JP5240813B2 - Method for creating metal surface microstructure - Google Patents

Description

  The present invention relates to a method for producing a metal surface microstructure that can be expected to have functions such as a superhydrophilic surface, a superhydrophobic surface, an antireflection film, an electronic device, a battery material, a sensor material, an optical device, and a structural material.

Conventionally, materials having nanostructures are rich in applications in various fields, and many researches and developments have been made. By controlling the nanostructure of metal oxides that have not been reported so far, the super-hydrophilic properties of TiO2 films, which had previously required ultraviolet irradiation for super-hydrophilic properties, can be exhibited without UV irradiation. If possible, the use is expected to expand greatly. Moreover, if a nanosheet film of aluminum oxide can be prepared as another metal oxide, the strength of the film is greatly improved.
For practical use in industry, it is considered that the most necessary technology is to easily control the microstructure of the metal surface itself in order to produce it in a short time with a simple and inexpensive method using an inexpensive material. It is done.
The present inventor succeeded in creating a super-water-repellent glass surface by coating a silane compound on the glass surface using a finely structured glass surface, and has already filed a patent application. (See Patent Document 1).
In addition, a glass substrate whose glass composition is not 100% silicon dioxide (SiO ₂ ) is immersed in an alkaline aqueous solution having a pH of 7 or more, and held at a temperature of 60 to 250 ° C. for 0.5 to 48 hours. A patent application has already been filed for a method for producing a glass surface microstructure characterized by taking out and washing and drying (see Patent Document 2).
Japanese Patent Application 2006-289386 Japanese Patent Application No. 2007-084244 DEVELOPMENTOF A TRANSPARENT AND ULTRAHYDROPHOBIC GLASS PLATE OGAWA K, SOGA M, TAKADA Y, NAKAYAMA I JAPANESE JOURNAL OF APPLIEDPHYSICS PART 2-LETTERS 32 (4B): L614-L615 (1993)

  The present invention provides a method for creating a metal surface microstructure on a metal substrate surface.

That is, the present invention is Mg, Al, Ca, Sc, Ti, V, Co, Mn, Fe, Co, Ni, Cu, Zn, Ga, Sr, Y, Zr, Nb, Mo, Ag, In, Sn, A metal substrate selected from Sb, Ba, La, Hf, Ta, W, Bi, and Ce is immersed in pure water or an alkaline aqueous solution having a pH of 7 or higher and maintained at a temperature of 50 to 250 ° C. for 0.05 to 96 hours. Thereafter, the metal substrate is taken out and washed and dried.
Moreover, this invention can be made into the board | substrate which coated the metal or the surface of the board | substrate as a metal substrate.
Furthermore, in the present invention, it is preferable to use a substrate made of Ti, Zn, Al, Mn, Mg, Ni or coated with Ti, Zn, Al, Mn, Mg, Ni as the metal substrate.
In the present invention, the alkali agent used in the alkaline aqueous solution in addition to ion-exchanged water, which is pure water, uses one kind selected from the group consisting of LiOH, NaOH, KOH, MnOOH, NH ₄ OH, and urea as an alkali. it can.
Further, in the present invention, it is preferable that the alkaline aqueous solution is NaOH having a pH of 9 to 11, the temperature of the alkaline aqueous solution is 95 to 200 ° C., and the immersion time is 1 to 24 hours.

  The method for creating a metal surface microstructure of the present invention is an epoch-making method for creating a metal surface microstructure that can be easily performed at low cost without requiring a special apparatus.

  As various metal substrates used in the present invention, in addition to ordinary metal substrates, other substrates (such as glass) may be coated in advance using various methods such as sputtering, electroless plating, plating, etc. The surface of any substrate can be covered with various nanostructured materials.

  In the present invention, the metal to which the present invention can be applied is any metal that corrodes with water or alkali, but typically, Mg, Al, Ca, Sc, Ti, V, Co, Mn, Fe, Co, Examples include metals selected from Ni, Cu, Zn, Ga, Sr, Y, Zr, Nb, Mo, Ag, In, Sn, Sb, Ba, La, Hf, Ta, W, Bi, and Ce. Particularly familiar metals include Ti, Zn, Al, Mn, Mg, Ni, and Sn.

In addition, by heat-treating the manufactured nanostructured material, a metal hydrate or metal hydroxide can be converted into a metal oxide without changing the form. Thereby, before and after the heat treatment, it can have different functions as an electron, a battery, a sensor, optics, and a structural material, and can improve device characteristics. As an example, a high-strength material can be obtained by forming an aluminum oxide nanosheet film by heat treatment, and a superhydrophilic TiO2 film that does not require ultraviolet light can be formed by forming an anatase TiO2 nanosheet film.
By using the obtained nanostructure as a base material and further producing a functional material thereon, a new device (electronic, battery, sensor, optical, structural material) or superhydrophilic, superhydrophobic surface, The function as an antireflection film can be expressed and the characteristics can be improved.

The nanostructured material produced in the present invention can be used for enhancing the functionality of a wide variety of devices such as electronic materials, battery materials, sensor materials, optical materials, structural materials, and interfacial phenomena such as superhydrophobic and superhydrophilic. it can.
For practical use in the industry, an inexpensive and simple manufacturing process is required. In addition, there are many processes for producing nanomaterials as powder, but considering higher functionality such as electrons, batteries, sensors, etc., suppression of aggregation and provision of crystal orientation, forms such as nanorods and nanosheets standing upright from the substrate, Since it is desirable that the nanostructured material is directly produced on various base materials (substrate and the like) from the viewpoint of adhesion to the substrate, etc., the metal surface microstructure production method of the present invention has a wide range of applications.

In the production method of the present invention, one kind or several kinds selected from the group consisting of LiOH, NaOH, KOH, MnOOH, NH ₄ OH, and urea can be used as the alkali.
Furthermore, in the production method of the present invention, it is desirable that the pure water or the alkaline aqueous solution is NaOH having a pH of 9 to 11, the temperature of the alkaline aqueous solution is 95 to 200 ° C., and the immersion time is 1 to 24 hours.
The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

  FIG. 1 (a) shows an SEM image of a sample in which a Ti plate is placed in an aqueous solution dissolved in urea and allowed to stand at 100 ° C. for 4 days. It can be seen that the film is composed of upright nanosheets. A similar form can be produced when ammonia water is added instead of urea. The obtained material is considered to be ammonium titanate, and when this was heat-treated at 400 ° C for 30 minutes in air, as shown in Fig. 1 (b), anatase-type crystals of TiO2 were maintained while maintaining the form. became. Further, when this was heat-treated at 600 ° C. for 30 minutes in the air, as shown in FIG. 1 (c), an anatase-type crystal of TiO 2 was maintained while maintaining the form. The anatase TiO2 nanosheet film prepared as shown in FIG. 1 (d) exhibited superhydrophilic properties without being irradiated with ultraviolet rays.

  Fig. 2 shows an SEM image of a sample that was placed in ion-exchanged water and allowed to stand at 200 ° C for 4 days. It can be seen that an octahedral anatase crystal is formed on the surface, and even when ion-exchanged water having a neutral pH is used, it has a nano uneven structure.

FIG. 3 (a) shows an SEM image of a sample in which a Ti plate was placed in an aqueous solution in which urea was dissolved and allowed to stand at 90 ° C. for 24 hours. It turns out that the film | membrane which consists of nanosheets is produced also below the temperature which water boils.
FIG. 3 (b) shows an SEM image of a sample in which a Ti plate was placed in a 5M NaOH aqueous solution and allowed to stand at 90 ° C. for 24 hours. It can be seen that the nanowire upright film is also produced below the temperature at which water boils. From these, it can be seen that nanostructures can be produced by an inexpensive and simple process.

  FIG. 4 (a) shows an SEM image of a sample that was sputtered with 30 nm of Ti on quartz glass, placed in a 5M NaOH aqueous solution, and allowed to stand at 90 ° C. for 90 minutes. It can be seen that the nanowire structure is formed on the quartz glass substrate, and it can be seen from FIG. 4 (b) that a transparent film has been produced.

  FIG. 5 (a) shows an SEM photograph of a sample in which an Mn plate is placed in ion exchange water and allowed to stand at 100 ° C. for 10 hours. It can be seen that the nanorods are upright.

  FIG. 6 shows an SEM photograph of a sample in which an Mg plate is placed in ion exchange water and allowed to stand at 90 ° C. for 30 minutes. It can be seen that a film in which the nanosheets are upright is formed at a low temperature in a short time.

  FIG. 7 (a) shows an SEM image of a sample obtained by sputtering Al on a glass substrate for 140 nm, placing in ion exchange water, and allowing to stand at 90 ° C. for 60 minutes. It can be seen that the nanosheet structure is formed on the glass substrate, and it can be seen from FIG. 7 (b) that a transparent film has been produced. FIG. 7 (c) shows an SEM image of a sample obtained by sputtering Al on a glass substrate to 70 nm, placing in ion-exchanged water, allowing to stand at 90 ° C. for 90 minutes, and then heat-treating at 1000 ° C. for 10 minutes. It can be seen that the nanosheet structure is maintained even after aluminum oxide is formed by heat treatment.

  FIG. 8 shows an SEM image of a sample in which a Ni plate is placed in a 5M NaOH aqueous solution and allowed to stand at 60 ° C. for 20 hours. It can be seen that the nanosheet structure is made even at a low temperature of 60 ° C.

  FIG. 9 shows an SEM image of a sample in which a Zn plate was placed in a 5M NaOH aqueous solution and allowed to stand at 100 ° C. for 20 hours. It can be seen that the uneven structure of the nanosheet is formed.

  The metal surface microstructure obtained by the present invention can be obtained by using a nanostructure as a base material, and further producing a functional material thereon, so that a superhydrophilic material or a new device (electronic, battery, It is possible to develop functions as a sensor, optics, and structural material), and it is extremely useful in industry.

(a) SEM photo of nanosheet on Ti plate (b) SEM photo of nanosheet of TiO2 anatase crystal (c) SEM photo of nanosheet of TiO2 anatase crystal (d) Super hydrophilicity of nanosheet of TiO2 anatase crystal Characteristic SEM photograph of the nano-relief structure octahedral anatase TiO ₂ on Ti plate (a) SEM photograph of nanosheet on Ti plate (b) SEM photograph of nanowire on Ti plate (a) SEM photograph of nanowires made from Ti sputtered on quartz glass (b) Transparent photograph of film in (a) (a) SEM photograph of nanorods on Mn plate SEM photo of nanosheet on Mg plate (a) SEM photo of nanosheets made from Al sputtered on glass (b) Transparent photo of film in (a) (c) Aluminum oxide nanosheets made by heat treatment of nanosheets made from Al sputtered on glass SEM photo SEM photo of nanosheet on Ni plate SEM photo of nanosheet on Zn plate

Claims (4)

A metal substrate selected from Mg, Ti, Mn, Ni, and Zn is immersed in neutral pure water or an alkaline aqueous solution having a pH of 7 or more, held at a temperature of 50 to 250 ° C. for 0.05 to 96 hours, and thereafter It is a method for creating a metal surface microstructure characterized by taking out a metal substrate and washing and drying,
When pure water is used, the metal substrate is a metal substrate selected from Mg, Ti, and Mn. In the case of Mg, the temperature is 90 ° C., the immersion time is 0.5 hours, and in the case of Ti, the temperature is 200 ° C. In the case of Mn, the temperature is 100 ° C., the immersion time is 10 hours,
In the case of using an alkaline aqueous solution, the alkaline aqueous solution is a 5 M NaOH aqueous solution, the temperature is 60 to 200 ° C., and the immersion time is 1 to 24 hours.   The metal substrate is a substrate made of a metal selected from Mg, Ti, Mn, Ni, and Zn, or a substrate in which a metal selected from Mg, Ti, Mn, Ni, and Zn is coated on the surface of the substrate. To create a fine metal surface microstructure.   The material produced by the method for producing a metal surface microstructure according to claim 1 or claim 2 is heat-treated in air at 400 to 1000 ° C, thereby being produced by the method according to claim 1 or 2. A method for producing a metal surface microstructure having a metal oxide microstructure, wherein a metal oxide microstructure in which the form of the metal surface microstructure is maintained by a metal hydrate or metal hydroxide is maintained.   A metal substrate provided with superhydrophilic properties by a metal surface microstructure produced by the method according to any one of claims 1 to 3.