JP2018145477A - Method of removing oxide film of metal surface - Google Patents

Method of removing oxide film of metal surface Download PDF

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JP2018145477A
JP2018145477A JP2017041568A JP2017041568A JP2018145477A JP 2018145477 A JP2018145477 A JP 2018145477A JP 2017041568 A JP2017041568 A JP 2017041568A JP 2017041568 A JP2017041568 A JP 2017041568A JP 2018145477 A JP2018145477 A JP 2018145477A
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oxide film
titanium
cathode
sulfuric acid
metal material
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JP6870389B2 (en
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南美 吉村
Nami Yoshimura
南美 吉村
永井 達夫
Tatsuo Nagai
達夫 永井
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Kurita Water Industries Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a method of removing an oxide film of a metal material surface, which can easily remove not only a natural oxide film formed on the surface of a titanium or titanium alloy but also a thick oxide film formed by anode oxidation etc., and which can form a renewable surface.SOLUTION: In a method of removing an oxide film of a metal material surface, a processing apparatus 1 comprises: a processing tank 2; and a cathode member 4 and an anode member 5 that are placed in the processing tank 2. The cathode member 4 and the anode member 5 are connected to a minus electrode and a plus electrode of a DC power supply 3, respectively. In the processing apparatus 1, the cathode member 4 composed of a titanium or titanium alloy member, on the surface of which a thick anode oxide film is formed, is used. As for the anode member 5, a diamond-based electrode, a platinum-group-based electrode, or the like is used. As for an electrolytic treatment solution accommodated in the processing tank 2, an electrolyte S of sulfuric acid concentration 5-75% in weight is used. The temperature of the electrolyte S is 10°C or more, preferably 20-90°C.SELECTED DRAWING: Figure 1

Description

本発明は、金属材表面上に形成されている金属酸化皮膜の除去方法に関する。特に不動態皮膜と称されるチタン又はチタン合金表面に形成される自然酸化皮膜や陽極酸化などによる厚い酸化皮膜を除去するのに好適な、金属材表面の酸化皮膜を除去する方法に関する。   The present invention relates to a method for removing a metal oxide film formed on a metal material surface. In particular, the present invention relates to a method for removing an oxide film on a metal material surface, which is suitable for removing a natural oxide film formed on a titanium or titanium alloy surface called a passive film or a thick oxide film by anodization.

チタン及びチタン合金部材は、高い硬度と強度を備えた軽い金属であり、かつ耐食性が高く、延性に富むという優れた特性を有することから広く利用されている。さらに、チタン及びチタン合金部材に陽極酸化処理を施して陽極酸化皮膜を形成することによって、着色、耐摩耗性の向上、光触媒の機能が発現されるため、その用途が拡大されている。   Titanium and titanium alloy members are widely used because they are light metals with high hardness and strength, and have excellent properties such as high corrosion resistance and high ductility. Furthermore, by applying anodizing treatment to titanium and titanium alloy members to form an anodized film, coloring, improved wear resistance, and the function of a photocatalyst are manifested, so that its application is expanded.

このチタン及びチタン合金部材は、表面に薄い自然酸化皮膜が形成されている。陽極酸化皮膜を形成するには酸化皮膜を一旦除去する必要があるが、チタン表面に形成される酸化皮膜は強固であるため、チタンの素地を出すために化学的手法や物理的手法などにより除去される。例えば、化学的手法であれば化学処理液を用いた化学研磨(特許文献1)、物理的手法であれば機械研磨(特許文献2)及び電解研磨(特許文献3)が行われている。   The titanium and titanium alloy members have a thin natural oxide film formed on the surface. In order to form an anodic oxide film, it is necessary to remove the oxide film once. However, since the oxide film formed on the surface of titanium is strong, it is removed by chemical or physical methods to obtain a titanium substrate. Is done. For example, chemical polishing using a chemical treatment liquid (Patent Document 1) is performed for a chemical method, and mechanical polishing (Patent Document 2) and electrolytic polishing (Patent Document 3) are performed for a physical method.

特開昭62−167895号公報Japanese Patent Laid-Open No. 62-167895 特開平06−170721号公報Japanese Patent Laid-Open No. 06-170721 特開平09−207029号公報JP 09-207029 A

しかしながら、化学研磨、機械研磨、電解研磨の公知のこれらの方法によるチタン酸化皮膜の除去方法では、薄い自然酸化皮膜の除去は可能であるが、チタン及びチタン合金部材の再生などを目的として一旦形成した陽極酸化皮膜などの厚い酸化皮膜を除去することは困難である。また、物理的手法は部分的にしか研磨できないため曲部や穴部の作業性が悪く皮膜が残留してしまい、再生品の性能低下の要因となってしまう。さらに、従来の化学的手法ではフッ酸や硝酸などにより化学的に研磨することが主流であるが、この手法では厚い陽極酸化皮膜を完全に除去するためには極端に基材を侵してしまい、健全な表面のチタン及びチタン合金部材とすることが困難である、という問題点がある。   However, the titanium oxide film removal method by these known methods of chemical polishing, mechanical polishing, and electrolytic polishing can remove the thin natural oxide film, but it is once formed for the purpose of regenerating titanium and titanium alloy members. It is difficult to remove a thick oxide film such as an anodic oxide film. Further, since the physical method can only be partially polished, the workability of the curved portion and the hole portion is poor, and the film remains, which causes the performance of the recycled product to deteriorate. Furthermore, in the conventional chemical method, it is the mainstream to chemically polish with hydrofluoric acid or nitric acid, but in this method, in order to completely remove the thick anodic oxide film, the substrate is extremely affected, There is a problem that it is difficult to obtain titanium and titanium alloy members having a healthy surface.

本発明は、上記課題に鑑みてなされたものであり、例えばチタン又はチタン合金部材の表面に形成される自然酸化皮膜のみならず陽極酸化などにより形成された厚い酸化皮膜除去を容易にし、再生可能な表面を形成することが可能な金属材表面の酸化皮膜の除去方法を提供することを目的とする。   The present invention has been made in view of the above problems. For example, it is easy to remove and regenerate a thick oxide film formed by anodization as well as a natural oxide film formed on the surface of titanium or a titanium alloy member. It is an object of the present invention to provide a method for removing an oxide film on a metal material surface capable of forming a smooth surface.

上記目的を達成するために本発明は、金属材を陰極として硫酸濃度5〜75重量%、温度10℃以上の電解液中で電解処理することによって前記金属材表面の酸化皮膜を除去する方法を提供する(発明1)。   In order to achieve the above object, the present invention provides a method for removing an oxide film on the surface of a metal material by subjecting the metal material as a cathode to electrolytic treatment in an electrolytic solution having a sulfuric acid concentration of 5 to 75% by weight and a temperature of 10 ° C or higher. Provided (Invention 1)

かかる発明(発明1)によれば、電解した硫酸の強い酸化作用により金属材の表面に形成された酸化皮膜を除去することができる一方、硫酸濃度5〜75重量%とすることで電解した硫酸による過度な酸化作用を抑制して金属材の表面に酸化皮膜が再度形成されることを防止することができ、金属材の素地を露出させることができる。   According to this invention (Invention 1), the oxide film formed on the surface of the metal material can be removed by the strong oxidizing action of the electrolyzed sulfuric acid, while the sulfuric acid electrolyzed by adjusting the sulfuric acid concentration to 5 to 75% by weight. It is possible to suppress an excessive oxidation action due to, thereby preventing an oxide film from being formed again on the surface of the metal material, and to expose the base material of the metal material.

上記発明(発明1)においては、前記金属材がチタン又はチタン合金であり、該金属材の表面に形成されているチタン酸化皮膜を電解液中で陰極として電解処理することが好ましい(発明2)。   In the said invention (invention 1), the said metal material is titanium or a titanium alloy, and it is preferable to electrolyze the titanium oxide film currently formed in the surface of this metal material as a cathode in electrolyte solution (invention 2). .

チタン又はチタン合金の表面に形成される酸化皮膜は安定しており除去が難しいが、かかる発明(発明2)によれば、この強固な酸化皮膜を除去して、チタン又はチタン合金の素地を露出させることができる。   Although the oxide film formed on the surface of titanium or titanium alloy is stable and difficult to remove, according to this invention (Invention 2), this strong oxide film is removed and the substrate of titanium or titanium alloy is exposed. Can be made.

上記発明(発明1,2)においては、前記電解処理において、前記陰極の金属材に−1V〜−5Vの電圧を印加することが好ましい(発明3)。   In the said invention (invention 1 and 2), it is preferable to apply the voltage of -1V--5V to the metal material of the said cathode in the said electrolytic treatment (invention 3).

かかる発明(発明3)によれば、陰極で金属酸化物が還元されて金属の素地を露出することができ、さらに還元が進むと陰極では水素が発生するので、これにより除去反応能の完了を判断することができる。   According to this invention (Invention 3), the metal oxide can be reduced at the cathode to expose the metal substrate, and as the reduction proceeds, hydrogen is generated at the cathode, thereby completing the removal reaction capability. Judgment can be made.

本発明の金属材表面の酸化皮膜を除去する方法によれば、電解した硫酸の強い酸化作用により金属材の表面に形成された酸化皮膜を除去するとともに金属材の表面に再度酸化皮膜が形成されることを防止して金属材の素地を露出させることができる。   According to the method of removing an oxide film on the surface of a metal material of the present invention, the oxide film formed on the surface of the metal material is removed by the strong oxidizing action of electrolyzed sulfuric acid, and an oxide film is formed again on the surface of the metal material. It can prevent that and the base material of a metal material can be exposed.

本発明の一実施形態による金属酸化皮膜の除去方法を適用可能な処理装置を示す概略図である。It is the schematic which shows the processing apparatus which can apply the removal method of the metal oxide film by one Embodiment of this invention. 上記実施形態の処理装置による本発明の金属酸化皮膜の除去方法の第一の実施形態の初期状態を示す概略図である。It is the schematic which shows the initial state of 1st embodiment of the removal method of the metal oxide film of this invention by the processing apparatus of the said embodiment. 第一の実施形態の除去方法の酸化皮膜の除去時の状態を示す概略図である。It is the schematic which shows the state at the time of removal of the oxide film of the removal method of 1st embodiment. 上記実施形態の処理装置による本発明の金属酸化皮膜の除去方法の第二の実施形態の酸化皮膜の除去時の状態を示す概略図である。It is the schematic which shows the state at the time of the removal of the oxide film of 2nd embodiment of the removal method of the metal oxide film of this invention by the processing apparatus of the said embodiment.

図1は本発明の一実施形態による金属酸化皮膜の除去方法を適用可能な処理装置を概念的に示しており、図1において処理装置1は、処理槽2とこの処理槽2内に設置された陰極部材4及び陽極部材5とを有し、これら陰極部材4及び陽極部材5はそれぞれ直流電源3のマイナス極及びプラス極に接続している。なお、処理槽2には処理槽2内の溶液を所望の温度に保つための恒温ヒータ(図示せず)を設けることができる。このような処理装置1において、陰極部材4は被処理部材となるものであり、本実施形態ではチタン又はチタン合金製の部材であって、その表面に厚い陽極酸化皮膜が形成されたものを用いる。また、陽極部材5としては、通電性の材料であれば特に制限はないが、導電性、耐食性などの点でダイヤモンド基材とした電極や白金族金属を基材とした電極等を用いることができる。   FIG. 1 conceptually shows a processing apparatus to which a method for removing a metal oxide film according to an embodiment of the present invention can be applied. In FIG. 1, a processing apparatus 1 is installed in a processing tank 2 and the processing tank 2. The cathode member 4 and the anode member 5 are connected to the negative pole and the positive pole of the DC power source 3, respectively. The treatment tank 2 can be provided with a constant temperature heater (not shown) for keeping the solution in the treatment tank 2 at a desired temperature. In such a processing apparatus 1, the cathode member 4 is a member to be processed, and in this embodiment, a member made of titanium or a titanium alloy and having a thick anodized film formed on the surface thereof is used. . The anode member 5 is not particularly limited as long as it is a conductive material, but an electrode based on a diamond base or an electrode based on a platinum group metal may be used in terms of conductivity and corrosion resistance. it can.

このような処理装置1の処理槽2に収容する電解処理の溶液としては、硫酸濃度5〜75重量%の電解液Sを用いる。硫酸濃度が5重量%未満では、後述する電解処理における硫酸の電解によるH(H)イオンが少ないため陰極部材4(被処理部材)表面の酸化皮膜を十分に除去できない一方、75重量%を超えると陰極部材4の表面に形成された酸化皮膜は除去できるものの硫酸の酸化作用により陰極部材4表面に新たな酸化皮膜が形成されてしまう。この電解液Sは、上述したような硫酸濃度であれば、硫酸のみであってよいし、硫酸を電気分解した電解硫酸溶液であってもよい。この電解液SはpH5以下であるのが好ましい。pHが5を超えるとH(H)イオンが不足して金属材の表面に形成された酸化皮膜の除去能が十分でなくなるため、好ましくない。 As an electrolytic treatment solution stored in the treatment tank 2 of such a treatment apparatus 1, an electrolytic solution S having a sulfuric acid concentration of 5 to 75% by weight is used. If the sulfuric acid concentration is less than 5% by weight, the oxide film on the surface of the cathode member 4 (member to be treated) cannot be sufficiently removed because there are few H + (H 3 O + ) ions due to the electrolysis of sulfuric acid in the electrolytic treatment described later. If the weight percentage is exceeded, the oxide film formed on the surface of the cathode member 4 can be removed, but a new oxide film is formed on the surface of the cathode member 4 due to the oxidizing action of sulfuric acid. The electrolytic solution S may be only sulfuric acid as long as the sulfuric acid concentration is as described above, or may be an electrolytic sulfuric acid solution obtained by electrolyzing sulfuric acid. The electrolyte S preferably has a pH of 5 or less. A pH exceeding 5 is not preferable because H + (H 3 O + ) ions are insufficient and the ability to remove the oxide film formed on the surface of the metal material becomes insufficient.

また、この電解液Sの温度は10℃以上、好ましくは20℃以上とする。電解液の温度が10℃未満では、陰極部材4の表面に形成された酸化皮膜の除去速度が低下し、これにより酸化皮膜を十分に除去できない。なお、温度の上限については特に制限はないが、90℃を超えると硫酸の濃度によっては電解液Sが沸騰してしまうため90℃以下とするのが好ましい。したがって、好ましい電解液Sの温度は20〜90℃である。   The temperature of the electrolytic solution S is 10 ° C. or higher, preferably 20 ° C. or higher. When the temperature of the electrolytic solution is less than 10 ° C., the removal rate of the oxide film formed on the surface of the cathode member 4 decreases, and the oxide film cannot be sufficiently removed. In addition, although there is no restriction | limiting in particular about the upper limit of temperature, since electrolyte solution S will be boiled depending on the density | concentration of a sulfuric acid when it exceeds 90 degreeC, it is preferable to set it as 90 degrees C or less. Therefore, the preferable temperature of the electrolytic solution S is 20 to 90 ° C.

〔第一実施形態〕
次に上述したような処理装置1を用いた金属酸化皮膜の除去方法の第一の実施形態について図1〜図3に基づいて説明する。まず、処理槽2に直流電源3に接続した被処理部材としての陰極部材4及び陽極部材5を吊設したら処理槽2を電解液Sである硫酸で満たし、必要に応じて恒温ヒータにより所定の温度に保持する。このとき図1に示すように処理槽2内には、硫酸に起因してH(H)イオンと水酸イオンOHイオンとが存在している。なお、図中においては、硫酸イオン(SO 2−)については省略している。
[First embodiment]
Next, 1st embodiment of the removal method of the metal oxide film using the processing apparatus 1 as mentioned above is described based on FIGS. First, when the cathode member 4 and the anode member 5 as the members to be processed connected to the DC power source 3 are suspended in the processing tank 2, the processing tank 2 is filled with sulfuric acid as the electrolyte S, and a predetermined temperature is applied by a constant temperature heater as necessary. Hold at temperature. At this time, as shown in FIG. 1, H + (H 3 O + ) ions and hydroxide ions OH ions are present in the treatment tank 2 due to sulfuric acid. In the figure, sulfate ions (SO 4 2− ) are omitted.

そして、直流電源3から電流を印加すると、図2に示すようにHイオンは陰極部材4側に移動する一方、OHイオンは陽極部材5側に移動する。このとき陰極部材4に印加する電圧は、−1V未満では陰極部材4(被処理部材)表面の酸化皮膜を十分に除去できない一方、−5Vを超えてもHガスの発生が多量となり、かえって酸化皮膜の除去の阻害要因となるので−1V〜−5Vの範囲とするのが好ましい。 When a current is applied from the DC power supply 3, as shown in FIG. 2, H + ions move to the cathode member 4 side, while OH ions move to the anode member 5 side. Voltage applied to the cathode member 4 this time, while not sufficiently remove the oxide film of the cathode member 4 (the member to be processed) surface is less than -1 V, be greater than -5V becomes large quantity generation of H 2 gas, rather Since it becomes a hindrance to the removal of the oxide film, the range of -1V to -5V is preferable.

これにより陰極では、下記式(1)によりチタン又はチタン合金製の部材からなる陰極部材4の表面に形成された酸化チタンが還元される一方、陽極では下記式(2)により酸素が発生する。
(陰極)TiO+4H++2e → Ti2++2HO ・・・(1)
(陽極)HO → 1/2O+2H++2e ・・・(2)
Thereby, in the cathode, titanium oxide formed on the surface of the cathode member 4 made of titanium or a titanium alloy member is reduced by the following formula (1), while oxygen is generated by the following formula (2) in the anode.
(Cathode) TiO 2 + 4H + + 2e → Ti 2 + + 2H 2 O (1)
(Anode) H 2 O → 1 / 2O 2 + 2H + + 2e (2)

この状態を継続することにより、チタン又はチタン合金製の部材からなる陰極部材4の表面に形成された酸化皮膜を除去することができるが、この酸化皮膜の除去が完了したか否かの判断タイミングは、チタンの素地の色である銀白色に戻ったことで確認すればよい。あるいは、図3に示すようにチタン又はチタン合金製の部材からなる陰極部材4の酸化皮膜が進行し、上記式(1)においてTiOが全て還元されると下記式(3)の反応により水素(気体)が発生する。したがって、気体としての水素(H)が発生した段階を終点とみなすことができる。なお、陽極では上記式(2)により酸素が発生する。
(陰極)2H++2e → H ・・・(3)
By continuing this state, the oxide film formed on the surface of the cathode member 4 made of a member made of titanium or a titanium alloy can be removed. Timing for determining whether or not the removal of this oxide film is completed Can be confirmed by returning to the silver-white color which is the color of the titanium base. Alternatively, as shown in FIG. 3, when the oxide film of the cathode member 4 made of titanium or a titanium alloy member proceeds and all of the TiO 2 is reduced in the above formula (1), hydrogen is reacted by the reaction of the following formula (3). (Gas) is generated. Therefore, the stage where hydrogen (H 2 ) as a gas is generated can be regarded as the end point. In the anode, oxygen is generated by the above formula (2).
(Cathode) 2H + + 2e → H 2 (3)

〔第二実施形態〕
続いて本発明の金属酸化皮膜の除去方法の第二の実施形態について、図1、図2及び図4に基づいて説明する。第二実施形態の金属酸化皮膜の除去方法は、電解液S1として硫酸を電気分解した電解硫酸溶液を用いた以外は上述した第一の実施形態と同じものである。また、電解硫酸溶液S1は、硫酸濃度5〜75重量%で、温度が10℃以上、好ましくは20〜90℃である点では上述した第一の実施形態と同じである。
[Second Embodiment]
Then, 2nd embodiment of the removal method of the metal oxide film of this invention is described based on FIG.1, FIG.2 and FIG.4. The method for removing the metal oxide film of the second embodiment is the same as that of the first embodiment described above except that an electrolytic sulfuric acid solution obtained by electrolyzing sulfuric acid is used as the electrolytic solution S1. The electrolytic sulfuric acid solution S1 is the same as the first embodiment described above in that the sulfuric acid concentration is 5 to 75% by weight and the temperature is 10 ° C. or higher, preferably 20 to 90 ° C.

まず、処理槽2に直流電源3に接続した被処理部材としての陰極部材4及び陽極部材5を吊設したら処理槽2を電解液S1である電解硫酸で満たす。この電解硫酸中には非常に酸化性の強い過硫酸が含まれている一方、図1に示すように処理槽2内には、過硫酸や硫酸に起因してH(H)イオンと水酸イオンOHイオンとが存在している。なお、図中においては、硫酸イオン(SO 2−)及び過硫酸イオン(S 2−)については省略している。 First, when the cathode member 4 and the anode member 5 as the members to be processed connected to the DC power source 3 are suspended in the processing tank 2, the processing tank 2 is filled with electrolytic sulfuric acid as the electrolytic solution S1. While this electrolytic sulfuric acid contains highly oxidizable persulfuric acid, the treatment tank 2 has H + (H 3 O + ) due to persulfuric acid and sulfuric acid as shown in FIG. Ions and hydroxide ions OH ions are present. In the figure, sulfate ions (SO 4 2− ) and persulfate ions (S 2 O 8 2− ) are omitted.

そして、直流電源3から電流を印加すると、図2に示すようにHイオンは陰極部材4側に移動する一方、OHイオンは陽極部材5側に移動する。このとき陰極部材4に印加する電圧は、−1V未満では陰極部材4(被処理部材)表面の酸化皮膜を十分に除去できない一方、−5Vを超えてもHガスの発生は多量となり、かえって酸化皮膜の除去の阻害要因となるので−1V〜−5Vの範囲とするのが好ましい。 When a current is applied from the DC power supply 3, as shown in FIG. 2, H + ions move to the cathode member 4 side, while OH ions move to the anode member 5 side. Voltage applied to the cathode member 4 this time, while not sufficiently remove the oxide film of the cathode member 4 (the member to be processed) surface is less than -1 V, the generation of H 2 gas be greater than -5V becomes large amount, rather Since it becomes a hindrance to the removal of the oxide film, the range of -1V to -5V is preferable.

これにより陰極では、下記式(1)によりチタン又はチタン合金製の部材からなる陰極部材4の表面に形成された酸化チタンが還元される一方、陽極では下記式(2)により酸素が発生する。
(陰極)TiO+4H++2e → Ti2++2HO ・・・(1)
(陽極)HO → 1/2O+2H++2e ・・・(2)
Thereby, in the cathode, titanium oxide formed on the surface of the cathode member 4 made of titanium or a titanium alloy member is reduced by the following formula (1), while oxygen is generated by the following formula (2) in the anode.
(Cathode) TiO 2 + 4H + + 2e → Ti 2 + + 2H 2 O (1)
(Anode) H 2 O → 1 / 2O 2 + 2H + + 2e (2)

この状態を継続することにより、チタン又はチタン合金製の部材からなる陰極部材4の表面に形成された酸化皮膜を除去することができるが、この酸化皮膜の除去が完了したか否かの判断タイミングは、チタンの色である銀白色に戻ったことで確認すればよい。あるいは図4に示すようにチタン又はチタン合金製の部材からなる陰極部材4の酸化皮膜が進行し、上記式(1)においてTiOが全て還元されると下記式(3)の反応により水素(気体)が発生する。したがって、気体としての水素(H)が発生した段階を終点とみなすことができる。なお、陽極では上記式(2)により酸素が発生する。また、下記式(4)に示すように溶液中では過硫酸イオンが消費されて酸化チタンイオンと硫酸イオンとが生成する。
(陰極)2H++2e → H ・・・(3)
(電解液中)Ti+S 2−+2H
→TiO 2++2SO 2−+4H+ ・・・(4)
By continuing this state, the oxide film formed on the surface of the cathode member 4 made of a member made of titanium or a titanium alloy can be removed. Timing for determining whether or not the removal of this oxide film is completed Can be confirmed by returning to silver-white which is the color of titanium. Alternatively, as shown in FIG. 4, when the oxide film of the cathode member 4 made of titanium or a titanium alloy member proceeds and all TiO 2 is reduced in the above formula (1), hydrogen ( Gas). Therefore, the stage where hydrogen (H 2 ) as a gas is generated can be regarded as the end point. In the anode, oxygen is generated by the above formula (2). In addition, as shown in the following formula (4), persulfate ions are consumed in the solution to generate titanium oxide ions and sulfate ions.
(Cathode) 2H + + 2e → H 2 (3)
(In electrolyte) Ti + S 2 O 8 2− + 2H 2 O
→ TiO 2 2+ + 2SO 4 2− + 4H + (4)

以上、本発明の金属酸化皮膜の除去装置及び除去方法について、上記各実施形態に基づいて説明してきたが、本発明は上記実施例に限定されず種々の変形実施が可能である。例えば、被処理部材はチタン又はチタン合金に限らず、他の金属酸化物の除去にも適用可能である。また、被処理部材の形状は制限されず、曲部や穴部を有する部材を電極として均一に処理することが可能である。   As mentioned above, although the removal apparatus and removal method of the metal oxide film of this invention have been demonstrated based on said each embodiment, this invention is not limited to the said Example, Various deformation | transformation implementation is possible. For example, the member to be treated is not limited to titanium or a titanium alloy, and can be applied to the removal of other metal oxides. Further, the shape of the member to be processed is not limited, and a member having a curved portion or a hole can be uniformly processed as an electrode.

以下に実施例及び比較例を示し、本発明をより具体的に説明する。ただし、本発明はこれらの記載により何ら限定されるものではない。   Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited by these descriptions.

[実施例1]
100mm×100mm×0.5mmのチタンの試験片を用意し、この試験片の表面に厚さ5μmの陽極酸化皮膜を形成し、この試験片を図1に示す処理装置1により処理した。すなわち、陽極酸化皮膜を形成した試験片を陰極部材4とするとともに同じサイズのダイヤモンド電極を陽極部材5として、処理槽2に30%の濃度硫酸を満たし、恒温ヒータにより温度を70℃に保持して、直流電源3から陰極側に−3Vの電圧をかけて処理を行った。そして、陰極部材4から気泡が発生した時点で処理を停止し、試験片の表面をSEM−EDS分析した結果、Tiピークのみが認められた。この結果を処理条件(硫酸濃度、温度及び電圧)とともに表1に示す。
[Example 1]
A test piece of titanium of 100 mm × 100 mm × 0.5 mm was prepared, an anodized film having a thickness of 5 μm was formed on the surface of the test piece, and this test piece was processed by the processing apparatus 1 shown in FIG. That is, the test piece on which the anodized film is formed is used as the cathode member 4 and the diamond electrode of the same size is used as the anode member 5. Then, the process was performed by applying a voltage of −3 V from the DC power source 3 to the cathode side. And when a bubble generate | occur | produced from the cathode member 4, a process was stopped and the surface of the test piece was analyzed by SEM-EDS, As a result, only Ti peak was recognized. The results are shown in Table 1 together with the treatment conditions (sulfuric acid concentration, temperature and voltage).

[実施例2、3及び比較例1〜4]
実施例1において、処理条件を表1に示すよう設定した以外は同様にして陽極酸化皮膜を形成した試験片を処理した。結果を表1にあわせて示す。なお、比較例4は電圧をかけずに硫酸に浸漬した例である。
[Examples 2 and 3 and Comparative Examples 1 to 4]
In Example 1, a test piece on which an anodized film was formed was treated in the same manner except that the treatment conditions were set as shown in Table 1. The results are shown in Table 1. In addition, the comparative example 4 is an example immersed in the sulfuric acid without applying a voltage.

Figure 2018145477
Figure 2018145477

表1から明らかなとおり、陽極酸化皮膜を形成したチタン製の試験片を陰極部材4として硫酸濃度5〜75重量%、温度10℃以上の電解液中で電解処理した実施例1〜3をSEM−EDS分析した結果、Tiピークのみが認められ、陽極酸化皮膜が除去できていることが確認された。これに対し、硫酸濃度が75重量%を超える電解液中で電解処理した比較例1は、酸化チタンのピークが検出された。これは高温の硫酸による酸化作用により、酸化皮膜が除去されるが、再度酸化皮膜が形成されるためであると考えられる。一方、硫酸濃度が5重量%未満の電解液中で電解処理した比較例2、及び硫酸濃度が5〜75重量%の範囲内であるが温度が10℃未満である比較例3では、酸化チタンのピークが検出された。これは、溶解したTi2+イオンの拡散速度が遅いため、酸化皮膜の除去が十分でなかったためであると考えられる。さらに、硫酸濃度5〜75重量%で温度10℃以上の電解液ではあるが、電気を通電しなかった比較例4でも、酸化チタンのピークが検出された。これは、電圧を印加しないため酸化皮膜の除去が行われないためであると考えられる。 As is clear from Table 1, Examples 1 to 3 were subjected to electrolytic treatment in an electrolytic solution having a sulfuric acid concentration of 5 to 75% by weight and a temperature of 10 ° C. or more as a cathode member 4 using a titanium test piece on which an anodized film was formed. As a result of -EDS analysis, only a Ti peak was observed, and it was confirmed that the anodized film could be removed. On the other hand, the peak of titanium oxide was detected in Comparative Example 1 in which the electrolytic treatment was performed in an electrolytic solution having a sulfuric acid concentration exceeding 75% by weight. This is considered to be because the oxide film is removed by the oxidizing action of high-temperature sulfuric acid, but the oxide film is formed again. On the other hand, in Comparative Example 2 in which the electrolytic treatment was performed in an electrolytic solution having a sulfuric acid concentration of less than 5% by weight, and in Comparative Example 3 in which the sulfuric acid concentration was in the range of 5 to 75% by weight but the temperature was less than 10 ° C., titanium oxide The peak was detected. This is considered to be because the oxide film was not sufficiently removed because the diffusion rate of dissolved Ti 2+ ions was slow. Furthermore, although it was an electrolyte solution having a sulfuric acid concentration of 5 to 75% by weight and a temperature of 10 ° C. or higher, a peak of titanium oxide was also detected in Comparative Example 4 in which electricity was not passed. This is presumably because the oxide film is not removed because no voltage is applied.

1 処理装置
2 処理槽
3 直流電源
4 陰極部材
5 陽極部材
S,S1 電解液
DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Processing tank 3 DC power supply 4 Cathode member 5 Anode member S, S1 Electrolyte

Claims (3)

金属材を陰極として硫酸濃度5〜75重量%、温度10℃以上の電解液中で電解処理することによって前記金属材表面の酸化皮膜を除去する方法。   A method of removing an oxide film on the surface of a metal material by subjecting the metal material as a cathode to electrolytic treatment in an electrolytic solution having a sulfuric acid concentration of 5 to 75% by weight and a temperature of 10 ° C. or higher. 前記金属材がチタン又はチタン合金であり、該金属材の表面に形成されているチタン酸化皮膜を電解液中で陰極として電解処理する、請求項1に記載の方法。   The method according to claim 1, wherein the metal material is titanium or a titanium alloy, and the titanium oxide film formed on the surface of the metal material is electrolytically treated as a cathode in an electrolytic solution. 前記電解処理において、前記陰極の金属材に−1V〜−5Vの電圧を印加する、請求項1又は2に記載の方法。   The method according to claim 1 or 2, wherein a voltage of -1 V to -5 V is applied to the metal material of the cathode in the electrolytic treatment.
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CN113818070B (en) * 2021-09-05 2023-09-19 重庆哈斯特铝板带有限公司 Aluminum alloy surface treatment method

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