WO2020179427A1 - Method for producing thin film made from oxide of titanium or titanium alloy and having sealed micropores - Google Patents

Method for producing thin film made from oxide of titanium or titanium alloy and having sealed micropores Download PDF

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WO2020179427A1
WO2020179427A1 PCT/JP2020/006170 JP2020006170W WO2020179427A1 WO 2020179427 A1 WO2020179427 A1 WO 2020179427A1 JP 2020006170 W JP2020006170 W JP 2020006170W WO 2020179427 A1 WO2020179427 A1 WO 2020179427A1
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titanium
sulfuric acid
thin film
electrolytic
titanium alloy
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PCT/JP2020/006170
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French (fr)
Japanese (ja)
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卓也 松田
南美 吉村
永井　達夫
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栗田工業株式会社
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/26—Anodisation of refractory metals or alloys based thereon

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  • the present invention relates to a method for producing a titanium or titanium alloy oxide thin film for sealing a titanium or titanium alloy oxide thin film having micropores formed therein.
  • Titanium or titanium alloy members are widely used because they are light metals with high hardness and strength, have high corrosion resistance, and have excellent ductility. Furthermore, by subjecting titanium and titanium alloy members to anodizing treatment to form an anodized film, not only coloring, improvement in abrasion resistance, function as a photocatalyst, but also high eco-compatibility are obtained. Its applications such as medical applications are expanding.
  • This method of forming an anodized film on titanium or a titanium alloy is known to perform electrolytic treatment in an electrolytic solution such as a mixed solution of sulfuric acid, phosphoric acid and hydrogen peroxide, using titanium or a titanium alloy as an anode.
  • an electrolytic solution such as a mixed solution of sulfuric acid, phosphoric acid and hydrogen peroxide
  • titanium or a titanium alloy as an anode.
  • Patent Document 1 Patent Document 2, etc.
  • the formed hole is large, about 1 ⁇ m.
  • the pores formed in the anodic oxide film are large as described above, there is a problem in that the titanium oxide film and the body such as human tissue are not densely embedded in the structure when bonded to each other and it is difficult to fix the structure. ..
  • the applicant of the present invention has previously proposed a sulfuric acid solution containing 0.5% by weight or less of a hydrogen fluoride compound or an electrolytic sulfuric acid solution containing 0.5% by weight or less of a hydrogen fluoride compound in an oxidizing agent concentration of 5 g/L or more.
  • a method for producing an oxide thin film of titanium or a titanium alloy having pores of 100 nm or less from a titanium or titanium alloy thin film by electrolytically treating with a current density of 1 to 20 A/dm 2 to form fine pores is proposed (Patent application 2017-198830).
  • microporous thin films of various metals may require sealing treatment because the bottoms of the micropores are the thinnest and have low chemical resistance.
  • the microporous thin film on the aluminum surface can be easily sealed because it hydrates to cause volume expansion. I can't adapt. If it is possible to form a thick oxide film by sealing a microporous thin film on titanium and a titanium alloy, the use thereof can be further expanded, which is desirable.
  • the present invention has been made in view of the above problems, and an object thereof is to provide a method for producing an oxide thin film of titanium or titanium alloy in which micropores are sealed.
  • the present invention uses a titanium or titanium alloy thin film as an anode and dissolves a hydrogen fluoride compound in an amount of 0.5 wt% or less in a sulfuric acid solution or a hydrogen fluoride compound in an amount of 0.5 wt% or less.
  • a method for producing an oxide thin film of titanium or a titanium alloy in which micropores are sealed which comprises performing an electrolysis treatment in a liquid at a current density of 0.1 A/dm 2 or less to seal the micropores. (Invention 1).
  • the oxide thin film of titanium or titanium alloy has a thickness of 100 nm or less, particularly 50 nm or less, due to the etching effect of the electrolytic treatment using a hydrogen fluoride compound at a current density of 1 to 20 A/dm 2 .
  • Micropores can be formed.
  • the fine pores can be sealed to form a thick oxide film. it can.
  • the sulfuric acid concentration of the sulfuric acid solution or electrolytic sulfuric acid is preferably 10% by weight or more (Invention 2).
  • an oxide thin film of titanium or titanium alloy having fine pores of 100 nm or less can be formed in a short time by the opening step, and the fine hole is sealed in the subsequent sealing step. Therefore, a thick oxide film can be formed.
  • the hydrogen fluoride compound is preferably ammonium fluoride (Invention 3).
  • the processing time in the opening step is 30 to 60 seconds and the processing time in the sealing step is 5 to 12 hours (Invention 4).
  • invention 4 it is possible to easily form fine pores of 100 nm or less in the oxide thin film of titanium or titanium alloy by the short-time opening step, while the fine holes are formed by the long-time sealing step.
  • the holes can be sealed to form a thick oxide film.
  • the first electrolytic treatment is performed with a sulfuric acid solution or an electrolytic sulfuric acid solution in which a hydrogen fluoride compound is dissolved, and then the second electrolytic treatment is performed without dissolving the hydrogen fluoride compound.
  • a sulfuric acid solution it is possible to stabilize fine pores of 100 nm or less in the oxide thin film of titanium or titanium alloy, and in the subsequent sealing step, the fine pores are sealed to form a thick oxide film. Can be formed.
  • an oxide thin film of titanium or titanium alloy in which micropores are sealed 1 to 20 A in a sulfuric acid solution or an electrolytic sulfuric acid solution in which a hydrogen fluoride compound is dissolved using a titanium or titanium alloy thin film as an anode.
  • a sulfuric acid solution or an electrolytic sulfuric acid solution in which a hydrogen fluoride compound is dissolved using a titanium or titanium alloy thin film as an anode By forming an oxide film and forming fine pores by performing electrolytic treatment at a current density of /dm 2 for a short time, by performing electrolytic treatment for a long time at a current density of 0.1 A/dm 2 or less, The micropores can be sealed. This makes it possible to efficiently manufacture a titanium or titanium alloy oxide thin film in which fine pores are sealed.
  • FIG. 1 is a schematic view showing a processing apparatus to which a method for producing a titanium or titanium alloy oxide thin film having micropores sealed therein according to an embodiment of the present invention can be applied.
  • FIG. 1 schematically shows a processing apparatus to which a method for producing a titanium or titanium alloy oxide thin film having micropores sealed therein according to an embodiment of the present invention can be applied.
  • FIG. It has a bath 2 and a cathode member 4 and an anode member 5 installed in the processing bath 2, and these cathode member 4 and anode member 5 are connected to the negative pole and the positive pole of a DC power supply 3, respectively.
  • the treatment tank 2 may be provided with a constant temperature heater (not shown) for keeping the solution in the treatment tank 2 at a desired temperature.
  • the anode member 5 is a member to be treated, and a member provided with a thin film made of titanium or titanium alloy on its surface is used.
  • the cathode member 4 is not particularly limited as long as it is an electrically conductive material, but a member (including a thin film) made of titanium or a titanium alloy can be used in terms of conductivity, corrosion resistance and the like.
  • an oxide thin film of titanium or titanium alloy having fine pores is manufactured by electrolytic treatment. This electrolytic treatment is preferably performed in two steps.
  • a sulfuric acid solution or electrolytic sulfuric acid S in which a hydrogen fluoride compound is dissolved is used as the electrolytic treatment solution to be stored in the treatment tank 2 of the electrolytic treatment apparatus 1. Since the sulfuric acid solution alone has no oxidizing power, titanium or titanium alloy is only dissolved, and the pore diameter of the fine pores can be 100 nm or less, but it is difficult to set it to 30 nm or less. In order to form finer pores, electrolytic sulfuric acid having oxidizing power is used.
  • the concentration of the oxidizing agent in the case of this electrolytic sulfuric acid may be the concentration of the oxidizing agent that can be produced when electrolyzing sulfuric acid to produce electrolytic sulfuric acid, but if it is less than 5 g/L, the oxidation rate becomes slow, and the anode member Since the hole diameter formed in the thin film made of titanium or titanium alloy used in No. 5 becomes large, it becomes difficult to perform the sealing in the sealing step described later.
  • the upper limit of the concentration of the oxidant is not particularly limited, but about 10 g/L is practical from the viewpoint of efficiency when electrolyzing sulfuric acid to produce electrolytic sulfuric acid.
  • the hydrogen fluoride compound a salt of hydrofluoric acid and a basic substance may be used, and ammonium fluoride is preferable because it is easy to handle and versatile.
  • the hydrogen fluoride compound is ammonium fluoride
  • its concentration is 0.5% by weight or less. If the concentration of ammonium fluoride exceeds 0.5% by weight, the dissolution of titanium will proceed excessively and the pores will become large, and the pores will become tubular. Further, if the lower limit of the concentration of ammonium fluoride is less than 0.1% by weight, the dissolution of titanium does not proceed, the formation of fine pores is not sufficient, and the dissolution of titanium does not proceed, so that an oxide film formed is also formed.
  • the concentration of ammonium fluoride is 0.25 ⁇ 0.05% by weight from the viewpoint of forming fine holes. Even in the case of a hydrogen fluoride compound other than ammonium fluoride, its concentration may be 0.5% by weight or less.
  • the sulfuric acid concentration in the sulfuric acid solution or the electrolytic sulfuric acid S when the sulfuric acid concentration is less than 5% by weight, the amount of H + (H 3 O + ) ions due to the electrolysis of sulfuric acid in the electrolytic treatment described later is small, so that the anode member 5 (processed The dissolution rate of titanium or titanium alloy as a member) becomes slow and an oxide film is formed on the surface to prevent the reaction from progressing.
  • the sulfuric acid concentration exceeds 80% by weight, the dissolution rate of titanium becomes too fast, The dissolution proceeds preferentially, and it becomes difficult to form an oxide film of titanium, so the content is preferably 5 to 80% by weight.
  • the sulfuric acid concentration is preferably 10 to 75% by weight.
  • a cathode member 4 as a member to be treated connected to a DC power source 3 and a member using a thin film made of titanium or a titanium alloy.
  • the anode member 5 made of the above is suspended in the processing tank 2.
  • the current density applied here is lower than 1 A/dm 2 , stable control becomes difficult, while if it is higher than 20 A/dm 2 , the current density becomes too large, so that a thin film made of titanium or a titanium alloy is formed. Not only does the hole diameter increase, but the hole becomes a tube. Therefore, the current density is 1 to 20 A/dm 2 , preferably 3 to 10 A/dm 2 .
  • the temperature of the sulfuric acid solution or the electrolytic sulfuric acid S in this electrolytic treatment is not particularly limited, but if the temperature of the sulfuric acid solution or the electrolytic sulfuric acid S is less than 10°C, the effect of the oxidizing agent in the electrolytic sulfuric acid is not sufficiently exhibited.
  • the oxide film is not sufficiently formed, when the temperature exceeds 50° C., the oxidation rate increases, and the formation of the passive oxide film prevents the titanium from being dissolved and makes it difficult to form fine pores.
  • the temperature of the preferable sulfuric acid solution or electrolytic sulfuric acid S is 10 to 50 ° C., particularly 20 to 50 ° C. Therefore, in the treatment tank 2, it is preferable that the temperature of the sulfuric acid solution or the electrolytic sulfuric acid S be maintained at a predetermined temperature by a constant temperature heater (not shown) so that the temperature becomes the above-mentioned temperature.
  • the time of the electrolysis treatment as described above is not particularly limited, but if it is less than 30 seconds, the titanium is not sufficiently dissolved and fine pores are difficult to be formed.
  • the upper limit of the electrolytic treatment time if it is too long, the dissolution of titanium proceeds, the pores formed become large and non-uniform, and the treatment efficiency decreases. Therefore, the upper limit is less than 360 seconds. It is preferable that the treatment time is about 30 to 60 seconds.
  • the titanium or titanium alloy thin film becomes a titanium or titanium alloy oxide thin film having fine pores by the following chemical reaction. That is, by electrolytic treatment with sulfuric acid in the sulfuric acid solution or electrolytic sulfuric acid solution S and a hydrogen fluoride compound, Ti 3+ is eluted at the anode to form fine pores. Ti+3H + ⁇ Ti 3+ +3/2H 2 (1)
  • electrolytic sulfuric acid is contained in the electrolytic sulfuric acid solution S, the following reaction also proceeds to form TiO 2 .
  • the anodizing treatment of titanium or a titanium alloy is a competitive reaction between the dissolution of Ti of formula (1) and the oxidation of Ti of formula (2), and the oxidation is caused by the oxidation rate of Ti and the etching action of TiO 2 by a hydrogen fluoride compound. It is possible to make fine holes while forming a film. If the concentration of this hydrogen fluoride compound is too high or if it is exposed for a long time, the etching action penetrates into the inside of TiO 2 and titanium inside is also dissolved. This increases the possibility of forming a tube-shaped weak oxide film. Therefore, the sulfuric acid concentration or oxidizing agent concentration, hydrogen fluoride compound concentration, and electrolytic treatment conditions of this sulfuric acid solution or electrolytic sulfuric acid S are sufficient. It is desirable to consider
  • the second-stage electrolytic treatment with only electrolytic sulfuric acid S that does not use the hydrogen fluoride compound. It is preferable to carry out.
  • the conditions of this second-stage electrolytic treatment may be basically the same as those of the above-described first-stage electrolytic treatment, but the treatment time depends on the thickness of the titanium or titanium alloy thin film used for the anode member 5. It may be appropriately set depending on the situation.
  • By performing such a second-stage electrolytic treatment in an electrolytic sulfuric acid solution that does not dissolve the hydrogen fluoride compound it is possible to stabilize the fine pores of 100 nm or less formed in the oxide thin film of titanium or titanium alloy.
  • the sealing step is basically performed subsequent to the opening step described above. That is, when the opening step is completed, electrolytic treatment is performed at a current density of 0.1 A/dm 2 or less, particularly 0.05 A/dm 2 or less. If the current density exceeds 0.1 A/dm 2 , the etching effect is also exhibited and the sealing is not sufficient. In addition, if the current density is less than 0.01 A/dm 2 , the sealing efficiency is too poor and the time is too long, which is not preferable.
  • the time of the sealing step as described above is not particularly limited, but if the time is less than 5 hours, it is not possible to sufficiently close the fine pores, while if it exceeds 12 hours, no further improvement of the sealing effect can be obtained. It is preferably 5 to 12 hours because the processing efficiency is lowered.
  • the anode member 5 may use a thin film made of titanium or a titanium alloy, and may have a shape in which the surface of a metal electrode material is covered with a thin film made of titanium or a titanium alloy.
  • the pore diameters of the micropores formed differ depending on the concentration of the hydrogen fluoride compound, the sulfuric acid concentration, the current density, the temperature of the electrolytic sulfuric acid and the time of the electrolytic treatment, these conditions are appropriately set according to the desired micropores. Can be adjusted.
  • the second-stage electrolysis treatment is not always necessary, and in that case, the electrolysis treatment with only electrolytic sulfuric acid S that does not use a hydrogen fluoride compound in the sealing step may be performed.
  • Example 1 A 100 mm ⁇ 100 mm ⁇ 0.04 mm (t) pure titanium test piece was prepared, and the cathode member 4 and the anode member 5 were formed using this test piece to configure the electrolytic treatment apparatus 1 shown in FIG.
  • the treatment tank 2 of this electrolytic treatment apparatus 1 was filled with an electrolytic sulfuric acid solution S having a sulfuric acid concentration of 10% by weight, an oxidizing agent concentration of 10 g/L and an ammonium fluoride concentration of 0.25% by weight, and the temperature was 30° C. and the current density was 3.5 A.
  • the first stage electrolysis treatment was performed at / dm 2 for 40 seconds.
  • the second stage electrolytic treatment was performed for 60 seconds using only the electrolytic sulfuric acid having the same concentration as that of the first stage, without dissolving ammonium fluoride, and the opening step was completed. Then, the electrolytic sulfuric acid solution S was left as it was, the current density was changed to 0.05/dm 2 , and the sealing step was performed for 12 hours.
  • the surface of the test piece of the pure titanium of the anode member 5 after the opening step (before the sealing step) and after the sealing step was observed with a field emission scanning electron microscope (FE-SEM) at a magnification of 100,000 times. As a result, it was confirmed that a titanium oxide film having fine pores of about 20 nm was formed on the pure titanium test piece of the anode member 5 after the opening step. On the other hand, no fine holes were confirmed on the surface of the pure titanium test piece of the anode member 5 after the sealing step, and the holes were filled. Table 1 shows the pore diameters of the fine holes of the pure titanium test piece of the anode member 5 after the hole-opening step and the hole-sealing step.
  • Example 2 A test piece of pure titanium was treated in the same manner as in Example 1 except that the electrolytic treatment condition in the opening step was changed to a sulfuric acid concentration of 75% by weight.
  • the surfaces of the pure titanium test piece of the anode member 5 after the hole-opening step (before the hole-sealing step) and after the hole-sealing step are observed by a field emission scanning electron microscope (FE-SEM) at a magnification of 100,000 times. As a result, it was confirmed that a titanium oxide film having a hole of about 40 nm was formed on the test piece of pure titanium of the anode member 5 after the hole opening step. On the other hand, no holes were found on the surface of the pure titanium test piece of the anode member 5 after the sealing step, and the holes were filled. Table 1 also shows the hole diameters of the fine holes of the pure titanium test pieces of the anode member 5 after the opening step and after the sealing step.

Abstract

An electrolytic treatment apparatus 1 is equipped with a treatment vessel 2 and a negative electrode member 4 and a positive electrode member 5 both installed in the treatment vessel 2, wherein the negative electrode member 4 and the positive electrode member 5 are connected to a minus electrode and a plus electrode, respectively, of a direct-current power supply 3. In the electrolytic treatment apparatus 1, the positive electrode member 5 serves as a member to be treated, and a member prepared using a titanium- or titanium-alloy-made thin film is used as the positive electrode member 5. An electrolyzed sulfuric acid solution S in which a hydrogen fluoride compound is dissolved at a concentration of 0.5% by weight or less and having an oxidizing agent concentration of 5 g/L or more is placed in the treatment vessel 2, and then an electrolytic treatment is carried out at a current density of 1 to 20 A/dm2 (pore-opening step). Subsequently, an electrolytic treatment is carried out at a current density of 0.1 A/dm2 or less (pore-sealing step). Thus, a method for producing a thin film made from an oxide of titanium or a titanium alloy and having sealed micropores is provided.

Description

微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法Method for manufacturing an oxide thin film of titanium or titanium alloy with fine pores sealed
　本発明は、微細孔を形成したチタン又はチタン合金の酸化薄膜を封孔するチタン又はチタン合金の酸化薄膜の製造方法に関する。 The present invention relates to a method for producing a titanium or titanium alloy oxide thin film for sealing a titanium or titanium alloy oxide thin film having micropores formed therein.
　チタン又はチタン合金部材は、高い硬度と強度と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、光触媒としての機能が発現されるだけでなく、生態適合性が高いことから医療用などその用途が拡大されている。 Titanium or titanium alloy members are widely used because they are light metals with high hardness and strength, have high corrosion resistance, and have excellent ductility. Furthermore, by subjecting titanium and titanium alloy members to anodizing treatment to form an anodized film, not only coloring, improvement in abrasion resistance, function as a photocatalyst, but also high eco-compatibility are obtained. Its applications such as medical applications are expanding.
　このチタン又はチタン合金への陽極酸化皮膜の形成方法は、例えばチタン又はチタン合金を陽極として、硫酸、リン酸、過酸化水素の混合液などの電解液中で電解処理を行うことが知られている（例えば特許文献１、特許文献２など）。これらの文献によると、１００Ｖ以上の高い電圧をかけて火花放電処理することにより、微細孔を形成することで光触媒の機能を付与し、有機化合物や細菌などの有害物質を除去することができるようになる。 This method of forming an anodized film on titanium or a titanium alloy is known to perform electrolytic treatment in an electrolytic solution such as a mixed solution of sulfuric acid, phosphoric acid and hydrogen peroxide, using titanium or a titanium alloy as an anode. (For example, Patent Document 1, Patent Document 2, etc.). According to these documents, by performing a spark discharge treatment by applying a high voltage of 100 V or more, it is possible to impart a photocatalytic function by forming fine pores and remove harmful substances such as organic compounds and bacteria. become.
　しかしながら、高電圧をかける火花放電処理によりチタン又はチタン合金の陽極酸化皮膜に孔を形成した場合には、形成される孔が約１μｍと大きい。このように陽極酸化皮膜に形成される孔が大きいと、チタン酸化皮膜と人体組織などの基体との結合の際に組織が密に埋まらず、固定するのが困難となる、という問題点がある。また、１μｍより小さい微細孔の孔を開けることができる技術もあるが、孔がチューブ状となっているため貫通した際に皮膜が離れてしまい、膜としての形状を維持できない、という問題点がある。 However, when a hole is formed in the anodized film of titanium or titanium alloy by a spark discharge treatment that applies a high voltage, the formed hole is large, about 1 μm. When the pores formed in the anodic oxide film are large as described above, there is a problem in that the titanium oxide film and the body such as human tissue are not densely embedded in the structure when bonded to each other and it is difficult to fix the structure. .. There is also a technology that can make fine pores smaller than 1 μm, but since the pores are tube-shaped, the coating separates when it penetrates and the shape of the membrane cannot be maintained. is there.
　そこで、本出願人は、先にフッ化水素化合物を０．５重量％以下溶解した硫酸溶液又はフッ化水素化合物を０．５重量％以下溶解した酸化剤濃度５ｇ／Ｌ以上の電解硫酸液中で１～２０Ａ／ｄｍ２の電流密度で電解処理して微細孔を形成する、チタン又はチタン合金薄膜から１００ｎｍ以下の孔を有するチタン又はチタン合金の酸化薄膜を製造する方法について提案した（特願２０１７－１９８８３０）。 Therefore, the applicant of the present invention has previously proposed a sulfuric acid solution containing 0.5% by weight or less of a hydrogen fluoride compound or an electrolytic sulfuric acid solution containing 0.5% by weight or less of a hydrogen fluoride compound in an oxidizing agent concentration of 5 g/L or more. A method for producing an oxide thin film of titanium or a titanium alloy having pores of 100 nm or less from a titanium or titanium alloy thin film by electrolytically treating with a current density of 1 to 20 A/dm 2 to form fine pores is proposed (Patent application 2017-198830).
特公平６－４１６４０号公報Japanese Patent Publication No. 6-41640 特公平８－９８４号公報Japanese Patent Publication No. 8-984
　しかしながら、各種金属の微細孔薄膜は、微細孔の底部が最も薄く耐薬品性が低いため封孔処理が必要になることがある。アルミ表面上の微細孔薄膜は水和することで体積膨張を起こすため、容易に封孔することができるが、チタンおよびチタン合金上の微細孔薄膜は水和しないため、同様の封孔技術が適応できない。もし、チタンおよびチタン合金上の微細孔薄膜を封孔して、厚みのある酸化皮膜を形成することができれば、その用途をさらに拡大することができるので望ましい。 However, microporous thin films of various metals may require sealing treatment because the bottoms of the micropores are the thinnest and have low chemical resistance. The microporous thin film on the aluminum surface can be easily sealed because it hydrates to cause volume expansion. I can't adapt. If it is possible to form a thick oxide film by sealing a microporous thin film on titanium and a titanium alloy, the use thereof can be further expanded, which is desirable.
　本発明は、上記課題に鑑みてなされたものであり、微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造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, and an object thereof is to provide a method for producing an oxide thin film of titanium or titanium alloy in which micropores are sealed.
　上記目的を達成するために本発明は、チタン又はチタン合金製薄膜を陽極として、フッ化水素化合物を０．５重量％以下溶解した硫酸溶液又はフッ化水素化合物を０．５重量％以下溶解した酸化剤濃度５ｇ／Ｌ以上の電解硫酸液中で１～２０Ａ／ｄｍ２の電流密度で電解処理して微細孔を形成する開孔工程と、硫酸溶液又は酸化剤濃度５ｇ／Ｌ以上の電解硫酸液中で電流密度を０．１Ａ／ｄｍ２以下で電解処理して前記微細孔を封孔する封孔工程とを行う、微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法を提供する（発明１）。 In order to achieve the above object, the present invention uses a titanium or titanium alloy thin film as an anode and dissolves a hydrogen fluoride compound in an amount of 0.5 wt% or less in a sulfuric acid solution or a hydrogen fluoride compound in an amount of 0.5 wt% or less. Opening step of forming fine pores by electrolytic treatment at a current density of 1 to 20 A/dm 2 in an electrolytic sulfuric acid solution having an oxidant concentration of 5 g/L or more, and a sulfuric acid solution or electrolytic sulfuric acid having an oxidant concentration of 5 g/L or more Provided is a method for producing an oxide thin film of titanium or a titanium alloy in which micropores are sealed, which comprises performing an electrolysis treatment in a liquid at a current density of 0.1 A/dm 2 or less to seal the micropores. (Invention 1).
　かかる発明（発明１）によれば、フッ化水素化合物を用いた１～２０Ａ／ｄｍ２の電流密度での電解処理によるエッチング効果により、チタン又はチタン合金の酸化薄膜に１００ｎｍ以下、特に５０ｎｍ以下の微細孔を形成することができる。そして、この開孔したチタン又はチタン合金の酸化薄膜に電流密度０．１Ａ／ｄｍ２以下で電解処理を施すことにより、この微細孔を封孔して、厚みのある酸化皮膜を形成することができる。 According to the invention (Invention 1), the oxide thin film of titanium or titanium alloy has a thickness of 100 nm or less, particularly 50 nm or less, due to the etching effect of the electrolytic treatment using a hydrogen fluoride compound at a current density of 1 to 20 A/dm 2 . Micropores can be formed. By subjecting the opened oxide thin film of titanium or titanium alloy to electrolytic treatment at a current density of 0.1 A/dm 2 or less, the fine pores can be sealed to form a thick oxide film. it can.
　上記発明（発明１）においては、前記硫酸溶液又は電解硫酸の硫酸濃度が１０重量％以上であることが好ましい（発明２）。 In the above invention (Invention 1), the sulfuric acid concentration of the sulfuric acid solution or electrolytic sulfuric acid is preferably 10% by weight or more (Invention 2).
　かかる発明（発明２）によれば、開孔工程により１００ｎｍ以下の微細孔を有するチタン又はチタン合金の酸化薄膜を短時間で形成することができ、その後の封孔工程でこの微細孔を封孔して、厚みのある酸化皮膜を形成することができる。 According to the invention (Invention 2), an oxide thin film of titanium or titanium alloy having fine pores of 100 nm or less can be formed in a short time by the opening step, and the fine hole is sealed in the subsequent sealing step. Therefore, a thick oxide film can be formed.
　上記発明（発明１，２）においては、前記フッ化水素化合物が、フッ化アンモニウムであることが好ましい（発明３）。 In the above inventions (Inventions 1 and 2), the hydrogen fluoride compound is preferably ammonium fluoride (Invention 3).
　かかる発明（発明３）によれば、開孔工程によりチタン又はチタン合金の酸化薄膜に１００ｎｍ以下の微細孔を容易に形成することができ、その後の封孔工程でこの微細孔を封孔して、厚みのある酸化皮膜を形成することができる。 According to the invention (Invention 3), fine holes of 100 nm or less can be easily formed in the oxide thin film of titanium or titanium alloy by the opening step, and the fine holes are sealed in the subsequent sealing step. , A thick oxide film can be formed.
　上記発明（発明１～３）においては、前記開孔工程の処理時間が３０～６０秒であり、前記封孔工程の処理時間が５～１２時間であることが好ましい（発明４）。 In the above inventions (Inventions 1 to 3), it is preferable that the processing time in the opening step is 30 to 60 seconds and the processing time in the sealing step is 5 to 12 hours (Invention 4).
　かかる発明（発明４）によれば、短時間の開孔工程によりチタン又はチタン合金の酸化薄膜に１００ｎｍ以下の微細孔を容易に形成することができる一方、長時間の封孔工程により微細孔を封孔して、厚みのある酸化皮膜を形成することができる。 According to the invention (Invention 4), it is possible to easily form fine pores of 100 nm or less in the oxide thin film of titanium or titanium alloy by the short-time opening step, while the fine holes are formed by the long-time sealing step. The holes can be sealed to form a thick oxide film.
　上記発明（発明１～４）においては、前記開孔工程が、前記フッ化水素化合物を溶解した硫酸溶液又は電解硫酸液による１段目の電解処理と、フッ化水素化合物を溶解しない電解硫酸液中で１～２０Ａ／ｄｍ２の電流密度による２段目の電解処理とを備えることが好ましい（発明５）。 In the above inventions (Inventions 1 to 4), in the opening step, the first step of electrolytic treatment with a sulfuric acid solution or an electrolytic sulfuric acid solution in which the hydrogen fluoride compound is dissolved, and an electrolytic sulfuric acid solution in which the hydrogen fluoride compound is not dissolved Among them, it is preferable to provide a second-stage electrolytic treatment with a current density of 1 to 20 A/dm 2 (Invention 5).
　かかる発明（発明５）によれば、１段目の電解処理をフッ化水素化合物を溶解した硫酸溶液又は電解硫酸液で行った後、２段目の電解処理をフッ化水素化合物を溶解しない電解硫酸液中で行うことにより、チタン又はチタン合金の酸化薄膜に１００ｎｍ以下の微細孔を安定化することができ、その後の封孔工程でこの微細孔を封孔して、厚みのある酸化皮膜を形成することができる。 According to the invention (Invention 5), the first electrolytic treatment is performed with a sulfuric acid solution or an electrolytic sulfuric acid solution in which a hydrogen fluoride compound is dissolved, and then the second electrolytic treatment is performed without dissolving the hydrogen fluoride compound. By performing in a sulfuric acid solution, it is possible to stabilize fine pores of 100 nm or less in the oxide thin film of titanium or titanium alloy, and in the subsequent sealing step, the fine pores are sealed to form a thick oxide film. Can be formed.
　本発明の微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法によれば、チタン又はチタン合金製薄膜を陽極としてフッ化水素化合物を溶解した硫酸溶液又は電解硫酸液中で１～２０Ａ／ｄｍ２の電流密度で短時間の電解処理をすることにより、酸化皮膜を形成するとともに微細孔を形成した後、電流密度０．１Ａ／ｄｍ２以下で長時間の電解処理を施すことにより、この微細孔を封孔することができる。これにより微細孔を封孔したチタン又はチタン合金の酸化薄膜を効率的に製造することができる。 According to the method for producing an oxide thin film of titanium or titanium alloy in which micropores are sealed according to the present invention, 1 to 20 A in a sulfuric acid solution or an electrolytic sulfuric acid solution in which a hydrogen fluoride compound is dissolved using a titanium or titanium alloy thin film as an anode. By forming an oxide film and forming fine pores by performing electrolytic treatment at a current density of /dm 2 for a short time, by performing electrolytic treatment for a long time at a current density of 0.1 A/dm 2 or less, The micropores can be sealed. This makes it possible to efficiently manufacture a titanium or titanium alloy oxide thin film in which fine pores are sealed.
本発明の一実施形態による微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法を適用可能な処理装置を示す概略図である。1 is a schematic view showing a processing apparatus to which a method for producing a titanium or titanium alloy oxide thin film having micropores sealed therein according to an embodiment of the present invention can be applied.
　以下、本発明の一実施形態による微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法について、添付図面を参照して詳細に説明する。 Hereinafter, a method of manufacturing a titanium or titanium alloy oxide thin film having micropores sealed therein according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
［電解処理装置］
　図１は本発明の一実施形態による微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法を適用可能な処理装置を概略的に示しており、図１において電解処理装置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には該処理槽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。このような電解処理装置１において、陽極部材５は被処理部材となるものであり、チタン又はチタン合金製の薄膜を表面に設けた部材を用いる。また、陰極部材４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、耐食性などの点でチタン又はチタン合金製の部材（薄膜を含む）を用いることができる。 [Electrolytic processing equipment]
FIG. 1 schematically shows a processing apparatus to which a method for producing a titanium or titanium alloy oxide thin film having micropores sealed therein according to an embodiment of the present invention can be applied. In FIG. It has a bath 2 and a cathode member 4 and an anode member 5 installed in the processing bath 2, and these cathode member 4 and anode member 5 are connected to the negative pole and the positive pole of a DC power supply 3, respectively. The treatment tank 2 may be provided with a constant temperature heater (not shown) for keeping the solution in the treatment tank 2 at a desired temperature. In such an electrolytic treatment apparatus 1, the anode member 5 is a member to be treated, and a member provided with a thin film made of titanium or titanium alloy on its surface is used. The cathode member 4 is not particularly limited as long as it is an electrically conductive material, but a member (including a thin film) made of titanium or a titanium alloy can be used in terms of conductivity, corrosion resistance and the like.
［微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法］
　次に上述したような電解処理装置１を用いた本実施形態の微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法について説明する。 [Manufacturing method of oxide thin film of titanium or titanium alloy with micropores sealed]
Next, a method of manufacturing the titanium or titanium alloy oxide thin film in which the micropores are sealed according to the present embodiment using the electrolytic treatment apparatus 1 as described above will be described.
（開孔工程）
　まず、微細孔を有するチタン又はチタン合金の酸化薄膜を電解処理により製造する。この電解処理は２段階で行うことが好ましい。 (Opening process)
First, an oxide thin film of titanium or titanium alloy having fine pores is manufactured by electrolytic treatment. This electrolytic treatment is preferably performed in two steps.
（１段目の電解処理）
　１段目の電解処理では、電解処理装置１の処理槽２に収容する電解処理の溶液として、フッ化水素化合物を溶解した硫酸溶液又は電解硫酸Ｓを用いる。硫酸溶液のみでは酸化力がないためチタン又はチタン合金が溶解するのみで、その微細孔の孔径を１００ｎｍ以下とすることはできるが、３０ｎｍ以下とするのは困難である。より微細孔を形成するためには、酸化力を有する電解硫酸を使用する。この電解硫酸の場合における酸化剤濃度は、硫酸を電解して電解硫酸を作製する際に生成可能な酸化剤濃度であればよいが、５ｇ／Ｌ未満では酸化速度が遅くなってしまい、陽極部材５に用いたチタン又はチタン合金製の薄膜に形成される孔径が大きくなるため、後述する封孔工程において、封孔が困難となってしまう。なお、酸化剤濃度の上限については特に制限はないが、硫酸を電解して電解硫酸を作製する際の効率の点から１０ｇ／Ｌ程度が現実的である。 (1st stage electrolysis treatment)
In the first-stage electrolytic treatment, a sulfuric acid solution or electrolytic sulfuric acid S in which a hydrogen fluoride compound is dissolved is used as the electrolytic treatment solution to be stored in the treatment tank 2 of the electrolytic treatment apparatus 1. Since the sulfuric acid solution alone has no oxidizing power, titanium or titanium alloy is only dissolved, and the pore diameter of the fine pores can be 100 nm or less, but it is difficult to set it to 30 nm or less. In order to form finer pores, electrolytic sulfuric acid having oxidizing power is used. The concentration of the oxidizing agent in the case of this electrolytic sulfuric acid may be the concentration of the oxidizing agent that can be produced when electrolyzing sulfuric acid to produce electrolytic sulfuric acid, but if it is less than 5 g/L, the oxidation rate becomes slow, and the anode member Since the hole diameter formed in the thin film made of titanium or titanium alloy used in No. 5 becomes large, it becomes difficult to perform the sealing in the sealing step described later. The upper limit of the concentration of the oxidant is not particularly limited, but about 10 g/L is practical from the viewpoint of efficiency when electrolyzing sulfuric acid to produce electrolytic sulfuric acid.
　前記フッ化水素化合物としては、フッ酸と塩基性物質との塩であれば良く、フッ化アンモニウムが取扱い性が良好で汎用的である点で好ましい。例えば、フッ化水素化合物がフッ化アンモニウムの場合、その濃度は０．５重量％以下である。フッ化アンモニウムの濃度が０．５重量％を超えると、チタンの溶解が進み過ぎて孔が大きくなり、孔がチューブ状となったりする。また、フッ化アンモニウムの濃度の下限については０．１重量％未満では、チタンの溶解が進まず、微細孔の形成が十分でなく、その上チタンの溶解が進まないため形成される酸化皮膜も薄くなり、チタン又はチタン合金製の薄膜を貫通できないため好ましくない。特に微細孔の形成の点でフッ化アンモニウムの濃度を０．２５±０．０５重量％とすることが好ましい。なお、フッ化アンモニウム以外のフッ化水素化合物の場合であってもその濃度は０．５重量％以下とすればよい。 As the hydrogen fluoride compound, a salt of hydrofluoric acid and a basic substance may be used, and ammonium fluoride is preferable because it is easy to handle and versatile. For example, when the hydrogen fluoride compound is ammonium fluoride, its concentration is 0.5% by weight or less. If the concentration of ammonium fluoride exceeds 0.5% by weight, the dissolution of titanium will proceed excessively and the pores will become large, and the pores will become tubular. Further, if the lower limit of the concentration of ammonium fluoride is less than 0.1% by weight, the dissolution of titanium does not proceed, the formation of fine pores is not sufficient, and the dissolution of titanium does not proceed, so that an oxide film formed is also formed. It is not preferable because it becomes thin and cannot penetrate a thin film made of titanium or titanium alloy. In particular, it is preferable that the concentration of ammonium fluoride is 0.25±0.05% by weight from the viewpoint of forming fine holes. Even in the case of a hydrogen fluoride compound other than ammonium fluoride, its concentration may be 0.5% by weight or less.
　さらに、硫酸溶液又は電解硫酸Ｓにおける硫酸濃度については、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＋（Ｈ３Ｏ＋）イオンが少ないため陽極部材５（被処理部材）としてのチタン又はチタン合金の溶解速度が遅くなり、表面に酸化皮膜が形成されてしまい反応が進まなくなる一方、硫酸濃度が８０重量％を超えるとチタンの溶解速度が速くなり過ぎ、チタンの溶解が優先的に進んでしまい、チタンの酸化皮膜が形成されにくくなるため５～８０重量％とすることが好ましい。特に硫酸濃度を１０～７５重量％とすることが好ましい。 Further, regarding the sulfuric acid concentration in the sulfuric acid solution or the electrolytic sulfuric acid S, when the sulfuric acid concentration is less than 5% by weight, the amount of H + (H 3 O + ) ions due to the electrolysis of sulfuric acid in the electrolytic treatment described later is small, so that the anode member 5 (processed The dissolution rate of titanium or titanium alloy as a member) becomes slow and an oxide film is formed on the surface to prevent the reaction from progressing. On the other hand, when the sulfuric acid concentration exceeds 80% by weight, the dissolution rate of titanium becomes too fast, The dissolution proceeds preferentially, and it becomes difficult to form an oxide film of titanium, so the content is preferably 5 to 80% by weight. In particular, the sulfuric acid concentration is preferably 10 to 75% by weight.
　このようなフッ化水素化合物を溶解した硫酸溶液又は電解硫酸Ｓを処理槽２に満たしたら、直流電源３に接続した被処理部材としての陰極部材４及びチタン又はチタン合金製の薄膜を用いた部材からなる陽極部材５を処理槽２に吊設する。 When the treatment tank 2 is filled with a sulfuric acid solution or electrolytic sulfuric acid S in which such a hydrogen fluoride compound is dissolved, a cathode member 4 as a member to be treated connected to a DC power source 3 and a member using a thin film made of titanium or a titanium alloy. The anode member 5 made of the above is suspended in the processing tank 2.
　そして、直流電源３から電流を印加する。これにより、陽極部材５のチタン又はチタン合金製の薄膜に酸化皮膜が形成される一方、フッ化水素化合物のエッチング効果により微細孔が形成される。ここで印加する電流密度は１Ａ／ｄｍ２よりも低いと安定した制御が困難となる一方、２０Ａ／ｄｍ２よりも高いと電流密度が大きくなりすぎるため、チタン又はチタン合金製の薄膜に形成される孔径が大きくなってしまうばかりか、孔がチューブとなったりする。したがって、電流密度は１～２０Ａ／ｄｍ２、好ましくは３～１０Ａ／ｄｍ２である。 Then, a current is applied from the DC power supply 3. As a result, an oxide film is formed on the titanium or titanium alloy thin film of the anode member 5, while fine holes are formed by the etching effect of the hydrogen fluoride compound. If the current density applied here is lower than 1 A/dm 2 , stable control becomes difficult, while if it is higher than 20 A/dm 2 , the current density becomes too large, so that a thin film made of titanium or a titanium alloy is formed. Not only does the hole diameter increase, but the hole becomes a tube. Therefore, the current density is 1 to 20 A/dm 2 , preferably 3 to 10 A/dm 2 .
　この電解処理における硫酸溶液又は電解硫酸Ｓの温度については、特に制限はないが、硫酸溶液又は電解硫酸Ｓの温度が１０℃未満であると電解硫酸中の酸化剤の効果が十分に発揮されず、十分に酸化皮膜が形成されない一方、５０℃を超えると酸化速度が上がってしまい、不動態である酸化皮膜の形成によりチタンの溶解が進まなくなり微細孔を形成しにくくなり、基材であるチタン又はチタン合金製の薄膜を貫通することが困難となるため好ましくない。したがって、好ましい硫酸溶液又は電解硫酸Ｓの温度は１０～５０℃、特に２０～５０℃とする。したがって、処理槽２では硫酸溶液又は電解硫酸Ｓの温度が上述した温度となるように必要に応じて恒温ヒータ（図示せず）により所定の温度に保持することが好ましい。 The temperature of the sulfuric acid solution or the electrolytic sulfuric acid S in this electrolytic treatment is not particularly limited, but if the temperature of the sulfuric acid solution or the electrolytic sulfuric acid S is less than 10°C, the effect of the oxidizing agent in the electrolytic sulfuric acid is not sufficiently exhibited. On the other hand, while the oxide film is not sufficiently formed, when the temperature exceeds 50° C., the oxidation rate increases, and the formation of the passive oxide film prevents the titanium from being dissolved and makes it difficult to form fine pores. Alternatively, it is not preferable because it becomes difficult to penetrate the thin film made of titanium alloy. Therefore, the temperature of the preferable sulfuric acid solution or electrolytic sulfuric acid S is 10 to 50 ° C., particularly 20 to 50 ° C. Therefore, in the treatment tank 2, it is preferable that the temperature of the sulfuric acid solution or the electrolytic sulfuric acid S be maintained at a predetermined temperature by a constant temperature heater (not shown) so that the temperature becomes the above-mentioned temperature.
　上述したような電解処理の時間は特に制限はないが３０秒未満では、チタンの溶解が不十分で微細孔が形成されにくい。なお、電解処理時間の上限については、あまり長すぎるとチタンの溶解が進み、形成される孔が大きく、不均一となってしまうばかりか、処理効率が低下するため、３６０秒未満とするのが好ましい、特に処理時間は３０～６０秒程度とすることが好ましい。 The time of the electrolysis treatment as described above is not particularly limited, but if it is less than 30 seconds, the titanium is not sufficiently dissolved and fine pores are difficult to be formed. Regarding the upper limit of the electrolytic treatment time, if it is too long, the dissolution of titanium proceeds, the pores formed become large and non-uniform, and the treatment efficiency decreases. Therefore, the upper limit is less than 360 seconds. It is preferable that the treatment time is about 30 to 60 seconds.
　上述した電解処理により、以下の化学反応によりチタン又はチタン合金製の薄膜が微細孔を有するチタン又はチタン合金の酸化薄膜となる。すなわち、硫酸溶液又は電解硫酸液Ｓ中の硫酸とフッ化水素化合物による電解処理により、陽極ではＴｉ３＋が溶出し、微細孔を形成する。
　　Ｔｉ＋３Ｈ＋→Ｔｉ３＋＋３／２Ｈ２　　…（１）
　電解硫酸液Ｓ中に電解硫酸が含まれる場合には以下の反応も進みＴｉＯ２を形成する。
　　Ｔｉ＋２Ｈ２Ｏ→ＴｉＯ２＋４Ｈ＋＋４ｅ－　　…（２） By the electrolytic treatment described above, the titanium or titanium alloy thin film becomes a titanium or titanium alloy oxide thin film having fine pores by the following chemical reaction. That is, by electrolytic treatment with sulfuric acid in the sulfuric acid solution or electrolytic sulfuric acid solution S and a hydrogen fluoride compound, Ti 3+ is eluted at the anode to form fine pores.
Ti+3H + →Ti 3+ +3/2H 2 (1)
When electrolytic sulfuric acid is contained in the electrolytic sulfuric acid solution S, the following reaction also proceeds to form TiO 2 .
Ti + 2H 2 O → TiO 2 + 4H + + 4e - ... (2)
　チタンまたはチタン合金の陽極酸化処理は式（１）のＴｉの溶解と式（２）のＴｉの酸化との競争反応であり、Ｔｉ酸化速度とフッ化水素化合物によるＴｉＯ２のエッチング作用により、酸化皮膜を形成しつつ微細な孔を開けることが可能となる。そして、このフッ化水素化合物の濃度が高すぎる場合や曝されている時間が長いとエッチング作用がＴｉＯ２の内部に浸透し、内側のチタンも溶解してしまう。これによりチューブ状の弱い酸化皮膜が形成される原因となる可能性が高くなることから、この硫酸溶液又は電解硫酸Ｓの硫酸濃度及び酸化剤濃度とフッ化水素化合物濃度と電解処理条件については十分に配慮するのが望ましい。 The anodizing treatment of titanium or a titanium alloy is a competitive reaction between the dissolution of Ti of formula (1) and the oxidation of Ti of formula (2), and the oxidation is caused by the oxidation rate of Ti and the etching action of TiO 2 by a hydrogen fluoride compound. It is possible to make fine holes while forming a film. If the concentration of this hydrogen fluoride compound is too high or if it is exposed for a long time, the etching action penetrates into the inside of TiO 2 and titanium inside is also dissolved. This increases the possibility of forming a tube-shaped weak oxide film. Therefore, the sulfuric acid concentration or oxidizing agent concentration, hydrogen fluoride compound concentration, and electrolytic treatment conditions of this sulfuric acid solution or electrolytic sulfuric acid S are sufficient. It is desirable to consider
（２段目の電解処理）
　さらに、本実施形態においては、上述した硫酸溶液又は電解硫酸Ｓとフッ化水素化合物とによる１段目の電解処理の後、フッ化水素化合物を用いない電解硫酸Ｓのみによる２段目の電解処理を行うことが好ましい。 (Second stage electrolysis treatment)
Further, in the present embodiment, after the first-stage electrolytic treatment with the sulfuric acid solution or electrolytic sulfuric acid S and the hydrogen fluoride compound described above, the second-stage electrolytic treatment with only electrolytic sulfuric acid S that does not use the hydrogen fluoride compound. It is preferable to carry out.
　この２段目の電解処理の条件は、基本的に前述した１段目の電解処理と同じでよいが、処理時間については、陽極部材５に用いたチタン又はチタン合金製の薄膜の厚さに応じて適宜設定すればよい。このような２段目の電解処理をフッ化水素化合物を溶解しない電解硫酸液中で行うことにより、チタン又はチタン合金の酸化薄膜に形成された１００ｎｍ以下の微細孔を安定化することができる。 The conditions of this second-stage electrolytic treatment may be basically the same as those of the above-described first-stage electrolytic treatment, but the treatment time depends on the thickness of the titanium or titanium alloy thin film used for the anode member 5. It may be appropriately set depending on the situation. By performing such a second-stage electrolytic treatment in an electrolytic sulfuric acid solution that does not dissolve the hydrogen fluoride compound, it is possible to stabilize the fine pores of 100 nm or less formed in the oxide thin film of titanium or titanium alloy.
（封孔工程）
　次にこのようにしてチタン又はチタン合金の酸化薄膜に形成した微細孔を封孔する。 (Seal process)
Next, the fine holes formed in the oxide thin film of titanium or titanium alloy in this manner are sealed.
　封孔工程は、基本的には前述した開孔工程から引き続いて行う。すなわち、開孔工程が完了したら、電流密度を０．１Ａ／ｄｍ２以下、特に０．０５Ａ／ｄｍ２以下で電解処理を行う。電流密度が０．１Ａ／ｄｍ２を超えると、エッチング効果も発揮されるため封孔が十分でない。なお、電流密度が、０．０１Ａ／ｄｍ２未満では、封孔効率が悪すぎて時間がかりすぎるため、好ましくない。 The sealing step is basically performed subsequent to the opening step described above. That is, when the opening step is completed, electrolytic treatment is performed at a current density of 0.1 A/dm 2 or less, particularly 0.05 A/dm 2 or less. If the current density exceeds 0.1 A/dm 2 , the etching effect is also exhibited and the sealing is not sufficient. In addition, if the current density is less than 0.01 A/dm 2 , the sealing efficiency is too poor and the time is too long, which is not preferable.
　この封孔工程の電解処理における硫酸溶液又は電解硫酸Ｓの濃度及び温度については、特に制限はなく、前述した開孔工程における条件と同じでよい。 There is no particular limitation on the concentration and temperature of the sulfuric acid solution or electrolytic sulfuric acid S in the electrolytic treatment in this sealing step, and the same conditions as in the above-described opening step may be used.
　上述したような封孔工程の時間は特に制限はないが、５時間未満では十分に微細孔を封じることができない一方、１２時間を超えてもそれ以上の封孔効果の向上が得られないばかりか処理効率が低下するため、５～１２時間とすることが好ましい。 The time of the sealing step as described above is not particularly limited, but if the time is less than 5 hours, it is not possible to sufficiently close the fine pores, while if it exceeds 12 hours, no further improvement of the sealing effect can be obtained. It is preferably 5 to 12 hours because the processing efficiency is lowered.
　上述した封孔処理では、電流密度が微弱であるので、Ｔｉの溶解の溶解（微細孔の形成）は進行しないが、ＴｉＯ２の形成は進行する。
　　Ｔｉ＋２Ｈ２Ｏ→ＴｉＯ２＋４Ｈ＋＋４ｅ－　　…（２）
　これにより開孔工程で酸化皮膜に形成された微細孔に酸化チタン（ＴｉＯ２）が蓄積さることで封孔を行い、この結果、厚みのある強度的に優れた酸化皮膜を形成することができる。 In the above-mentioned sealing treatment, since the current density is weak, the dissolution of Ti dissolution (formation of fine pores) does not proceed, but the formation of TiO 2 progresses.
Ti + 2H 2 O → TiO 2 + 4H + + 4e - ... (2)
As a result, titanium oxide (TiO 2 ) is accumulated in the fine pores formed in the oxide film in the opening step to perform the sealing, and as a result, a thick and excellent oxide film can be formed. ..
　以上、本発明の微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法について、前記実施形態に基づいて説明してきたが、本発明は前記実施形態に限定されず種々の変形実施が可能である。例えば、陽極部材５はチタン又はチタン合金製の薄膜を用いていればよく、金属製の電極材の表面をチタン又はチタン合金製の薄膜で覆う形状としてもよい。また、フッ化水素化合物の濃度、硫酸濃度、電流密度、電解硫酸の温度及び電解処理の時間により形成される微細孔の孔径が異なるので、所望とする微細孔に応じて、これらの条件を適宜調整することができる。さらに、２段目の電解処理は必ずしも必要なく、その場合には、封孔工程においてフッ化水素化合物を用いない電解硫酸Ｓのみによる電解処理を行えばよい。 The method for manufacturing the titanium or titanium alloy oxide thin film with the micropores sealed according to the present invention has been described above based on the above embodiment, but the present invention is not limited to the above embodiment and various modifications can be made. Is. For example, the anode member 5 may use a thin film made of titanium or a titanium alloy, and may have a shape in which the surface of a metal electrode material is covered with a thin film made of titanium or a titanium alloy. Further, since the pore diameters of the micropores formed differ depending on the concentration of the hydrogen fluoride compound, the sulfuric acid concentration, the current density, the temperature of the electrolytic sulfuric acid and the time of the electrolytic treatment, these conditions are appropriately set according to the desired micropores. Can be adjusted. Furthermore, the second-stage electrolysis treatment is not always necessary, and in that case, the electrolysis treatment with only electrolytic sulfuric acid S that does not use a hydrogen fluoride compound in the sealing step may be performed.
　以下に実施例により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。 The present invention will be described in more detail below by way of examples. However, the present invention is not limited to these descriptions.
［実施例１］
　１００ｍｍ×１００ｍｍ×０．０４ｍｍ（ｔ）の純チタンの試験片を用意し、この試験片を用いて陰極部材４及び陽極部材５を形成し、図１に示す電解処理装置１を構成した。この電解処理装置１の処理槽２に硫酸濃度１０重量％、酸化剤濃度１０ｇ／Ｌ、フッ化アンモニウム濃度０．２５重量％の電解硫酸液Ｓを充填し、温度３０℃、電流密度３．５Ａ／ｄｍ２で４０秒間１段目の電解処理を行った。次に２段目の電解処理を、フッ化アンモニウムを溶解することなく１段目と同濃度の電解硫酸のみで６０秒行い、開孔工程を完了した。その後、電解硫酸液Ｓはそのままにして電流密度を０．０５／ｄｍ２に変更し、１２時間かけて封孔工程を行った。 [Example 1]
A 100 mm×100 mm×0.04 mm (t) pure titanium test piece was prepared, and the cathode member 4 and the anode member 5 were formed using this test piece to configure the electrolytic treatment apparatus 1 shown in FIG. The treatment tank 2 of this electrolytic treatment apparatus 1 was filled with an electrolytic sulfuric acid solution S having a sulfuric acid concentration of 10% by weight, an oxidizing agent concentration of 10 g/L and an ammonium fluoride concentration of 0.25% by weight, and the temperature was 30° C. and the current density was 3.5 A. The first stage electrolysis treatment was performed at / dm 2 for 40 seconds. Next, the second stage electrolytic treatment was performed for 60 seconds using only the electrolytic sulfuric acid having the same concentration as that of the first stage, without dissolving ammonium fluoride, and the opening step was completed. Then, the electrolytic sulfuric acid solution S was left as it was, the current density was changed to 0.05/dm 2 , and the sealing step was performed for 12 hours.
　この陽極部材５の純チタンの試験片の開孔工程後（封孔工程前）と封孔工程後の表面を電界放出型走査電子顕微鏡（ＦＥ－ＳＥＭ）で１００，０００倍に拡大して観測したところ、開孔工程後の陽極部材５の純チタンの試験片には、約２０ｎｍの微細孔を有するチタン酸化皮膜が形成されていることが確認できた。一方、封孔工程後の陽極部材５の純チタンの試験片の表面には微細孔は確認されず、孔が埋まっていた。この開孔工程後と封孔工程後の陽極部材５の純チタンの試験片の微細孔の孔径を表１に示す。 The surface of the test piece of the pure titanium of the anode member 5 after the opening step (before the sealing step) and after the sealing step was observed with a field emission scanning electron microscope (FE-SEM) at a magnification of 100,000 times. As a result, it was confirmed that a titanium oxide film having fine pores of about 20 nm was formed on the pure titanium test piece of the anode member 5 after the opening step. On the other hand, no fine holes were confirmed on the surface of the pure titanium test piece of the anode member 5 after the sealing step, and the holes were filled. Table 1 shows the pore diameters of the fine holes of the pure titanium test piece of the anode member 5 after the hole-opening step and the hole-sealing step.
［実施例２］
　実施例１において、開孔工程の電解処理条件を、硫酸濃度を７５重量％に変更した以外は同様にして、純チタンの試験片を処理した。 [Example 2]
A test piece of pure titanium was treated in the same manner as in Example 1 except that the electrolytic treatment condition in the opening step was changed to a sulfuric acid concentration of 75% by weight.
　この陽極部材５の純チタンの試験片の開孔工程後（封孔工程前）と封孔工程後の表面を電界放出型走査電子顕微鏡（ＦＥ－ＳＥＭ）で１００，０００倍に拡大して観測したところ、開孔工程後の陽極部材５の純チタンの試験片には、約４０ｎｍの孔が形成されたチタン酸化皮膜が形成されていることが確認できた。一方、封孔工程後の陽極部材５の純チタンの試験片の表面には孔は確認されず、孔が埋まっていた。この開孔工程後と封孔工程後の陽極部材５の純チタンの試験片の微細孔の孔径を表１にあわせて示す。 The surfaces of the pure titanium test piece of the anode member 5 after the hole-opening step (before the hole-sealing step) and after the hole-sealing step are observed by a field emission scanning electron microscope (FE-SEM) at a magnification of 100,000 times. As a result, it was confirmed that a titanium oxide film having a hole of about 40 nm was formed on the test piece of pure titanium of the anode member 5 after the hole opening step. On the other hand, no holes were found on the surface of the pure titanium test piece of the anode member 5 after the sealing step, and the holes were filled. Table 1 also shows the hole diameters of the fine holes of the pure titanium test pieces of the anode member 5 after the opening step and after the sealing step.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１から明らかなように硫酸濃度を変化させても微細孔を有する酸化チタン薄膜を製造することができ、この微細孔の封孔が可能であることが確認できた。 As is apparent from Table 1, it was possible to manufacture a titanium oxide thin film having fine pores even when the sulfuric acid concentration was changed, and it was confirmed that this fine pore can be sealed.
１　電解処理装置
２　処理槽
３　直流電源
４　陰極部材
５　陽極部材
Ｓ　硫酸溶液又は電解硫酸 DESCRIPTION OF SYMBOLS 1 Electrolytic treatment apparatus 2 Treatment tank 3 DC power supply 4 Cathode member 5 Anode member S Sulfuric acid solution or electrolytic sulfuric acid

Claims (5)

  1. 　チタン又はチタン合金製薄膜を陽極として、
    　フッ化水素化合物を０．５重量％以下溶解した硫酸溶液又はフッ化水素化合物を０．５重量％以下溶解した酸化剤濃度５ｇ／Ｌ以上の電解硫酸液中で１～２０Ａ／ｄｍ２の電流密度で電解処理して微細孔を形成する開孔工程と、
    　硫酸溶液又は酸化剤濃度５ｇ／Ｌ以上の電解硫酸液中で電流密度を０．１Ａ／ｄｍ２以下で電解処理して前記微細孔を封孔する封孔工程と
    　を行う、微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法。     Using a titanium or titanium alloy thin film as the anode
    A current of 1 to 20 A/dm 2 in a sulfuric acid solution containing 0.5% by weight or less of a hydrogen fluoride compound or an electrolytic sulfuric acid solution containing 0.5% by weight or less of a hydrogen fluoride compound and an oxidizing agent concentration of 5 g/L or more. A pore-opening process that electrolyzes with density to form micropores,
    And a step of sealing the fine pores by electrolytically treating the fine pores with a current density of 0.1 A/dm 2 or less in a sulfuric acid solution or an electrolytic sulfuric acid solution having an oxidizer concentration of 5 g/L or more. A method for producing an oxide thin film of titanium or a titanium alloy.
  2. 　前記硫酸溶液又は電解硫酸の硫酸濃度が１０重量％以上である、請求項１に記載の微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法。 The method for producing an oxide thin film of titanium or a titanium alloy in which the fine pores are sealed according to claim 1, wherein the sulfuric acid concentration of the sulfuric acid solution or electrolytic sulfuric acid is 10% by weight or more.
  3. 　前記フッ化水素化合物が、フッ化アンモニウムである、請求項１又は２に記載の微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法。 The method for producing a titanium or titanium alloy oxide thin film having micropores sealed therein according to claim 1 or 2, wherein the hydrogen fluoride compound is ammonium fluoride.
  4. 　前記開孔工程の処理時間が３０～６０秒であり、前記封孔工程の処理時間が５～１２時間である、請求項１～３のいずれか１項に記載の微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法。 The titanium with micropores sealed therein according to any one of claims 1 to 3, wherein the processing time of the opening step is 30 to 60 seconds and the processing time of the sealing step is 5 to 12 hours. Alternatively, a method for producing a titanium alloy oxide thin film.
  5. 　前記開孔工程が、前記フッ化水素化合物を溶解した硫酸溶液又は電解硫酸液による１段目の電解処理と、フッ化水素化合物を溶解しない電解硫酸液中で１～２０Ａ／ｄｍ２の電流密度による２段目の電解処理とを備える、請求項１～４のいずれか１項に記載の微細孔を封孔したチタン又はチタン合金の酸化薄膜の製造方法。 In the opening step, the first step of electrolytic treatment with a sulfuric acid solution or an electrolytic sulfuric acid solution in which the hydrogen fluoride compound is dissolved, and a current density of 1 to 20 A/dm 2 in an electrolytic sulfuric acid solution in which the hydrogen fluoride compound is not dissolved. The method for producing an oxide thin film of titanium or a titanium alloy with micropores sealed therein according to any one of claims 1 to 4, further comprising a second-stage electrolytic treatment by.
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