TWI472424B - A metal material, a surface treatment method of a metal material, a method of manufacturing a water repellent material using a metal material as a substrate, and a manufacturing apparatus for a metal material - Google Patents

Description

Metal material, surface treatment method of metal material, method for producing water-repellent material using metal material as substrate, and manufacturing device for metal material

The present invention relates to a metal material, a surface treatment method for a metal material, a method for producing a water-repellent material using a metal material as a substrate, a surface treatment device for a conductive material, and a surface treatment method for a conductive material.

In recent years, it is strongly expected to give novel functions to metallic materials. Specifically, it means that in addition to the advantageous properties of metal materials such as strength, workability, and corrosion resistance, such as hydrophilic properties, water-repellent properties, and luminescent properties, the novel functions of related metal surfaces, and the novel use of metal materials. , subject to great expectations. From such a background, recently, a reforming layer such as a plating layer, an oxide layer, a surface hardened layer, and a modified layer for improving the surface roughness has been developed, and research on a metal surface has been carried out in full swing. For example, a technique of forming a fine structure by anodizing a metal surface (see Non-Patent Document 1), a technique of forming a surface fine structure by electrolytic processing (see Non-Patent Document 2), and the like.

[Previous Technical Literature] [Non-patent literature]

Non-Patent Document 1: Takahashi Hideaki, Otsuka Masami, Kikuto Ryo, JHA Himendra Surface Technology Vol. 60(2009) No. 3 p.14

Non-Patent Document 2: Application and Theory of Electrolytic Machining for Microfabrication Xia Heng Surface Technology Vol.61(2010)No.4 294

In order to impart a novel function of hydrophilic properties, water repellency, and luminescent properties to the surface of a metal material, it is necessary to design the structure and composition of the surface modifying layer from a microscopic viewpoint of 1 μm or less. However, the research to the prior art is aimed at improving the functions such as workability and corrosion resistance, because the structure and composition of the surface modification layer are designed in accordance with the micron level, and thus the appearance of the new function is insufficient. For example, a method of increasing the surface roughness has been proposed to press a roller having a dull structure against a surface of a metal material. However, the unevenness of the surface of the metal material formed according to this method has a size of a micron or more. Therefore, the surface of the metal material has the effect of being maintained by the oil to improve the workability and uniformity of the surface appearance, but does not exhibit a new function. Further, in order to improve the adhesion of the outer panel of an automobile, there has been proposed a method of forming a phosphate crystal on the surface of a metal material. However, the particle size of the phosphate crystal formed according to this method has a size of several micrometers. Therefore, the surface of the metal material does not show new functions.

On the other hand, in the technique of forming a fine structure of the prior art, as described in Non-Patent Document 1, the technique of performing anodization on a metal surface to form a fine structure forms fine pores and defines the function that can be imparted. Further, since the surface becomes an oxide layer, the surface properties are defined by the oxide species. Further, as a method of electrolytic machining using the method described in Non-Patent Document 2, it is necessary to shorten the distance between the surface to be treated and the counter electrode in order to form a fine surface structure, but this control is extremely difficult.

The present invention has been made in view of the above problems, and an object thereof is to provide a metal material having novel functions such as hydrophilic properties and luminescent properties.

Furthermore, another object of the present invention is to provide: no need to spend more time In the case of labor and expense, a surface treatment method of a metal material that imparts high water repellency to a surface of a metal material, and a method of producing a water repellent material using a metal material as a base material.

Furthermore, another object of the present invention is to provide a surface of a conductive material capable of producing a conductive material of a nano-scale fine structure by performing treatment at a predetermined area or a wide area across a surface at a low cost and efficiently. Processing device and surface treatment method.

The metal material of the present invention includes a metal material substrate and a modified layer formed on the surface of the metal material substrate, wherein the modified layer has an average of three or more in the range of 10 μm ² The metal material base material has an average diameter of 1 μm or less when viewed in the vertical direction, and a projection protruding from the surface of the above-mentioned metal material substrate.

According to the invention of the present invention, the modified layer includes: a base protruding from a surface of the base material substrate; and a front end portion formed at an end portion of the base; and an average of 10 μm ² It is provided with one or more protrusions having an average diameter of 1 μm or less when viewed from the vertical direction of the surface of the metal material substrate, and having a thin waist structure in which the base outer diameter is smaller than the outer diameter of the front end portion.

The metal material according to the invention is the above invention, wherein the protrusion has an average diameter of 500 nm or less when viewed from a direction perpendicular to a surface of the metal material substrate.

The metal material according to the invention is the above invention, wherein the position formed by the protruding portion is not periodic in the in-plane direction of the metal material substrate.

In the above-mentioned invention, the modified layer is provided with a concave portion having an average diameter of 500 nm or less when viewed from a direction perpendicular to the surface of the metal material substrate.

The metal material of the present invention is the above invention, wherein the metal material is The substrate is formed of alloy steel.

The metal material according to the invention is the above invention, wherein the metal material substrate is formed of a steel material.

The metal material according to the invention is the above invention, wherein the composition of the metal material substrate is different from the composition of the protrusions.

The metal material according to the invention is the above invention, wherein the metal material substrate is continuously connected to the protruding portion.

The surface treatment method of the metal material according to the first aspect of the present invention includes the step of immersing the material to be treated, which is formed of a metal material and used as a cathode electrode, and the anode electrode in an electrolytic solution. a step of forming a fine structure on the surface to be treated by applying a voltage of 70 V or more between the cathode electrode and the anode electrode without causing oxidation or melting of the material to be processed; and taking out from the electrolytic solution a step of washing the material to be processed, and a step of performing a water repellent treatment on the surface to be treated of the treated material to be treated.

The surface treatment method of the metal material according to the second aspect of the present invention includes the step of immersing the material to be treated which is formed of a metal material and serving as a cathode electrode, and immersing the anode electrode in the electrolytic solution. a step of forming a fine structure on the surface to be treated by applying a voltage of 70 V or more and 200 V or less between the cathode electrode and the anode electrode; taking out the material to be processed from the electrolytic solution, and washing the material a step of treating the material; and a step of performing a water repellent treatment on the surface to be treated of the washed material to be treated.

The method for producing a water-repellent material using a metal material as a substrate according to the present invention includes a step of immersing a metal material having a surface to be treated as a material for a cathode electrode and immersing the anode electrode in an electrolytic solution. By the above cathode electrode a step of forming a fine structure on the surface of the metal material of the material to be processed by applying a voltage of 70 V or more and 200 V or less to the anode electrode; and removing the metal material from the electrolytic solution and washing the metal material And a step of applying a water repellent treatment to the surface to be treated of the washed metal material.

The surface treatment apparatus for a conductive material according to the present invention includes: an anode electrode that is mutually immersed in an electrolytic solution, and a cathode electrode that is made of a conductive material; and is interposed between the anode electrode and the cathode electrode, and a shield having an opening defining the portion of the cathode electrode to be processed; and a power source for applying a voltage between the anode electrode and the cathode electrode.

The surface treatment apparatus for a conductive material according to the present invention includes the mechanism for changing a position of the opening and/or a relative position between the anode electrode and the cathode electrode.

In the above-described invention, the surface treatment apparatus of the conductive material according to the invention is characterized in that the power source applies a voltage of 60 V or more and 300 V or less between the anode electrode and the cathode electrode.

The surface treatment apparatus of the conductive material according to the invention is the above-mentioned invention, wherein the shielding material is an insulating heat-resistant material having a surface of the cathode electrode and having the opening.

The surface treatment apparatus for a conductive material according to the invention is the above invention, wherein the conductive material is a metal material.

In the surface treatment method of the conductive material of the present invention, the surface of the conductive material is treated by the surface treatment apparatus of the conductive material of the present invention.

The metal material according to the present invention can provide hydrophilic properties and luminescent properties Metal materials such as sex and other novel functions.

According to the surface treatment method of the metal material of the present invention and the method for producing a water-repellent material using the metal material as a base material, it is possible to impart high water-repellent characteristics to the surface of the metal material without requiring a lot of labor and expense.

According to the surface treatment apparatus and the surface treatment method of the conductive material of the present invention, a conductive material having a nano-scale fine structure can be produced at a low cost and efficiently at a predetermined area on the surface or across a wide area of the surface.

1‧‧‧Metal materials

2‧‧‧Substrate

3‧‧‧Protruding

11‧‧‧ Container

12‧‧‧Electrolysis solution

13‧‧‧Anode electrode

14‧‧‧Processed material (cathode electrode)

15‧‧‧Wire

16‧‧‧Power supply

17‧‧‧ thermometer

21‧‧‧ Surface treatment equipment

22‧‧‧Modification treatment tank

23‧‧‧Electrolysis solution

24‧‧‧Anode electrode

25‧‧‧Cathode electrode (treated material)

26‧‧‧DC power supply

27‧‧‧ box

28‧‧‧ openings

28a‧‧‧ inclined section

Fig. 1A is a plan view showing the structure of a metal material according to an embodiment of the present invention.

Fig. 1B is a cross-sectional view taken along line A-A of Fig. 1A.

Fig. 2 is a SEM photograph of an example of a projection formed on the surface of a cold rolled steel sheet.

Fig. 3 is a schematic view showing the calculation method of the outer diameter of the protrusion.

Fig. 4 is a schematic view showing the structure of the thin waist of the projection.

Fig. 5 is a SEM photograph showing an example of a projection having a thin waist structure formed on a cold-rolled steel sheet.

Fig. 6 is a cross-sectional TEM photograph of an example of a projection having a thin waist structure formed on a cold-rolled steel sheet.

Fig. 7 is a SEM photograph of an example of a concave portion formed on the surface of a stainless steel.

Fig. 8 is a SEM photograph of an example of a concave portion formed on a surface of a stainless steel.

Fig. 9 is a cross-sectional TEM photograph showing an example of a projection having a composition different from that of the substrate.

Fig. 10 is a cross-sectional TEM photograph of a state in which a projection is continuously formed on a cold-rolled steel sheet.

Figure 11 is a flow chart showing the surface treatment process of a metal material according to an embodiment of the present invention.

Fig. 12 is a view showing a configuration example of a device used in the surface treatment method of a metal material according to an embodiment of the present invention.

Figure 13 is a SEM photograph of the surface of a surface treated SUS316L stainless steel.

Fig. 14 is a view showing a state in which distilled water is dripped on the surface as seen from the lateral direction after the water-repellent treatment is performed on the surface of the stainless steel shown in Fig. 13.

Fig. 15 is a view showing the configuration of a surface treatment apparatus for a conductive material according to an embodiment of the present invention.

Fig. 16 is a view showing a modification of the surface treatment apparatus shown in Fig. 15.

Fig. 17 is a view showing a modification of the surface treatment apparatus shown in Fig. 15.

Fig. 18 is a configuration diagram of an opening.

Fig. 19A is a view of a secondary electron image on the left side in the longitudinal direction of the opening when 150 V is applied between the anode electrode and the cathode electrode.

Fig. 19B is a secondary electron image showing the center in the longitudinal direction of the opening when 150 V is applied between the anode electrode and the cathode electrode.

Fig. 19C is a secondary electron image showing the right side in the longitudinal direction of the opening when 150 V is applied between the anode electrode and the cathode electrode.

Figure 20 shows the size of the opening as 5mm × 5mm and 5mm The appearance of the cathode electrode after the treatment is performed.

Figure 21 is the size of the opening is set to 5mm And after the treatment, the SEM image of the surface of the cathode electrode.

Figure 22 is an SEM image of the surface of a cathode electrode not subjected to surface treatment.

〔metallic material〕

1A and 1B are a plan view showing a metal material according to an embodiment of the present invention, and a cross-sectional view taken along line A-A in Fig. 1A. As shown in FIGS. 1A and 1B, a metal material 1 according to an embodiment of the present invention includes a base material 2 and a projection 3 for forming a modified layer on the surface of the base material 2. The substrate 2 is formed of a metal material. The metal material may be, for example, a steel material containing stainless steel, a steel material such as a cold-rolled steel sheet containing Fe and C and, if necessary, a trace amount of alloying elements of 3% by mass or less, a soft steel sheet, a high-strength steel sheet having a tensile strength of 2 GPa, or the like. Hot rolled steel sheets, etc. The shape of the substrate 2 is not particularly limited, and a shape such as a plate shape, a rod shape, a wire shape, or a tubular shape can be used. Further, the substrate 2 may be welded by a plurality of members. Further, when the base material 2 is in the form of a plate, the thickness thereof is not limited, and it can be used from a metal foil of 100 μm or less to a thick steel plate having a thickness of 3 mm or more.

The projections 3 are formed by a fine structure in which the average diameter R is 1 μm, preferably 500 nm or less, from the surface of the base material 2 when viewed from the vertical direction of the surface of the base material 2. Fig. 2 is a scanning electron microscope (SEM) photograph of an example of a projection formed on the surface of a cold-rolled steel sheet. In the figure, the protrusions 3 are shown by arrows. The projections 3 were formed by using a cold-rolled steel sheet and a platinum electrode as cathode electrodes and anode electrodes, respectively, and conducting electricity at 135 V for 30 minutes in a K ₂ CO ₃ aqueous solution having a concentration of 0.3 mol/L. In this case, as shown in FIG. 3, the average diameter R of the projection 3 when viewed from the vertical direction of the surface of the cold-rolled steel sheet is intended to have a circle C having the same area as the area surrounded by the outline of the projection 3, by Calculating the diameter R of the circle C can be obtained. By forming the protrusions 3 in an average of three or more in the range of 10 μm ² , it is possible to impart luminescent properties and hydrophilic properties to the surface of the substrate 2 . By improving the hydrophilic property, it is difficult to form droplets on the metal surface, and as a result, it is easy to adhere to dirt such as organic substances, and it is expected to be used in various applications such as a light reflection plate in which the reflection intensity is not easily lowered. The in-plane distribution of the protrusions 3 is not limited, and it is advantageous in terms of manufacturing without particularly periodicity. For example, in order to produce a surface having the periodicity of the protrusions 3 in a row, an excessive number of steps are required, resulting in a disadvantage in manufacturing.

As shown in FIG. 4, when the protrusion 3 has a structure in which the outer diameter Lrmin of the base portion 3a is smaller than the outer diameter Lrmax of the front end portion 3b (that is, a thin waist structure), the substrate is compared to the case where the thin waist structure is not provided. The specific surface area and internal voids of 2 are apparently large. Therefore, the hydrophilic property which affects the surface area can be further improved. Moreover, the protrusion 3 having a thin waist structure is expected to have an effect of imparting a chemical reaction to the surface of the substrate 2, promoting the function thereof, and improving the adhesion to the film layer formed on the surface of the substrate 2. Therefore, the projections 3 having the thin waist structure in which the outer diameter Lrmin of the base portion 3a is smaller than the outer diameter Lrmax of the distal end portion 3b are preferably formed on average by one or more in the range of 10 μm ² . Since the hydrophilic property is higher as the specific surface area is larger, the smaller the protrusion size, the more the number of protrusions is, the more advantageous it is, and the surface having the fine waist structure is formed, since the specific surface area is further increased, and the hydrophilic property is further enhanced.

The protrusion 3 having a thin waist structure can be confirmed by the following method: (1) A profile sample of a surface of a metal material is produced by a FIB (Focused Ion Beam) method, and an SEM or a transmission electron is used. A method of observing the cross-section sample by a transmission electron microscope (TEM); (2) a method of inclining a metal material and observing it by SEM. Fig. 5 is a SEM photograph showing an example of a projection 3 having a thin waist structure formed on a cold-rolled steel sheet. This is an image in which the sample is tilted at 70 degrees and photographed. Fig. 6 is a cross-sectional TEM photograph showing an example of a projection 3 having a thin waist structure formed on a cold-rolled steel sheet. The protrusion having a thin waist structure refers to the following formula (1), and the outer diameter Lrmin of the base portion 3a is 90% or less of the outer diameter Lrmax of the tip end portion 3b, preferably the following formula (2), outside the base portion 3a The diameter Lrmin is a structure in which the outer diameter Lrmax of the distal end portion 3b is 80% or less. In the example shown in Fig. 5, the value of Lrmin/Lrmax is 0.38, as shown in Fig. 6, The value of Lrmin/Lrmax is 0.62. The outer diameter Lrmin of the base portion 3a is the minimum outer diameter of the base portion 3a when the base portion 3a is viewed from the vertical direction of the surface of the metal material substrate; and the outer diameter Lrmax of the front end portion 3b is viewed from the vertical direction of the surface of the metal material substrate, the front end The maximum outer diameter of the portion 3b.

[Number 1] Lrmin/Lrmax≦0.9......(1)

[Number 2] Lrmin/Lrmax≦0.8...(2)

On the surface of the substrate 2, in addition to the protrusions 3, it is preferable to form a concave portion having an average diameter of 1 μm or less, preferably 500 nm or less when viewed from the direction perpendicular to the surface of the substrate 2. By forming the recesses in addition to the protrusions 3, the surface area of the metal material can be made larger, so that the luminescent properties and hydrophilic properties of the surface of the metal material can be further enhanced. Further, since the concave portion is present outside the convex portion, more lubricating oil and functional liquid can be held and kept longer, so that the surface of the substrate 2 can be given novel functions.

Fig. 7 and Fig. 8 are SEM photographs showing an example of a concave portion formed on the surface of a stainless steel. Fig. 7 shows the appearance of the metal material as viewed from directly above the surface of the metal material, and Fig. 8 shows the appearance of the metal material observed when the metal material is inclined at 60 degrees. The concave portions shown in Fig. 7 and Fig. 8 were formed by using SUS430 stainless steel and platinum electrodes as cathode electrodes and anode electrodes, respectively, and conducting electricity at 115 V for 30 minutes in a 0.1 mol/L K ₂ CO ₃ aqueous solution. The arrows in the figure indicate the recesses. As is understood from Fig. 7 and Fig. 8, a recess having a size of about 200 nm to 500 nm is formed everywhere on the surface of the stainless steel.

The substance forming the protrusions 3 may have the same composition as the substrate 2 or may have a different composition, and may be used separately for the purpose. Fig. 9 is a cross-sectional TEM photograph showing an example of a projection 3 having a different composition of the base material 2. Figure 9 shows an example of a substrate 2 It is formed of SUS316 stainless steel, and the Cr concentration in the protrusion 3 becomes smaller than the Cr concentration in the substrate 2. According to this configuration, it is expected that the catalytic function of Ni can be utilized more effectively under the characteristics of using SUS316 stainless steel. As an example, a steam reforming catalyst containing Ni as an active component may be directly usable. In this case, it is known that Cr deteriorates the performance of the catalyst, and thus it is expected to reduce the influence of Cr. Moreover, since the protrusion structure of the present invention has a large specific surface area, it is excellent in heat exchange property. This phenomenon is also advantageous as a catalyst reaction substrate.

The substrate 2 and the protrusions 3 are preferably in a continuous body. The strength of the protrusions 3 can be improved by the continuous formation of the base material 2 and the projections 3. Fig. 10 is a cross-sectional TEM photograph showing a state in which a projection is continuously formed on a cold-rolled steel sheet. Although not shown, the crystal orientation analysis is performed on the region R1 of the protrusion 3 and the region R2 of the substrate 2, and as a result, the protrusion 3 is a single crystal and has substantially the same crystal orientation as the substrate 2. Such a continuous structure is stable against mechanical action and chemical action, and is not effective in the case where the protruding portion 3 is not favored by the dissimilar substance and the dissimilar element, except that the protruding portion 3 is not easily peeled off. Further, such a continuous structure can be formed by using a steel material or a metal having a small content of an oxidizable alloying element (for example, Cr) as the substrate 2.

An example of a method for producing the metal material 1 having such a structure can be produced by discharge in an electrolytic solution. Specifically, the material to be treated and the passive metal such as platinum are used as the cathode electrode and the anode electrode, respectively, and a DC voltage of about 60 to 140 V is applied to the electrode in the electrolytic solution. The range in which the voltage is applied varies depending on the material to be processed, and the surface structure of the material to be processed can be easily determined by SEM. The average diameter of the protrusions can be controlled by changing the processing time and the applied voltage within a suitable range. Specifically, in the case of the same material, the larger the applied voltage, the longer the processing time, and the deeper the position of the liquid surface of the electrolytic solution, the more the average diameter of the protrusions can be increased.

However, if the applied voltage becomes a value in the state of complete plasma, the surface of iron or stainless steel or the like may be excessively melted or oxidized. It is difficult to form a fine protrusion structure. In order to impart a fine waist structure, it is necessary to select a condition in which the discharge energy density is high in a range in which the surface is not excessively melted or oxidized. For example, it is effective to increase the applied voltage or to narrow the processing target in such a manner as to concentrate the electric field. In this case, the preferable conditions can be determined by comparing the results of the treatment of the surface by SEM and comparing with the processing conditions. Further, as shown in Fig. 9, Ni is concentrated, and the protrusion structure lacking Cr is formed by increasing the set discharge voltage. Others, by making a raised structure and then supplying the element in solution, a new element can be imparted to the surface. The "completely plasma state" refers to a state in which an orange light is mixed or an orange light is emitted during discharge to cover the surface of the cathode electrode.

[Example 1]

A soft cold-rolled steel sheet (CRS, size 2 mm × 20 mm × 0.7 mm) and Pt were respectively used as a cathode electrode and an anode electrode, and immersed in a K ₂ CO ₃ aqueous solution having a concentration of 0.3 mol/L to energize the cathode electrode and the anode electrode. Samples were prepared with different energization voltages. Then, the surface of the soft cold-rolled steel sheet after electric conduction was observed by SEM, and the average diameter and density of the protrusions formed on the surface were evaluated. At this time, since the degree of treatment is different depending on the depth from the liquid surface of the aqueous solution, a part of the samples are cut from the soft cold-rolled steel sheet according to the depth of the liquid surface, and the sample is taken and executed. Surface observation. The average diameter of the protrusions is an average value of the diameters of the 20 protrusions arbitrarily selected from the range of 12 μm × 9 μm which is arbitrarily selected; the density is the number of protrusions in the above range divided by 108 μm ² (= 12 μm × 9 μm) and multiplied 10 μm ² was obtained, and the number of protrusions on the average of 10 μm ² was obtained. The evaluation results are shown in Table 1 below. The sample of the experiment No. 1-7 shown in Table 1 was a soft cold-rolled steel sheet before energization in the above aqueous solution. From the comparison of the samples of Experiment Nos. 1-1 to 1-6 shown in Table 1 with the samples of Experiment No. 1-7, it was confirmed that the modification of the present invention having the protrusions was obtained by the energization treatment. Floor. Further, by lowering the applied voltage, it was confirmed that the average diameter of the projections can be reduced and the density of the projections can be increased. Further, as shown in the sample of Experiment No. 1-6, by shortening the distance between the liquid surface and the treated surface, the average diameter of the projections can be made small, and the density of the projections can be increased.

[Example 2]

SUS316 stainless steel (size 25mm × 2.5mm × 0.8mm) and Pt were respectively used as a cathode electrode and an anode electrode, and immersed in a K ₂ CO ₃ aqueous solution having a concentration of 0.3 mol/L to energize the cathode electrode and the anode electrode. The sample was prepared by voltage. Then, the surface of the SUS316 stainless steel after the energization was observed by SEM, and the same evaluation as in Example 1 was carried out on the average diameter and density of the protrusions formed on the surface. At this time, since the degree of treatment is different depending on the depth from the liquid surface of the aqueous solution, a part of the samples are cut from the soft cold-rolled steel sheet according to the depth of the liquid surface, and the sample is taken and executed. Surface observation. Further, the photoluminescence of the surface of the SUS316 stainless steel after the energization was measured. The apparatus was measured using a FP6200 manufactured by JASCO Corporation, based on a starting wavelength of 350 nm, a final wavelength of 600 nm, and an excitation wavelength of 435 nm. Specifically, the photoluminescence spectrum obtained from the surface of the stainless steel after the energization was confirmed, and in the photoluminescence spectrum obtained on the surface of the stainless steel before the energization, the light-emitting peak centered around the wavelength of 430 nm was not observed. Here, in the present embodiment, the intensity of the luminescent peak was measured during photoluminescence measurement. The illuminating peak height of Experiment No. 2-5 in which the maximum luminescence intensity was obtained in the present Example was set to 10, and the illuminating peak height of Experiment No. 2-7 which was not treated and the illuminating peak was not observed was set to 0. Evaluation. The evaluation results are shown in Table 2 below. As shown in Table 2, the stainless steel surface of the present invention having protrusions (samples of Experiment Nos. 2-1 to 2-5) was compared with the untreated stainless steel surface having no protrusions (Experiment No. 2-7) The sample of Test No. 2-6 having a sample or a protrusion far exceeding 1000 nm was confirmed to have high luminescence characteristics. The smaller the size of the light-emitting characteristics, the larger the size of the protrusions, and the higher the average diameter of the protrusions is 500 nm or less, and particularly high light-emitting characteristics can be obtained. From this result, it is expected that the stainless steel having the projections of the present invention can be used as a display element and a metal material using an element of visible light.

[Example 3]

SUS316 stainless steel (thickness 1 mm x width 2.5 mm x length 30 mm) was used. The surface was mirror polished using a Dia Wrap ML-150P. The stainless steel and Pt were used as a cathode electrode and an anode electrode, respectively, and immersed in 300 cm ³ of a K ₂ CO ₃ aqueous solution having a concentration of 0.1 mol/L, and the cathode electrode and the anode electrode were energized with different energization voltages for 15 minutes to prepare a sample. After the experiment, the electrode (SUS316 stainless steel) was sufficiently washed with distilled water, and then sufficiently dried, and then subjected to a contact angle measurement experiment of a partial surface having a depth of 30 mm, 28 mm, and 26 mm from the liquid surface. 1 μl of distilled water (manufactured by Wako Pure Chemical Industries, Ltd.) was dropped by a micropipette, and each water droplet was photographed from the front side by a camera (EOS Kiss X2 manufactured by Canon Co., Ltd.), and the height (h) and contact length (l) of the droplet were measured from the photograph. The respective contact angles (θ _R ) were obtained from θ _R = 2 tan ^-1 (2 h / l) and the average value was calculated and set as the contact angle of the portion having a depth of 30 mm with respect to the liquid surface.

After the end of the contact angle measurement experiment, it was sufficiently dried, and the average diameter and density of the protrusions formed on the surface were evaluated in the same manner as in Example 1. Further, in order to evaluate how much the surface area of the obtained sample increases the smooth surface, the surface area of the sample when the surface area of the smooth surface is set to 1 is regarded as the specific surface area, and is calculated based on the following assumptions. That is, it is assumed that the hemispherical projection having the average diameter obtained as described above exists on the smooth surface in accordance with the above-described density, and is calculated to be several times with respect to the smooth surface system. The results are shown in Table 3 below. As shown in Table 3, the examples within the scope of the present invention were compared with the samples which were not treated and which did not have the modified layer of the present invention (Experiment No. 3-1), or the samples whose modified layer properties exceeded the scope of the present invention ( Experiment No. 3-6), it was found that the contact angle was small and the hydrophilic property was improved.

[Example 4]

The soft cold-rolled steel sheet (size 1.5 mm × 20 mm × 0.7 mm) and Pt were respectively used as a cathode electrode and an anode electrode, and immersed in a K ₂ CO ₃ aqueous solution having a concentration of 0.3 mol/L, and the electrification voltage was set to 110 V, and the cathode electrode was used. The anode electrode was energized for 30 minutes to prepare a sample. In the present embodiment, in order to concentrate the electric field, the sample width was set to be 1.0 mm different from that of Examples 1 and 2. Then, after energization, the contact angle of one place was measured in the same manner as in Example 3, with a depth of 15 mm from the liquid surface. The result is a contact angle of 45°. Further, after the contact angle was measured, the surface of the same portion was observed by SEM after drying, and the average diameter and density of the protrusions formed on the surface were evaluated in the same manner as in Example 1. Representative SEM photographs are shown in Figure 5. As a result of the evaluation, the average diameter of the protrusions seen from above was 350 nm. Further, the density of the protrusion having the thin waist structure was evaluated. The density of the protrusion having the thin waist structure is counted in the same portion as the average diameter and density portion (range) of the evaluation protrusion portion, and the number of protrusions having a thin waist structure is the same as the density of the protrusion portion, and an average of 10 μm is calculated. The average of ² is obtained. As a result, it was confirmed that there were three on average.

[Example 5]

The soft cold-rolled steel sheet (size 1.5 mm × 20 mm × 0.7 mm) and Pt were respectively used as a cathode electrode and an anode electrode, and immersed in a K ₂ CO ₃ aqueous solution having a concentration of 0.3 mol/L, and the electrification voltage was set to 95 V and the cathode electrode was used. The anode electrode was energized for 10 minutes to prepare a sample. Then, after energization, the contact angle of one place was measured in the same manner as in Example 3 at a depth of 15 mm from the liquid surface. The result is a contact angle of 60°. Further, after the contact angle was measured, the surface of the same portion was observed by SEM after drying, and the average diameter and density of the protrusions formed on the surface and the density of the protrusion having a fine waist structure were carried out in the same manner as in Example 1. Evaluation. As a result of the evaluation, it was confirmed that the average diameter of the projections seen from above was 350 nm, and the projections having the fine waist structure had an average of one in 10 μm ² .

[Example 6]

The 6% mass% C-2 mass% Si-2 mass% Cr steel was subjected to rolling processing, and the Vickers strength of 25 g was evaluated for the cross section. As a result, it was found to be 900, and ultrahigh strength steel belonging to the 2 GPa grade was confirmed. The steel material was cut into a size of 1 mm × 20 mm × 0.7 mm, and Pt was used as a cathode electrode and an anode electrode, respectively, and immersed in a K ₂ CO ₃ aqueous solution having a concentration of 0.1 mol/L, and the energization voltage was set to 110 V, and the cathode electrode was used. The anode electrode was energized for 30 minutes. Then, after energization, the surface of the soft cold-rolled steel sheet at a depth of 18 mm from the liquid surface was observed by SEM, and the average diameter of the protrusions formed on the surface and the density of the protrusion having the fine waist structure were evaluated. As a result of the evaluation, it was confirmed that the average diameter of the protrusions seen from above was 400 nm, and the protrusions having the fine waist structure had an average of two in 10 μm ² .

[Method of surface treatment of metal materials]

Fig. 11 is a flow chart showing the surface treatment flow of a metal material according to an embodiment of the present invention. Fig. 12 is a schematic view showing a configuration example of a device used in the surface treatment method of a metal material according to an embodiment of the present invention. As shown in Fig. 11, in the surface treatment of a metal material according to an embodiment of the present invention, first, a material to be treated which is a metal material and used as a cathode electrode, and an anode electrode are immersed in an electrolytic solution, and a cathode electrode and an anode are used. A voltage is applied between the electrodes to form a fine structure on the surface of the material to be processed (step S1). Specifically, as shown in FIG. 12, the anode electrode 13 and the material to be processed 14 are immersed in the electrolytic solution 12 in the container 11, and the anode electrode 13 and the material to be processed 14 are supplied from the power source 16 via the wire 15 such as a copper wire. A voltage is applied to form a fine structure on the surface of the material to be processed 14.

The electrolytic solution 12 is not particularly limited and is electrically conductive, and when the surface treatment of the material to be processed 14 is performed, it is less likely to occur, for example, the surface of the material to be processed 14 is excessively etched, adhered, or precipitated from the anode electrode 13 and the material to be treated. 14 A solution on the surface where a precipitate or the like is formed. The electrolyte of the electrolytic solution 12 can be exemplified by potassium carbonate (K ₂ CO ₃ ), sodium carbonate (Na ₂ CO ₃ ), sodium hydrogencarbonate (NaHCO ₃ ), ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), Lithium hydroxide (LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH ₄ OH), sodium chloride (NaCl), potassium chloride (KCl), ammonium chloride (NH _{4 )} Cl), sodium salt of sulfuric acid, potassium salt of sulfuric acid, ammonium salt of sulfuric acid, sodium salt of nitric acid, potassium salt of nitric acid, ammonium salt of nitric acid, sodium citrate (NaH ₂ (C ₃ H ₅ O(COO) ₃ ) And the like, such as sodium salt of citric acid, potassium salt of citric acid, ammonium salt of citric acid, nitric acid, hydrochloric acid and the like.

The electrolytic solution 12 is provided before the surface of the material to be processed 14 can be modified. Below, it can be set to any pH and concentration. For example, when the potassium carbonate aqueous solution is used as the electrolytic solution 12, the concentration is not particularly limited, and may be 0.001 mol/L or more, preferably 0.005 mol/L or more. The reason is that if the concentration of the electrolytic solution 12 is too low, when a voltage is applied between the anode electrode 13 and the material to be processed 14, it is difficult to maintain a good discharge state. The upper limit of the concentration of the electrolytic solution 12 is not particularly set, and may be, for example, 0.5 mol/L or less. Further, the pH of the electrolytic solution 12 can be set to any value without causing excessive corrosion and etching of the electrode, and can be set, for example, to pH 10 to 12.

The anode electrode 13 is formed of a material that is thermally and chemically stable when discharged. Such an anode electrode 13 can be exemplified by, for example, Pt, Ir, graphite, or the like.

The material to be processed 14 is removed before being a metal material, and the rest is not particularly limited. If it is a steel material, a cold-rolled material, a hot-rolled material, or a cast material, and a processed product thereof (including welding, etc.) can be used. Further, the steel type is not particularly limited, and carbon steel, low alloy steel, or stainless steel can be used. Further, a plated steel sheet typified by an electrogalvanized steel sheet can also be used. Further, the shape of the material to be processed 14 is not particularly limited, and a plate shape, a wire shape, a rod shape, a tubular shape, or a machined component can be used. Further, the material to be processed 14 must be immersed in the electrolytic solution 12, and at least it must be set to be deeper than 1 mm from the liquid surface.

The discharge condition can be in a range from a partial plasma state in which irregularities are formed on the surface of the material to be processed 14 to a completely plasma state. However, it is necessary to carry out the voltage range which is lower than the voltage at which the material to be processed 14 is melted. Specifically, from the time when the discharge voltage is raised, the light that can be visually confirmed in a dark place is started until the state immediately before the red heat is generated from the voltage at which the orange dot is emitted. The applied voltage is preferably in the range of about 70 to 200 V, more preferably in the range of 80 to 150 V, when the size of the material to be processed 14 is set to 1 mm × 1 mm × 20 mm. This voltage range is suitable for almost all steel materials including alloy steels such as stainless steel. However, since this voltage range is in accordance with the type and configuration of the material 14 to be processed. However, it is determined by observing the surface of the workpiece 14 subjected to the treatment by changing the voltage condition by SEM.

The necessary condition for the discharge voltage is a voltage at which fine protrusions are formed on the surface of the steel material. When the lower limit voltage is not applied, fine protrusions cannot be formed on the surface, and it is determined by SEM to confirm the presence or absence of fine protrusions. If the upper limit is exceeded, the treated surface will be melted. Therefore, the voltage at which the surface will melt can be determined as the upper limit. However, better systems do not oxidize the surface. In this case, the voltage at which the surface is oxidized can be easily determined by investigation using an X-ray energy dispersive analyzer (EDS) attached to the SEM and SEM. When oxygen is detected in accordance with the X-ray intensity of the same degree as the oxide of the material to be treated 14, it can be judged that the surface is oxidized. Further, with respect to the oxide of the material to be processed 14 (for example, an oxide of Fe in the case of a cold-rolled steel sheet or a low-alloy steel), the X-ray intensity of oxygen normalized by the L-ray intensity of Fe is The X-ray intensity of the material to be treated 14 normalized by the Fe-L ray intensity of oxygen must be 1/3 or less. In the surface investigation, after the voltage was changed and discharged for 30 minutes, the material to be processed 14 was taken out, washed with water, dried, and then introduced into an SEM and observed.

The discharge processing time must be set to 3 seconds or longer. However, the discharge treatment time may be a long time such as 60 minutes. However, if the discharge treatment time is too long, the material to be treated 14 may be subjected to wear, and therefore it is preferable not to have a treatment time of 30 minutes or more. It is known that in the preferred voltage range, the larger the applied voltage, the higher the surface water repellency characteristic after the final step. Therefore, the optimum condition is to select an applied voltage close to the upper limit in the preferred condition range.

Fig. 13 shows an example of processing a SUS316L stainless steel plate having a thickness of 0.8 mm. The SUS316L stainless steel plate was cut into a width of 2 mm and a length of 30 mm, and was turned on by a copper wire to form a cathode electrode. The anode electrode was formed by bending and forming a Pt wire having a length of 50 cm so as not to be in contact with each other. The connection portion between the SUS316L stainless steel plate and the copper wire is immersed in the electrolytic solution in a 20 mm length portion of the electrode by heating and pressing the heat resistant resin so that the copper wire does not come into contact with the electrolytic solution. The electrolytic solution was a K ₂ CO ₃ aqueous solution having a concentration of 0.1 mol/L, the voltage was set to 130 V, and discharge was performed for 10 minutes, and immediately after completion, water washing was performed.

As a result, as shown in FIG. 13, it was confirmed that a fine protrusion structure having an average diameter of 1 μm or less was formed on the surface of the SUS316L stainless steel plate. Further, elemental analysis by EDS confirmed that the surface of the SUS316L stainless steel plate was not oxidized. Moreover, if the applied voltage exceeds 160 V, the front end of the SUS316L stainless steel plate is melted. Therefore, the upper limit value of the applied voltage can be found to be 160V. Moreover, it was confirmed by elemental analysis by EDS that the surface of the SUS316L stainless steel plate was not oxidized when the applied voltage was 140 V or less, so that the upper limit of the applied voltage under the experimental conditions and the test material was known. It is 140V. On the other hand, the lower limit of the applied voltage is determined to be 80 V from the presence or absence of the protrusion structure. The optimum applied voltage can be determined to be 140V.

Please return to Figure 11. As described above, when a fine structure is formed on the surface of the material to be processed 14, the material 14 to be processed is taken out from the electrolytic solution 12, and the material 14 to be processed is washed (step S2). Then, the treated surface of the treated material 14 to be treated is finally subjected to water repellent treatment (step 3). The washing method is carried out for the purpose of removing the electrolytic solution on the surface, and may be, for example, a method of immersing in pure water or spraying. It is not limited to pure water, and if the fine structure of the surface is not damaged, a weak acid or alkali solution can also be used. At this time, electrolysis can also be performed. Drying can also be carried out after washing. According to the subsequent water repellent treatment, there will be cases where the drying is carried out and the next step is directly carried out. The water-repellent treatment method may be a method in which a water-spraying spray is applied, or a method of adsorbing an organic substance having a water-repellent function such as a fluorine-based resin in a liquid phase or a gas phase. In the present embodiment, NANOPRO (component: fluorocarbon tree) manufactured by Collonil Co., Ltd. The grease and the resin are blown onto the surface of the material to be treated 14, and dried for 12 hours or more, and the surface of the material to be treated 14 is subjected to water repellent treatment. This completes a series of surface treatments.

Fig. 14 shows the results of water-repellent treatment of the surface of the sample shown in Fig. 13 and observation of the state of the distilled water droplets from the lateral direction. The water contact angle measured by the observation was 152°, and it was confirmed that the super-water was achieved. The water contact angle of the sample which was not subjected to water repellent treatment was 51°. Further, the same water-repellent treatment was applied to the material which was not subjected to the plasma discharge in the solution, and as a result, the water contact angle was 125°. Therefore, it was confirmed that in order to obtain the super-water-removing surface, both the plasma discharge and the water-repellent treatment in the solution are necessary.

[Example 1]

A commercially available 0.8 mm stainless steel SUS316L steel sheet was cut into a width of 2 mm and a length of 30 mm, and was degreased by immersion in dilute hydrochloric acid, and then turned on to form a cathode electrode via a copper wire. The anode electrode is used without depending on the length of 50cm 0.5mm The Pt wires are not bent into each other and are formed into a flat shape. The connection portion between the cathode electrode and the copper wire is immersed in the electrolytic solution by a portion of 20 mm in length of the electrode so that the copper wire does not come into contact with the electrolytic solution by heating and pressing the heat resistant resin. The electrolytic solution was a K ₂ CO ₃ aqueous solution having a concentration of 0.1 mol/L, and the applied voltage was set to be in the range of 60 to 180 V, and discharge was performed for 10 minutes. Immediately after completion, the mixture was washed with pure water and dried. Then, NANOPRO manufactured by Collonil Co., Ltd. was blown onto the surface of the material to be treated, and dried for 12 hours or more, and water-repellent treatment was performed to investigate water wettability. The water wettability was measured by dropping the distilled water at equal intervals on the electrode surface by using a micropipette, and dropping 6 ml of distilled water each time, and photographing from the lateral direction using a digital camera EOS Kiss X2 manufactured by Cannon Co., Ltd., and measuring the contact angle from the obtained photograph, The evaluation was performed using the average of six places. The distilled water was distilled water 049-16787 manufactured by Wako Pure Chemical Industries, Ltd. Table 4 shows the test results. As shown in Table 4, the inventive examples were confirmed to have a higher contact angle than the untreated materials. In particular, inventive examples 3, 4, and 5 in which the voltage is applied in the range of 120 to 140 V, the super-water-repellent water having a contact angle of 150 or more is realized, and the invention example 5 in which the applied voltage is set to 140 V is 153.6°, which is the highest contact. angle.

[Surface treatment device for conductive materials]

The inventors of the present invention have an object of producing a conductive material having a nano-scale fine structure on the surface at a low cost and efficiently, and also for utilizing a liquid-plasma discharge using a nano-scale fine structure. The possibility to delve deeper. As a result, the inventors of the present invention have found that a nano-scale fine structure can be formed on the surface of the conductive material by using the conductive material as the cathode electrode and discharging the plasma in the partial initiator liquid. Moreover, the inventors of the present invention reviewed a method of forming a nano-scale fine structure on a specific portion of the surface of a conductive material, and found that the treated portion of the conductive material is immersed in the electrolyte together with the anode electrode, and By providing a shield having an opening between the conductive material and the anode electrode, a nano-scale fine structure can be formed at a specific portion of the surface of the conductive material. Moreover, the inventors of the present invention have found that by changing the relative position between the opening portion and/or the anode electrode of the shield and the conductive material, it is possible to form a fine nanometer level on the surface of the conductive material in continuity or discreteness. structure.

Fig. 15 is a view showing the configuration of a surface treatment apparatus for a conductive material according to an embodiment of the present invention. As shown in FIG. 15, a surface treatment apparatus 21 for a conductive material according to an embodiment of the present invention includes a reforming treatment tank 22, an electrolytic solution 23 stored in the reforming treatment tank 22, and a solution in the electrolytic solution 23. The anode electrode 24 which is mutually immersed and the cathode electrode 25 which consists of electroconductive material, and the DC power source 26 connected to the anode electrode 24 and the cathode electrode 25. The cathode electrode 25 is covered by a case 27 made of an insulating material, and an opening portion 28 for defining a portion to be processed of the cathode electrode 25 is formed in the case 27. The tank 27 is disposed in a position where the upper portion is higher than the liquid surface of the electrolytic solution 23. The upper portion of the tank 27 may be open or may be provided with a hole or cover for the passage of the wire connecting the cathode electrode 25 to the DC power source 26.

As the reforming treatment tank 22, a known tank made of a material which is stable to the electrolytic solution 23, for example, a glass, Teflon (registered trademark), or a polyethylene ether ketone (PEEK) tank can be used. Further, a ceramic groove can be used as the reforming treatment tank 22. A metal groove can also be used for the surface treatment apparatus 21 shown in Fig. 16 which will be described later.

The electrolytic solution 23 is electrically conductive, and when a voltage is applied between the anode electrode 24 and the cathode electrode 25, and a nano-scale fine structure is formed on the surface to be treated (the surface of the cathode electrode 25), it is less likely to occur, for example, to be processed. The surface is overetched, adhered, or deposited on the surface of the anode electrode 24 and the cathode electrode 25 to form a precipitate or the like. Such an electrolytic solution 23 can be used, for example, from potassium carbonate (K ₂ CO ₃ ), sodium carbonate (Na ₂ CO ₃ ), sodium hydrogencarbonate (NaHCO ₃ ), ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), Lithium hydroxide (LiOH), sodium hydroxide (NaOH), magnesium hydroxide (Mg(OH) ₂ ), potassium hydroxide (KOH), ammonium hydroxide (NH ₄ OH), sodium chloride (NaCl), chlorination Potassium (KCl), magnesium chloride (MgCl ₂ ), ammonium chloride (NH ₄ Cl), lithium sulfate, sodium sulfate, magnesium sulfate, potassium sulfate, ammonium sulfate, lithium nitrate, Sodium citrate such as sodium nitrate, magnesium nitrate, potassium nitrate, ammonium nitrate, lithium citrate, sodium citrate (NaH ₂ (C ₃ H ₅ O(COO) ₃ )) At least one aqueous solution selected from the group consisting of magnesium citrate, potassium citrate, ammonium citrate, sulfuric acid, nitric acid, hydrochloric acid, and citric acid.

The electrolytic solution 23 can be set to any pH and concentration before the surface treatment of the cathode electrode 25 can be performed. For example, when the potassium carbonate aqueous solution is used as the electrolytic solution 23, the concentration is not particularly limited, and can be set to 0.001. Mol/L or more, preferably 0.005 mol/L or more. The reason is that if the concentration of the electrolytic solution 23 is too low, when a voltage is applied between the anode electrode 24 and the cathode electrode 25, it may be difficult to maintain a good discharge state. The upper limit of the concentration is not particularly set, and for example, it can be set to 0.5 mol/L or less. Further, the pH of the electrolytic solution 23 can be set to any value without causing excessive corrosion and etching of the electrode, and can be set, for example, to pH 5 to 12.

When the anode electrode 24 forms a nano-scale fine structure on the surface to be treated by applying a voltage between the anode electrode 24 and the cathode electrode 25, it is ionized and dissolved in the electrolytic solution 23, and does not hinder the precipitation. On the cathode electrode 25, an insoluble anode electrode composed of an electrode material having a nano-scale fine structure is formed. As the anode electrode 24, for example, a platinum (Pt) electrode, a palladium (Pd) electrode, an iridium (Ir) electrode, an electrode whose surface is covered with Pt, Pd, Ir, or a graphite electrode can be used.

The cathode electrode 25 is a material to be processed whose surface is modified by voltage application, and is made of a conductive material (conductive material) such as a metal material or an alloy material. The material to be treated which functions as the cathode electrode 25 can be, for example, a carbon steel material, an alloy steel material, a stainless steel material, a nickel material or the like. Further, the shape of the cathode electrode 25 (the material to be processed) is not particularly limited, and may be a plate-like shape, a strip shape, or a member having a conductive material portion. The material to be processed can also be mirror-polished on the surface by sandpaper or the like, and used as the cathode electrode 25.

The DC power source 26 is a modification of the surface of the cathode electrode 25 belonging to the material to be processed. The voltage necessary for the quality treatment (for example, a voltage of 60 V or more and 300 V or less) is applied between the anode electrode 24 and the cathode electrode 25. The DC power source 26 can use a known power source.

In the present embodiment, the cathode electrode 25 is covered by the case 27, but as shown in Fig. 16, the anode electrode 24 may be covered by the case 27 having the opening portion 28. Further, instead of using the case 27 having the opening portion 28 to define the portion to be processed of the cathode electrode 25, as shown in Fig. 17, at least the cathode electrode 25 may be immersed in the surface of the electrolytic solution 23, using a heat resistant resin or glass. The insulating heat-resistant material is coated and formed as an opening portion 28 for defining a portion to be processed of the cathode electrode 25 at a part of the heat-resistant material.

The shape and size of the opening portion 28 are not particularly limited, and the case 27 may have a plurality of openings. When the number of the openings 28 is plural, the opening 28 is not limited to the same surface as the cathode electrode 25. For example, the opening portion 28 can be provided on the front side and the back side of the cathode electrode 25. Further, as shown in FIG. 18, an inclined portion 28a may be provided at an upper end (liquid surface side) end portion of the opening portion 28. By the design of the inclined portion 28a, the gas generated from the portion to be processed can be efficiently escaped into the electrolytic solution 23.

The surface treatment apparatus 21 may have a heating means such as a heater for heating the electrolytic solution 23 or a thermometer for measuring the temperature of the electrolytic solution 23. Further, the angle at which the cathode electrode 25 is disposed may be perpendicular to the liquid surface of the electrolytic solution 23, but is not limited thereto. Further, in order to promote plasma generation on the surface of the cathode electrode 25, a mechanism for supplying a gas such as hydrogen, argon or water vapor to the surface of the cathode electrode 25 may be provided.

The surface treatment apparatus 21 having such a configuration produces a surface-modified conductive material as follows. Hereinafter, a surface treatment method of a conductive material using the surface treatment apparatus 21 will be described.

[Method of Surface Treatment of Conductive Materials]

When manufacturing a conductive material that is surface-modified by the surface treatment device 21, the first First, after the tank 27 is immersed in the electrolytic solution 23 stored in the reforming treatment tank 22, the anode electrode 24 and the cathode electrode 25 are separated from each other, and a system for performing surface modification treatment of the cathode electrode 25 is constructed (surface modification) Quality processing system). At this time, the cathode electrode 25 is immersed in the tank 27, and the portion to be treated can be seen from the opening portion 28 of the tank 27. The surface modification treatment of the cathode electrode 25 is performed from the opening portion 28 to the portion exposed on the side of the electrolytic solution 23. The surface treatment apparatus 21 shown in Fig. 16 has a configuration in which the anode electrode 24 is placed in the tank 27, and the tank 27 is provided such that the opening portion 28 of the tank 27 faces the treated portion of the cathode electrode 25. If the portion to be treated is farther away from the mouth portion 28, the processed portion becomes larger than the opening portion, and thus the interval (distance) between the opening portion 28 and the portion to be processed of the cathode electrode 25 is usually preferably 5 mm or less. More preferably, it is 1 mm or less.

Next, a predetermined voltage is applied between the anode electrode 24 and the cathode electrode 25, and the surface of the cathode electrode 25 is subjected to a modification treatment (surface modification treatment step). The "predetermined voltage" is a voltage that can be determined experimentally in advance, and can be determined according to the following method. That is, first, the voltage applied to the surface modification processing system and the processing time are changed within a desired range. When the processing time is not specified, it is best to perform for 15 minutes. Further, the range in which the voltage changes is preferably about 50 to 300V. Next, the surface to be treated was observed by SEM, and it was confirmed that the surface had a protrusion structure having an average of 1 μm or less, the surface was not oxidized (except for the natural oxide layer having a thickness of several nanometers), and was not melted. Whether or not the surface is oxidized can be confirmed using EDS in the SEM.

The voltage range varies depending on the kind of the cathode electrode 25, and is preferably in the range of 60 V to 300 V, more preferably in the range of 80 to 180 V. The lower limit voltage corresponds to the voltage at which the plasma is generated. The upper limit voltage is determined in accordance with a phenomenon in which the surface is oxidized or the surface is melted due to high temperature, and the fine protrusion structure disappears. According to the above, the preferred voltage range can be determined. When it is desired to process in a short time, or when it is desired to increase the structure of the protrusion, it is best Set a higher applied voltage.

The specific example will be described. In this specific example, the surface modification processing system shown in Fig. 15 is constructed using a stainless steel plate (SUS316). The size of the opening portion 28 is set to 25 mm × 4 mm. Then, a 0.1 mol/L potassium carbonate (K ₂ CO ₃ ) aqueous solution was used as the electrolytic solution 23 and was energized for 15 minutes. The surface of the treated stainless steel plate was observed by SEM, and as a result, the lower limit voltage was found to be 80V. Further, it was found that the upper limit voltage was 250V. When 150 V is applied between the anode electrode 24 and the cathode electrode 25, secondary electronic images of (a) left side, (b) center, and (c) right side of the opening portion 28 in the longitudinal direction are respectively shown in FIGS. 19A and 19B. Figure 19C shows.

As shown in FIG. 19A, FIG. 19B, and FIG. 19C, it was confirmed that a fine protrusion structure having a diameter of 1 μm or less was formed on the surface of the stainless steel plate. Further, since the same projection structure was found on the left side, the right side, and the center of the longitudinal direction of the opening portion 28, it was confirmed that the opening portion was appropriately treated as a whole. Further, it has been confirmed that the lower the voltage in a preferable voltage range, the smaller the size of the protrusion structure is, and the more the number of protrusion structures is increased. Therefore, it is only necessary to adjust the applied voltage in accordance with the necessary surface characteristics. For example, when the luminescent property is to be obtained, since the projection structure is as small as possible, it is only necessary to set a lower applied voltage.

Although the principle of formation of the fine protrusions is not clear, it is presumed that it is formed by causing a plasma discharge in a partial liquid in the vicinity of the cathode electrode 25. That is, in this method, if the voltage applied between the anode electrode 24 and the cathode electrode 25 is less than the lower limit voltage, the plasma discharge in the partial liquid is not caused, and fine protrusions cannot be formed; if the voltage exceeds the upper limit voltage, The surface of the cathode electrode 25 is melted due to the generation of complete plasma, which is disadvantageous for the formation of fine protrusions.

The liquid plasma discharge is judged by the application of a voltage to cause the cathode electrode 25 The temperature of the nearby electrolytic solution 23 is locally higher than the boiling point, and is caused by generation of a plasma discharge in the gas phase when a gas phase is generated in the vicinity of the cathode electrode 25. Therefore, the application of the voltage can be carried out from room temperature, but it is more effective if the temperature of the entire electrolytic solution 23 or the vicinity of the cathode electrode 25 is formed from 80 ° C to 100 ° C. The reason is that the temperature in the vicinity of the cathode electrode 25 is efficiently increased, and the plasma discharge in the liquid can be efficiently induced. The application time of the voltage may be any time, and is, for example, 1 second or longer and 30 minutes or shorter. Since the shorter the application time of the voltage, the smaller the size of the fine protrusions formed, the voltage application time can be appropriately selected in accordance with the desired surface shape and characteristics.

As is apparent from the above description, according to such a surface treatment method, it is possible to control only between the anode electrode 24 and the cathode electrode 25 impregnated in the electrolytic solution 23 without using a high-priced device and a high-level technique. By applying the voltage, it is possible to manufacture a conductive material having a nano-scale fine structure on the surface at a low cost and efficiently. A conductive material having a fine nanostructure is formed on the surface, and various functions can be exhibited by the fine structure. By moving the cathode electrode 25 or fixing the cathode electrode 25 by the fixed tank 27, the tank 27 is moved, and the surface modification can be performed on the wide area by the cathode electrode 25. Further, by continuously performing the processing while performing the treatment, a continuous processing surface can be obtained. Further, a discrete pattern can be obtained by moving in a stepwise manner or by repeatedly moving and discharging. In particular, since the surface treatment device 21 shown in Fig. 16 does not have to be covered by the case 27, the cathode electrode 25 can be expanded into a continuous processing apparatus and a continuous processing method by forming a large sample or a strip sample.

[Example 1]

1.7mm thick aluminum plate is made with various sizes of openings (5mm × 5mm, 5mm , 10mm Five kinds of boxes 27 of 10 mm × 2 mm and 20 mm × 1 mm. The upper end surface of the opening portion 28 is processed to be inclined at 30 degrees as shown in Fig. 18 . The cathode electrode 25 was made of SUS316 stainless steel having a thickness of 1 mm, and Pt was used as the anode electrode 24, and immersed in a K ₂ CO ₃ aqueous solution having a concentration of 0.3 mol/L to construct a surface modification treatment system shown in Fig. 15 . A voltage is applied between the cathode electrode 25 and the anode electrode 24. Then, the surface of the SUS316 stainless steel after the voltage application was observed by SEM. The size of the opening portion 28 is set to 5 mm × 5 mm and 5 mm. An example of the appearance of the treated cathode electrode 25 is shown in FIG. The applied voltage was 160 V and the application time was 15 minutes. As shown in FIG. 20, it was confirmed that the surface of the cathode electrode 25 was processed into the shape of the opening portion 28.

The opening portion 28 is set to a size of 5 mm. An example of the surface SEM image of the treated cathode electrode 25 is shown in FIG. As shown in FIG. 21, it was confirmed that the surface of the cathode electrode 25 has a fine protrusion structure having a diameter of 1 μm or less which is not present on the surface (see FIG. 22) when the surface treatment is not performed. Further, even if the shape of the other opening portion 28 is used, the fine protrusion structure can be formed with an applied voltage of 90 to 200 V, but it is found that the fine protrusion structure is reduced if it is 220 V or more. This phenomenon can be presumed to be caused by surface melting. Further, by performing the same water repellent treatment on the cathode electrode 25 shown in Fig. 20, high water repellency can be obtained as compared with the surface which is not subjected to the surface treatment. Also, use 5mm on both sides In the case of the case 27 of the opening portion 28 of the 5 mm × 5 mm, an experiment of 170 V (application time: 15 minutes) was applied, and it was confirmed by SEM observation that the fine protrusion structure was formed on both surfaces, and the surface modification was simultaneously performed on the front and back surfaces.

[Example 2]

A stainless steel plate (SUS316) was used as a cathode electrode, and the anode electrode 24 was covered with a casing 27 made of alumina (thickness: 1.7 mm) provided with a 1 mm (longitudinal) × 20 mm (lateral) opening portion 28, and constructed as shown in Fig. 16. Surface modification processing system. One surface of the opening portion 28 is provided to be apart from the cathode electrode 25 by 1 mm. The applied voltage between the electrodes was set to 140V and 220V. Apply a voltage of 5 minutes between the electrodes, then move the stainless steel plate upwards (longitudinal) 5mm, apply voltage for 5 minutes again. Repeat the movement up to 10 times with the voltage application meter. Two experiments were carried out in the case where the applied voltage between the electrodes was 140 V and in the case of 220 V. As a result, a stainless steel plate having a region in which the fine protrusion structure exists at intervals of 5 mm can be obtained in either case.

[Example 3]

The galvanized steel sheet was used as a cathode electrode, and the anode electrode 24 was covered with a box 27 made of alumina (thickness: 1.7 mm) provided with a 1 mm (longitudinal) × 20 mm (lateral) opening portion 28, and the surface modification shown in Fig. 16 was constructed. Quality processing system. One surface of the opening portion 28 is provided to be apart from the cathode electrode 25 by 1 mm. The applied voltage between the electrodes was set to 120 V, and the galvanized steel sheet was moved downward (longitudinal direction) by 20 mm at a speed of 1 mm/min while applying a voltage between the electrodes. A galvanized steel sheet of 20 mm × 20 mm area can be produced. A methylene blue decolorization reaction test was carried out on the surface, and as a result, a particularly high photocatalytic effect was obtained as compared with the surface which was not subjected to the surface treatment.

[Example 4]

A commercially available cold-rolled steel sheet having a thickness of 0.8 mm was cut into a length of 80 mm × a width of 6 mm and used as a cathode electrode. The bending process is performed in the width direction so that the longitudinal direction becomes the axis, and the cross section in the width direction is formed into an arc shape having a curvature radius of 10 mm. A heat-resistant resin was applied to the surface of the cathode electrode 25 except for the connection portion with the electrode, and an opening portion 28 having a length of 25 mm was formed on one side of the bent process by a width of 2 mm and 4 mm. A voltage of 150 V was applied between the cathode electrode 25 and the Pt. Regardless of which sample, a fine protrusion structure having an average diameter of 1 μm or less was formed on the surface of the opening portion 28.

(industrial availability)

According to the present invention, a metal material having novel functions such as hydrophilic properties and luminescent properties can be provided.

According to the present invention, it is possible to provide a surface treatment method for a metal material which can impart a high water-repellent property to a surface of a metal material without consuming a lot of labor and expense, and a water-repellent material using a metal material as a base material. Manufacturing method.

According to the present invention, it is possible to provide a surface treatment apparatus and a surface treatment apparatus capable of producing a conductive material which is formed by a predetermined area or a wide area of a surface at a low cost and efficiently, and which forms a nano-scale fine structure conductive material. method.

1‧‧‧Metal materials

2‧‧‧Substrate

3‧‧‧Protruding

Claims (17)

A metal material comprising: a metal material substrate; and a modified layer formed on a surface of the metal material substrate; wherein the modified layer has an average of three or more from the metal material in a range of 10 μm ² a projection having a mean diameter of 1 μm or less when viewed from a direction perpendicular to the surface of the substrate, and protruding from a surface of the metal material substrate; and a base protruding from a surface of the base material substrate and forming an end portion of the base portion And an average diameter of 1 μm or more in the range of 10 μm ² when viewed from the vertical direction of the surface of the metal material substrate is 1 μm or less, and the base outer diameter is smaller than the outer diameter of the front end portion. The protrusion of the thin waist structure. A metal material comprising: a metal material substrate; and a modified layer formed on a surface of the metal material substrate; wherein the modified layer is provided with a base protruding from a surface of the metal material substrate, and a tip end portion formed at the end portion of the base portion; and an average diameter of 1 μm or more in a range of 10 μm ² when viewed from a vertical direction of the surface of the metal material substrate is 1 μm or less, and the outer diameter of the base portion is small. a protrusion of a thin waist structure having an outer diameter of the front end portion. A metal material comprising: a metal material substrate; and a modified layer formed on a surface of the metal material substrate; wherein the modified layer has an average of three or more from the metal material in a range of 10 μm ² The average diameter of the surface of the substrate when viewed in the vertical direction is 1 μm or less, and the protrusions protrude from the surface of the metal material substrate; and the average diameter of the surface of the metal substrate is 500 nm or less when viewed from the vertical direction of the surface of the substrate. Concave. A metal material comprising: a metal material substrate; and a modified layer formed on a surface of the metal material substrate; wherein the modified layer has an average of three or more from the metal material in a range of 10 μm ² The average diameter of the surface of the substrate when viewed in the vertical direction is 1 μm or less, and the protruding portion protrudes from the surface of the metal material substrate; and the metal material substrate is continuously connected to the protruding portion. The metal material according to any one of claims 1 to 4, wherein the protrusion has an average diameter of 500 nm or less when viewed from a direction perpendicular to a surface of the metal material substrate. The metal material according to any one of claims 1 to 4, wherein the position formed by the protrusion is not periodic in the in-plane direction of the metal material substrate. The metal material according to claim 5, wherein the protrusion is formed at a position that is not periodic in the in-plane direction of the metal material substrate. The metal material according to the first, second or fourth aspect of the invention, wherein the modified layer has a concave portion having an average diameter of 500 nm or less when viewed from a direction perpendicular to a surface of the metal material substrate. The metal material according to any one of claims 1 to 4, wherein the metal material substrate is formed of alloy steel. The metal material according to any one of claims 1 to 4, wherein the metal material substrate is formed of a steel material. A metal material according to any one of claims 1 to 3, wherein the metal The composition of the material substrate is different from the composition of the above-mentioned protrusions. The metal material according to any one of claims 1 to 3, wherein the metal material substrate is continuously connected to the protruding portion. A metal material manufacturing method according to any one of claims 1 to 12, which comprises: a processed material having a surface to be treated and composed of a metal material and serving as a cathode electrode a step of immersing the anode electrode in the electrolytic solution; forming a fine layer on the surface to be treated by applying a voltage of 70 V or more between the cathode electrode and the anode electrode and the range of the material to be treated is not oxidized or melted a step of constructing; and removing the material to be treated from the electrolytic solution and washing the material to be processed. A metal material manufacturing method according to any one of claims 1 to 12, which comprises: a processed material having a surface to be treated and composed of a metal material and serving as a cathode electrode And a step of immersing the anode electrode in the electrolytic solution; and applying a voltage of 70 V or more and 200 V or less between the cathode electrode and the anode electrode to form a fine structure on the surface to be treated; and The step of taking out the above-mentioned material to be treated and washing the material to be processed is carried out. The method for producing a metal material according to claim 13 or claim 14, further comprising the step of subjecting the surface to be treated of the treated material to be treated to a water repellent treatment. A method for producing a water-repellent material using a metal material according to any one of claims 1 to 12 as a substrate, comprising: a metal material having a surface to be treated and used as a material for processing a cathode electrode a step of immersing the anode electrode in the electrolytic solution; and applying a voltage of 70 V or more and 200 V or less between the cathode electrode and the anode electrode to form a fine structure on the surface of the metal material of the material to be processed; And removing the metal material from the electrolytic solution and washing the metal material; and performing a water-repellent treatment on the surface to be treated of the washed metal material. An apparatus for manufacturing a metal material according to any one of claims 1 to 12, comprising: an anode electrode which is mutually immersed in an electrolytic solution, and a cathode electrode which is made of a metal material; and is disposed on the anode electrode And a shielding device for defining an opening of the portion of the cathode electrode to be processed; and a power source for applying a voltage between the anode electrode and the cathode electrode.