electrolytic processing. Therefore, the electrolytic solution does not penetrate into the graphite electrode. Further, since the metal coating having good electric conductivity is formed, the electrode is not damaged by a sudden short circuit.
Further, by forming a metal coating having good electrical conductivity on the surface of the graphite electrode, it is possible to obtain the effect peculiar to the present invention that the processing amount is increased as compared with the case of the electrode made of only graphite.
【図１】電圧降下法の模式図である。FIG. 1 is a schematic diagram of a voltage drop method.
１１ 試験片 １２ 電圧計 １３ 電流計 １４ 電源 11 Test piece 12 Voltmeter 13 Ammeter 14 Power supply
【表１】 [Table 1]
───────────────────────────────────────────────────── フロントページの続き (72)発明者 新井 美代治 香川県三豊郡財田町財田上宮坂1335−22 東炭化工株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Miyoji Arai 1335-22 Zaida Miyamiyazaka, Zaita Town, Mitoyo District, Kagawa Prefecture Tokai Kogyo Co., Ltd.
Claims (1)
あって且つ累積気孔容積が１０×１０−２・ｍ３／Ｍｇ
以下の黒鉛材料に、電気伝導性の良い金属の被膜を形成
させてなる電解加工用黒鉛電極。1. An average pore radius of 0.1 to 3.0 μm and a cumulative pore volume of 10 × 10 −2 · m 3 / Mg.
A graphite electrode for electrolytic processing, which is obtained by forming a metal coating having good electrical conductivity on the following graphite material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3407194A JPH07204936A (en) | 1994-01-21 | 1994-01-21 | Graphite electrode for electrochemical machining |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3407194A JPH07204936A (en) | 1994-01-21 | 1994-01-21 | Graphite electrode for electrochemical machining |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07204936A true JPH07204936A (en) | 1995-08-08 |
Family
ID=12404039
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3407194A Pending JPH07204936A (en) | 1994-01-21 | 1994-01-21 | Graphite electrode for electrochemical machining |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07204936A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007129897A (en) * | 2006-12-25 | 2007-05-24 | Totan Kako Kk | Electric motor |
| DE102004016149B4 (en) * | 2003-04-09 | 2014-09-04 | Totankako Co., Ltd. | Metal coated carbon brush |
-
1994
- 1994-01-21 JP JP3407194A patent/JPH07204936A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102004016149B4 (en) * | 2003-04-09 | 2014-09-04 | Totankako Co., Ltd. | Metal coated carbon brush |
| JP2007129897A (en) * | 2006-12-25 | 2007-05-24 | Totan Kako Kk | Electric motor |
| JP4611966B2 (en) * | 2006-12-25 | 2011-01-12 | 東炭化工株式会社 | Electric motor |
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