JP4788880B2 - Method for producing valve metal oxide nanostructure - Google Patents

Description

  The present invention relates to a method for producing a valve metal oxide nanostructure using anodization. More specifically, the present invention relates to a method for producing a valve metal oxide nanostructure by producing a two-layer structure made of Al / valve metal, in which an aluminum metal film is formed on the surface of a valve metal substrate, and anodizing this.

  To date, nanostructures made of metal oxides on the surface are produced by anodization using valve metal foil materials, plate materials, and odd-shaped extrusion materials centering on Al, and are used for various applications and applications. Attempts and efforts have been made. Through these years of efforts and experience, it can be said that aluminum is a special metal in the fabrication of nanostructures among various valve metals, and aluminum is easily anodized in acid or alkaline solutions and easily It has been proposed that nanostructures can be obtained by being converted into nanostructures such as nanorods, nanofibers, nanotubes, and nanoholes and used in various fields (Patent Documents 1 and 2).

  For metals other than Al, some information on Ti and Mg is mainly found, but nanostructures such as Al have not yet been successful. The reason is that the state of the oxide film obtained by anodic oxidation of Ti and Mg does not form a well-structured porous structure like aluminum oxide (alumina) obtained by the anodic oxidation of Al. In addition, the state is that sponge-like large and small pores and holes are randomly distributed, and therefore, it cannot be used as a template for producing a nanostructure like anodization of Al.

  However, in recent years, the need for various material designs has led to the creation of nanostructures of valve metal oxides, and the nanostructures of these metal oxides have also been anticipated for Ti, Mg, etc. Realization of the body is expected and demanded. The same can be said for other valve metals, and nanostructured technology of these metal oxides is expected for metals such as Ta, Nb, Zr, and Si. However, there are very few reports about these today, and Nb and Ta have only a few results on a deposited film by a physical method.

  Among them, silicon oxide nanostructures are disclosed in patent documents. Although this nanostructure fabrication process is disclosed by anodizing a film in which an aluminum columnar structure is surrounded by silicon (Patent Document 3), it is extremely complicated, and is in terms of production efficiency and cost. It is difficult to say that it is a simple process.

  As described above, as the means for producing the nanostructure introduced above, the one based on the anodic oxidation method has been introduced. The reason is that if the production method by the metal anodic oxidation method can be established, the production means, the production conditions, or This is because any manufacturing efficiency is advantageous, and the manufacturing apparatus can provide a large amount of nanostructures by diverting an existing electrolysis facility.

Based on this background, provision of oxide nanostructures for valve metals other than Al (aluminum) by anodic oxidation also increases the freedom of material selection from various technical fields and creates new material designs. Highly expected and sought after. In response to these requests, the inventors first prepared a substrate on which a Ti film was formed by sputtering on a glass substrate, and then used an Al film formed by sputtering, followed by anodic oxidation of the Al layer. It has been proposed and published in academic literature that nanostructures of titanium oxide can be produced by anodizing the Ti layer (Non-patent Document 1). However, in the method proposed in this document, when the anodic oxidation is performed, the Ti layer and the Al layer are separated from each other, the electrolytic solution enters between the layers, and electrolytic concentration occurs there, and various titanium oxides are deposited. Titanium oxide using porous alumina as a template could not be obtained, and as it was, it could not be said that it was an industrially completed invention of titanium oxide nanostructures.

JP-A-7-62595 JP 2003-73859 A JP 2003-266400 A The Electrochemical Society of Japan, 2003 Fall Meeting Abstracts, page 162, date of issue September 11, 2003

  The present invention is intended to provide an inexpensive and high-quality valve metal oxide nanostructure with reproducibility by an anodizing method, and to provide an anodizing process therefor.

  In the present inventors, in order to solve the above-mentioned problem, first, in the Al layer / Ti layer anodic oxidation process described in the above-mentioned report, why peeling occurs and how this peeling can be prevented. I have studied earnestly. As a result, when the aluminum film is formed on the surface of the Ti metal substrate by physical film-forming means, the above peeling phenomenon is caused when an oxide film or impurities such as oil are mixed in or present at the interface between the two metals. It has been found that the adhesion of the metal is impaired, and when the electrolyte solution is touched, the electrolyte solution penetrates there, so that a so-called liquid leakage phenomenon occurs.

  In order to prevent this, when depositing Al on the surface of the Ti metal substrate, make sure that no impurities are present at the interface between the two layers. In particular, when the Ti metal substrate is a substrate provided by physical film deposition means. Discovered that it is important to avoid the contact with a reactive gas such as air and perform the next Al metal film forming means. It has been found that the aluminum film formed thereon by such consideration can be stably anodized without being peeled off even in the anodizing step.

As a result, an alumina layer is formed by anodic oxidation, and the Ti metal of the underlayer is masked by the alumina layer. Further, by continuing the anodic oxidation, the underlying layer is formed through the fine holes formed in the alumina layer. It has been found that Ti metal can be anodized to stably produce a Ti oxide nanostructure.
This invention is made | formed based on the above series of knowledge, The structure of the invention is as describing in the following (1)-(6).

That is, the present invention relates to (1) a film containing aluminum as a main component on the surface of a substrate mainly containing any one valve metal selected from the group of Ti, Mg, Ta, Nb, Zr, and Si. A step of forming by a phase growth method, a step of forming an alumina film in which pores are arranged by anodizing the film containing aluminum as a main component, and anodizing a substrate mainly containing the valve metal; A method for producing a nanostructure having a structure in which impurities are not interposed between a surface of a substrate mainly composed of the valve metal and a film mainly composed of aluminum. It is.

Here, as the base material having valve metal as a main component, a valve metal film formed on a substrate such as glass, ceramic, or synthetic resin by a physical vapor deposition method or a sheet obtained by rolling the valve metal is adopted. However, it is not necessarily limited to a film-like one, and one having an appropriate shape can be adopted depending on the application. When the valve metal is in the form of a film, the thickness is not particularly limited, but the thickness is preferably 10 nm to 10 μm, desirably 50 nm to 5000 nm, and more desirably 100 nm to 3000 nm.

  One reason for forming a film containing aluminum as a main component by physical vapor deposition is that a thin film can be formed uniformly by physical vapor deposition. Also, unlike bulk metals, there are gaps between the fine particles of the laminated thin film, and the ultrafine particles of the appropriate size are piled up reasonably densely, so the electrolyte can penetrate into these fine gaps during anodization. This is because the control for making the pore diameter and pore arrangement of the generated oxide film appropriate is easy.

  The thickness of the film containing aluminum as a main component is not particularly limited, but is preferably 200 nm to 10 μm, desirably 500 nm to 5000 nm, and more desirably 1000 nm to 3000 nm. Further, the alumina film in which pores are arranged by anodizing a film containing aluminum as a main component is not limited as long as the diameter of the pores corresponds to the nanostructure. Specifically, the diameter is preferably 10 nm to 600 nm, preferably 10 nm to 200 nm, and more preferably 20 nm to 100 nm. The alumina film is for anodizing the valve metal limited to the pores.

  In addition, the meaning that impurities are not interposed between the surface of the substrate mainly composed of valve metal and the film mainly composed of aluminum means that an oxide film, oil film, dust, etc. of these metals are substantially present at the interface between the valve metal and aluminum. This means that the metal does not exist, and high purity metals are in contact with each other. For example, a method of producing a smooth and high-purity surface on the valve metal surface by reverse sputtering and sputtering aluminum while maintaining the state can be employed. By doing in this way, the film | membrane which has aluminum as a main component on the base | substrate which has valve metal as a main component does not peel by the process of anodization.

  The present invention also includes (2) a step of forming a substrate mainly composed of a valve metal on a substrate by a physical vapor deposition method, and aluminum on the surface of the substrate without exposing the substrate to a reactive atmosphere. Forming a film as a component by physical vapor deposition, anodizing the film containing aluminum as a main component to form an alumina film in which pores are arranged, and using the valve metal as a main component And a step of anodizing the substrate.

  As a method for forming a film containing aluminum as a main component on the surface of the substrate by exposing the substrate mainly containing valve metal to a reactive atmosphere by physical vapor deposition, the valve metal film is formed on the substrate by physical vapor deposition. After forming by a growth method, a method such as forming an aluminum film by a physical vapor deposition method while maintaining a high vacuum can be employed. In this manner, by forming a film mainly composed of aluminum on a substrate mainly composed of valve metal by physical vapor deposition, aluminum on the substrate mainly composed of valve metal is formed by an anodic oxidation process. The film containing as a main component does not peel off.

  Although it is preferable to form the film | membrane which has a valve metal as a main component by physical vapor deposition method, the reason is that a thin film can be formed uniformly by physical vapor deposition method. Also, unlike bulk metals, there are gaps between the particles, and moderately sized ultrafine particles are piled up reasonably densely. It may be mentioned that control for making the nanostructure appropriate is easy.

The present invention is also characterized in that (3) in the method for producing a nanostructure according to (1) or (2), the anodic oxidation of the substrate mainly comprising the valve metal is a constant potential or constant current method. It is the manufacturing method of the nanostructure which makes.
Here, the constant potential method is to perform anodic oxidation while keeping the potential substantially constant, and the current during electrolysis decreases as the anodic oxide film thickness increases. Further, in the constant current method, in order to keep the current during electrolysis substantially constant, the resistance increases as the thickness of the pole oxide increases, so the potential is increased.

  Further, according to the present invention, (4) in the method for producing a nanostructure according to (1) or (2), the anodization of the base body containing the valve metal as a main component is a constant potential method, and the constant potential method anode The electrolytic solution used for oxidation is an acidic solution in which at least one kind of salt or acid containing fluorine ions, chloric acid, and nitric acid or nitrate is added, using an inorganic acid or organic acid alone or as a main liquid. This is a method for producing a nanostructure.

  As the acidic solution, a single inorganic acid, a mixed solution of a plurality of types of inorganic acids, a single organic acid, a mixed solution of a plurality of types of organic acids, or a mixed solution thereof can be used. The inorganic acid is preferably selected from sulfuric acid, phosphoric acid, and chromic acid. The organic acid is preferably selected from malonic acid and oxalic acid. It is also preferable to add at least one kind of salt or acid containing fluorine ions, chloric acid and nitric acid or nitrate to the acidic solution. Furthermore, the electrolytic solution is preferably a strongly acidic electrolytic solution having a pH of 2 or less, and more preferably a strongly acidic electrolytic solution having a pH of 1 or less. By defining the conditions for anodic oxidation in this way, nanoholes (nanostructures) of valve metals can be easily formed.

Further, according to the present invention, (5) in the method for producing a nanostructure according to (1) or (2), the anodization of the base body containing the valve metal as a main component is a constant current method, and the constant current method anode The electrolytic solution used for oxidation is an inorganic acid or an organic acid alone or a mixture thereof, and F ⁻ , C
l ^-, or NO ₃ ^- is a method for producing a nano-structure, characterized in that the acidic solution containing no ions.

Further, according to the present invention, (6) in the method for producing a nanostructure according to (1) or (2), the anodization of the base body containing the valve metal as a main component is a constant current method, and the constant current method anode The nanostructure characterized in that the electrolytic solution used for oxidation is a single solution or a mixture solution of sulfuric acid, phosphoric acid, oxalic acid, or organic acid, and does not contain F ⁻ , Cl ⁻ , or NO ₃ ⁻ ions. It is a manufacturing method of a body.
As the acidic solution, a single inorganic acid, a mixed solution of a plurality of types of inorganic acids, a single organic acid, a mixed solution of a plurality of types of organic acids, or a mixed solution thereof can be used. Further, it is preferable not to contain F ⁻ , Cl ⁻ , or NO ₃ ⁻ ions. Moreover, as said inorganic acid, it is preferable that 1 type or multiple types is chosen from a sulfuric acid and phosphoric acid. Moreover, as an organic acid, it is preferable that 1 type or multiple types are chosen from malic acid, tartaric acid, a citric acid, and an oxalic acid. The electrolytic solution is preferably an acidic electrolytic solution having a pH of 3 or more and 6.5 or less.

  By defining the conditions for anodic oxidation in this way, valve metal nanodots, nanorods, nanowires, and nanofibers (nanostructures) can be easily formed.

  According to the manufacturing method of the valve metal oxide nanostructure of the present invention, an insulating material and an electronic material in the advanced technology field can be efficiently manufactured. Moreover, application to a circuit board is possible. Further, it can be used as an electronic material such as a dielectric or a piezoelectric body, and can also be used as a partition wall in the field of fuel cells and the like.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In the present invention, as shown in FIG. 10, a film 3 mainly composed of aluminum is formed on the surface of the substrate 2 mainly composed of the valve metal formed on the substrate 1 by physical vapor deposition. As shown in FIG. 11, the step of forming the alumina film 31 in which the pores 32 are arranged by anodizing the film 3 mainly composed of aluminum and the step of anodizing the base body 2 mainly composed of the valve metal. And a method for producing a nanostructure of a valve metal oxide having a feature that no impurities are interposed between the surface of the substrate 2 mainly containing the valve metal and the film 3 mainly containing aluminum. is there.

  The base body 1 mainly composed of a valve metal is manufactured, for example, by forming a valve metal film 2 on a transparent glass substrate by a physical vapor deposition method such as sputtering, vacuum deposition, ionization deposition, or pulsed laser deposition. Is done. Further, the aluminum film 3 is formed on the base 2 containing the valve metal as a main component by physical vapor deposition such as sputtering, vacuum deposition, ionization deposition, pulse laser deposition, etc. while maintaining the degree of vacuum. As described above, since the film 3 mainly composed of aluminum is formed on the substrate 2 mainly composed of the valve metal, impurities are not interposed therebetween. Further, the film 3 containing aluminum as a main component is anodized to form an alumina film 31 in which the pores 32 are arranged. At this time, the base 2 containing the valve metal as a main component and the film 3 containing the aluminum as a main component do not peel off. Further, these pores 32 need to penetrate substantially from the front surface to the back surface of the alumina coating 31. The meaning of substantially penetrating means that it has an electrical property capable of anodizing the valve metal at the pore 32 portion of the alumina coating 31.

  A constant potential or constant current method can be adopted as a method for anodizing a substrate mainly composed of a valve metal. In the case of constant potential anodization, the electrolyte used is preferably an acidic solution. As the acidic solution, a single inorganic acid, a mixed solution of a plurality of types of inorganic acids, a single organic acid, a mixed solution of a plurality of types of organic acids, or a mixed solution thereof can be used. The inorganic acid is preferably selected from sulfuric acid, phosphoric acid, and chromic acid. The organic acid is preferably selected from malonic acid and oxalic acid.

  It is also preferable to add at least one kind of salt or acid containing fluorine ions, chloric acid and nitric acid or nitrate to the acidic solution. Furthermore, the electrolytic solution is preferably a strongly acidic electrolytic solution having a pH of 2 or less, and more preferably a strongly acidic electrolytic solution having a pH of 1 or less. By defining the conditions for anodic oxidation in this way, as shown in FIG. 12, nanoholes 22 (nanostructures) can be easily formed in the base 2 containing valve metal as a main component. The nanohole 22 is considered to be formed in order to selectively and strongly anodize the surface of the substrate 2 mainly composed of the valve metal through the pores 32 of the alumina layer 31. Further, by removing the alumina film 31 on the surface, a nanohole structure in which the valve metal oxide 21 shown in FIG. 13 is exposed on the surface can be obtained.

Moreover, it is preferable that the electrolyte solution used for constant current system anodization is an acidic solution. As the acidic solution, a single inorganic acid, a mixed solution of a plurality of types of inorganic acids, a single organic acid, a mixed solution of a plurality of types of organic acids, or a mixed solution thereof can be used. Further, it is preferable not to contain F ⁻ , Cl ⁻ , or NO ₃ ⁻ ions. Moreover, as said inorganic acid, it is preferable that 1 type or multiple types is chosen from a sulfuric acid and phosphoric acid. Moreover, as an organic acid, it is preferable that 1 type or multiple types are chosen from malic acid, tartaric acid, a citric acid, and an oxalic acid. The electrolytic solution is preferably an acidic electrolytic solution having a pH of 3 or more and 6.5 or less.

By determining the conditions of the anodic oxidation in this way, the growth of the valve metal oxide product 23 is optimized by adjusting the ratio between the dissolution rate of the base body 2 mainly composed of the valve metal and the oxide formation rate. Therefore, the valve metal oxide product 23 can be grown in the pores 32 as shown in FIG. It is possible to form valve metal nanodots, nanorods, nanowires or nanofibers (nanostructures) by adjusting the growth degree of the product 23 of the valve metal oxide, specifically by adjusting the reaction time. it can. Further, by removing the alumina film 31 on the surface, a nanostructure in which the valve metal oxide 23 shown in FIG. 15 is exposed on the surface can be obtained.

  By anodizing a substrate mainly composed of a valve metal by the above-described method, by controlling the electrolyte, voltage, current, anodizing time, etc., the pore structure of nanodots, nanorods, nanotubes, nanoholes, etc. The nanostructure which has can be manufactured.

  Here, the shape of the valve metal is not particularly limited, but usually a plate-like shape is preferably employed. Further, the term “on the valve metal” means one side or both sides of the valve metal plate when the valve metal is plate-shaped.

  A thinner valve metal can effectively form a nanostructure. A method for forming a thin valve metal is not particularly limited, but it is effective to form a valve metal film on a substrate such as glass by a physical vapor deposition method. In addition, the nanostructure or nanostructure in the present invention includes individual nanodots, nanorods, and other nanoproducts formed on the substrate or substrate and separated from the substrate or substrate, as well as in the substrate or substrate form. Also refers to and includes those that are attached.

Using a transparent coning glass plate, a 300 nm thick Si layer is RF (high frequency) sputtered on the surface, and then an 1.5 μm thick Al layer is RF (high frequency) sputtered without exposure to air. A sample that had been subjected to ultrasonic cleaning in acetone for 10 minutes as a pretreatment was subjected to anodization using the film-formed substrate. In the anodic oxidation of Al, constant potential electrolysis was performed at 165 V in a 10 vol% phosphoric acid solution, and the electrolysis was stopped when the current density dropped rapidly from the steady state. As a result, the Al layer was completely oxidized, and a porous alumina film was obtained on the valve metal. Subsequently, anodization of the valve metal was performed. Anodization of valve metal is carried out by immersion in a mixed solution containing 10 vol% sulfuric acid solution as a main component, 2 wt% ammonium fluoride (NH ₄ F) and 1 vol% perchloric acid, and controlled potential electrolysis at 60 V. For 15 minutes. The local anodic oxidation and electrolytic etching of the Si layer were simultaneously performed through the alumina film. The alumina film was dissolved and removed by immersing this sample in a mixed solution of 5 vol% phosphoric acid and 3 wt% chromic acid at 80 ° C. for 5 minutes to produce a silica nanostructure (nanohole) (FIG. 1).

  As in Example 1, a transparent coning glass plate was used as a pretreatment using a substrate on which a 300 nm thick Si layer and a 1.5 μm thick Al layer were formed by RF (high frequency) sputtering. A sample ultrasonically cleaned in acetone for 10 minutes was subjected to anodization. First, the sample was subjected to constant potential electrolysis at 165 V in a 10 vol% phosphoric acid solution at 0 ° C., and anodized until the current reached a value close to zero. Next, this sample was immersed in a mixed solution of 5 vol% phosphoric acid and 3 wt% chromic acid at 80 ° C. for 5 minutes to dissolve and remove the alumina film, thereby producing a silica nanostructure (nanodot) (FIG. 2).

Using a transparent coning glass plate, a 300 nm thick Si layer is RF (high frequency) sputtered on the surface, and then an 1.5 μm thick Al layer is RF (high frequency) sputtered without exposure to air. A sample that had been subjected to ultrasonic cleaning in acetone for 10 minutes as a pretreatment was subjected to anodization using the film-formed substrate. The sample was subjected to constant potential electrolysis at 20 V in a 10 wt% sulfuric acid solution at 15 ° C., and anodization of Al was performed until the current became a value close to zero. Then,
Anodization was performed to 250 V at a current of 10 A / m ^{2 in} the same solution. Next, this sample is 5
A silica nanostructure (nanodot) was manufactured by immersing in a mixed solution (75 ° C.) of vol% phosphoric acid and 3 wt% chromic acid for 5 minutes to dissolve and remove the alumina film (FIG. 3).

  Using a transparent coning glass plate, a 300 nm thick Ti layer RF (radio frequency) sputtering film is formed on the surface, and then a 1.7 μm thick Al layer is formed by RF (radio frequency) sputtering without exposure to air. A sample that had been ultrasonically cleaned in acetone as a pretreatment for 10 minutes was subjected to anodization using the filmed substrate. The anodic oxidation of Al was performed by electrolytic treatment in a 10 vol% sulfuric acid solution at 1 ° C. with a constant potential of 27 V until the current became almost zero. Next, the alumina film was dissolved and removed by immersing this sample in a mixed acid solution of 5 vol% phosphoric acid and 3 wt% chromic acid at 75 ° C. for 5 minutes to produce a nanostructure in which nanodots were arranged (FIG. 4).

A sample pretreated in the same manner as in Example 4 was subjected to anodization using a transparent glass substrate on which the same Ti and Al layers as in Example 4 were formed by sputtering. First, the sample was subjected to constant potential electrolysis at 65 V in a 3 wt% oxalic acid solution at 3 ° C., and anodized until the current reached a value close to zero. Subsequently, anodic oxidation was performed up to 150 V at a constant current of 10 A / m ^{2 in} a 3 wt% oxalic acid solution at 1 ° C. Next, this sample was immersed in a mixed solution (75 ° C.) of 5 vol% phosphoric acid and 3 wt% chromic acid for 5 minutes to dissolve and remove the alumina film, thereby producing a titania nanostructure in which nanorods were arranged (FIG. 5). ).

  A sample pretreated in the same manner as in Example 4 was subjected to anodization using a transparent glass substrate on which the same Ti and Al layers as in Example 4 were formed by sputtering. First, the sample was subjected to constant potential electrolysis at 27 V in a 5 vol% sulfuric acid solution at 1 ° C., and the Al layer was anodized until the current reached a value close to zero. Subsequently, the Ti layer was anodized at a constant potential of 30 V in a 3 vol% nitric acid solution at 1 ° C. In this way, a transparent porous titania nanostructure was produced (FIG. 6).

Using a transparent coning glass substrate, a 300 nm thick Zr layer is formed on the surface by RF (radio frequency) sputtering, and then an Al layer having a thickness of 1.5 μm is RF (radio frequency) sputtered without exposure to air. A sample that had been subjected to ultrasonic cleaning in acetone for 10 minutes as a pretreatment was subjected to anodization using the film-formed substrate. The anodic oxidation of Al was performed by constant potential electrolysis at 28 V in a 10 vol% sulfuric acid solution. Next, anodic oxidation of Zr was performed by using a mixed solution obtained by adding 2 mg / L ammonium fluoride in a 10 vol% sulfuric acid solution as an electrolytic solution, and completely oxidizing the Zr film by constant potential electrolysis at 30V. A nanostructure made of transparent ZrO ² crystals thus produced and having nanoholes arranged perpendicular to the substrate was produced (FIG. 7).

  A sample pretreated in the same manner as in Example 7 was subjected to anodization using a transparent glass substrate on which the same Zr and Al layers as in Example 7 were formed by sputtering. First, the sample was subjected to constant potential electrolysis at 28 V in a 5 vol% sulfuric acid solution at 1 ° C., and anodized until the current reached a value close to zero. Next, the alumina film was dissolved and removed by immersing this sample in a mixed solution of 5 vol% phosphoric acid and 3 wt% chromic acid at 75 ° C. for 5 minutes to produce a zirconia nanostructure in which nanodots were arranged (FIG. 8). ).

A sample pretreated in the same manner as in Example 7 was subjected to anodization using a transparent glass substrate on which the same Zr and Al layers as in Example 7 were formed by sputtering. The sample was subjected to constant potential electrolysis at 50 V in a 3 wt% boric acid solution (pH 6.0) at 20 ° C., and anodized until the current reached a value close to zero. Subsequently, 250 ° C. at a constant current of 10 A / m ² in a 4 wt% malic acid solution at 20 ° C.
Anodization was performed up to V. Next, this sample was immersed in a mixed solution (75 ° C.) of 5 vol% phosphoric acid and 3 wt% chromic acid for 5 minutes to dissolve and remove the alumina film, thereby producing a zirconia nanostructure in which nanorods were arranged. (Fig. 9)

  Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration of the present invention is not limited to these embodiments, and the present invention can be changed even if there is a design change or the like without departing from the gist of the present invention. include. For example, the valve metal or aluminum may be an alloy containing them as a main component.

  In the present invention, valve metal oxide nanostructures arranged in direct bonding on a substrate have a high specific surface area, and have physical properties such as chemical resistance, heat resistance (heat insulation), and wear resistance (hardness). It contributes greatly to the development of piezoelectric elements, ceramic capacitors, devices, special porcelains, optical fiber connectors, etc., consisting of nanostructures with excellent strength and electrical properties such as electrical insulation, dielectric properties, and piezoelectricity. be able to.

It is an electron micrograph of the nanostructure (nanohole) of this invention. It is an electron micrograph of the other nanostructure (nanodot) of this invention. It is an electron micrograph of the other nanostructure (nanodot) of this invention. It is an electron micrograph of the other nanostructure (nanodot) of this invention. It is an electron micrograph of the other nanostructure (nanorod) of this invention. It is an electron micrograph of the other nanostructure (nanohole) of this invention. It is an electron micrograph of the other nanostructure (nanohole) of this invention. It is an electron micrograph of the other nanostructure (nanodot) of this invention. It is an electron micrograph of another nanostructure (nanorod) of the present invention. It is sectional drawing for demonstrating the manufacturing method of the nanostructure of this invention. It is sectional drawing for demonstrating the process following FIG. It is sectional drawing for demonstrating the manufacturing method of the nanohole of this invention. It is sectional drawing for demonstrating the process following FIG. It is sectional drawing for demonstrating the manufacturing method of the nanorod of this invention. It is sectional drawing for demonstrating the process following FIG.

Explanation of symbols

1. Substrate 2. 21. Substrate mainly composed of valve metal Bubble metal oxide 22. Nanohole 23. 2. Product of bubble metal oxide Base body mainly composed of aluminum 31. Alumina coating 32. pore

Claims (6)

Forming a film mainly composed of aluminum on a substrate surface mainly composed of any one valve metal selected from the group consisting of Ti, Mg, Ta, Nb, Zr and Si by physical vapor deposition; A method for producing a nanostructure, comprising: anodizing the film containing aluminum as a main component to form an alumina film in which pores are arranged; and anodizing a substrate containing the valve metal as a main component Because
A method for producing a valve metal oxide nanostructure, wherein impurities are not interposed between a surface of a substrate mainly containing the valve metal and a film mainly containing aluminum.   2. The valve metal oxide nanostructure according to claim 1, wherein the base body is obtained by forming a film containing a valve metal as a main component on an arbitrary substrate by physical vapor deposition. Production method.   The substrate is obtained by forming a film mainly containing a valve metal on an arbitrary substrate by physical vapor deposition, and a film mainly containing aluminum is formed on the substrate by physical vapor deposition. In the step of forming by a method, a surface obtained by forming a film mainly composed of a valve metal on the arbitrary substrate by a physical vapor deposition method without exposing the substrate to a reactive atmosphere. The method for producing a valve metal oxide nanostructure according to claim 1 or 2, further comprising forming a film containing aluminum as a main component by physical vapor deposition.   3. The method for producing a nanostructure according to claim 1, wherein the anodic oxidation of the substrate mainly composed of the valve metal is a constant potential or constant current method.   3. The nanostructure according to claim 1, wherein the anodization of the substrate containing the valve metal as a main component is performed by a constant potential method, and the electrolyte used for the constant potential method anodization is an acidic solution. Production method. 3. The nanostructure according to claim 1, wherein the anodization of the base body containing the valve metal as a main component is performed by a constant current method, and the electrolyte used for the constant current method anodization is an acidic solution. Production method.

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