KR101687462B1 - Metal material, and surface treatment method and device - Google Patents

Abstract

The metal material comprises a metal material base material (2) and a modified layer formed on the surface of the metal material base material (2), and the modified layer has an average diameter when viewed in a direction perpendicular to the surface of the metal material material (3) protruding from the surface of the metal material base (2) is not more than ¹占 퐉 in an average of not less than 10 占 퐉 ² . The reforming layer has a base portion protruding from the surface of the metal material base 2 and a tip portion formed at the end of the base portion and has an average diameter when viewed in a direction perpendicular to the surface of the metal material base 2 of 1 占 퐉 And the projections having a constriction structure in which the outer diameter of the base portion is smaller than the outer diameter of the distal end portion may be provided in an average of one or more within a range of 10 탆 ² . Thus, it is possible to provide a metal material having new functions such as a hydrophilic property and a luminescent property.

Description

TECHNICAL FIELD [0001] The present invention relates to a metal material, a surface treatment method,

TECHNICAL FIELD [0001] The present invention relates to a metal material, a surface treatment method of a metal material, a water-repellent material production method based on a metal material, a surface treatment apparatus of a conductive material, and a surface treatment method of a conductive material.

In recent years, it is strongly expected that a new function is given to a metal material. Specifically, in addition to advantageous properties originally possessed by metal materials such as strength, workability, and corrosion resistance, new functions relating to metal surfaces such as hydrophilic properties, water repellency characteristics, and luminescent properties are greatly expected in terms of pioneering new fields of use of metal materials . From these backgrounds, studies for forming a modified layer such as a plating layer, an oxide layer, a surface hardened layer, and a modified layer having improved surface roughness on a metal surface have been actively carried out in recent years. For example, there is a technique of forming a fine structure by oxidizing a metal surface by an anode (see Non-Patent Document 1) and a technique of forming a surface fine structure by electrolytic processing (see Non-Patent Document 2).

[Non-Patent Document 1] Hideaki Takahashi, Masatoshi Sakai, Tatsuya Kikuchi, JHA Himendra Surface Technology Vol.60 (2009) No.3 p.14 [Non-Patent Document 2] Application and theory to microfabrication of electrolytic machining Wataru Natsu Surface Technology Vol.61 (2010) No.4 294

It is necessary to design the structure and composition of the surface modification layer at a microstructure of 1 탆 or less in order to impart new functions such as hydrophilicity, water repellency and light emission to the surface of the metal material. However, conventional researches are aimed at improving functions such as workability and corrosion resistance, and since the structure and composition of the surface-modified layer are designed with micron numbers, it is insufficient for the expression of new functions. For example, as a method of improving the surface roughness, a method of pushing a roll having a dull structure on the surface of a metal material has been proposed. However, the irregularities on the surface of the metal material formed by this method have a size larger than a micron value. For this reason, the surface of the metal material has the effect of improving the workability due to oil retention and the effect of making the surface appearance uniform, but does not exhibit new functions. Further, as a method for enhancing the paint adhesion of the automobile outer plate, a method of forming phosphate crystals on the surface of the metal material has been proposed. However, the particle diameter of the phosphate crystals formed by this method has a size of several microns. Therefore, the surface of the metal material does not exhibit new functions.

On the other hand, among the reported microstructure forming techniques, the technique of forming a fine structure by oxidizing a metal surface such as the technique described in the non-patent document 1 by forming an anode has a limited ability to be imparted by forming fine holes . Further, since the surface is an oxide layer, the surface physical properties are limited to oxide species. In the method using electrolytic processing such as the method described in Non-Patent Document 2, it is necessary to make the distance between the surface to be treated and the counter electrode very short in order to form the surface fine structure, but this control is very difficult.

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

Another object of the present invention is to provide a method of surface treatment of a metal material and a method of manufacturing a water-repellent material based on a metal material, which can impart a high water repellency to the surface of a metal material without requiring much labor and cost .

Another object of the present invention is to provide a surface treatment apparatus and surface treatment method of a conductive material capable of efficiently carrying out a treatment over a wide area of a predetermined place or surface of a surface and efficiently forming a conductive material having a nano- And the like.

The metal material according to the present invention comprises a metal material base and a modified layer formed on the surface of the metal material base, wherein the modified layer has an average diameter when viewed in a direction perpendicular to the surface of the metal material base is 1 Mu m or less, and protrusions protruding from the surface of the metal material base are provided in an average of 3 or more in the range of 10 mu m < ^{2 &} gt ;.

The metal material according to the present invention is characterized in that the modified layer has a base portion protruded from a surface of the metal material base and a tip portion formed at an end portion of the base portion, And a protruding portion having an average diameter of 1 占 퐉 or less as viewed from the center of the base portion and an outer diameter of the base portion being smaller than an outer diameter of the tip portion is provided in an average of one or more within a range of 10 占 퐉 ² .

The metal material according to the present invention is characterized in that the average diameter of the protrusions in a direction perpendicular to the surface of the metal material base is 500 nm or less in the above invention.

The metal material according to the present invention is characterized in that, in the above invention, the position where the protrusion is formed does not have periodicity in the in-plane direction of the metal material base.

The metal material according to the present invention is characterized in that, in the above invention, the modified layer has a concave portion having an average diameter of 500 nm or less when viewed in a direction perpendicular to the surface of the metal material base.

The metal material according to the present invention is characterized in that, in the above invention, the metal material base is formed of an alloy steel.

The metal material according to the present invention is characterized in that, in the above invention, the metal material base is formed of a steel material.

The metal material according to the present invention is characterized in that the composition of the metal material base and the composition of the protrusions are different from each other in the above invention.

The metallic material according to the present invention is characterized in that the metallic material base and the protruding portion are continuously connected.

A method for surface treatment of a metallic material according to a first aspect of the present invention includes the steps of: immersing a member to be treated as a cathode electrode made of a metal material having a surface to be treated and an anode electrode in an electrolytic solution; Forming a microstructure on the surface to be treated by applying a voltage in a range not lower than 70 V to the target material so as not to oxidize or dissolve the target material; And performing a water repellent treatment on the surface of the object to be treated which has been cleaned.

A method for surface treatment of a metallic material according to a second aspect of the present invention includes the steps of: immersing a material to be treated as a cathode electrode made of a metal material having a surface to be treated and an anode electrode in an electrolytic solution; A step of forming a microstructure on the surface to be treated by applying a voltage of 70 V to 200 V to the surface of the substrate to be treated, And performing a water repellent treatment on the surface to be treated of the material to be treated.

A method of manufacturing a water-repellent material using a metal material as a base material according to the present invention comprises the steps of: immersing a metal material and a cathode electrode as a cathode material having a surface to be treated as a cathode electrode in an electrolytic solution; Forming a microstructure on the surface of the metal material as the material to be treated by applying a voltage of 70V to 200V; removing the metal material from the electrolytic solution and cleaning the metal material; And performing a water repellent treatment on the surface to be treated of the metallic material.

The surface treatment apparatus for a conductive material according to the present invention comprises a cathode electrode made of a conductive material and a cathode electrode immersed and immersed in an electrolytic solution and a cathode electrode interposed between the anode electrode and the cathode electrode, And a power source for applying a voltage between the positive electrode and the negative electrode.

The surface treatment apparatus for a conductive material according to the present invention is characterized in that it comprises a mechanism for changing the position of the opening and / or the relative position of the anode electrode and the cathode electrode.

The surface treatment apparatus for a conductive material according to the present 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 for a conductive material according to the present invention is characterized in that the shield is an insulating heat-resistant material having the opening covered with the surface of the cathode.

The surface treatment apparatus for a conductive material according to the present invention is characterized in that, in the above invention, the conductive material is a metal material.

The surface treatment method of a conductive material according to the present invention is characterized in that the surface of a conductive material is treated by using the surface treatment apparatus of the conductive material according to the present invention.

According to the metal material of the present invention, it is possible to provide a metal material having new functions such as a hydrophilic property and a luminescent property.

According to the surface treatment method of a metal material and the method of manufacturing a water-repellent material based on a metal material according to the present invention, high water repellency can be imparted to the surface of a metal material without requiring much labor and cost.

According to the surface treatment apparatus and surface treatment method of the conductive material of the present invention, it is possible to efficiently manufacture a conductive material having a nano-level microstructure formed over a wide area of a predetermined place or surface of the surface at a low cost.

1A is a plan view showing a configuration of a metal material according to an embodiment of the present invention.
FIG. 1B is a cross-sectional view taken along the line AA in FIG. 1A.
2 is an SEM photograph showing an example of a protrusion formed on the surface of the cold-rolled steel sheet.
3 is a schematic diagram for explaining a method of calculating the outer diameter of the protruding portion.
4 is a schematic view for explaining the constriction structure of the projections.
5 is an SEM photograph showing an example of a projection having a constriction structure formed on a cold-rolled steel sheet.
6 is a cross-sectional TEM photograph showing an example of a projection having a constriction structure formed on a cold-rolled steel sheet.
7 is an SEM photograph showing an example of a recess formed on the surface of stainless steel.
8 is an SEM photograph showing an example of a recess formed on the surface of stainless steel.
9 is a cross-sectional TEM photograph showing an example of a protrusion having a composition different from that of the base material.
10 is a cross-sectional TEM photograph showing a state in which protrusions are continuously formed on the cold-rolled steel sheet.
11 is a flowchart showing the flow of the surface treatment of the metal material according to one embodiment of the present invention.
12 is a schematic view showing one configuration example of an apparatus used in a surface treatment method of a metal material according to one embodiment of the present invention.
13 is a SEM photograph showing the surface of the surface-treated SUS316L stainless steel.
14 is a view showing a state in which distilled water is dropped on the surface after the water-repellent treatment is performed on the surface of the stainless steel shown in Fig. 13 in the lateral direction.
15 is a schematic diagram showing a configuration of a surface treatment apparatus for a conductive material according to one embodiment of the present invention.
16 is a schematic view showing a modified example of the surface treatment apparatus shown in Fig.
17 is a schematic view showing a modification of the surface treatment apparatus shown in Fig.
Fig. 18 is a view showing a configuration of an opening portion. Fig.
19A is a diagram showing a secondary electron image at the left side in the longitudinal direction of the opening portion when 150 V is applied between the anode electrode and the cathode electrode.
FIG. 19B is a diagram showing a secondary electron image at the center in the longitudinal direction of the opening portion when 150 V is applied between the anode electrode and the cathode electrode. FIG.
19C is a view showing a secondary electron image in the right side portion in the longitudinal direction of the opening portion when 150 V is applied between the anode electrode and the cathode electrode.
Fig. 20 is a view showing the appearance of the cathode electrode after the openings have been processed to have dimensions of 5 mm x 5 mm and 5 mm phi.
21 is a view showing an SEM image of the surface of the cathode electrode after the size of the opening is treated to 5 mm ?.
22 is a view showing an SEM image of a surface of a negative electrode not subjected to surface treatment.

[Metal material]

Figs. 1A and 1B are a plan view showing the configuration of a metallic material according to an embodiment of the present invention, and Fig. 1A is a sectional view taken along the line A-A in Fig. 1A. 1A and 1B, a metallic material 1 according to an embodiment of the present invention comprises a base material 2 and a protruding portion 3 as a modified layer formed on the surface of the base material 2. The substrate 2 is formed of a metal material. Examples of the metal material include alloy steels including stainless steel, steel such as cold rolled steel sheets containing Fe and C and optionally a trace amount of alloy elements of about 3 mass% or less, soft steel sheets, high strength steel sheets with a tensile strength of 2 GPa, hot rolled steel sheets Can be exemplified. The shape of the substrate 2 is not particularly limited, and a shape such as a plate shape, a rod shape, a line shape, or a pipe shape can be used. The base material 2 may be a plurality of members welded. When the base material 2 is in the form of a plate, its thickness is not limited, and a metal foil of 100 m or less and a thick steel plate of 3 mm or more in thickness can be used.

The protrusions 3 are formed by a microstructure protruding from the surface of the base material 2 having an average diameter R of 1 μm, preferably 500 nm or less as viewed in a direction perpendicular to the surface of the base material 2. 2 is a scanning electron microscope (SEM) photograph showing an example of a protrusion formed on the surface of a cold-rolled steel sheet. In the drawing, the protrusion 3 is indicated by an arrow. The protrusions 3 were made of a cold-rolled steel sheet and a platinum electrode as cathode and anode electrodes, respectively, with a concentration of 0.3 mol / L K ₂ CO ₃ In an aqueous solution at 135 V for 30 minutes. 3, the average diameter R of the projections 3 when viewed in a direction perpendicular to the surface of the cold-rolled steel sheet is a circle C (see Fig. 3) having an area equal to the area surrounded by the contour of the projections 3 , And calculating the diameter R of the circle C was obtained. By forming three or more protrusions 3 on an average in the range of 10 mu m < ^{2 &} gt ;, the light emitting property and the hydrophilic property can be imparted to the surface of the substrate 2. [ By increasing the hydrophilic property, it becomes difficult to form a droplet on the metal surface. As a result, various applications such as a light reflecting plate which has a cleaning function that does not easily contaminate organic matters and the like and which is less likely to deteriorate the reflection strength can be expected. The in-plane distribution of the protruding portions 3 is not limited, but it is advantageous in manufacturing to have no specific periodicity. For example, in order to manufacture a surface having periodicity in the shape of a row, the protruding portion 3 requires an excessive process, which is disadvantageous in manufacturing.

As shown in Fig. 4, when the projecting portion 3 has a 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, that is, a constriction structure, 2) and the internal voids are apparently large. Therefore, the hydrophilic properties and the like which are influenced by the specific surface area can be further improved. The protruding portion 3 having a constriction structure has an effect of imparting a chemical reaction on the surface or a promoting function thereof to the surface of the base material 2 or improving the adhesion with the thin film layer formed on the surface of the base material 2 You can expect. For this reason, it is preferable to form one or more protrusions 3 having a constriction 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, within a range of 10 mu m < ² > Since the hydrophilic property is higher as the specific surface area is larger, it is advantageous when the projection size is smaller and the number of projections is larger, and on the surface having the projected projection structure, the specific surface area is further increased.

The protruding portion 3 having a constriction structure can be obtained by [1] preparing a section sample of the surface of a metal material by a FIB (Focused Ion Beam) method or the like, and observing the section sample with an SEM or a transmission electron microscope , [2] a method in which a metal material is inclined and observed with an SEM. 5 is an SEM photograph showing an example of the projecting portion 3 having a constriction structure formed on the cold-rolled steel sheet. This is an image obtained by inclining the sample by 70 degrees. 6 is a cross-sectional TEM photograph showing an example of the protruding portion 3 having a constriction structure formed on the cold-rolled steel sheet. The protruding portion having the constriction structure is formed so that the outer diameter Lrmin of the base portion 3a is 90% or less of the outer diameter Lrmax of the distal end portion 3b, preferably, as shown in the following Expression (1) Means that the outer diameter Lrmin of the base portion 3a is 80% or less of the outer diameter Lrmax of the distal end portion 3b. In the example shown in Fig. 5, the value of Lrmin / Lrmax was 0.38, and in the example shown in Fig. 6, the value of Lrmin / Lrmax was 0.62. The outer diameter Lrmax of the base portion 3a refers to the minimum outer diameter of the base portion 3a when the base portion 3a is viewed in a direction perpendicular to the surface of the metal material base, Quot; refers to the maximum outer diameter of the tip portion 3b when viewed in a direction perpendicular to the surface of the substrate.

 [Formula 1]

 [Formula 2]

The surface of the base material 2 is provided with recesses having an average diameter of 1 탆 or less, preferably 500 nm or less as viewed in a direction perpendicular to the surface of the base material 2 in addition to the projections 3 desirable. By forming the recessed portion in addition to the protruding portion 3, the surface area of the metal material can be further increased, so that the light emitting property and the hydrophilic property of the surface of the metal material can be further improved. In addition, since the concave portion exists in addition to the convex portion, the lubricating oil and the functional liquid can be held longer and longer, and new functions can be imparted to the surface of the base material 2.

7 and 8 are SEM photographs showing an example of a recess formed on the surface of stainless steel. Fig. 7 shows a state in which the metal material is observed just above the surface of the metal material, and Fig. 8 shows a state in which the metal material is observed by tilting the metal material at 60 degrees. 7 and concave portion 8 shown in Fig. SUS430 stainless steel, and a platinum electrode to each of the cathode electrode and the anode electrode of the concentration 0.1mol / L K ₂ CO ₃ In an aqueous solution at 115 V for 30 minutes. Arrows in the drawing indicate concave portions. 7 and 8, recesses having a size of about 200 nm to 500 nm are formed all over the surface of the stainless steel.

The material forming the protrusions 3 may have the same composition as the base material 2, may be of different composition, and may be used in accordance with the purpose. 9 is a cross-sectional TEM photograph showing an example of the protruding portion 3 having a composition different from that of the base material 2. In the example shown in Fig. 9, the substrate 2 is made of SUS316 stainless steel, but the Cr concentration in the projections 3 is smaller than the Cr concentration in the substrate 2. [ According to this structure, it is expected that the catalytic function of Ni can be more effectively utilized while taking advantage of the advantage of SUS316 stainless steel. For example, there is a possibility that it can be used as a steam reforming catalyst containing Ni as an effective component as it is. In this case, since Cr is known to lower the catalyst performance, it is expected that the influence of Cr can be reduced. Further, the projecting structure of the present invention is excellent in heat exchange property because it has a large specific surface area. This is also advantageous as a catalyst reaction substrate.

The substrate 2 and the protruding portion 3 are preferably continuous. When the substrate 2 and the protrusion 3 are continuous, the strength of the protrusion 3 can be increased. 10 is a cross-sectional TEM photograph showing a state in which protrusions are continuously formed on the cold-rolled steel sheet. Analysis of the crystal orientation with respect to the region R1 of the protruding portion 3 and the region R2 of the base material 2 was carried out, though not shown. As a result, the protruding portion 3 was a single crystal and had substantially the same crystal orientation as the base material 2. This continuous structure is effective even when it is stable to mechanical action or chemical action, and in addition to the one in which the protruding portion 3 is difficult to fall off, it is not desired to use a different material or a different kind of element in the protruding portion 3. This continuous structure can be formed by using a steel material or a metal having a small content of an easily oxidizing alloy element (for example, Cr) as the base material 2.

An example of a method for producing the metal material 1 having such a structure can be produced by using a discharge in an electrolytic solution. More specifically, a DC voltage of about 60 to 140 V is applied to the electrode in an electrolytic solution using the material to be treated and an inert metal such as platinum as a cathode electrode and an anode electrode, respectively. Although the range of the applied voltage differs depending on the material to be treated, it can be easily determined while confirming the surface structure of the material to be treated by SEM. By changing the processing time or the applied voltage within a suitable range, the average diameter of the protrusions can be controlled. Specifically, in the case of the same material, the larger the applied voltage, the longer the processing time, the larger the average diameter of the protrusions, the deeper the position from the electrolyte solution surface.

However, when the applied voltage reaches a value at which the applied voltage becomes a completely plasma state, the surface is excessively melted or oxidized in the case of iron or stainless steel, and a fine projection structure is hardly formed. In order to provide a constriction structure, it is necessary to select a condition having a high discharge energy density within a range where the surface is not excessively melted or oxidized. For example, it is effective to set the applied voltage to be slightly higher or reduce the area to be processed so that the electric field is concentrated. Even in this case, preferable conditions can be determined by comparing the result of observing the treated surface with the SEM with the treatment conditions. 9 can be formed by setting the discharge voltage to a slightly higher value. In addition, a protruding structure may be prepared, and a new element may be added to the surface by continuously supplying the element in the solution. The " completely plasma state " indicates a state in which luminescence mixed with orange color or orange luminescence mainly covers the surface of the cathode during discharge.

[Example 1]

A soft cold-rolled steel sheet (CRS, size 2 mm x 20 mm x 0.7 mm) and Pt were used as a cathode electrode and an anode electrode, respectively, and K ₂ CO ₃ Was immersed in an aqueous solution, and a different electrification voltage was applied to the cathode electrode and the anode electrode to prepare a sample. Then, the surface of the soft rolled steel sheet after the energization was observed by SEM, and the average diameter and density of protrusions formed on the surface were evaluated. At that time, in order to observe how the treatment differs according to the depth from the liquid surface of the aqueous solution, samples were cut out from the soft cold-rolled steel sheet at portions where the depth from the liquid surface was different for some samples, and surface observation was performed. The average diameter of the protrusions is an average value of the diameters of twenty protrusions arbitrarily selected from a range of arbitrarily selected 12 占 퐉 占 9 占 퐉. The density is determined by dividing the number of protrusions within the above range by 108 占 퐉 ² (= 12 占 퐉 占 9 占 퐉) 10 mu m < ² > to obtain the number of protrusions per 10 mu m < ^{2 &} gt ;. The evaluation results are shown in Table 1 below. The sample of Experiment No. 1-7 shown in Table 1 is a soft cold-rolled steel sheet before energization in the aqueous solution. As apparent from the comparison of the samples of Experiments Nos. 1-1 to 1-6 and the sample of Experiment No. 1-7 shown in Table 1, it was confirmed that the modified layer having the projections according to the present invention could be obtained by the energization treatment . It has also been confirmed that by reducing the applied voltage, the average diameter of the protrusions can be reduced and the density of the protrusions can be increased. It was also confirmed that the average diameter of the protrusions can be reduced and the density of protrusions can be increased by shortening the distance from the liquid surface to the treatment surface as in the samples of Experiments Nos. 1-6.

 [Table 1]

 [Example 2]

SUS316 stainless steel (size 25㎜ × 2.5㎜ × 0.8㎜) and concentration by the Pt in each of the cathode electrode and the anode electrode of 0.3mol / L K ₂ CO ₃ Was immersed in an aqueous solution, and a different electrification voltage was applied to the cathode electrode and the anode electrode to prepare a sample. Then, the surface of the SUS316 stainless steel after the energization was observed by SEM, and the average diameter and density of the protrusions formed on the surface were evaluated in the same manner as in Example 1. [ At that time, in order to observe how the treatment differs according to the depth from the liquid surface of the aqueous solution, samples were cut out from the soft cold-rolled steel sheet at portions where the depth from the liquid surface was different for some samples, and surface observation was performed. In addition, the photoluminescence of the surface of the SUS316 stainless steel after energization was measured. The measurement was carried out using an FP6200 manufactured by JASCO Corporation, with an initial wavelength of 350 nm, an end wavelength of 600 nm, and an excitation wavelength of 435 nm. Concretely, in the optical luminescence spectrum obtained from the surface of the stainless steel after energization, an emission peak centered at around 430 nm in wavelength, which is not visible in the optical luminescence spectrum obtained from the stainless steel surface before energization, was confirmed. Thus, in this embodiment, the intensity of the luminescence peak was measured in the luminousness measurement. The height of the luminescence peak in Experiment No. 2-5 in which the maximum luminescence intensity was obtained in this example was 10, and the height of luminescence peak in Experiment No. 2-7 in which no luminescence peak corresponding to the untreated was observed was evaluated as 0 . The evaluation results are shown in Table 2 below. As shown in Table 2, the stainless steel surface (samples of Experiments Nos. 1-2 to 2-5) having the protrusions according to the present invention was a stainless steel surface having no untreated protrusions (Sample of Experiment No. 2-7 ), Or the sample of Experimental Nos. 2-6 having protrusions far exceeding 1000 nm. The luminescence characteristics become larger as the size of the protrusions becomes smaller, and especially the luminescence characteristics are obtained when the average diameter of the protrusions is 500 nm or less. From these results, it is expected that the stainless steel having the protrusions according to the present invention can be used as a metal material for a display element or a device using light in a visible light region.

 [Table 2]

[Example 3]

SUS316 stainless steel (thickness 1 mm x width 2.5 mm x length 30 mm) was used. The surface was mirror-polished with a Dia-Lap ML-150P. This stainless steel and Pt were used as a cathode electrode and an anode electrode, respectively, and a K ₂ CO ₃ And the sample was immersed in 300 cm 3 of an aqueous solution and energized for 15 minutes to the negative electrode and the positive electrode under different energizing voltages. After the experiment, the electrode (SUS316 stainless steel) was thoroughly rinsed with distilled water and sufficiently dried to conduct contact angle measurement experiments on the surfaces of three portions 30 mm deep, 28 mm wide and 26 mm deep from the liquid surface. One liter of distilled water (manufactured by Wako Pure Chemical Industries, Ltd.) was dropped by a micropipette, and each droplet was photographed by a camera (Canon EOS Kiss X2) from the side, and the height of the droplet h and the contact length l were measured and the respective contact angles? _R were calculated from? _R = 2tan ^{- 1} (2h / l) to calculate average values and the contact angles at 30 mm depth from the liquid surface were determined.

After the contact angle measurement experiment was completed, the sample was thoroughly dried and the average diameter and density of the protrusions formed on the surface were evaluated in the same manner as in Example 1. [ In order to evaluate to what extent the surface area of the obtained sample is increased with respect to the smooth surface, the surface area of the sample when the surface area of the smooth surface is 1 is calculated as the specific surface area based on the following assumptions . That is, assuming that the hemispherical protrusion having the average diameter obtained in the above is present on the smooth surface at the density obtained above, how many times as many times as the smooth surface is calculated is calculated. The results are shown in Table 3 below. As shown in Table 3, the examples within the scope of the present invention are samples (Experiment No. 3-1) which do not have the modified layer of the present invention in an untreated state, or samples in which the property of the modified layer deviates from the scope of the present invention The contact angle is smaller and the hydrophilic property is improved compared to the case of.

 [Table 3]

[Example 4]

A soft cold-rolled steel sheet (size: 1.5 mm x 20 mm x 0.7 mm) and Pt were used as a cathode electrode and an anode electrode, respectively, with a concentration of 0.3 mol / L K ₂ CO ₃ Immersed in an aqueous solution, and energized for 30 minutes with a negative electrode and a positive electrode at an energizing voltage of 110 V to prepare a sample. In this embodiment, the width of the sample is set to 1.0 mm, which is different from that of Examples 1 and 2, in order to concentrate the electric field. After the energization, the contact angle of one portion was measured in the same manner as in Example 3 with respect to the depth of 15 mm from the liquid surface. The result was a contact angle of 45 [deg.]. The surface of the same portion was observed by SEM, and the average diameter and density of the protrusions formed on the surface were evaluated in the same manner as in Example 1. [ A representative SEM photograph is shown in Fig. As a result of the evaluation, the average diameter of the projections viewed from above was 350 nm. The density of the protrusions having the constriction structure was evaluated. The density of projections having a confinement structure count the number of protrusions having a confinement structure in which the same parts and portions mentioned the average diameter and density of the protrusions (range), in the same manner as the density of protrusions, the average number per 10㎛ ² Respectively. As a result, it was confirmed that there were three on average.

[Example 5]

A soft cold-rolled steel sheet (size: 1.5 mm x 20 mm x 0.7 mm) and Pt were used as a cathode electrode and an anode electrode, respectively, with a concentration of 0.3 mol / L K ₂ CO ₃ Immersed in an aqueous solution, and energized for 10 minutes with a negative electrode and a positive electrode at an energizing voltage of 95 V to prepare a sample. After the energization, the contact angle of one portion was measured in the same manner as in Example 3 with respect to the depth of 15 mm from the liquid surface. The result was a contact angle of 60 °. The contact angle was measured, and the surface of the same portion was observed by SEM. The average diameter and density of protrusions formed on the surface and the density of protrusions having a constriction structure were evaluated in the same manner as in Example 1. As a result of the evaluation, it was confirmed that the average diameter of the protrusions viewed from above was 350 nm, and the average number of protrusions having a constriction structure was within 10 탆 ² .

[Example 6]

6% by mass C-2% by mass Si-2% by mass Cr steel was subjected to rolling processing and the Vickers strength of 25 g in cross section was evaluated. As a result, it was confirmed that the steel was 900 and the super high strength steel of 2 GPa class. This steel material was cut into a size of 1 mm x 20 mm x 0.7 mm, and Pt was used as a cathode electrode and an anode electrode, respectively, and K ₂ CO ₃ And an electric current was applied to the cathode electrode and the anode electrode for 30 minutes at an energizing voltage of 110V. After energization, the surface of the soft rolled steel sheet at a depth of 18 mm from the liquid surface was observed by SEM, and the density of protrusions having an average diameter and a constriction structure formed on the surface was evaluated. As a result of the evaluation, it was confirmed that the average diameter of the protrusions viewed from above was 400 nm, and ^two protrusions having a constriction structure were present in an average of 10 탆 ² .

[Surface Treatment Method of Metal Material]

11 is a flowchart showing the flow of the surface treatment of the metal material according to one embodiment of the present invention. 12 is a schematic view showing one configuration example of an apparatus used in a surface treatment method of a metal material according to one embodiment of the present invention. As shown in Fig. 11, in the surface treatment of the metallic material, which is one embodiment of the present invention, the object to be treated as the cathode material, which is a metallic material, and the anode electrode are immersed in the electrolytic solution, A voltage is applied to form a fine structure on the surface of the material to be treated (step S1). 12, the anode electrode 13 and the material to be treated 14 are immersed in the electrolytic solution 12 in the vessel 11, and the power source 16 (for example, To form the microstructure on the surface of the material to be treated 14 by applying a voltage to the anode electrode 13 and the material 14 to be treated.

The surface of the material to be treated 14 is excessively etched when the surface treatment of the material 14 to be treated is conducted and the surface of the material 14 to be treated is excessively etched, It is a solution which adheres to or precipitates on the surface of the treatment material 14 or hardly forms a precipitate. The electrolytic solution of the electrolytic solution 12 may be an aqueous solution of potassium carbonate (K ₂ CO ₃ ), sodium carbonate (Na ₂ CO ₃ ), sodium hydrogen carbonate (NaHCO ₃ ), ammonium carbonate ((NH ₄ ) ₂ CO ₃ ) 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 and potassium salt of the sulfuric acid in sulfuric acid , Sodium salt of citric acid such as ammonium salt of sulfuric acid, sodium salt of nitric acid, potassium salt of nitric acid, ammonium salt of nitric acid and sodium citrate (NaH ₂ (C ₃ H ₅ O (COO) ₃ ), potassium salt of citric acid Ammonium salts, nitric acid, hydrochloric acid, and the like.

The electrolytic solution 12 can have any pH and concentration as long as it can modify the surface of the material 14 to be treated. For example, when an aqueous potassium carbonate solution is used as the electrolytic solution 12, the concentration thereof is not particularly limited and may be 0.001 mol / L or more, and more preferably 0.005 mol / L or more. If the concentration of the electrolytic solution 12 is too low, it may become difficult to maintain a desirable discharge state when a voltage is applied between the anode electrode 13 and the material 14 to be treated. The upper limit of the concentration of the electrolytic solution 12 is not particularly specified, but may be 0.5 mol / L or less, for example. The pH of the electrolytic solution 12 can be set to any value as long as it does not cause excessive corrosion or etching of the electrode. For example, the pH may be 10 to 12.

The anode electrode 13 is formed of a material that is thermally and chemically stable at the time of discharge. As the anode electrode 13, Pt, Ir, graphite and the like can be exemplified.

The material to be treated 14 is not particularly limited as long as it is a metal material. As the steel material, a cold rolled steel sheet, a hot rolled steel sheet, a casting material, and a workpiece (including welding) may be used. The steel type is not particularly limited, and carbon steel, low alloy steel, stainless steel, or the like can be used. Also, electroplated steel sheets including an electrogalvanized steel sheet may be used. The shape of the material to be treated 14 is not particularly limited, and a plate, a line, a rod, a pipe, or a machining part can be used. The material to be treated 14 needs to be immersed in the electrolytic solution 12 and must be at least 1 mm larger than the liquid level.

The discharge condition may be a range from a partial plasma state where unevenness is formed on the surface of the material 14 to a complete plasma state. However, it is necessary to perform the process at a voltage range lower than the voltage at which the material to be treated 14 is melted. Concretely, when the discharge voltage is being raised, light emission which can be visually confirmed in a dark place is started, and the state from the voltage indicating orange light emission to the moment immediately before the entire material is heated up. 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 14 to be treated is 1 mm x 1 mm x 20 mm. This voltage range is applicable to most steel materials including alloy steels such as stainless steel. However, since the voltage range varies depending on the type and arrangement of the material to be treated 14, the surface of the material 14 to be treated after changing the voltage condition may be determined by observing with SEM.

The discharge voltage is a necessary condition to form a fine protrusion on the surface of the steel material. Since the fine protrusions are not formed on the surface at a voltage lower than the lower limit, it can be determined by confirming the presence or absence of fine protrusions by SEM. If the upper limit is exceeded, the surface to be treated is dissolved. Therefore, the upper limit can be determined as the voltage dissolving the surface. However, it is more preferable not to oxidize the surface. In this case, the voltage at which the surface is oxidized can be easily determined by irradiating the SEM with an energy dispersive X-ray spectroscope (EDS) attached to the SEM. When oxygen is detected with the same X-ray intensity as the oxide of the material to be treated 14, it can be determined that the surface is oxidized. The X-ray intensity of the oxygen standardized by the intensity of the L line of Fe in the oxide of the material to be treated 14 (for example, the oxide of Fe in the cold-rolled steel sheet or the low alloy steel) ), The X-ray intensity normalized by the Fe-L ray intensity of oxygen needs to be 1/3 or less. The above surface irradiation is carried out by changing the voltage and discharging for 30 minutes, taking out the material to be treated 14, washing it with water, drying it, introducing it into an SEM and observing it.

Discharge processing time is required for 3 seconds or more. However, the discharge treatment time can be as long as 60 minutes, for example. However, if the discharge treatment time is too long, the treatment material 14 may be worn out, so that the treatment time of 30 minutes or more is not preferable. It can be seen that the larger the applied voltage is in the preferable voltage range, the higher the water repellency of the surface after the final process. Therefore, the most preferable condition is to select an applied voltage close to the upper limit of the preferable condition range.

Fig. 13 shows an example of processing a SUS316L stainless steel sheet having a thickness of 0.8 mm. The SUS316L stainless steel sheet was cut into 2 mm wide and 30 mm long, and conduction was carried out by the copper wire to form a cathode electrode. The positive electrode was formed by bending a 50-cm-long Pt wire so as not to contact each other and forming it into a plane shape. SUS316L Stainless steel plate and the copper wire are heat-pressed with a heat-resistant resin, and the length of 20 mm of the electrode is immersed in the electrolytic solution so that the copper wire does not contact the electrolytic solution. The electrolytic solution contained K ₂ CO ₃ at a concentration of 0.1 mol / L An aqueous solution was used and the discharge was carried out for 10 minutes by setting the voltage to 130 V, and immediately after the completion of the water washing.

As a result, as shown in Fig. 13, it was confirmed that a fine protrusion structure with an average diameter of 1 占 퐉 or less was formed on the surface of the SUS316L stainless steel plate. It was also confirmed by elemental analysis by EDS that the surface of the SUS316L stainless steel sheet was not oxidized. Further, at an applied voltage exceeding 160 V, the tip of the SUS316L stainless steel plate was fused. Therefore, the upper limit value of the applied voltage was found to be 160V. Elemental analysis by EDS confirmed that the surface of the SUS316L stainless steel sheet was not oxidized at an applied voltage of 140 V or lower. Therefore, it was found that the preferable upper limit value of the applied voltage in this test condition and the test material was 140 V. On the other hand, the lower limit value of the applied voltage was determined to be 80 V from the presence or absence of the projection structure. The most desirable applied voltage could be determined as 140V.

Returning to Fig. After the microstructure is formed on the surface of the material to be treated 14 as described above, the material to be treated 14 is taken out from the electrolytic solution 12 and the material 14 to be treated is cleaned (step S2 ). Finally, water-repellent treatment is performed on the surface to be treated of the material 14 to be treated which has been cleaned (step S3). The cleaning method is performed for the purpose of removing the electrolytic solution on the surface, and a method of immersing in pure water or spraying. If it is not limited to pure water and does not destroy the fine structure of the surface, a weak acid or an alkali solution may be used. At that time, it is also possible to apply electrolysis. It may be dried after the washing, and may proceed to the next step without drying by the subsequent water repellent treatment. The water-repellent treatment method may be a method of applying a water-repellent spray or a method of adsorbing an organic matter having a water-repellent function, such as a fluorine resin, in a liquid phase or a vapor phase. In the present embodiment, by spraying the surface of the material to be treated 14 with the Nanopro (component: fluorocarbon resin, silicone resin) manufactured by Collonil and drying for 12 hours or more, ) Was subjected to water-repellent treatment. Thus, a series of surface treatments are terminated.

Fig. 14 is a result of observing the state of the sample surface shown in Fig. 13 in a state in which water-repellent treatment is performed and distilled water is dropped in the lateral direction. As a result of observation, the contact angle of water was measured at 152 °, and it was confirmed that super water repellency was realized. The contact angle of water in the sample in which the water repellent treatment was not performed was 51 °. The same water-repellent treatment was applied to the material not subjected to the plasma discharge in the solution, and as a result, the contact angle of water was 125 占. Therefore, it has been confirmed that both plasma discharge and water-repellent treatment are required in order to obtain a super water-repellent surface.

[Example 1]

A commercially available stainless steel SUS316L steel sheet having a thickness of 0.8 mm was cut to a width of 2 mm and a length of 30 mm and was degreased by dipping in diluted hydrochloric acid, and conduction was conducted through the copper wire to form a cathode electrode. The positive electrode was formed by bending a 50 mm long Pt wire of 0.5 mm phi so as not to contact each other and forming it into a plane shape. The connecting portion between the cathode electrode and the copper wire was heat-pressed with a heat-resistant resin so that the copper wire was not brought into contact with the electrolytic solution so that a length of 20 mm of the electrode was immersed in the electrolytic solution. The electrolytic solution contained K ₂ CO ₃ at a concentration of 0.1 mol / L Aqueous solution, the applied voltage was set within a range of 60 to 180 V, the discharge was carried out for 10 minutes, and immediately after completion, it was rinsed with pure water and dried. Thereafter, nanoproducts made by Coronel Corporation were sprayed onto the surface of the treated material and dried for 12 hours or longer to perform water repellency, and the wettability was examined. The wettability was measured by using a micropipette to distill the distilled water six times in 1 mu m distilled water so that the distilled water was equally spaced on the electrode surface, taking a picture side by side using a digital camera EOS Kiss X2 manufactured by Canon Inc., , And an average of 6 places. 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, it was confirmed that all of the inventive examples exhibited a higher contact angle than the untreated materials. Particularly in Inventive Examples 3, 4, and 5 in which the applied voltage is in the range of 120 to 140 V, super-water repellency of 150 ° or more is achieved, and Example 5 in which the applied voltage is 140V shows 153.6 ° .

 [Table 4]

[Surface Treatment Apparatus for Conductive Material]

DISCLOSURE OF THE INVENTION The inventors of the present invention have found that it is possible to efficiently produce a conductive material having a nano-level microstructure on the surface at low cost and to solve the problem of the possibility of the use of the submerged plasma discharge which was conventionally considered impossible to form a nano- The study was also included in the study. As a result, the inventors of the present invention have found that a nano-level microstructure can be formed on the surface of a conductive material by partially discharging an in-situ plasma discharge using a conductive material as a cathode electrode. The inventors of the present invention have studied a method of forming a nano-level microstructure in a specific portion of the surface of a conductive material and have found that a portion to be treated of the conductive material is immersed in the electrolyte solution together with the anode electrode, It is found that a nano-level microstructure can be formed in a specific portion of the surface of the conductive material by providing a shield having openings in between. Further, the inventors of the present invention have found that by changing the relative positions of the openings of the shield and / or the anode electrode and the conductive material, the nanostructures can be formed continuously or discretely on the surface of the conductive material.

15 is a schematic diagram showing a configuration of a surface treatment apparatus for a conductive material according to one embodiment of the present invention. 15, a surface treatment apparatus 21 for a conductive material, which is an embodiment of the present invention, includes a reforming treatment cell 22, an electrolytic solution 23 stored in the reforming treatment cell 22, And a DC power source 26 connected to the anode electrode 24 and the cathode electrode 25. The anode electrode 24 and the cathode electrode 25 are made of a material having conductivity, . The cathode electrode 25 is covered by a box 27 made of an insulating material and the box 27 is provided with an opening 28 for defining a portion to be processed of the cathode electrode 25. The box 27 is disposed such that the upper portion thereof is positioned higher than the liquid level of the electrolytic solution 23. The upper portion of the box 27 may be open or may have a hole through which a conductor for connecting the cathode electrode 25 and the DC power source 26 is passed.

Cells made of a well-known material, such as glass, Teflon (registered trademark), or polyethyl ether ketone (PEEK), which are made of a stable material for the electrolytic solution 23, can be used as the reforming treatment cell 22. As the reforming treatment cell 22, a cell made of ceramics may also be used. It is also possible to use a metallic cell in the surface treatment apparatus 21 shown in Fig. 16 to be described later.

The electrolytic solution 23 has electrical conductivity and also applies a voltage between the anode electrode 24 and the cathode electrode 25 to form a nano-level microstructure on the surface to be treated (the surface of the cathode electrode 25) , The surface to be treated is excessively etched or adhered to or deposited on the surfaces of the anode electrode 24 and the cathode electrode 25, or a solution difficult to form a precipitate. Examples of the electrolytic solution 23 include potassium carbonate (K ₂ CO ₃ ), sodium carbonate (Na ₂ CO ₃ ), sodium hydrogencarbonate (NaHCO ₃ ), ammonium carbonate ((NH ₄ ) ₂ CO ₃ ) (LiOH), magnesium hydroxide, sodium hydroxide _{(NaOH), (Mg (OH) 2)} , potassium hydroxide (KOH), ammonium hydroxide (NH ₄ OH), sodium chloride (NaCl), potassium chloride (KCl), magnesium chloride (MgCl ₂₎ , Ammonium chloride (NH ₄ Cl), lithium sulfate, sodium sulfate, magnesium sulfate, potassium sulfate, ammonium sulfate, lithium nitrate, sodium nitrate, magnesium nitrate, potassium nitrate, ammonium nitrate, lithium Citrate of sodium such as sodium citrate (NaH ₂ (C ₃ H ₅ O (COO) ₃ ), citrate of magnesium, citrate of potassium, citrate of ammonium, sulfuric acid, nitric acid, hydrochloric acid, and citric acid An aqueous solution containing at least one species selected may be used.

The electrolytic solution 23 can be set to any pH and concentration as long as the surface treatment of the cathode electrode 25 can be performed. For example, when an aqueous potassium carbonate solution is used as the electrolytic solution 23, But is not limited to, 0.001 mol / L or more, and more preferably 0.005 mol / L or more. If the concentration is too low, it may become difficult to maintain a desirable discharge state when a voltage is applied between the anode electrode 24 and the cathode electrode 25. [ The upper limit of the concentration is not particularly specified, but may be 0.5 mol / L or less, for example. The pH of the electrolytic solution 23 can be set to any value as long as it does not cause excessive corrosion or etching of the electrode. For example, the pH of the electrolytic solution 23 may be 5 to 12.

The positive electrode 24 is ionized and dissolved in the electrolytic solution 23 when a voltage is applied between the positive electrode 24 and the negative electrode 25 to form a nano-level microstructure on the surface to be treated, Is an insoluble anode electrode consisting of an electrode material that does not inhibit the formation of nanostructures in the nano-level microstructure. As the anode electrode 24, for example, a platinum (Pt) electrode, a palladium (Pd) electrode, an iridium (Ir) electrode, an electrode whose surface is coated with Pt, Pd or Ir or a graphite electrode can be used.

The cathode electrode 25 is an object to be treated whose surface is modified by application of a voltage, and is made of a conductive material (conductive material) such as a metal material or an alloy material. Examples of the material to be treated serving as the cathode electrode 25 include carbon steel, alloy steel, stainless steel, nickel and the like. The shape of the cathode electrode 25 (material to be processed) is not particularly limited, and may be a plate, a strip, or a part having a conductive material portion. The material to be treated may optionally be used as the cathode electrode 25 after its surface is polished by sandpaper or the like.

The DC power source 26 applies a voltage required for the modification treatment of the surface of the cathode electrode 25 which is the material to be treated, for example, between 60 V and 300 V, between the anode electrode 24 and the cathode electrode 25 . As the DC power source 26, a well-known power source can be used.

The cathode electrode 25 is covered by the box 27 as shown in Fig. 16, but the anode electrode 24 may be covered by the box 27 in which the opening 28 is formed. The box 27 having the opening 28 is not limited to the portion to be treated of the cathode electrode 25 but may be immersed in at least the electrolytic solution 23 of the cathode electrode 25, And the opening 28 for defining the portion to be treated of the cathode electrode 25 may be formed on a part of the heat resistant material.

The shape and size of the opening 28 are not particularly limited, and the box 27 may have a plurality of openings. In the case of providing a plurality of openings 28, the openings 28 are not limited to the same side of the cathode electrode 25. For example, the opening 28 may be provided on the front surface side and the back surface side of the cathode electrode 25. 18, an inclined portion 28a may be provided on the upper end (liquid level side) of the opening portion 28. [ By providing the inclined portion 28a, the gas generated from the portion to be treated can be efficiently discharged 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. [ The angle at which the cathode electrode 25 is provided may be perpendicular to the liquid level of the electrolytic solution 23, but the present invention is not limited thereto. A mechanism for supplying gas such as hydrogen, argon or water vapor to the surface of the cathode electrode 25 may be provided for the purpose of promoting the generation of plasma on the surface of the cathode electrode 25. [

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 material]

When the surface-modified conductive material is produced by using the surface treatment apparatus 21, the box 27 is first immersed in the electrolytic solution 23 stored in the reforming treatment cell 22, The surface of the cathode electrode 25 is subjected to the surface modification treatment by immersing the cathode electrode 25 in a spaced apart state. At that time, the cathode electrode 25 is immersed in the box 27 so that the portion to be treated is seen from the opening 28 of the box 27. [ The surface modification treatment of the cathode electrode 25 is performed on the portion exposed from the opening 28 side to the electrolytic solution 23 side. In the structure of the surface treatment apparatus 21 shown in Fig. 16, the anode electrode 24 is placed in the box 27, and the opening 28 of the box 27 is opposed to the portion to be treated of the cathode electrode 25 27). As the portion to be processed away from the opening 28 is farther away, the portion to be processed becomes larger than the opening portion. The distance (distance) to be processed between the opening 28 and the cathode electrode 25 is generally preferably 5 mm or less, more preferably 1 mm or less.

Next, a predetermined voltage is applied between the anode electrode 24 and the cathode electrode 25 to modify the surface of the cathode electrode 25 (surface modification processing step). The predetermined voltage is a voltage which can be determined in a preliminary experiment, and can be determined by 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. If there is no designation of the processing time, it may be executed for 15 minutes. The range for changing the voltage may be about 50 to 300V. Next, the treated surface was observed with an SEM, and a surface having a protrusion structure with an average size of 1 탆 or less was formed on the surface. The surface was not oxidized (except for the natural oxide layer having a thickness of several nanometers) And determines the condition. Whether or not the surface is oxidized can be confirmed by using the EDS in the SEM.

The voltage range varies somewhat depending on the type of the cathode electrode 25, but is in the range of 60 V to 300 V, preferably in the range of 80 to 180 V. The lower limit voltage corresponds to the voltage generated by the plasma. The upper limit voltage is determined by the fact that the surface is oxidized by the high temperature, or the surface melts and the fine protrusion structure disappears. As described above, a desirable voltage range can be determined. However, in the case of short-time processing or a large protrusion structure, a slightly higher applied voltage may be set.

Specific examples will be described. In this specific example, the surface modification treatment system shown in Fig. 15 was constructed using the stainless steel plate (SUS316) as the cathode electrode 25. The size of the opening 28 was 25 mm x 4 mm. Then, an aqueous solution of 0.1 mol / L potassium carbonate (K ₂ CO ₃ ) was supplied as electrolytic solution 23 for 15 minutes. The surface of the stainless steel sheet after the SEM treatment was observed, and the lower limit voltage was found to be 80V. It was also found that the upper limit voltage was 250V. The secondary electron images of the left portion of (a), the middle portion of (b), and the right portion of (c) in the longitudinal direction of the opening portion 28 when 150 V is applied between the anode electrode 24 and the cathode electrode 25 19a, 19b and 19c.

As shown in Figs. 19A, 19B and 19C, it was confirmed that a fine protrusion structure with a diameter of 1 mu m or less was formed on the surface of the stainless steel plate. In addition, since the same projecting structure is seen in the left side portion, the right side portion and the central portion in the lengthwise direction of the opening portion 28, it can be confirmed that appropriate processing is performed all over the opening portion. It was also confirmed that the lower the voltage in the preferable voltage range, the smaller the size of the projection structure and the larger the number of projection structures. Therefore, the applied voltage may be adjusted in accordance with the required surface characteristics. For example, when it is desired to obtain a light emitting property, it is preferable that the projection structure is smaller, so that the applied voltage may be set slightly lower.

It is presumed that the principle of formation of the fine protrusions is not clearly defined, but is formed by partial sub-plasma discharge 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, partial submerged plasma discharge does not sufficiently take place and fine protrusions are not formed. If the voltage is higher than the upper limit voltage, The surface of the cathode electrode 25 is melted, which is disadvantageous to the formation of the fine protrusions.

In the liquid-under-plasma discharge, when the temperature of the electrolytic solution 23 in the vicinity of the cathode electrode 25 locally becomes equal to or higher than the boiling point due to voltage application and a gas phase is generated in the vicinity of the cathode electrode 25, Is considered to be happening. For this reason, although the application of the voltage may be started from room temperature, it is more effective to perform the operation after the temperature of the entire electrolytic solution 23 or the vicinity of the cathode electrode 25 is set in the range of 80 캜 to 100 캜. This is because the temperature in the vicinity of the cathode electrode 25 can be efficiently raised to effectively cause the in-liquid plasma discharge. The voltage application time can be set to an arbitrary time, for example, 1 second or more and 30 minutes or less. The shorter the application time of the voltage is, the smaller the size of the fine protrusions to be formed. Therefore, the voltage application time may be appropriately selected depending on the desired surface shape and characteristics.

As apparent from the above description, according to this surface treatment method, the voltage applied between the anode electrode 24 and the cathode electrode 25 immersed in the electrolytic solution 23, without using an expensive apparatus and a high- It is possible to efficiently manufacture a conductive material having a nano-level microstructure on its surface at low cost. The conductive material having a nano-level microstructure on its surface can exhibit various functions due to its microstructure. The box 27 is fixed and the cathode electrode 25 is moved or the cathode electrode 25 is fixed and the box 27 is moved to move the box 27 to a larger area of the cathode electrode 25 Reforming can be performed. In addition, a continuous processed surface is obtained by continuously moving while being processed. It is also possible to attach discrete patterns by moving in a step shape or repeating movement and discharge. Particularly, in the surface treatment apparatus 21 shown in Fig. 16, it is not necessary to cover the cathode electrode 25 with the box 27, so that the cathode electrode 25 is made into a large sample and a band- It is possible to extend the method.

[Example 1]

A box 27 having openings (5 mm x 5 mm, 5 mm phi, 10 mm phi, 10 mm x 2 mm and 20 mm x 1 mm) having various sizes was prepared on an alumina plate having a thickness of 1.7 mm . As shown in Fig. 18, the upper end surface of the opening 28 was worked at an angle of 30 degrees. SUS316 stainless steel having a thickness of 1 mm was used as the cathode electrode 25, and K ₂ CO ₃ having a concentration of 0.3 mol / L was used as the anode electrode 24 And immersed in an aqueous solution to construct a surface modification treatment system as shown in Fig. A voltage was applied between the cathode electrode (25) and the anode electrode (24). Then, the surface of SUS316 stainless steel after voltage application was observed by SEM. 20 shows an example of a photograph of the appearance of the cathode electrode 25 after the opening 28 has been processed to have dimensions of 5 mm x 5 mm and 5 mm phi. The applied voltage is 160 V and the application time is 15 minutes. It was confirmed that the surface of the cathode electrode 25 was processed in the form of the opening 28 as shown in Fig.

An example of the SEM of the surface of the cathode electrode 25 after the opening 28 is processed to have a size of 5 mm? Is shown in Fig. As shown in Fig. 21, it was confirmed that a fine protrusion structure with a diameter of 1 m or less is formed on the surface of the cathode electrode 25, which is not present on the surface (see Fig. 22) It was also found that the microprojection structure could be formed at an applied voltage of 90 to 200 V even if the shape of the other opening portion 28 was used. This is presumably due to surface fusion. In addition, as a result of performing the uniform water repellent treatment on the entire surface of the cathode electrode 25 shown in Fig. 20, the water repellent performance was higher than that on the surface on which the surface treatment was not performed. In the experiment in which 170 V (application time is 15 minutes) was applied using a box 27 having openings 28 of 5 mmφ and 5 mm × 5 mm on both sides, the microprojection structure was observed on both sides by SEM observation And it was confirmed that the surface modification treatment can be carried out simultaneously at the front and back.

[Example 2]

The positive electrode 24 was bonded to the box 27 made of alumina (1.7 mm thick) provided with an opening 28 having a width of 1 mm (longitudinal direction) × 20 mm (transverse direction) using a stainless steel plate (SUS316) And a surface modification treatment system as shown in Fig. 16 was constructed. An arbitrary surface of the opening 28 was provided at a distance of 1 mm from the cathode electrode 25. The applied voltage between the electrodes was 140V and 220V. A voltage was applied between the electrodes for 5 minutes, and then the stainless steel plate was moved 5 mm upward (in the longitudinal direction), and a voltage was applied again for 5 minutes. The upward movement and the application of the voltage were repeated 10 times. Two experiments were carried out: the applied voltage between the electrodes was 140 V and 220 V. As a result, a stainless steel sheet having a region in which fine protrusion structures exist at intervals of 5 mm was obtained.

[Example 3]

The anode electrode 24 was covered with a box 27 made of alumina (thickness: 1.7 mm) provided with the Zn-plated steel sheet as the cathode and the opening portion 28 of 1 mm (longitudinal direction) × 20 mm A surface modification treatment system as shown in Fig. An arbitrary surface of the opening 28 was provided at a distance of 1 mm from the cathode electrode 25. The applied voltage between the electrodes was 120 V, and the Zn-plated steel sheet was moved downward (in the longitudinal direction) by 20 mm at a speed of 1 mm / minute while applying a voltage between the electrodes. A Zn-plated steel sheet having a surface area of 20 mm x 20 mm could be produced. As a result of the methylene blue discoloration reaction test on this surface, a remarkably high photocatalytic effect was obtained as compared with the surface on which no surface treatment was carried out.

[Example 4]

A commercially available cold-rolled steel sheet having a thickness of 0.8 mm was cut into a length of 80 mm and a width of 6 mm to form a negative electrode. And was bent in the width direction so that the longitudinal direction was an axis so that the cross-section in the width direction was machined to have an arc shape with a radius of curvature of 10 mm. A heat-resistant resin was applied to the surface of the cathode electrode 25 except for the connection with the electrode, and an opening 28 having a width of 2 mm and a length of 25 mm was formed on one side of the curved surface. And a voltage of 150 V was applied between the cathode electrode 25 and the Pt electrode. In either of the samples, a fine protrusion structure with an average diameter of 1 탆 or less was formed on the surface of the opening portion 28.

[Industrial Availability]

According to the present invention, it is possible to provide a metal material having new functions such as a hydrophilic property and a luminescent property.

According to the present invention, it is possible to provide a surface treatment method of a metal material and a method of manufacturing a water-repellent material based on a metal material, which can impart high water repellency to the surface of a metal material without requiring much labor and cost.

According to the present invention, there are provided a surface treatment apparatus and a surface treatment method of a conductive material which can perform a treatment over a large area of a predetermined place or surface of a surface and efficiently manufacture a conductive material having a nano- .

One; Metal material 2; materials
3; A protrusion 11; Vessel
12; Electrolytic solution 13; Anode electrode
14; (Cathode electrode) 15; ferry
16; Power supply 17; thermometer
21; A surface treatment device 22; Reforming treatment cell
23; Electrolytic solution 24; Anode electrode
25; Cathode electrode (material to be processed) 26; DC power
27; Box 28; Opening
28a; Inclined portion

Claims (19)

A metal material substrate,
And a modified layer formed on the surface of the metal material base,
Wherein the modifying layer has an average of at least 3 protrusions protruding from the surface of the metal material base having an average diameter of 1 占 퐉 or less as viewed in a direction perpendicular to the surface of the metal material base within a range of 10 占 퐉 ² ,
Wherein the reforming layer has a base portion protruding from a surface of the metal material base and a tip portion formed at an end of the base portion, wherein an average diameter when viewed in a direction perpendicular to the surface of the metal material base is 1 m or less An average of at least one projecting portion having a constriction structure whose outer diameter of the base portion is smaller than the outer diameter of the distal end portion within a range of 10 탆 ² ,
Wherein the metallic material comprises at least one of an alloy steel including stainless steel, a cold rolled steel sheet, a soft steel sheet, a high strength steel sheet having a tensile strength of 2 GPa or more, and a hot rolled steel sheet. The method according to claim 1,
Wherein an average diameter of the protrusions when viewed in a direction perpendicular to the surface of the metal material base is 500 nm or less. The method according to claim 1,
Wherein a position where the protrusion is formed does not have a periodicity in an in-plane direction of the metal material base. The method according to claim 1,
Wherein the modifying layer has a concave portion having an average diameter of 500 nm or less when viewed in a direction perpendicular to the surface of the metal material base. The method according to claim 1,
Wherein the metal material base is formed of an alloy steel. 6. The method of claim 5,
Wherein the metal material base is formed of a steel material. The method according to claim 1,
Wherein a composition of the metal material base and a composition of the projecting portion are different. The method according to claim 1,
Wherein the metal material base and the protrusions are continuously connected to each other. 9. A method of manufacturing a metallic material according to any one of claims 1 to 8,
A step of immersing the material to be treated as a cathode electrode made of a metal material having a surface to be treated and the anode electrode in an electrolytic solution;
Forming a microstructure on the surface to be treated by applying a voltage between the cathode electrode and the anode electrode in a range that does not oxidize or dissolve the material to be treated at 70 V or more;
Removing the object to be treated from the electrolytic solution and cleaning the object to be processed,
And performing a water repellent treatment on the surface to be treated of the washed material to be treated. 9. A method of manufacturing a metallic material according to any one of claims 1 to 8,
A step of immersing the material to be treated as a cathode electrode made of a metal material having a surface to be treated 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 not less than 70 V and not more than 200 V between the cathode electrode and the anode electrode,
Removing the object to be treated from the electrolytic solution and cleaning the object to be processed,
And performing a water repellent treatment on the surface to be treated of the washed material to be treated. 9. A method for producing a water-repellent material based on a metal material according to any one of claims 1 to 8,
A step of immersing a metal material and a cathode electrode as a cathode material having a surface to be treated in an electrolytic solution;
Forming a fine structure on the surface of the metal material, which is the material 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;
Removing the metal material from the electrolytic solution and cleaning the metal material,
And performing a water repellent treatment on the surface to be treated of the washed metal material. 9. An apparatus for manufacturing a metallic material according to any one of claims 1 to 8,
A cathode electrode made of an anode electrode and a metal material immersed and immersed in an electrolytic solution,
A shield member interposed between the anode electrode and the cathode electrode and having an opening portion defining a portion to be processed of the cathode electrode;
And a power source for applying a voltage between the anode electrode and the cathode electrode. 13. The method of claim 12,
And a mechanism for changing a position of the opening and / or a relative position of the anode electrode and the cathode electrode. 13. The method of claim 12,
Wherein the power source applies a voltage between 60 V and 300 V between the anode electrode and the cathode electrode. 13. The method of claim 12,
Wherein the shield is an insulating heat-resistant material having the opening covered with the surface of the cathode electrode. A method of manufacturing a metallic material, characterized in that the surface of a metallic material is modified by using the apparatus for manufacturing a metallic material according to claim 12. A method for producing a metallic material, characterized in that the surface of the metallic material is modified by using the apparatus for producing a metallic material according to claim 13. A method for producing a metal material, characterized by modifying the surface of a metal material by using the apparatus for producing a metal material according to claim 14. A method for producing a metallic material, characterized in that the surface of a metallic material is modified using the apparatus for producing a metallic material according to claim 15.

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