KR20100103968A - Processing method of the surface for aluminum or aluminum alloy materials - Google Patents

Abstract

PURPOSE: A surface modification method for aluminum and aluminum alloy materials is provided to achieve a product of high material property by performing vacuum vapor deposition after forming a thick oxide film. CONSTITUTION: A surface modification method for aluminum and aluminum alloy materials comprises steps of: cleaning a material(S10), dipping the cleaned material in a neutral aqueous solution and applying pulse voltage between the aqueous solution and the material to oxidize the surface layer of the material(S20), and taking the oxidized material out of the aqueous solution and grinding the surface layer with ultrasonic wave(S30).

Description

Processing method of the surface for aluminum or aluminum alloy materials

The present invention relates to a surface modification method for modifying the surface layer of aluminum or aluminum material, in particular oxidizing the surface layer of a product made of aluminum or aluminum alloy material, by depositing a specific material, heat resistance, chemical resistance, wear resistance, lubricity, non- The present invention relates to a surface modification method for improving physical properties such as adhesion, non-toxicity to human body and surface hardness.

Aluminum containers used in kitchens are known as containers that have been widely used in daily life for a long time because they are light and have good thermal conductivity, and their use is expected to continue to increase in the future.

In the case of a frying pan made of aluminum, the cooking surface lacks hardness, lubricity and non-tackiness, and until now, silane compounds (see Documents 1 to 3), Teflon (PTFE) (see Documents 4 to 5), PEEK A material in which organic materials such as (see Document 6) and inorganic powders such as silica, MoS ₂ , and WS ₂ are mixed is coated to improve physical properties such as non-tackiness.

However, organic coatings are easily decomposed during high temperature heating, and are weak in scratch resistance, and thus deteriorate due to deterioration when washed repeatedly with a loofah.

Recently, fluorocarbon-containing resins such as PTFE (PTFE) are known to be hardly decomposable, bioaccumulative, and toxic, and have been shown to affect fetal toxicity, liver toxicity, and facial developmental toxicity.

In particular, PFOA perfluorooctanoic acid and PFOS Perfluorooctane sulfonates accumulated in the liver or placenta of the human body by decomposing from fluoropolymers have been identified as carcinogenic toxic substances. Since there is a tendency to prohibit the use of processing equipment, a lot of research and development is required in terms of technology development and surface modification methods for alternative materials thereof.

As a surface modification method for an aluminum material, improvement of physical properties such as corrosion resistance and surface hardness is achieved by forming an oxide film on the surface by a conventional anodization method (see Documents 7 to 8) or micro-arc oxidation method (see Documents 9 to 10). Although it is possible, environmental pollution has emerged as a problem due to the generation of waste liquids such as waste acid and waste alkali, etc. However, there is still a shortage of demands for the development of technology that satisfies these environmental pollution problems, biocompatibility, and physical and chemical properties at the same time.

In particular, since anodization using an acidic electrolyte such as sulfuric acid applies a low voltage of 10 to 20 volts, since an oxide film having a thickness of 20 to 30 µm is formed, it is difficult to oxidize the aluminum inside through the already formed oxide film. There is a problem that the thickness of the oxide film cannot be made thick.

In addition, until now, the color of kitchen appliances such as a frying pan made of aluminum and an aluminum alloy material is gray or black, and there is a problem in that various designs cannot be implemented in the design.

(Document 1) US Patent Publication 4,366,286

(Document 2) U.S. Patent Publication 6,054,522

(Document 3) United States Patent Publication 5,531,182

(Document 4) United States Patent Publication 4.087,394

(Document 5) Korean Utility Model Publication 20-0301176

(Document 6) US Patent No. 6,382,454

(Document 7) Japanese Patent Laid-Open No. 6-322590

(Document 8) Republic of Korea Patent Publication No. 10-1998-0009527

(Document 9) RU 2039133, Bolotov A. N.

(Document 10) US Patent Publication No. 2008/0283410

Accordingly, an object of the present invention is to solve the above problems, aluminum and aluminum that improves the physical and chemical properties such as heat resistance, corrosion resistance, non-tackiness, lubricity and surface hardness through surface modification of the cooker of aluminum material It is to provide a method of surface modification of the alloy material.

In addition, another object of the present invention is to provide a method for surface modification of aluminum and aluminum alloy material to have a beautiful appearance, that is to change the color of the surface to have a beautiful color and molding beauty.

Method for modifying the surface layer of aluminum or aluminum alloy material according to the present invention for achieving the above object is a washing step of washing the material, the washed material is immersed in a neutral aqueous solution diluted with an extract of the vegetable material and the aqueous solution and the material And an oxidizing step of oxidizing the surface layer of the material by applying a pulse voltage in between, and a polishing step of removing the oxidized material from the aqueous solution and polishing the surface layer with ultrasonic waves.

In the method for modifying the surface layer of an aluminum or aluminum alloy material according to the present invention, the pulse voltage is 220 to 1,000 V, and the current density is 0.3 to 8 A / cm 2.

In addition, in the surface layer modification method of the aluminum or aluminum alloy material according to the present invention, the thickness of the oxidized surface layer is characterized in that 50 to 500㎛.

In addition, in the method of modifying the surface layer of an aluminum or aluminum alloy material according to the present invention, the neutral aqueous solution is prepared by using 99.9% by weight of water and 0.1% by weight of the extract.

In addition, in the method of modifying the surface layer of the aluminum or aluminum alloy material according to the present invention, the extract is characterized in that the extract of any one extract or extract of two or more extracts from chrysanthemum, seaweed, nettle, thistle, peppermint, chili pepper do.

In addition, in the method for modifying the surface layer of an aluminum or aluminum alloy material according to the present invention, a washing step of washing the polished material after the polishing step, TiN, TiOx, TiCN, AlTiN or TiB ₂ to the surface layer of the ion-washed material It characterized in that it further comprises a deposition process for depositing.

In addition, in the surface layer modification method of the aluminum or aluminum alloy material according to the present invention, the washing is characterized in that the ion washing with argon gas.

In addition, in the surface layer modification method of the aluminum or aluminum alloy material according to the present invention, the deposition is characterized in that the deposition to a thickness of 0.5 ~ 5㎛.

As described above, according to the surface modification method of the aluminum and aluminum alloy material according to the present invention, the neutral aqueous solution and the vegetable additive are compared with the conventional anodizing method using an acidic electrolyte solution or the micro-arc oxidation method using an alkaline solution. Because it uses the effect that does not cause environmental pollution.

In addition, according to the surface modification method of the aluminum and aluminum alloy material according to the present invention, it is possible to form a thick oxide film, by using a vacuum plasma deposition method after forming the oxide film, it is possible to produce a product with more excellent physical properties It also works.

In addition, since the neutral aqueous solution is used as the electrolyte, there is an effect that can modify the surface of the aluminum and aluminum alloy material without generation of pollution.

The present invention is a method for modifying the physical properties of the surface of an aluminum cooker, such as a frying pan, which is currently used, a micro-arc oxidized cooker, such as a frying pan formed of aluminum and aluminum alloy material in a neutral aqueous solution of 50 ~ 500㎛ thick oxide film Ultrasonic polishing is performed to produce products with excellent physical properties such as heat resistance, abrasion resistance, lubricity, adhesion resistance, and non-toxicity to human body, or the surface of cooker on which micro-arc oxide film is formed. Hard films such as AlTiN and TiB ₂ are coated with a thickness of 0.5 to 5 μm by a vacuum deposition method at room temperature, and thus have excellent surface properties such as corrosion resistance, non-tackiness, and surface hardness.

Hereinafter, a preferred embodiment of the surface modification method of aluminum and aluminum alloy material according to the present invention will be described in detail with reference to the accompanying drawings.

Example 1

Example 1 relates to a micro-arc oxidation process.

The conventional anodic oxidation method was to form a thin and relatively soft porous film having an oxide film thickness of 30 μm or less in an acidic aqueous solution (sulfuric acid, hydroxyl acid, chromic acid, etc.), but the micro-arc oxidation method of the present invention was extracted from a vegetable material. By dipping aluminum or aluminum alloy material in a neutral aqueous solution diluted with distilled water and applying a high voltage, a hard thick oxide film is formed on the surface of the aluminum or aluminum alloy material for a short time.

As the extract diluted in distilled water, distilled chrysanthemum or wakame in 50 ~ 90 ℃ hot water, soaked for more than 24 hours, filtered and concentrated to extract only the extract evaporated again. The oxidized surface is yellow when using the extract extracted from bilateral chrysanthemum and the oxidized surface is blue when using the extract extracted from seaweed.

In addition, it is also possible to use nettle, thistle, peppermint, pepper, etc. to oxidize the oxide film to other colors. For the combination of colors, the extract may be used by mixing two or more extracts extracted from chrysanthemum, seaweed, nettle, thistle, peppermint, and pepper.

The electrical conduction in the electrolytic solution is achieved by containing the organic and inorganic salts of each plant in the extract.

In the conventional anodic oxidation method, since the oxidation process is performed in an acidic solution, the complexity of the process, environmental pollution by treatment of waste electrolyte, color implementation of the coating layer, that is, impossible to express various colors, limitation of physical properties, that is, wear resistance, heat resistance, adhesiveness And, there was a limit in the denseness of the coating layer, etc., according to the micro-arc oxidation method according to the present invention as described above, the neutral aqueous solution, the type of extract added to the neutral aqueous solution (that is, the type of colored plants to be extracted), Surface polishing, process automation, and physical properties have a difference from the conventional anodizing method, and according to these differences, an oxide film layer having improved wear resistance, heat resistance, corrosion resistance, non-toxicity of the human body, surface hardness, etc. can be obtained. .

And the color of the coating layer has a variety of colors according to the type of the extract is added to the neutral aqueous solution, the oxidation process is environmentally friendly because the neutral solution diluted in distilled water using the extract extracted from the colored plants as the electrolyte.

The technical details of the process, such as the composition of the electrolyte solution, the power supply and power control, and the surface polishing method is summarized as follows.

[Table] Process characteristics of micro-arc oxidation method

Item Contents Electrolyte 99.9% by weight of distilled water, 0.1% by weight of extract extracted from colored plants power 220 to 380 V Current density 0.3 ~ 8A / ㎠ Samhwa Film Formation Rate 6 μm / min Oxide film formation thickness Up to 500㎛ Electrolyzer Treatment Capacity 0.3㎥ treatment in 300l electrolytic cell Power Consumption 15dmx150ℓ, 30kw / hr Cloth material Al, Ti, Si, Ni, and alloys thereof Type of colored plants Chrysanthemum, seaweed, nettle, thistle, peppermint, pepper, etc.

As shown in the table, the power consumption per unit time is large, but the reaction time is short, so the total amount of power consumed is similar to the conventional anodized acid solution. The material to be oxidized is not limited to aluminum and aluminum alloys, but is also applicable to ceramic composites, magnesium, silicon and nickel and alloys thereof.

In actual micro-arc oxidation process, samples are extracted from colored plants in an electrolytic cell containing a neutral aqueous solution diluted in distilled water, and the sample is deposited at a voltage of 200 to 1,000 V, a pulse period of 100 to 1000 mA, and a current density of 0.3 to 0.8 A / dm. After the energization, the reaction time was adjusted to adjust the thickness of the oxide film to 50 to 500 µm, and the final surface polishing was performed by ultrasonic polishing.

1 is a micro-arc oxidizer applied to the present invention, Figure 2 is a vacuum plasma deposition apparatus applied to the present invention, Figure 3 is a flow chart for explaining a surface modification method of the aluminum or aluminum alloy material according to the present invention. .

Hereinafter, a micro arc oxidizer applied to the present invention will be described with reference to FIG. 1.

In FIG. 1, reference numeral 1 denotes an electrolytic cell made of plastic, and the electrolytic cell 1 has a double structure through which the coolant 2 can flow, and a coolant inlet and a coolant outlet are provided at an upper portion thereof.

In addition, inside the electrolytic cell 1, a stainless steel container 3 constituting the negative electrode is interpolated, and the stainless steel container 3 is filled with an electrolyte solution 4, and the electric power of the aluminum pan 5 for oxidizing is supplied. The + side of the supplying power supply 6 is connected to the aluminum frying pan 5 via the wire 8 insulated by the insulator 7, and the-side of the power supply 6 is connected to the stainless steel container 3. It is connected.

Hereinafter, a method of surface oxidation of an aluminum frying pan made of aluminum or an aluminum alloy will be described with reference to FIG. 3.

In the micro-arc oxidizer 10 as shown in FIG. 1, the aluminum frying pan 5 is washed with a general detergent (S10) to remove contaminants such as dust and oil contaminated on the surface, and as shown in FIG. 4) After fully immersed in, and energized by the power supply device 6 for 20 minutes at a voltage of 1,000 V, a pulse period of 100 mA, and a current density of 1.0 A / dm 2, an oxide film having a thickness of 100 μm on the surface of the aluminum frying pan 5. A layer was formed (S20).

At this time, the surface of the frying pan (5) is intense arc oxidation action, pink arc discharge (9) occurs and exothermic reaction occurs. Therefore, the cooling water 2 is circulated in order to keep the temperature of the aqueous solution at room temperature.

The frying pan 5 whose surface is oxidized in this way is removed from the micro-arc oxidizing apparatus and polished on its surface by using an ultrasonic polishing apparatus, so that the sealing process for sealing the micropores of the oxide film and the degree of lubrication of the surface are performed. Increased.

The physical properties of the oxide layer had a friction coefficient of 0.01 to 0.02 and a dielectric loss of 6x10 ^-5 % at Brinell hardness HV 400 to 800 and a load of 20 kg / mm2. The wear resistance was 3 to 4 times higher than that of stainless steel.

[Example 2]

Example 2 relates to a vacuum plasma deposition process.

Hereinafter, a plasma vacuum deposition apparatus applied to the present invention will be described with reference to FIG. 2.

In Fig. 2, reference numeral 11 is a vacuum chamber, 12 is an arc electrode, 13 is an argon gas supply pipe for supplying argon gas into the vacuum chamber 11, and 14 is a Ti target. The vacuum chamber 11 is provided with a valve 15 for supplying nitrogen (N ₂ ) and oxygen (O ₂ ) gas therein, for closing the valve 15 and evacuating the interior of the vacuum chamber 11. The vacuum pump 16 is provided.

And an aluminum frying pan 17 for deposition in the vacuum chamber 11 is suspended over the rack.

Hereinafter, a deposition method for depositing a coating film on an oxidized surface of an aluminum frying pan made of aluminum or an aluminum alloy will be described with reference to FIG. 3.

Plasma vacuum deposition according to the present invention charges the deposits 17, such as a frying pan, into the vacuum chamber 11 of such a vacuum plasma deposition apparatus, exhausts them at high vacuum, and then passes through the argon gas supply pipe 13 to form argon ( Ar) gas is injected to form an argon ion film on the deposit under high voltage and ion washing (S40).

Then, plasma deposition is performed on the surface of the oxide film whose surface is polished in step S30 to deposit gold TiN or pearly TiOx to form a coating film.

In this case, Ti target and nitrogen are used for TiN deposition, Ti target and oxygen are used for TiOx deposition, and Ti ions vaporized from the arc rod 12 react with nitrogen gas or oxygen gas to form TiN or TiOx is generated. At this time, the thickness of the coating film is about 0.5 ~ 5㎛.

In the specific implementation of the process, a frying pan made of aluminum and an aluminum alloy material is placed in the vacuum chamber 1, and the vacuum pump is operated to maintain the vacuum degree so that the vacuum degree in the chamber is 10 ^-4 to 10 ^-5 torr, and then the ion electrode (3). After argon gas is injected through the ion cleaning process for 10 to 20 minutes, and nitrogen gas is injected to perform plasma deposition by applying a high voltage of 200 to 500 eV to the arc electrode 2 for 10 to 20 minutes, the thickness of the TiN film layer is increased. A gold coating film having a thickness of 0.5 to 5 µm was obtained.

The Brinell hardness of the TiN-coated frying pan 17 surface was about Hv1000, which is high in hardness, and the surface thereof was excellent in hydrophobicity, lubricity and corrosion resistance in strong alkali solution, and was harmless to human body.

According to the surface modification method of the aluminum and aluminum alloy material according to the present invention, as well as the production of aluminum frying pans, air bearings, oil-free plane bearings, components such as aircraft engines, cylinders and pistons of internal combustion engines, rotary blades such as slurry pumps, It can be used in the manufacture of air compressor rotors, various friction devices (spinner guide pins), high frequency electromagnetic plates, air conditioner heating parts, ceramic composite materials, and building interior materials.

1 is a micro arc oxidizer applied to the present invention

2 is a vacuum plasma deposition apparatus applied to the present invention

3 is a flowchart illustrating a surface modification method of an aluminum or aluminum alloy material according to the present invention.

* Description of the symbols for the main parts of the drawings *

1: electrolyzer 3: stainless steel container

6: power supply 5: aluminum frying pan

9: discharge 10: micro arc oxidizer

11: vacuum chamber 12: arc electrode (arc rod)

13 argon gas supply pipe 14 target

16: vacuum pump 20: vacuum plasma deposition apparatus

Claims (8)

In the surface layer modification method of aluminum or aluminum alloy material, Washing process for washing the material, An oxidizing process of immersing the washed material in a neutral aqueous solution diluted with an extract of a vegetable material and oxidizing a surface layer of the material by applying a pulse voltage between the aqueous solution and the material; And removing the oxidized material from the aqueous solution and polishing the surface layer by ultrasonic waves. The method of claim 1, The pulse voltage is 220 to 1,000V, the current density is 0.3 to 8A / ㎠, characterized in that the surface layer modification method of aluminum or aluminum alloy material. 3. The method of claim 2, The thickness of the oxidized surface layer is a surface layer modification method of aluminum or aluminum alloy material, characterized in that 50 to 500㎛. 3. The method of claim 2, The neutral aqueous solution is a method of modifying the surface layer of aluminum or aluminum alloy, characterized in that the formulation of 99.9% by weight of water and 0.1% by weight of the extract. The method of claim 4, wherein The extract is a method of modifying the surface layer of aluminum or aluminum alloy material, characterized in that the extract of any one extracted from two chrysanthemum, wakame, nettle, thistle, peppermint, pepper, or two or more extracts. 5. The method according to any one of claims 1 to 4, A washing step of washing the polished material after the polishing step, Method for modifying the surface layer of the aluminum or aluminum alloy material, characterized in that further comprising a deposition process for depositing TiN, TiOx, TiCN, AlTiN or TiB ₂ on the surface layer of the ion-washed material. The method of claim 6, The washing is a method of modifying the surface layer of the aluminum or aluminum alloy material, characterized in that the ion washing with Ar gas. The method of claim 7, wherein The deposition method is a surface layer modification method of aluminum or aluminum alloy, characterized in that the deposition to a thickness of 0.5 to 5㎛.

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