KR101404128B1 - Surface fabricating method of metal substrate and metal substrate with the surface fabricated by the method - Google Patents

Abstract

Provided is a method for machining a surface of a metal base material which is capable of quickly and easily machining the surface of the metal base material to an extremely hydrophilic or extremely water-soluble surface. A method for machining a surface of a metal substrate includes the steps of preparing a metal substrate, forming micrometer scale fine irregularities on the surface of the metal substrate through physical or chemical treatment, and forming a metal nano- To form a layer. The surface processing method of the metal substrate may further include forming a hydrophobic polymer layer on the metal nano-layer.

Description

TECHNICAL FIELD [0001] The present invention relates to a metal substrate, and more particularly, to a metal substrate having a surface processed by the method and a metal substrate having a surface processed by the metal substrate,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for machining a surface of a metal base material, and more particularly, to a method for machining a surface of a metal base material.

In general, the surface of a solid has a unique surface energy, which is the contact angle of the liquid to the solid when any liquid is in contact with the solid. If the contact angle is less than 90 °, the water droplets lose their shape and exhibit a hydrophilic property to wet the solid surface. On the other hand, if the contact angle is larger than 90 °, the water droplet shows hydrophobicity flowing without wetting the surface of the solid while maintaining the shape of the sphere.

Particularly, when the contact angle is smaller than 10 degrees, it is called an extremely hydrophilic surface, and when the contact angle is larger than 150 degrees, it is called a very small surface.

In order to change the contact angle of the solid surface, a micrometer or nano-scale concave-convex structure should be formed on the surface of the solid. Such a surface structure can be formed using a microelectromechanical system (MEMS), a coating, an anodic oxidation process, or the like.

However, in the case of microelectromechanical system process, it is difficult to process large area, there are restrictions on working environment and manufacturing machine, and manufacturing cost is limited. The coating process has a disadvantage in that it is relatively easy to treat a large area, but the bonding strength of the coating layer to the solid surface and the durability of the coating layer are weak. In addition, the anodizing process consumes a lot of electricity and can cause defects on the solid surface if the process steps are not kept constant.

The present invention relates to a method for machining a surface of a metal substrate which can simplify the manufacturing process and lower the production cost and which can quickly and easily process large and large area metal substrates into an extremely hydrophilic or low water- To provide a metal substrate having a high thermal conductivity.

According to an embodiment of the present invention, there is provided a method of machining a surface of a metal substrate, comprising the steps of: preparing a metal substrate; forming micrometer scale fine irregularities on the surface of the metal substrate by physical or chemical treatment; To form nanometer-scale metal nanocrystals to create an extreme hydrophilic surface.

The fine unevenness can be formed by any one of sandblasting, sandpapering, shot blasting, plasma etching, discharge processing, laser processing, acid etching or base etching.

The metal nano-layer may be formed by acid treatment or base treatment of the metal substrate. The acid treatment is carried out in at least one acid solution selected from hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid and acetic acid, and the base treatment is carried out in the presence of sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, copper hydroxide, ammonium hydroxide, Can be carried out in at least one base solution selected.

The metal nano-layer may be formed by acid treatment or base treatment of the metal substrate, followed by immersion in boiling water for 30 minutes to 24 hours.

A metal substrate according to an embodiment of the present invention is processed by the above-described method, and a metal nano-layer is formed on the surface of fine irregularities to realize an extremely hydrophilic surface.

According to another embodiment of the present invention, there is provided a method of machining a surface of a metal substrate, comprising the steps of: preparing a metal substrate; forming micrometer-scale fine irregularities on the surface of the metal substrate by physical or chemical treatment; Forming a nanometer-scale metal nano-layer on the surface, and forming a hydrophobic polymer layer on the metal nano-layer to create a microscopic surface.

The hydrophobic polymer layer includes at least one hydrophobic substance selected from a fluororesin, a fluorine-based silane coupling agent, a fluorine-based isocyanate compound, an alkane thiol, an organosilane compound, a fatty acid, an aromatic azide compound, .

The hydrophobic polymer layer may be formed by coating a hydrophobic material on the metal nano-layer, or may be formed by chemical bonding between the metal nano-layer and the hydrophobic material. The hydrophobic polymer layer may have a thickness ranging from 1 to 5 nm.

The metal substrate according to another embodiment of the present invention is processed by the above-described method, and the metal nano-layer and the hydrophobic polymer layer are laminated on the surface of the fine unevenness in order to realize a surface with a very small surface area.

The manufacturing process is simple, the manufacturing cost is low, and the metal substrate of large and large area can be quickly and easily processed into an extremely hydrophilic or micro-porous surface.

Fig. 1 is a process flow chart showing a surface machining method of a metal base according to the first embodiment of the present invention.
Fig. 2 is a schematic sectional view showing the surface state of the metal substrate in each step shown in Fig. 1. Fig.
3 is a scanning electron microscope (SEM) image showing the surface of a metal substrate on which fine irregularities have been formed by sandblasting.
4 is a scanning electron microscope (SEM) image showing the surface of the metal substrate on which the fine irregularities and the metal nano layer are formed.
5 is an enlarged photograph showing the contact angle test result of the liquid with respect to the metal substrate.
6 is a process flow chart showing a method of machining a surface of a metal substrate according to a second embodiment of the present invention.
7 is a schematic cross-sectional view showing the surface state of the metal substrate in each step shown in Fig.
8 is an enlarged photograph showing a contact angle test result of a liquid with respect to a metal substrate on which a hydrophobic polymer layer is formed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

FIG. 1 is a process flow chart showing a method for machining a surface of a metal substrate according to a first embodiment of the present invention, and FIG. 2 is a schematic sectional view showing the surface state of each metal substrate in each step shown in FIG.

1 and 2, a method of machining a surface of a metal substrate according to the first embodiment includes a first step S1 of preparing a metal substrate 10, And a third step S3 of forming a nano-scale metal nano-layer 30 on the surface of the fine irregularities 20, .

Since the metal nano-layer 30 is formed along the bending of the fine unevenness 20 on the surface of the fine unevenness 20, the surface of the metal substrate 10 is provided with a dual scale mixed micrometer scale and nanometer scale, Is formed. Due to this uneven structure, the surface of the metal substrate 10 implements an extremely hydrophilic surface having a contact angle of less than 10 [deg.].

Here, the micrometer scale means a size belonging to a range from 1 μm to less than 1000 μm, and the nanometer scale means a size belonging to a range from 1 nm to less than 1000 nm.

In the first step S10, the metal substrate 10 may include at least one selected from aluminum, zinc, tin, lead, and titanium.

In the second step S20, the fine irregularities 20 are formed by any one of sandblasting, sandpapering, shot blasting, plasma etching, discharge processing, laser processing, acid etching or base etching.

The sand blast is a method of forming fine irregularities 20 by injecting fine sand particles with compressed air to physically collide with the surface of the metal base 10. The sandpaper operation is to rub the surface of the metal substrate 10 with a sand paper, and the shot blast is a process of spraying fine particles of metal or non-metal, such as shot or grit. Sandpaper work and shot blast are also subjected to a physical collision with the surface of the metal substrate 10 like the sand blast to form fine irregularities 20.

Plasma etching is dry etching using a gas plasma instead of an etching solution, and acid or base etching is a wet etching using an acid solution or a base solution as an etching solution. The etching solution may be a fluoric acid dilution solution, a nitric acid dilution solution, a phosphoric acid dilution solution, an acetic acid dilution solution, a hydrochloric acid dilution solution, a sulfuric acid dilution solution or a mixture thereof. Micro-irregularities 20 of micrometer scale are formed by etching the surface of the metal substrate 10 by using an etching process, which is a type of chemical process.

The discharge treatment is a treatment method in which the surface of the metal base 10 is re-solidified after the surface of the metal base 10 is subjected to high heat generated by electric discharge. The surface of the metal base 10 subjected to the discharge treatment is coated with a micrometer scale of irregular cracks and bubbles Fine irregularities 20 are formed. In the laser processing, a laser pulse of high output is made incident on the metal substrate 10, and the surface of the metal substrate 10 is abraded to form micrometer scale fine unevenness 20.

3 is a scanning electron microscope (SEM) image showing the surface of a metal substrate on which fine irregularities have been formed by sandblasting. 3 (a) is an enlarged photograph of 5,000 times, (b) is an enlarged photograph of 10,000 times, and (c) is an enlarged photograph of 20,000 times.

Referring to FIG. 3, microscopic scale micro-irregularities due to physical impact are formed on the surface of the metal substrate by sandblasting. The metal substrate implements a hydrophilic surface by forming fine irregularities.

Referring again to FIGS. 1 and 2, in the third step S30, the metal nano-layer 30 is formed by acid treatment or base treatment of the metal substrate 10 on which the fine irregularities 20 are formed.

The acid treatment may be carried out by immersing the metal substrate 10 in which the fine irregularities 20 are formed on the surface in at least one acid solution selected from hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid and acetic acid. The base treatment is carried out by immersing the metal substrate 10 having fine unevenness 20 formed on the surface thereof in at least one base solution selected from sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, copper hydroxide, ammonium hydroxide, iron hydroxide and ammonia .

In this case, the acid solution and the base solution may have a concentration of 0.001 to 1 mol, and those heated at a temperature of 50 to 100 ° C may be used.

The metal nano-layer 30 is subjected to acid treatment or base treatment on the metal substrate 10 on which the fine irregularities 20 are formed on the surface and then immersed in boiling water for 30 minutes to 24 hours, specifically 30 minutes to 3 hours As shown in FIG. By further performing such a process, the metal nano-layer 30 can be stabilized.

The metal nanocrystals 30 in the form of flakes smaller than 1000 nm are formed on the surface of the metal substrate 10 by the above-described third step (S30).

The metal nano-layer 30 is adhered firmly to the surface of the metal substrate 10 by the stabilization treatment, thereby enhancing the durability of the surface of the metal substrate 10. The metal nano-layer 30 is formed on the surface of the metal substrate 10 along the curvature of the fine irregularities 20, so that a dual-scale concave-convex structure in which a micrometer scale and a nanometer scale are mixed is formed on the surface of the metal substrate 10.

4 is a scanning electron microscope (SEM) image showing the surface of the metal substrate on which the fine irregularities and the metal nano layer are formed. 4A is an enlarged photograph of 600 times, FIG. 4B is an enlarged photograph of 5,000 times, FIG. 4C is an enlarged photograph of 10,000 times, and FIG. 4D is an enlarged photograph of 20,000 times.

The metal substrate used in the experiment of Fig. 4 was surface-processed in the following manner.

The surface of the aluminum substrate was subjected to a sandblast process to form micrometer scale fine irregularities. Thereafter, an aluminum substrate having micro concavity and convexity formed on its surface was immersed in a 0.05 molar concentration sodium hydroxide solution heated at 80 DEG C to form an aluminum nano-layer.

Referring to FIG. 4, a flake-shaped aluminum hydroxide layer is formed on the surface of the fine unevenness along the bending of fine unevenness to a size smaller than 1000 nm (1 탆), that is, on the scale of nanometer scale, .

The nanometer-scale metal nano-layer 30 functions to maximize the hydrophilicity by further reducing the contact angle at the surface of the metal base 10 having the hydrophilic property enhanced by the process of the second step S20. Therefore, the metal base 10 of the present embodiment can obtain the effect of increasing the hydrophilicity by the dual scale uneven structure combining the micrometer scale and the nanometer scale, and realizes an extreme hydrophilic surface.

5 is an enlarged photograph showing the contact angle test result of the liquid with respect to the metal substrate.

FIG. 5 (a) shows a case of a metal substrate on which micrometer scale fine irregularities are formed through a first step and a second step, and FIG. 5 (b) Quot; indicates the case of a metal base on which scale fine irregularities are formed. In Figures 5 (a) and 5 (b), the black bar located at the top of the photograph is a dropping device.

5 (a), the contact angle of the liquid is 33 °, which indicates that the water drops lose its shape and wet the surface of the metal base. The contact angle of the liquid observed in (b) is 9 °, which indicates extreme hydrophilicity in which the liquid completely wetts the surface of the metal substrate.

6 is a process flow chart showing a method of machining a surface of a metal substrate according to a second embodiment of the present invention, and Fig. 7 is a schematic sectional view showing the surface state of each metal substrate in each step shown in Fig.

6 and 7, a method for machining a surface of a metal substrate according to the second embodiment includes a first step (S10) of preparing a metal substrate 10, a step of applying a physical or chemical treatment to the surface of the metal substrate 10 A second step (S20) of forming micrometer scale fine irregularities (20) on the surface of fine irregularities (20), a third step of forming nanometer scale metal nanolayers (30) on the surface of fine irregularities (20) And a fourth step (S40) of forming a hydrophobic polymer layer (40) on the surface of the layer (30).

Since the first to third steps S30 to S30 are the same as those of the first embodiment, a detailed description thereof will be omitted.

In the fourth step S40, the hydrophobic polymer layer 40 is formed of a fluororesin, a fluorine-based silane coupling agent, a fluorine-based isocyanate compound, an alkanethiol, an organosilane compound, a fatty acid, an aromatic azide compound, At least one hydrophobic material selected.

The hydrophobic polymer layer 40 may be formed by coating a hydrophobic material on the metal nano-layer 30. In this case, the coating may be performed by immersing the coating solution in a coating solution, applying a coating solution to the surface using a low-pressure spraying method, washing the coating solution with nucleic acid and distilled water, and drying in a high-temperature oven.

The hydrophobic polymer layer 40 may be formed by chemical bonding of the hydrophobic substance to the metal nano-layer 30. Specifically, the hydrophobic material may be formed in the form of a monomolecular layer or a multimolecular layer through a covalent bond with the surface of the metal nano-layer 30.

The hydrophobic polymer layer 40 exhibits hydrophobicity as a material itself and has a very thin thickness on the metal nano-layer 30, thereby exhibiting the same pattern as the metal nano-layer 30. The concavo-convex structure corresponding to the fine irregularities 20 and the metal nano-layers 30 is formed in the hydrophobic polymer layer 40 as well. The hydrophobic polymer layer 40 may have a thickness in the range of 1 to 5 nm as a monolayer.

The concavo-convex structure formed in the hydrophobic polymer layer 40 corresponding to the fine irregularities 20 has a high portion corresponding to the peak and a low portion corresponding to the valley, and a high portion corresponding to the peak functions as a microprojection for hydrophobic implementation do. The nano-scale protrusion structure formed on the hydrophobic polymer layer 40 corresponding to the flake-shaped metal nano-layer 30 functions as a nano-protrusion for minimizing the hydrophobicity.

The hydrophobic polymer layer 40 contains air between the microprotrusions and the nano protrusions to minimize the contact area with the water, thereby exhibiting a water repellency of more than 150 degrees.

8 is an enlarged photograph showing a contact angle test result of a liquid with respect to a metal substrate on which a hydrophobic polymer layer is formed.

The metal substrate used in the experiment of Fig. 8 was surface-processed in the following manner.

The surface of the aluminum substrate was subjected to a sandblast process to form micrometer scale fine irregularities. Thereafter, an aluminum substrate having micro concavity and convexity formed on its surface was immersed in a 0.05 molar concentration sodium hydroxide solution heated at 80 DEG C to form an aluminum nano-layer. Then, a fluorine-based silane coupling agent was coated on the aluminum nano-layer to form a hydrophobic polymer layer.

Referring to FIG. 8, the metal substrate on which the hydrophobic polymer layer is formed exhibits a contact angle of 160.6 ° and provides a very low surface area.

The metal substrate having a very low surface area can be applied to the condenser of the air conditioner to increase the condensation efficiency and to apply the same to the surface of the vessel to obtain higher thrust by the same power. In addition, the metal base having a very small number of surfaces can be applied to a water supply pipe to increase a flow rate and a flow rate of a fluid flowing through the water supply pipe, and can be applied to the surface of a dish type antenna to prevent water or snow from accumulating on the antenna.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

10: metal substrate 20: fine irregularities
30: metal nano-layer 40: hydrophobic polymer layer

Claims (8)

Preparing a metal substrate;
Forming micrometer scale fine concavities and convexities on the surface of the metal substrate through physical or chemical treatment in a range of 1 μm or more and less than 1,000 μm;
Forming an nano-scale metal nano-layer on the surface of the fine irregularities in the range of 1 nm or more and less than 1,000 nm;
Stabilizing the metal nano-layer using boiling water; And
Forming a hydrophobic polymer layer on the metal nano-layer to form a highly hydrophobic surface
Wherein the surface of the metal substrate is a metal surface. The method according to claim 1,
Wherein the fine irregularities are formed by any one of sandblasting, sandpapering, shot blasting, plasma etching, discharge processing, laser processing, acid etching or base etching. The method according to claim 1,
The acid treatment is carried out in at least one acid solution selected from hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid and acetic acid,
Wherein the base treatment is carried out in at least one base solution selected from sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, copper hydroxide, ammonium hydroxide, iron hydroxide and ammonia. The method according to claim 1,
Wherein stabilizing the metal nano-layer comprises immersing the metal substrate in boiling water for 30 minutes to 24 hours. The method according to claim 1,
The hydrophobic polymer layer includes at least one hydrophobic substance selected from a fluorine resin, a fluorine-based silane coupling agent, a fluorine-based isocyanate compound, an alkane thiol, an organosilane compound, a fatty acid, an aromatic azide compound, Of the surface of the metal substrate. 6. The method of claim 5,
Wherein the hydrophobic polymer layer is formed by coating the hydrophobic substance on the metal nano-layer, or the metal nano-layer and the hydrophobic substance are chemically bonded to each other. The method according to claim 1,
Wherein the hydrophobic polymer layer has a thickness ranging from 1 to 5 nm. 8. A metal substrate which is processed by the method of any one of claims 1 to 7 and which implements a surface that is extremely hydrophobic by the fine irregularities, the metal nano-layer and the hydrophobic polymer layer.

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