KR20160140241A - Method of coating specimen based on plasma electrolytic oxidation - Google Patents
Method of coating specimen based on plasma electrolytic oxidation Download PDFInfo
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- KR20160140241A KR20160140241A KR1020150076629A KR20150076629A KR20160140241A KR 20160140241 A KR20160140241 A KR 20160140241A KR 1020150076629 A KR1020150076629 A KR 1020150076629A KR 20150076629 A KR20150076629 A KR 20150076629A KR 20160140241 A KR20160140241 A KR 20160140241A
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/024—Anodisation under pulsed or modulated current or potential
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
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Abstract
Description
The present invention relates to a method of coating a plasma electrolytic base, and more particularly, to a plasma electrolytic plating method for plasma electrolytic oxidation, which is capable of reducing the thickness of an aluminum oxide film and improving the strength of a polycarbonate film by performing coating of an aluminum oxide film using a plasma electrolytic oxidation apparatus Based sample coating method.
Conventional heat sinks use aluminum oxide (Al 2 O 3 ), which is anodized aluminum metal plate as an insulator, to form an insulator on the surface for insulation to aluminum material.
The heat sink improves the thermal conductivity of the insulator and can provide high heat dissipation. However, the heat sink that implements the insulator with the aluminum oxide formed by the existing anodizing process has a limit to enhance the heat dissipation due to the minute hole structure of the aluminum oxide. If the insulator is realized through a dense structure of aluminum oxide having no hole structure, the heat sink may improve heat dissipation, and therefore, a process for fabricating aluminum oxide having a dense structure without a hole structure is required. That is, aluminum oxide having a dense structure without such a hole structure is required to improve the heat radiation effect of the heat sink and to improve the durability through improvement of the film adhesion, and therefore there is a demand for a technique for forming a film having a film adhesion with a dense structure without a hole structure .
Korean Patent Laid-Open No. 10-2009-0083489 relates to a method and apparatus for electrolytic coating, and more particularly, to an apparatus for electrolytically coating a structural or surface-type base layer on a surface of a substrate.
One embodiment of the present invention is to provide a plasma electrolytic-based sample coating method capable of reducing the thickness of an oxide film such as aluminum and improving the strength of the polycrystalline silicon film.
An embodiment of the present invention is to provide a plasma electrolytic-based sample coating method for forming an oxide film on a sample to be coated by generating a plasma on a surface of a sample to be coated.
An embodiment of the present invention is to provide a plasma electrolytic-based sample coating method for improving the hardness, film thickness, insulation, and thermal conductivity of an oxide film through voltage, current conditions, and composition ratio of an electrolytic solution in a plasma electrolytic oxidation apparatus.
An embodiment of the present invention is to provide a plasma electrolytic-based sample coating method for improving the uniformity of an oxide film by determining a composition ratio of an electrolyte composition and a composition for forming an oxide film.
Among the embodiments, the plasma electrolytic-based sample coating method includes the steps of (a) preparing an electrolytic solution in a pre-process, (b) immersing a sample to be coated in the electrolytic solution, Generating a plasma on the surface of the immersed coating target sample; and (c) forming an oxide film on the coating target sample through the generated plasma.
The step (c) may include the step of applying an electric power of an amplitude modulated AC waveform to the coating object sample through the plasma electrolytic oxidation apparatus to form the oxide coating.
The Amplitude Modulated AC waveform may be implemented as a {± 10, +7, ± 10, -3} waveform sequence or a {± 10, +3, ± 10, -7} waveform sequence.
The power source of the amplitude modulated AC waveform may have a current density ranging from 0.18 A / cm 2 to 0.24 A / cm 2.
The electrolytic solution may include at least one selected from the group consisting of potassium hydroxide (KOH), sodium silicate (Na2SiO3), sodium pyrophosphate (Na3P2O7), and hydrogen peroxide (H2O2).
Wherein the concentration ratio of potassium hydroxide (KOH) and sodium silicate (Na2SiO3) in the electrolyte is in the range of 10:10 (g / L) to 5:10 (g / L) and the sodium pyrophosphate (Na3P2O7) And the hydrogen peroxide (H 2 O 2) may be added in the range of 1 to 5 g per liter.
The disclosed technique may have the following effects. It is to be understood, however, that the scope of the disclosed technology is not to be construed as limited thereby, as it is not meant to imply that a particular embodiment should include all of the following effects or only the following effects.
The plasma electrolytic-based sample coating method according to an embodiment of the present invention can reduce the thickness of the oxide film such as aluminum and improve the strength of the polycrystalline silicon film.
The plasma electrolytic-based sample coating method according to an embodiment of the present invention can generate plasma on the surface of a sample to be coated to form an oxide film on a sample to be coated.
The plasma-based sample coating method according to an embodiment of the present invention can improve the hardness, film thickness, insulation, and thermal conductivity of an oxide film through the voltage, current conditions, and composition ratio of the electrolytic solution in the plasma electrolytic oxidation apparatus.
The plasma electrolytic-based sample coating method according to an embodiment of the present invention can improve the uniformity of an oxide film by determining a composition ratio of an electrolyte composition and a composition for forming an oxide film.
1 is a view showing an oxide film structure of a hard anodizing coating and a plasma electrolytic oxide coating.
2 is a scanning electron microscope (SEM) image of a cross section of an oxide film according to a process time in a general plasma electrolytic oxidation process.
3 is a flowchart illustrating a method of coating a plasma electrolysis based sample according to an embodiment of the present invention.
4 is a scanning electron microscope (SEM) image of a cross section of an oxide film coated according to the experimental conditions in the first experiment of the present invention.
5 is a graph showing a waveform of a power source applied to a sample to be coated in a second experiment of the present invention.
6 is a scanning electron microscope (SEM) image of a cross section of an oxide film coated according to the waveform of the power source in the second experiment of the present invention.
7 is a scanning electron microscope (SEM) image of a cross section of an oxide film coated according to the concentration of the electrolyte additive in the third experiment of the present invention.
8 is a scanning electron microscope (SEM) image of a cross section of an oxide film coated according to a change in current density of a power source in a fourth experiment of the present invention.
9 is a scanning electron microscope (SEM) image of a cross section of an oxide film coated according to the concentration of the additive for electrolyte solution in the fifth experiment of the present invention.
The description of the present invention is merely an example for structural or functional explanation, and the scope of the present invention should not be construed as being limited by the embodiments described in the text. That is, the embodiments are to be construed as being variously embodied and having various forms, so that the scope of the present invention should be understood to include equivalents capable of realizing technical ideas. Also, the purpose or effect of the present invention should not be construed as limiting the scope of the present invention, since it does not mean that a specific embodiment should include all or only such effect.
Meanwhile, the meaning of the terms described in the present application should be understood as follows.
The terms "first "," second ", and the like are intended to distinguish one element from another, and the scope of the right should not be limited by these terms. For example, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.
It should be understood that the term " and / or " includes all possible combinations from one or more related items. For example, the meaning of " first item, second item and / or third item " may be presented from two or more of the first, second or third items as well as the first, second or third item It means a combination of all the items that can be.
It is to be understood that when an element is referred to as being "connected" to another element, it may be directly connected to the other element, but there may be other elements in between. On the other hand, when an element is referred to as being "directly connected" to another element, it should be understood that there are no other elements in between. On the other hand, other expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.
It should be understood that the singular " include "or" have "are to be construed as including a stated feature, number, step, operation, component, It is to be understood that the combination is intended to specify that it does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.
All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used predefined terms should be interpreted to be consistent with the meanings in the context of the related art and can not be interpreted as having ideal or overly formal meaning unless explicitly defined in the present application.
1 is a view showing an oxide film structure of a hard anodizing coating and a plasma electrolytic oxidation coating (PEO).
1, in the hard anodizing coating, most of the oxide coating layer is formed into a porous amorphous oxide film structure, whereas the plasma electrolytic oxide coating is formed by forming most of the oxide coating film into a porous oxide film structure having no porosity, A porous layer is formed.
The aluminum oxide film formed by the plasma electrolytic oxidation has a dense structure when compared with the columnar pores structure formed by the hard anodizing coating, and its thermal conductivity and hardness are determined by the thermal conductivity and hardness of the aluminum oxide film by hard anodizing . However, the oxide film formed by the plasma electrolytic oxidation has to have a film thickness of 60 탆 or more through a thick film process to form a dense structure.
In the plasma electrolytic oxidation, the components and concentrations of the electrolytic solution may be one of the important factors in the plasma electrolytic oxidation process. Experiments using various electrolyte components to form an oxide film by a crack-less plasma electrolytic oxidation process will be described below.
2 is a scanning electron microscope (SEM) image of a cross section of an oxide film according to a process time in a general plasma electrolytic oxidation process.
In FIG. 2, the thickness of the oxide film becomes thicker as the processing time becomes longer, and the oxide film becomes more dense as its thickness becomes thicker. In other words, in the general plasma electrolytic oxidation process, the oxide film has a dense oxide film structure when the thickness of the oxide film is 60 탆 or more, whereas it does not form a dense oxide film structure when the thickness of the oxide film is 20 탆 or less.
In order to increase the thermal conductivity, the oxide film should have a thickness of 20 μm or less and a hardness of 1,000 Hv (Vickers hardness) or more. The thermal conductivity of the aluminum oxide formed by the anodizing process is about 1.5 W / m 占 이고, the thermal conductivity of the aluminum oxide formed by the plasma electrolytic oxidation is about 2.0 W / m 占 K, the aluminum oxide formed by the plasma electrolytic oxidation is anodized It has a heat radiation enhancement effect of about 33% or more as compared with the aluminum oxide formed by the aluminum oxide. On the other hand, a heat sink formed through plasma electrolytic oxidation can be applied to a power source, a notebook computer, an electric car, and the like.
3 is a flowchart illustrating a method of coating a plasma electrolysis based sample according to an embodiment of the present invention.
3, the plasma electrolytic-based sample coating method includes a step of preparing an electrolytic solution for plasma electrolytic oxidation in a pre-process (step S10), a step of immersing a sample to be coated in an electrolytic solution, (Step S20) connecting the plasma electrolytic oxidation apparatus to generate a plasma in the coating target sample, and forming an oxide coating on the coating target sample through the plasma (step S30).
Here, the sample to be coated is a metal on which an oxide film is formed on the surface, and may be aluminum (Al), magnesium (Mg), or an alloy thereof. The oxide film formed by the plasma electrolytic oxidation must have high hardness, electrical insulation and thermal conductivity in order to obtain optimum physical properties, and must be formed thinly and uniformly. The coating target sample may be a metal for a heat sink of an electronic component and a light metal, and the surface of the sample may be anodized to further improve the characteristics of the light metal. Therefore, an anodized coated sample can be widely used as a component material in various industrial fields requiring excellent corrosion resistance, abrasion resistance, and high thermal conductivity, such as automobile, electronic industry, aerospace, and fiber. In one embodiment, an Al6000 series aluminum material was used as the sample to be coated. The Al 6000 series can facilitate formation of an oxide film by plasma electrolytic oxidation.
Step S10 represents a process for preparing an electrolytic solution necessary for plasma electrolytic oxidation in a pre-process. The components and the composition ratio of the electrolytic solution can be different from those of the intended oxide film, so that the oxide film can have a thickness of less than 20 μm and high hardness and high thermal conductivity through the characteristics of the electrolytic solution. That is, the oxide film for the high heat sink can be produced according to the composition and the composition ratio of the electrolytic solution.
The electrolytic solution may include at least one selected from the group consisting of potassium hydroxide (KOH), sodium silicate (Na2SiO3), sodium pyrophosphate (Na3P2O7), and hydrogen peroxide (H2O2). Here, the concentration ratio of potassium hydroxide (KOH) to sodium silicate (Na2SiO3) ranges from 10:10 (g / L) to 5:10 (g / L) and sodium pyrophosphate (Na3P2O7) ranges from 1 to 5 g per liter And hydrogen peroxide (H 2 O 2) may be added in the range of 1 to 5 g per liter.
Next, step S20 shows a process of immersing the sample to be coated in the electrolyte solution and connecting it to the plasma electrolytic oxidation apparatus. Plasma can be generated on the surface of the sample to be coated immersed through the plasma electrolytic oxidation apparatus. The sample to be coated functions as the anode by the plasma electrolytic oxidation apparatus, and the electrolytic solution functions as the cathode.
Finally, step S30 shows a process of forming an oxide film on the coating object sample through the plasma generated by the plasma electrolytic oxidation apparatus. When power is applied through the plasma electrolytic oxidation apparatus, an electrolytic cell functioning as a counter electrode interacts with a sample to be coated, and an oxide film can be formed on the surface of the coating target sample. The plasma electrolytic oxidation apparatus can apply an electric power of an amplitude modulated AC waveform to an object to be coated to form an oxide film. In one embodiment, an Amplitude Modulated AC waveform can be implemented as a {± 10, +7, ± 10, -3} waveform sequence or a {± 10, +3, ± 10, -7} have. In another embodiment, a power source of an Amplitude Modulated AC waveform may have a current density ranging from 0.18 A / cm2 to 0.24 A / cm2.
4 is a scanning electron microscope (SEM) image of a section of an oxide film coated according to experimental conditions in the first experiment.
[First Experiment]
The first experiment includes a step of observing a cross section of an oxide film formed according to the KOH and Na 2 SiO 3 component ratios of an electrolytic solution of the plasma electrolytic oxidation through a scanning electron microscope. Here, the KOH and Na 2 SiO 3 component ratios were 5 (g / L): 10 (g / L), 5 (g / L): 20 (G / L), 20 (g / L), 10 (g / L) and 10 (g / L).
For the first experiment, the values obtained from previous experiments were applied as process conditions. Specifically, the voltage was 400 V, the current density was 0.20 A / cm 2, and the sine waveform was applied to the plasma power waveform.
Experimental results of the first experiment
The cross-sectional structure shown in Fig. 4 shows that the concentrations of KOH and Na 2 SiO 3 are 5 (g / L): 10 (g / L), 5 ): 10 (g / L), 10 (g / L): 20 (g / L), 15 (g / To a scanning electron microscope (SEM) image of the cross section of the oxide film formed.
In FIG. 4, it can be seen that the uniformity of the oxide film is deteriorated when the component ratio of Na 2 SiO 3 is increased. On the other hand, the oxide film formed when the concentration of KOH and Na 2 SiO 3 is 10 (g / L): 10 (g / L) shows high film uniformity. Therefore, the component concentration of the electrolytic solution was selected as 10 (g / L): 10 (g / L).
The plasma electrolytic oxidation apparatus alternately provides a positive current and a negative current to the sample to be coated to form an oxide film on the surface of the sample to be coated. In this case, the formed oxide film may have a thickness of several hundred [mu] m. Here, the formation speed of the oxide film may correspond to 2 탆 / min to 10 탆 / min. The plasma electrolytic oxidation apparatus alternately provides positive current and negative current to the sample to be coated to induce a limited plasma discharge on the surface of the sample to be coated. The energy due to the plasma discharge can be used to shift the surface of the sample to be coated into an oxide film. Thus, an oxide film having high density and excellent adhesion can be produced.
When positive and negative currents are alternately supplied to the coating target sample, gaseous oxygen is generated on the surface of the coating target sample to oxidize the coating target sample, and gaseous hydrogen is generated in the electrolyte functioning as a cathode, Is reduced. That is, the surface of the sample to be coated is ionized and an oxide film is formed on the surface of the sample to be coated. As a result, a thick and dense oxide film can be produced by directly applying a power source to a coating target sample (for example, an aluminum alloy) and performing a direct plasma electrolytic oxidation treatment.
On the other hand, by adjusting the process parameters of the plasma electrolytic oxidation apparatus, an oxide film having a characteristic (for example, thickness of oxide film, thermal conductivity, hardness and electrical conductivity) is formed on the surface of the sample to be coated, . Here, the process parameters of the controllable plasma electrolytic oxidation apparatus are frequency, positive voltage application time, negative voltage application time, positive current application time, negative current application time, dwell time between positive voltage and negative voltage, The ratio of the negative charge amount to the positive charge amount, the maximum applied positive voltage, the maximum applied negative voltage, or the maximum current value arrival time, and the like.
FIG. 5 is a graph showing a waveform of a power source applied to a sample to be coated in the second experiment, and FIG. 6 is a scanning electron microscope photograph of a cross section of an oxide film coated according to the waveform of the power source in the second experiment.
5 and 6, a second experiment related to the wave form and waveform conditions of the power source, which is one of the process parameters for forming an oxide film of a coating target sample (for example, aluminum) will be described in detail.
[Second Experiment]
In the second experiment, the wave process was controlled to improve film thickness and uniformity while maintaining the process time to 10 minutes.
In the second experiment, the plasma power source has a sinusoidal waveform repeatedly, and the frequency of the power source is 60 Hz. The oxide film formed by the corresponding power waveform shows a high growth rate.
5, an amplitude-modulated AC waveform, which is a modulated waveform, outputs a complete sinusoidal wave and then generates a + pulse or a? Pulse in a sinusoidal wave, + Pulse or? Means a waveform in which only a pulse is generated. The number of +, - pulses can be arbitrarily determined and ranges from 1 to 60. In this experiment, amplitude modulation AC waveforms with + pulses of 7, 3, and - 7 pulses were also used to simplify the experiment. That is, in the plasma electrolytic oxidation apparatus of the present invention, an electric power of an amplitude modulated AC waveform can be applied to a coating target sample to form an oxide coating on the surface of the coating target sample. For example, an amplitude-modulated AC waveform can be implemented with {± 10, +7, ± 10, -3} waveform sequences or {± 10, +3, ± 10, -7} waveform sequences . Here, the waveform sequence means the number of +, - pulses of the amplitude modulation AC waveform.
Experimental results of the second experiment
In FIG. 6, when the waveform conditions are ± 10, +3, ± 10, and -7, the oxide film thickness is 12.2 μm in the 10-minute processing time and the oxide film thickness is 19.3 μm in the 15-minute processing time. However, it can be seen that the uniformity of the oxide film is not ensured in the waveform sequence of {± 10, +3, ± 10, -7} as shown in the scanning electron microscope photograph of the cross section of the oxide film in FIG.
When the waveform conditions were ± 10, +7, ± 10, -3, the oxide film thickness was 19.7 ㎛ in 10 min process time, the oxide film thickness was 34.7 ㎛ in 15 min process time and the oxide film uniformity was secured I could.
( × 10 2 MΩ )
The thickness of the oxide film was measured to be 20 μm or less. However, the thermal conductivity, hardness and electrical insulation resistance of the oxide film did not reach the development target, and the process improvement to improve the performance of the oxide film proceeded.
7 is a scanning electron microscope (SEM) image of a cross section of an oxide film coated according to the concentration of the electrolyte additive in the third experiment of the present invention.
[Third experiment]
In the third experiment, additives were added to the electrolyte to improve the physical properties of the oxide film. Among them, Na 4 P 2 O 7 has been reported to increase the surface movement of the oxide film and to improve the denseness of the film structure. Therefore, the process improvement is experimented by injecting Na 4 P 2 O 7 as an additive into the selected electrolyte .
The composition ratio was 1 g of pure water, 10 g of KOH, 10 g of Na 2 SiO 3 , and 1 g, 3 g and 5 g of Na 4 P 2 O 7 .
The process conditions were as follows: a current density of 0.2 A / cm 2, a plasma power supply waveform of ± 10, +7, ± 10, -3, and a 10 minute process time were applied to the electrolytes of KOH (10 g) and Na2SiO3 to be.
Experimental results of the third experiment
The electrolyte component ratio KOH: Na 2 SiO 3: Na 4 P 2
As the concentration of Na 4 P 2 O 7 as the electrolyte additive increases, the thickness of the film becomes thinner. Na 4 P 2 O 7 has been reported to increase the surface strength and texture densities but slow the formation of the oxide film.
The thermal conductivity, hardness and electrical insulation resistance of each sample were measured. The results are shown in Table 2 below.
Electrolyte conditions KOH: Na 2 SiO 3: Na 4 P 2
( × 10 2 MΩ )
The addition of 5 g of Na 4 P 2 O 7 as the electrolyte additive thinner thickness of 13.4 ㎛ and the thermal conductivity, hardness and electric insulation resistance tend to be poor. This is because the formation rate is slow, Is not formed.
As a result of the above experiment, the process condition was improved to 3 g of Na 4 P 2 O 7 as the electrolyte additive.
However, since the thermal conductivity and the hardness are less than the development target, experiments were conducted to control the process current by increasing the hardness of the oxide film.
8 is a scanning electron microscope (SEM) image of a cross section of an oxide film coated according to a change in current density of a power source in a fourth experiment of the present invention.
[Fourth Experiment]
The current density was changed from 0.20 A / cm2 to 0.18 A / cm2, 0.22 A / cm2 and 0.24 A / cm2.
Experiment result of the fourth experiment
Other process parameters except the current density proceeded in the same manner as in the previous experiment.
In FIG. 8, the film thickness was measured as 13.3 占 퐉 at 0.18 A / cm2, 18.7 占 퐉 at 0.22 A / cm2, and 20.3 占 퐉 at 0.24 A / cm2.
Thermal conductivity, hardness, and electrical insulation resistance were measured for all coated samples. The results are shown in the table below.
At a current density of 0.18 A / cm 2, the thermal conductivity was 1.92 W / m · k and the hardness was 940. At 0.22 A / cm 2, the thermal conductivity was 1.98 W / m · k and the hardness was 1010 Hv and 0.24 A / The thermal conductivity was measured to be 1.98 W / m · k and a hardness of 1000 Hv.
When the current density was 0.22 A / cm2 and 0.24 A / cm2, the hardness was greatly improved, but the thermal conductivity still did not reach 2.0 W / m · k, requiring further process improvement.
Condition
Item
(× 102 MΩ)
However, when comparing the current density of 0.22 A / cm2 with that of 0.24 A / cm2, the current density process was selected as 0.22 A / cm2 because the 0.22 A / cm2 0.24 A / cm2 characteristic did not show any significant difference.
9 is a scanning electron microscope (SEM) image of a cross section of an oxide film coated according to the concentration of the additive for electrolyte solution in the fifth experiment of the present invention.
[Fifth Experiment]
In order to further improve the thermal conductivity of the oxide film, the second additive was considered in the electrolytic solution. The second additive proceeded to H 2 O 2 in consideration of the characteristics of Na 4 P 2 O 7 as the first additive.
The test method was the same as that of the previous process, and H 2 O 2 as an electrolyte additive was mixed with 1 L of pure water to make a composition ratio of 1 g, 3 g, and 5 g.
Result of the fifth experiment
The thickness of the oxide film due to the H 2 O 2 additive was measured to be approximately 19 μm without significant change.
Thermal conductivity, hardness, and electrical insulation resistance were measured for the oxide film thus formed. The results are shown in Table 4 below.
In the case of 1g of additive H 2 O 2, there was no significant change in the characteristics of the oxide film. When 3g of H 2 O 2 was added, thermal conductivity and hardness were improved, and when 5g was added, no significant change was observed.
Condition
Item
( × 10 2 MΩ )
When 3 g of H 2 O 2 was added , the thickness of the oxide film was 19.1 μm, the thermal conductivity was 2.14 W / mk, the Vickers hardness value was 1,060 Hv, and the electrical insulation resistance value was 4.7 × 10 2 MΩ / 500V.
The characteristic value of the oxide film reaches the characteristic value targeted in the development project. The properties of the oxide film were measured with these process values and the prototype was manufactured by applying it to the heat sink.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the present invention as defined by the following claims It can be understood that
Claims (6)
(b) immersing a sample to be coated in the electrolytic solution and generating a plasma on the surface of the sample to be coated through the plasma electrolytic oxidation apparatus; And
(c) forming an oxide film on the coating target sample through the generated plasma.
And applying an electric power of an amplitude modulated AC waveform to the coating object sample through the plasma electrolytic oxidation apparatus to form the oxide coating.
Wherein the waveform is implemented as a {± 10, +7, ± 10, -3} waveform sequence or a {± 10, +3, ± 10, -7} waveform sequence.
Wherein the current density is in the range of 0.18 A / cm2 to 0.24 A / cm2.
Wherein the electrolytic solution comprises at least one selected from the group consisting of potassium hydroxide (KOH), sodium silicate (Na2SiO3), sodium pyrophosphate (Na3P2O7), and hydrogen peroxide (H2O2).
Wherein the concentration ratio of potassium hydroxide (KOH) and sodium silicate (Na2SiO3) in the electrolyte is in the range of 10:10 (g / L) to 5:10 (g / L) and the sodium pyrophosphate (Na3P2O7) And the hydrogen peroxide (H 2 O 2) is added in the range of 1 to 5 g per liter.
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| WO2019198895A1 (en) * | 2018-04-13 | 2019-10-17 | 주식회사 글로우원 | Magnesium led illumination lamp |
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| KR20090083489A (en) | 2006-11-28 | 2009-08-03 | 바스프 에스이 | Method and device for electrolytic coating |
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| KR20090083489A (en) | 2006-11-28 | 2009-08-03 | 바스프 에스이 | Method and device for electrolytic coating |
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| WO2019198895A1 (en) * | 2018-04-13 | 2019-10-17 | 주식회사 글로우원 | Magnesium led illumination lamp |
| JP2020518089A (en) * | 2018-04-13 | 2020-06-18 | グローワン カンパニー リミテッド | Magnesium LED lighting |
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