KR101543926B1 - Color-treated magnesium and color-treatment method thereof - Google Patents

Abstract

The present invention relates to a color-treated magnesium and a magnesium color-treating treatment method therefor. According to the present invention, when forming a hydroxide film that is a chromogenic film on a magnesium surface, a different temperature region is formed on the surface to induce a thickness variation of the hydroxide film, whereby one or more hues can be obtained by performing a chromogenic treatment on the magnesium surface . Accordingly, the color-treated magnesium according to the present invention can be effectively used in the field of electric and electronic parts such as building exterior materials, automobile interior, mobile phone case parts, etc., in which magnesium materials are used.

Description

COLOR-TREATED MAGNESIUM AND COLOR-TREATMENT METHOD THEREOF [0002]

The present invention relates to a color-treated magnesium and a magnesium color-treating treatment method therefor.

Magnesium is a metal belonging to an ultra-light metal among practical metals, has excellent abrasion resistance, is strong in sunlight and environmentally friendly, but has difficulty in realizing metal texture and various colors. In addition, since it is extremely active as an electrochemically lowest metal, if it is not color-treated, it is very quickly corroded in the air or in a solution, so that it is difficult to apply to industry.

In recent years, due to the trend toward lighter weight of the industry, the magnesium industry has been attracting attention, and research has been actively conducted to improve such problems of magnesium with the trend of metal casing materials in electric and electronic parts materials such as mobile phone case parts .

As a result, a PVD-sol-gel method in which a metal-containing material is dry-coated and then sol-gel coated to obtain a metal texture and corrosion resistance on a magnesium alloy surface; Anodic oxidation method for imparting gloss to the magnesium surface by chemical polishing and coloring the substrate surface by anodizing the magnesium base material with the basic electrolyte in which the pigment is dissolved has been developed (Patent Documents 1 and 2).

However, in the case of the PVD-sol-gel method, a metal texture is formed on the surface of the magnesium substrate, but it is not a metal texture inherent to magnesium, and it is difficult to realize various colors. In addition, when the surface of the magnesium base material is subjected to color development treatment using the anodic oxidation method, an opaque oxide film is formed on the surface of the base material, and it is difficult to realize the metal texture inherent to magnesium.

Therefore, in order to put magnesium into practical use, there is a desperate need for a technique for chemically, electrochemically, or physically treating the surface of a magnesium substrate to improve resistance to corrosion and to realize a desired color on the surface of magnesium.

Korean Patent Publication No. 2011-0016750; Korea Patent Publication No. 2011-0134769.

An object of the present invention is to provide a color-treated magnesium.

It is another object of the present invention to provide a method for treating magnesium with color-developed magnesium.

In order to achieve the above object,

In one embodiment, the present invention relates to a method of manufacturing a semiconductor device comprising: a magnesium matrix; And a hydroxide film formed on the surface of the magnesium matrix,

For any point A present on the magnesium matrix,

Color-treated magnesium satisfying the following equations (1) and (2): < EMI ID =

[Equation 1]

? E ₁ < 1.0

&Quot; (2) &quot;

ΔE ₂ > 2.0

Here,? E ₁ denotes a deviation between color coordinates of an arbitrary point B on the same axis as the color coordinate at the point A, and? E ₂ denotes a color coordinate of the point A on the second axis having a deviation of 75 ° to 105 ° from the first axis And the deviation between the color coordinates of the point C at a distance of 3 cm or more.

The present invention also provides, in another embodiment, a process for preparing magnesium, comprising the step of immersing magnesium in a hydroxide solution,

Magnesium immersed in the hydroxide solution,

A region having a first temperature (T ₁ ); And

A region having a second temperature (T &lt; ₂ &gt;),

And the difference between the first temperature (T ₁ ) and the second temperature (T ₂ ) is 5 ° C or more.

In the color-treated magnesium of the present invention, one or more hues can be obtained by performing a color development treatment on the magnesium surface by forming a different temperature region on the surface of the magnesium surface to form a chromatic film, which is a chromogenic film, to induce a thickness variation of the hydroxide film . In addition, the surface of magnesium is homogeneous to maintain the texture of magnesium, and scratch resistance and durability can be improved by including a clear layer.

1 is an image of a magnesium-coated magnesium film in one embodiment:
At this time, the point A is an arbitrary point existing on the magnesium surface,
Point B is an arbitrary point existing on the first axis, and
The point C is at a point at a distance of 3 cm or more from the point A on a second axis having a deviation? Between 75 占 and 105 占 with the first axis;
Fig. 2 is an image showing the structure of the color-treated magnesium in one embodiment; Fig.
FIG. 3 is an image obtained by scanning electron microscope (SEM) photographing of the surface of the chromogenic magnesium in one embodiment; FIG.
4 is a schematic view showing the structure of a color-treated magnesium having a patterned structure according to the present invention;
5 is a schematic view showing a structure of a color-treated magnesium having a patterned structure according to the present invention;
FIG. 6 is an image of a surface of a magnesium-treated magnesium according to the type of hydroxide solution in one embodiment. FIG. Here, I is a specimen immersed in a 10% NaOH aqueous solution at 100 ° C. for 40 minutes, II is a specimen immersed in distilled water at 100 ° C. for 40 minutes, III is a specimen immersed in distilled water at 100 ° C. for 1 hour, And IV are specimens immersed in distilled water at 100 DEG C for 2 hours;
FIG. 7 is an image obtained by scanning electron microscopy of the surface of the chromogenic magnesium according to the type of hydroxide solution in one embodiment. FIG. Here, I is a specimen immersed in a 10% NaOH aqueous solution at 100 ° C. for 40 minutes, II is a specimen immersed in distilled water at 100 ° C. for 40 minutes, III is a specimen immersed in distilled water at 100 ° C. for 1 hour, And IV are specimens immersed in distilled water at 100 DEG C for 2 hours;
11 is an image showing the thickness of a chromogenic film formed on the surface of magnesium and the shape of the surface of the chromium film according to the time of color development in one embodiment. In this case, A is an image obtained by measuring the thickness of a chromogenic film using a transmission electron microscope (TEM), B is an image taken by a scanning electron microscope (SEM) of the surface shape; And
FIG. 12 is an image showing the change in color of magnesium undergoing color development according to immersion time of magnesium hydroxide solution in one embodiment; FIG.
FIG. 13 is an image of a result of performing a cross-cut tape test method of color-cured magnesium containing a clear layer in one embodiment. In this case, A is an experimental result on a test piece including a matte clear coating layer And B is the experimental result for the specimen including the glossy / matt clear coating layer.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the present invention, the terms "comprising" or "having ", and the like, specify that the presence of a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Hereinafter, the present invention will be described in detail with reference to the drawings, and the same or corresponding components are denoted by the same reference numerals regardless of the reference numerals, and a duplicate description thereof will be omitted.

In the present specification, "%" can be used as a concentration unit of a solution. Specifically, for example, a 10% NaOH solution means a solution in which 900 mL of water and 100 g of NaOH are mixed.

The present invention provides a color-treated magnesium and a magnesium color-treating treatment method therefor.

Conventionally, as a method of embodying a color in a magnesium material, a PVD-sol-gel method and an anodic oxidation method in which a magnesium-containing surface is coated with a metal-containing material or a pigment are known. However, these methods may not realize the metal texture inherent to magnesium, or the durability of magnesium may deteriorate. Further, it is difficult to realize various colors, and the coating layer to be coated easily peels off, failing to satisfy the reliability.

In order to overcome these problems, the present invention proposes a color-treated magnesium and a magnesium coloring treatment method therefor. The color-treated magnesium according to the present invention is a color-coded coating formed on a magnesium surface by forming a different temperature region on the surface to induce a thickness variation of the hydroxide film, .

Hereinafter, the present invention will be described more specifically.

The present invention relates to a magnesium matrix; And a hydroxide film formed on the surface of the magnesium matrix,

For any point A present on the magnesium matrix,

Color-treated magnesium satisfying the following equations (1) and (2): &lt; EMI ID =

[Equation 1]

? E ₁ < 1.0

&Quot; (2) &quot;

ΔE ₂ > 2.0

Here,? E ₁ denotes a deviation between color coordinates of an arbitrary point B on the same axis as the color coordinate at the point A, and? E ₂ denotes a color coordinate of the point A on the second axis having a deviation of 75 ° to 105 ° from the first axis And the deviation between the color coordinates of the point C at a distance of 3 cm or more.

Fig. 1 is an image of a magnesium-coated magnesium film in one embodiment.

Referring to FIG. 1, in one embodiment, for any point A present on the magnesium matrix, the color coordinate deviation with any point B present on the first axis may satisfy? E ₁ <1.0. At this time, the above-mentioned? E ₁ means the color coordinate deviation of the point A and the point B, and the definition is as shown in the following equation (4). Also, when ΔE ₁ is 1.0 or less, it means that the point A and the point B produce the same color uniformly.

&Quot; (4) &quot;

Further, the color coordinate deviation of the point C existing at a point at a distance of 3 cm or more from the point A on the second axis forming the deviation? Between 75 ° and 105 ° with the first axis can satisfy? E ₂ > 2.0. Specifically, it may be satisfactory to ΔE _2> 2.5. This means that the point A and the point C do not have the same color but different colors. At this time, the larger the distance between the point A and the point C, the larger the color coordinate deviation can be.

In the color-treated magnesium according to the present invention, the deviation of the thickness of the hydroxide film at any point A present on the magnesium matrix and the thickness of the hydroxide film at the point C existing on the second axis can satisfy the following equation :

&Quot; (3) &quot;

10 nm || d ₁ - d ₂ |

Where d ₁ is the thickness of the hydroxide film at point A, and d ₂ is the thickness of the hydroxide film at point C.

Fig. 2 is an image showing the structure of magnesium subjected to color development in one embodiment. Fig.

Referring to FIG. 2, a hydroxide film is formed on the magnesium matrix. The formed hydroxide film may have a structure having a thickness variation rather than a structure having the same thickness. That is, the hydroxide film thickness d ₁ at an arbitrary point A on the magnesium matrix may have a thickness difference with the hydroxide film thickness d ₂ at the point C existing on the second axis. The larger the deviation of the thickness of the hydroxide film of the two points is, the larger the color coordinate deviation of the two points is, and the thickness deviation thereof may be 10 nm or more.

At this time, the thickness of the hydroxide film according to the present invention is not particularly limited, but may be 50 nm to 2 탆, more specifically, 100 nm to 1 탆.

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Here, the kind of the hydroxide film according to the present invention is not particularly limited as long as it can scatter and refract the light incident on the surface, and specifically may be a magnesium hydroxide.

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In one embodiment, it is confirmed that magnesium hydroxide (Mg (OH) ₂ ) is a component of the hydroxide film formed on the surface after immersing the magnesium specimen in the hydroxide solution for 80 minutes, 170 minutes, and 240 minutes.

Meanwhile, the color-treated magnesium according to the present invention may have a structure in which the magnesium surface is patterned.

4 and 5 are schematic views showing the structure of magnesium having a patterned structure according to the present invention.

Referring to FIGS. 4 and 5, the color-treated magnesium according to the present invention has a structure in which the hydroxide film 102 or 202 is laminated on the magnesium matrix 101 or 201. Here, the pattern to be introduced into the magnesium surface is divided into a patterning region 103 or 203 and a non-patterning region 104 or 204, and a difference in thickness between the two regions is set so that a color difference The pattern can be introduced by. At this time, the thickness deviation of the patterned region 103 or 203 and the hydroxide film 102 or 202 of the non-patterned region 104 or 204 may satisfy the following expression (5).

&Quot; (5) &quot;

5 nm ≤│T ₁ - T ₂ │ <2.0 μm

Here, T ₁ denotes the average thickness of the hydroxide film of the non-patterned region 104 or 204, and T ₂ denotes the average thickness of the hydroxide film of the patterned region 103 or 203.

Specifically, Equation (5) may show a deviation of the average thickness of the hydroxide film of the non-patterned region (104 or 204) and the average thickness of the hydroxide film of the patterned region (103 or 203). More specifically, the deviation of the average film thickness of the non-patterned region 104 or 204 and the patterned region 103 or 203 may be between 5 nm and 2.0 μm. For example, the average thickness variation may be between 5 nm and 100 nm, between 50 nm and 0.5 μm, or between 0.5 and 2.0 μm. The average thickness deviation of the hydroxide film 102 or 202 may be adjusted within the above range to induce a color difference between the non-patterned region 104 or 204 and the patterned region 103 or 203.

The color-treated magnesium according to the present invention may further comprise a clear layer formed on the hydroxide film.

The clear layer may further include magnesium to improve the scratch resistance and durability of the surface. At this time, the clear coating agent for forming the clear layer is not particularly limited as long as it is a clear coating agent applicable to metal coating. More specifically, a matt clear coating agent or a glossy / matt clear coating agent applicable to a metal coating can be given.

In addition, the color-treated magnesium according to the present invention may further include a metal layer between the hydroxide film and the clear layer.

More specifically, the magnesium may have a structure in which a metal layer and a clear layer are sequentially formed on the hydroxide film. The metal layer can prevent the hue realized by the hydroxide film from being discolored by the clear layer.

At this time, if the color component of the metal layer is capable of maintaining the color developed by the hydroxide film by minimizing the refraction and scattering of the chromatic light refracted and scattered in the hydroxide film and inducing the reflection of the wavelength, The form is not particularly limited. Specifically, it may include at least one metal selected from the group consisting of Al, Cr, Ti, and Au. In addition, the metal layer may be included in various forms such as metal ions, metal oxides, and metal particles.

The thickness of the metal layer according to the present invention is not particularly limited as long as it can prevent discoloration of the color developed by the hydroxide film. In particular, the condition of 10 nm to 50 nm can be satisfied. Specifically, the thickness of the metal layer is from 10 nm to 20 nm; 15 nm to 40 nm; Or from 30 nm to 50 nm.

Further, the color-treated magnesium having the clear layer according to the present invention may have a clear layer peel ratio of 5% or less when the adhesion is evaluated after 72 hours at 35 ° C under 5% salt water spraying conditions.

Referring to FIG. 13, in one embodiment, a color-treated magnesium having a matte or glossy / non-matte clear layer according to the present invention is sprayed with 5% salt water at 35 DEG C and after 72 hours, a cross- , It can be confirmed that the area of the peeled clear layer is 5% or less as compared with the entire area of the specimen.

From these results, it can be seen that the magnesium in which the clear layer according to the present invention is formed has excellent adhesion between the magnesium-colored layer and the clear layer.

The present invention also includes, in one embodiment, a process for preparing magnesium, comprising the step of immersing magnesium in a hydroxide solution,

Magnesium immersed in the hydroxide solution,

A region having a first temperature (T ₁ ); And

A region having a second temperature (T &lt; ₂ &gt;),

And the difference between the first temperature (T ₁ ) and the second temperature (T ₂ ) is 5 ° C or more.

The method for color development treatment of magnesium according to the present invention can be carried out by immersing the magnesium matrix in a hydroxide solution to form a hydroxide film on the surface. At this time, a region having a different temperature is formed on the surface of the magnesium matrix when dipped in a hydroxide solution so as to induce a thickness variation of the hydroxide film. At this time, the temperature difference between the first temperature T ₁ and the second temperature T ₂ having different temperatures may be 5 ° C or more, specifically 10 ° C or more. For example, the temperature difference may be below 60 占 폚.

More specifically, in one embodiment, a vessel containing an aqueous solution of 10% NaOH at 100 占 폚 may be placed in a heating reactor heated to 150 占 폚, and the bottom of the vessel may be adjusted to 150 占 폚 by a heating reactor hot wire. Thereafter, the magnesium surface of the magnesium surface can be treated by immersing the container in a volume of 4 cm x 7 cm once for 80 minutes. Here, the magnesium surface is immersed in an aqueous solution of NaOH and maintained at a surface temperature of at least 100 ° C, and at a position distant from the bottom of the container, the surface temperature gradually increases to a point contacting the bottom of the container heated to 150 ° C Area.

The first temperature (T ₁ ) and the second temperature (T ₂ ) according to the present invention may be 95 ° C or higher. For example, a method may be employed in which color development proceeds while a temperature of 100 ° C or more is adjacent to one side of magnesium while controlling the average temperature of the hydroxide solution to 100 ° C or less.

More specifically, the first temperature T ₁ may be in the range of 95 to 100 ° C, 98 to 105 ° C, or 100 to 115 ° C. Further, the second temperature (T ₂ ) may be in the range of 100 to 115 ° C, 105 to 120 ° C, or 105 to 150 ° C. The first temperature T ₁ and the second temperature T ₂ are not particularly limited as long as various colors can be achieved through a temperature difference.

In addition, as the hydroxide solution according to the present invention, a solution containing hydroxyl group (-OH group) is not particularly limited. More specifically, a solution in which at least one member selected from the group consisting of NaOH, KOH, Mg (OH) ₂ , Ca (OH) ₂ and Ba (OH) ₂ is dissolved can be used.

Referring to FIGS. 6 and 7, it can be seen that the magnesium using the NaOH solution has a high color development speed, strong color, and a uniform magnesium surface. However, in the case of magnesium using distilled water, the color development speed is four times slower than that in the case of using NaOH solution, the color development is weak, and the surface of magnesium is not uniform.

From these results, it can be seen that when a solution such as a NaOH solution is used as the hydroxide solution, the hydroxide film is formed rapidly on the magnesium surface, the color development speed is fast, and the surface is uniform.

Further, in the magnesium color development treatment method according to the present invention, the concentration of the hydroxide solution may be 1% to 40%, more specifically 5% to 20%. In addition, the hydroxide solution may be run at a temperature ranging from 90 占 폚 to 200 占 폚, more specifically from 100 占 폚 to 150 占 폚, and still more specifically from 95 占 폚 to 110 占 폚. In addition, the color development treatment time can be performed for 1 minute to 500 minutes, specifically 10 minutes to 90 minutes. It is possible to economically realize various colors on the magnesium surface in the range of the magnesium coloring treatment conditions and to prevent the intrinsic gloss of magnesium from decreasing due to the increase in the thickness of the hydroxide film.

Referring to FIGS. 11 and 12, it can be seen that the thickness of the hydroxide film formed on the magnesium surface increases according to the elapsed time of the chromogenic treatment of magnesium, and the color developed is changed. This means that the color developed by the hydroxide film changes depending on its thickness.

Accordingly, it is possible to control the rate of formation of the hydroxide film on the magnesium surface by controlling the coloring treatment conditions such as the concentration of the hydroxide solution, the immersion temperature, and the immersion time, and it can be seen that the color developed on the magnesium surface can be controlled.

Meanwhile, the magnesium color development treatment method according to the present invention may include: electrolytic degreasing using an alkaline cleaning solution before the step of immersing magnesium in a hydroxide solution; And

After the step of immersing the magnesium in the hydroxide solution, the step of rinsing may further include at least one of the steps.

The electrolytic degreasing step is a step of electrolytically degreasing the magnesium surface with an alkaline cleaning liquid before the magnesium is immersed in the hydroxide solution, thereby cleaning the contaminants on the magnesium surface. At this time, the alkaline cleaning liquid is not particularly limited as long as it is commonly used for cleaning the surface of the metal.

In addition, the step of rinsing is a step of removing the hydroxide solution remaining on the magnesium surface by rinsing the magnesium surface after the step of immersing the magnesium in the hydroxide solution. In this step, by removing the hydroxide solution remaining on the magnesium surface, it is possible to prevent the formation of additional hydroxide film by the residual hydroxide solution.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples.

However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the present invention is not limited to the following Examples and Experimental Examples.

Example 1

A magnesium specimen of 4 cm x 7 cm was immersed in an alkaline cleaning liquid and degreased. Thereafter, a vessel containing an aqueous solution of NaOH at 100 캜 was placed in a heating reactor having a surface heated to 150 캜, and the bottom of the vessel was adjusted to 150 캜 by a heating coil of a heating reactor. The magnesium specimens were immersed in the vessel for 80 minutes to rinse the specimens with distilled water and then dried in a drying oven to prepare color-treated magnesium specimens.

When the magnesium specimen was observed with the naked eye, it was confirmed that at least one color such as red, yellow, and green was developed on the surface. The results are shown in Fig. Also, the surface of the specimen was observed by a scanning electron microscope (SEM) and the surface morphology of the laminated hydroxide film was observed. The results are shown in FIG.

As shown in FIG. 3, the surface of the magnesium according to the present invention is homogeneous, and the texture of magnesium is maintained without deforming the surface shape.

Example 2

A magnesium specimen of 4 cm x 7 cm was immersed in an alkaline cleaning liquid and degreased. Thereafter, a vessel containing an aqueous solution of 10% NaOH at 100 占 폚 was placed in a heating reactor having a surface heated to 150 占 폚, and the bottom of the vessel was adjusted to 150 占 폚 by a heating reactor heating wire. A 4 cm x 7 cm magnesium specimen was immersed in the vessel once for 80 minutes, the specimen was rinsed with distilled water, and then dried in a drying oven. Thereafter, a chromium (Cr) layer was formed on the hydroxide film by a sputtering method and matt clear coating was carried out to prepare a color-treated magnesium in which a matte clear layer was formed. At this time, the thickness of the coated matt clear is 5 占 퐉 or less.

Example 3

The procedure of Example 2 was repeated to prepare a colorless magnesium-coated magnesium / chromium-coated specimen, except that the gloss / clear coating was performed instead of the matte clear coating in Example 2. At this time, the coated glossy / non-glossy clear thickness is 5 占 퐉 or less.

Experimental Example 1. Evaluation of surface change of magnesium according to hydroxide solution

The following experiment was conducted to evaluate the surface change of the color-treated magnesium according to the solvent used as the hydroxide solution.

First, a magnesium specimen of 1 cm X 1 cm was immersed in an alkaline cleaning solution to degrease, and the degreased specimen was immersed in a 10% NaOH solution at 100 ° C for 40 minutes. Thereafter, the specimen was rinsed with distilled water and dried in a drying oven to prepare a color-treated magnesium specimen I.

Next, magnesium specimens II to IV were prepared in the same manner as above except that distilled water was used instead of aqueous NaOH solution and the immersion time was adjusted to 40 minutes, 1 hour and 2 hours, respectively.

The color of the specimens was visually evaluated, and the surface of each specimen was evaluated by scanning electron microscopy (SEM). The results are shown in Fig. 6 and Fig.

Referring to Figures 6 and 7, the color development processing of magnesium according to the invention is short by processing color hydroxide solution, or the like NaOH, KOH, Mg (OH) 2, Ca (OH) 2, Ba (OH) 2 It can be seen that the hydroxide film is uniformly formed within the time.

Referring to FIG. 6, the specimen I of Example 1 treated with NaOH solution as a hydroxide solution shows a faster color development rate of the specimen as compared with the specimen using distilled water as the hydroxide solution. More specifically, in the case of the sample I treated with NaOH solution, it was confirmed that silver color was developed at the time when the immersion time was 10 minutes, and then it was confirmed to be orange color within 40 minutes after gold coloring. However, immersion of the Comparative Examples 1 to 3 of the specimen to the specimen Ⅱ Ⅳ treated with distilled water and the process time of 40 minutes the specimen Ⅱ was born larger color difference and a color-developing the color change amount mimihayeo untreated magnesium. In addition, the specimen Ⅲ , which had an immersion time of 1 hour, gradually developed color and developed a yellow color, and the specimen Ⅳ, which had been dipped for 2 hours, showed a gold color.

Next, referring to FIG. 7, it can be seen that the surface of the magnesium specimen subjected to color development by using the hydroxide solution containing NaOH is uniform. More specifically, the surface of the specimen I subjected to color development treatment with 10% NaOH solution was uniform throughout. However, in the case of specimens II to IV treated with magnesium surface using distilled water, it was confirmed that the magnesium surface was not uniform.

From this, the color development processing of magnesium according to the invention are hydroxide solution, such as distilled water by color development processing of magnesium hydroxide solution, or the like NaOH, KOH, Mg (OH) 2, Ca (OH) 2, Ba (OH) 2 It can be seen that a hydroxide film as a chromogenic film is formed within a short time as compared with magnesium that has undergone chromogenic treatment. In addition, it can be seen that the magnesium has excellent magnesium texture since the hydroxide film is homogeneously formed without surface deformation and the surface is uniform.

EXPERIMENTAL EXAMPLE 2 Evaluation of color development of magnesium according to immersion time of a hydroxide solution

The following experiment was conducted to evaluate the degree of color development according to the immersion time of the magnesium hydroxide coloring solution according to the present invention.

A 1 cm X 1 cm magnesium specimen was immersed in an alkaline cleaning solution and degreased. The degreased specimen was immersed in a 10% NaOH solution at 100 ° C for 240 minutes. At this time, immediately after immersing the magnesium specimen in the NaOH solution, the color of the specimen was visually evaluated at intervals of 5 to 10 minutes. In order to confirm the state of the hydroxide film formed on the surface, analysis of the surface components of the color-treated specimen, transmission electron microscope and scanning electron microscope (SEM) were performed at 80 minutes, 170 minutes and 240 minutes after immersion . The results are shown in FIG. 11 and FIG.

Referring to FIG. 11, it can be seen that the chromogenic film component formed on the magnesium surface is magnesium hydroxide (Mg (OH) ₂ ), and the thickness of the film increases as the immersion time in the hydroxide solution becomes longer have. More specifically, as a result of examining the composition of the chromogenic film on the specimen after 80 minutes, 170 minutes and 240 minutes after immersing the magnesium specimen in the hydroxide solution, the components of the chromogenic film were magnesium hydroxide (Mg (OH) ₂ ). Also, the thickness of the magnesium hydroxide film was found to increase with the passage of time to 400 nm, 700 nm and 800 nm, respectively.

Next, referring to FIG. 12, it can be seen that the color-developed magnesium is colored in various colors depending on the immersion time in the hydroxide solution. More specifically, when the untreated silver magnesium specimen is immersed in a hydroxide solution, the color gradually develops to gold, red, purple, indigo and green as time elapses, and the color developed is repeated with a constant cycle .

From this, it can be seen that the color-treated magnesium according to the present invention is colored by the magnesium hydroxide (Mg (OH) ₂ ) coating formed through the immersion of the hydroxide solution. Also, as the immersion time passes, the thickness of the coating formed on the surface increases, and various colors can be realized by changing the thickness of the coating depending on the immersion condition.

EXPERIMENTAL EXAMPLE 3 Evaluation of Color Evaluation of Color-Treated Magnesium

The following experiment was conducted to evaluate the uniformity and diversity of the color developed by the color-developed magnesium according to the present invention.

An arbitrary point A existing on the magnesium specimen produced in Example 1 was set and the color coordinates (L *, a *, b *) at point A were measured. Further, as shown in Fig. 1, an arbitrary point B existing on the first axis with respect to the point A was set, and the color coordinates of the point B were measured. Further, a point C existing at a point 3 cm apart from the point A is present on a second axis which forms a deviation (?) Of 75 ° to 105 ° with the first axis, and a color coordinate Respectively. The deviations of the color coordinates of the three points measured above were measured to evaluate the uniformity and diversity of colors developed on the magnesium surface. The results are shown in Table 1 below. At this time, the color coordinate deviation (? E) was derived using the following equation (4).

&Quot; (4) &quot;

Any point L * a * b * DELTA L * Δa * Δb * ΔE * A 47.66 7.67 -1.88 - - - - B 47.61 8.02 -1.42 0.05 -0.35 -0.46667 0.58547227 C 53.75 -7.35 10.71 6.09 15.02 12.59 20.523075

As shown in Table 1, it can be seen that the color-treated magnesium according to the present invention can realize one or more colors on the surface of magnesium by a single color development treatment and has excellent color uniformity for the same color.

More specifically, the color coordinate deviation (ΔE ₁ ) of the point A existing on the magnesium specimen subjected to the color development treatment in Example 1 and the arbitrary point B existing on the first axis with respect to the point A is 0.585 and ΔE ₁ <1.0 Satisfaction. Further, the first axis and 75 ° to and present on the second axis constituting the deviation (α) of 105 °, the color coordinate deviation of the point A with the point C, which distance is present in the 3 cm point (ΔE ₂₎ is a 20.523 , And ΔE ₂ > 2.0. This means that the point B is uniformly colored with the same color as the point A, and the point C means that the color completely different from the point A is developed.

1 showing the specimen of Example 1, the specimen was immersed so that its lateral side was in contact with the bottom of the container at 150 ° C, and color was discolored based on the specimen region abutted against the bottom of the container. That is, the points A and B where the hydroxide film is formed on the magnesium matrix at the same temperature can produce the same hue satisfying? E ₁ <1.0 because the thickness variation of the hydroxide film as the chromogenic film is remarkably low.

On the other hand, in the case of the point C where the temperature difference at which the hydroxide film with the point A is formed is 5 DEG C or more, a completely different color satisfying DELTA E2 &_gt; 2.0 is developed due to the thickness deviation of the hydroxide film of 10 nm or more.

From this, it can be seen that the color-treated magnesium according to the present invention provides a different temperature range on the magnesium surface during the formation of the hydroxide film, which is a chromogenic film, to induce a thickness variation of the hydroxide film, .

EXPERIMENTAL EXAMPLE 4. Evaluation of Physical Properties of Color-Treated Magnesium Having a Clear Layer

The following experiment was conducted to evaluate the adhesion and corrosion resistance of the color-treated magnesium having the clear layer according to the present invention.

In the above Example 2 and Example 3, the color of the color-treated magnesium specimen before coating the clear layer and the color of the color-treated magnesium in which the clear layer was formed were visually compared.

Further, magnesium chloride color-treated in Examples 2 and 3 was uniformly sprayed with salt water having a salt concentration of 5% and a temperature of 35 캜 using a salt spray tester (SST, Salt Spray Tester) The surface of the plate material after the elapse was visually observed. Thereafter, the adhesion between the magnesium-colored layer and the clear layer was evaluated. At this time, the adhesion was evaluated by a cross-cut tape test method. More specifically, a coated clear layer was cut using a knife so as to intersect the 6 horizontal lines and the 6 vertical lines at intervals of 1 mm. Thereafter, the tape was firmly attached to the intersection of the horizontal line and the vertical line, and the peeling area of the thin film relative to the entire area of the sample at the time of fast peeling was evaluated. The results are shown in Fig.

As shown in Fig. 13, it can be seen that the color-treated magnesium according to the present invention has excellent corrosion resistance and excellent adhesion between magnesium and the clear layer. More specifically, the specimens of Examples 2 and 3, in which a matte or glossy / non-matte clear layer was formed, were found to be salty fountain and showed no surface deformation due to corrosion even after 72 hours.

Further, as a result of the adhesion test between the magnesium layer and the clear layer subjected to the color development treatment with respect to the specimen on which the surface corrosion test was performed, it was confirmed that the area of the clear layer peeled off to the tape was 5% or less of the total area.

From this, it can be seen that the color-developed magnesium having a clear layer has improved corrosion resistance against salt water, and the adhesion between the clear layer and the magnesium subjected to color development is excellent.

Therefore, in the magnesium color development treatment method of the present invention, since the magnesium matrix containing the region having different temperatures is immersed in the hydroxide solution to induce the thickness variation of the hydroxide film as the chromogenic film, Can be implemented. In addition, the hydroxide film formed on the magnesium surface is uniformly laminated without surface deformation, and the surface of the magnesium that has undergone color development is homogeneous, so that the texture inherent to magnesium can be maintained and the internal property is excellent.

101: Magnesium matrix
102: hydroxide film
103: patterning area
104: non-patterning area
201: Magnesium matrix
202: Hydroxide film
203: patterning area
204: non-patterning area.

Claims (12)

Magnesium matrix; And a hydroxide film formed on the surface of the magnesium matrix,
For any point A present on the magnesium matrix,
Color-treated magnesium satisfying the following equations (1) and (2): <
[Equation 1]
? E ₁ &lt; 1.0
&Quot; (2) &quot;
ΔE ₂ > 2.0
Here,? E ₁ denotes a deviation between color coordinates of an arbitrary point B on the same axis as the color coordinate at the point A, and? E ₂ denotes a color coordinate of the point A on the second axis having a deviation of 75 ° to 105 ° from the first axis And the deviation between the color coordinates of the point C at a distance of 3 cm or more.
The method according to claim 1,
The deviation of the hydroxide film thickness of the point A existing on the magnesium matrix and the hydroxyl film thickness of the point C existing on the second axis is expressed by the following expression:
&Quot; (3) &quot;
10 nm ≤│d ₁ -d ₂ │
Where d ₁ is the thickness of the hydroxide film at point A, and d ₂ is the thickness of the hydroxide film at point C.
The method according to claim 1,
And the thickness of the hydroxide film is 50 nm to 2 占 퐉.
delete The method according to claim 1,
The hydroxide film is a magnesium hydroxide, which is a color-treated magnesium.
The method according to claim 1,
A color-treated magnesium further comprising a clear layer formed on the hydroxide film.
The method according to claim 6,
The color-developed magnesium having the clear layer formed thereon,
In the evaluation of adhesion after 72 hours at 35 DEG C and 5% salt spray,
The degree of peeling of the clear layer is 5% or less,
The concentration unit% of the saline solution represents the weight percentage of the salt dissolved in the saline solution.
Immersing the magnesium in the hydroxide solution,
Magnesium immersed in the hydroxide solution,
A region having a first temperature (T ₁ ); And
A region having a second temperature (T &lt; ₂ &gt;),
Wherein the difference between the first temperature (T ₁ ) and the second temperature (T ₂ ) is 5 ° C or higher.
9. The method of claim 8,
Wherein the first temperature (T ₁ ) and the second temperature (T ₂ ) are independently 95 ° C or higher.
9. The method of claim 8,
Wherein the hydroxide solution comprises at least one selected from the group consisting of NaOH, KOH, Mg (OH) ₂ , Ca (OH) ₂ and Ba (OH) ₂ .
9. The method of claim 8,
In the step of immersing magnesium in the hydroxide solution,
The concentration of the hydroxide solution is 1% to 40%
Wherein the concentration unit% represents the weight percentage of the salt dissolved in the brine.
9. The method of claim 8,
Prior to the step of immersing the magnesium in the hydroxide solution,
Electrolytic degreasing using an alkaline cleaning liquid; And
After the step of immersing the magnesium in the hydroxide solution, the step of rinsing
The method further comprising at least one of the steps of:

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