KR20190110178A - High Corrosion Resistant Surface Treatment Coating Method of Magnesium Die-Casting Alloy - Google Patents

Abstract

According to the present invention, a high-corrosion-resistant surface treatment coating method for a magnesium diecasting alloy includes the following steps of: (a) casting and post-treating a magnesium alloy material; (b) coating the magnesium alloy material with Al and forming an intermetallic compound after the step (a); (c) pretreating and painting the magnesium alloy material after the step (b); and (d) plating the magnesium alloy material after the step (c). Therefore, Mg17Al12 and Mg2Al3 layers, which are Mg-Al intermetallic compounds, are formed to secure high-corrosion resistance, and glosses of various colors can be maintained without discoloration caused by the aging of colors after the elapse of a predetermined time, and also, weight lightening and a cost reduction are possible.

Description

High Corrosion Resistant Surface Treatment Coating Method of Magnesium Die-Casting Alloy

The present invention relates to a surface treatment coating method for securing high corrosion resistance of magnesium die casting alloy, and before coating, forming a compound layer between Mg-Al metal by NCP process treatment technology, which is a non-chromium coating technology, to enhance corrosion resistance and corrosion. It is possible to prevent the occurrence of the present invention relates to a surface treatment coating method of magnesium die casting alloy that can ensure more improved product reliability.

With the recent development of industrial technology for communication parts, the properties of lightweight materials and their development have been concentrated. In particular, magnesium (Mg) is the lightest metal among the metal materials used for structural purposes. It is known and has a density of 1.74 (g / cm ² , room temperature) and has a significantly lower density than other metals such as aluminum (Al), titanium (Ti), and iron (Fe).

On the other hand, magnesium has higher rigidity and strength than conventional plastics, has excellent workability, and can be thinned. Therefore, magnesium has high precision and high value added, which requires technologies in various fields such as design, precision mold, precision processing, metallurgy, and painting. As a product, the usage is rapidly expanding in the fields of automotive, aerospace, electric and electronic communication parts. In addition, magnesium alloy is a light alloy that has a mechanical strength by adding various elements to magnesium, computer, OA equipment, video, audio, MD / CD player case, television frame, portable electronic devices, laptop computer, MP3 player, digital camera It is a material of major parts of electric, electronic and information communication that requires light weight and high strength, such as TV camera, liquid crystal projector, etc., and is a material of major parts of the vehicle such as steering wheel, center fascia, cylinder head and ventilation fan, and fishing or climbing It is a material of major parts of high-grade lightweight sporting goods and is applied as a new material in aerospace field.

However, magnesium alloys have a relatively low standard electrode potential, which is very poor in corrosion resistance. Therefore, the surface treatment of magnesium alloys is essential. In addition, surface treatment is also required to improve surface functions such as appearance characteristics and wear resistance characteristics of magnesium alloy products.

On the other hand, forming a thin film of an oxide film or an inorganic salt by chemical treatment on the metal surface is called chemical conversion treatment, in order to apply excellent properties such as anticorrosion, coating, painting, coloring to the metal.

Korean Patent Publication No. 10-0967713 relates to a surface treatment method of magnesium alloy and a surface-treated magnesium alloy, comprising the steps of chemically treating the surface of the magnesium alloy, corrosion-resistant coating of the surface of the chemically treated magnesium alloy with a corrosion resistant coating composition It discloses a method of surface treatment of magnesium alloy to improve the corrosion resistance of the surface of the magnesium alloy, including the step, coating the surface of the corrosion-resistant coated magnesium alloy with a coating composition.

However, in the conventional technology as described above, there is a problem in that chemical waste is generated in the step of chemically treating the surface of the magnesium alloy and in the coating of the corrosion resistance, and the chemical waste is generated. The surface of the degreased and degreased magnesium plate is washed, the surface of the cleaned magnesium plate is etched, the surface of the etched magnesium plate is rinsed, the surface of the cleaned magnesium plate is desmuted, and the surface of the desmuted magnesium plate is cleaned. Economic losses are incurred due to complex processes, including the steps of.

In addition, various thick film coating (approximately tens of micrometers) processes have been applied to overcome the disadvantages that are very susceptible to corrosion of magnesium alloy materials, but the thickness of the magnesium oxide coating layer after the surface treatment is several micrometers thin due to the application characteristics of the electronic component parts. A uniform coating treatment technology is required while forming an oxide layer having excellent corrosion resistance and wear resistance.

On the other hand, in the case of the aluminum alloy material (Al ² O ₃ ), scratching is easy to occur at the coating site for enhancing corrosion resistance, and an oxide film is formed to cause discoloration. However, the magnesium alloy material has high corrosion resistance and abrasion resistance as described above. As well as high degree of gloss, high glossiness and uniform and diverse color tones, it is highly regarded as a metallic material having a high corrosion-resistant color oxide film layer on the surface of Ni plating layer which is beautiful and has excellent decorativeness in recent portable smart devices. As the industry develops and the life is improved, the demand for colored metal materials reflecting various color concepts that can be applied to various household goods, decorations, metal crafts, etc., while still retaining the unique characteristics of metals. Increasingly, the color oxide layer on the metal material The attempt to get the province to color tones have been made.

As a method of forming a color oxide film layer on a metal material, conventionally, the surface of the metal material is directly colored with a color paint to perform coloring, zinc plating, gold plating, chromium plating, or the like, or by heat treatment after coating with a color coating composition. Although a method of expressing color is used, a method of forming a color oxide film layer on a metal material, as in the prior art, has a high processing cost or a limitation in implementing various colors, and it is washed after manufacture and repeated with foreign matter. Discoloration or glossiness may occur due to abrasion, peeling, etc. of the coating layer due to contact, scratches, etc.

In addition, as a conventional method of manufacturing magnesium die casting alloy, a metal material having a color oxide film layer having various colors was obtained by a non-chromate plate (NCP) process, but a simple NCP coating process and a coating process may provide corrosion resistance. There was a problem that can not guarantee the reliability.

Registered Patent Publication No. 10-0967713 (2010.06.25)

The present invention has been made to solve the above problems, the present invention, it is possible to ensure high corrosion resistance by forming an intermetallic compound layer by Al sputtering coating and diffusion heat treatment before the NCP process step and coating process It is an object of the present invention to provide a highly corrosion-resistant surface treatment coating method of magnesium die-casting alloy which can reduce the weight and the processing cost while maintaining the gloss of various colors without changing color due to aging of a certain time.

Highly corrosion-resistant surface treatment coating method of magnesium die casting alloy according to an embodiment of the present invention, the casting and post-casting treatment step of the magnesium alloy material (S-a); Forming an Al coating and an intermetallic compound on the magnesium alloy material after performing the step (S-a); Performing a painting pretreatment and painting on the magnesium alloy material after performing the step (S-b) (S-c); And plating the magnesium alloy material after performing the step (S-c) (S-d). It may include.

The step of forming the Al coating and Mg-Al intermetallic compound, the sputtering coating step by Al for thin film deposition coating Al on magnesium alloy material, and to form an intermetallic compound on the Al-coated magnesium alloy material It is characterized in that the diffusion heat treatment step.

The intermetallic compound formed on the magnesium alloy material is Mg ₁₇ Al _12, Mg ₂ Al _{3 It} is characterized in that.

Casting and post-cast processing step of the magnesium alloy material, the casting treatment step of casting a magnesium alloy material (S-1); A finishing step (S-2) of polishing the surface of the magnesium alloy material to remove foreign substances and impurities after the step (S-1) of casting the magnesium alloy material; A sand blasting step (S-3) for removing an oxide film which is a foreign matter remaining on the surface of the magnesium alloy material cast after the step of polishing the magnesium alloy material surface (S-2); Machining step (S-4) performed after the step (S-3) of removing the oxide film remaining on the surface of the magnesium alloy material; It is characterized by that.

Forming the Al coating and the intermetallic compound on the magnesium alloy material, the sputtering coating step by Al for thin film deposition coating Al on the magnesium alloy material (S-5); A diffusion heat treatment step (S-6) to form an intermetallic compound in the Al-coated magnesium alloy material by the step (S-5); It is characterized by that.

The pre-painting and painting of the magnesium alloy material may include: an NCP process step (S-7) of coating with non-chromium; A heat treatment step of drying the non-chromium coated magnesium alloy surface (S-8); A masking treatment step (S-9) of attaching a mask to the magnesium alloy surface to perform painting; A coating step for strengthening corrosion resistance by performing liquid coating after the mask is attached (S-10); A heat treatment step of drying the undercoated magnesium alloy (S-11); A phase coating step (S-12) to increase the plastering and corrosion resistance of the powder coating on the surface of the magnesium alloy subjected to the undercoating; A heat treatment step of drying the top coat coated magnesium alloy (S-13); Removing the mask of the magnesium alloy surface of the coating is completed (S-14);

The plating of the surface of the magnesium alloy material may include: performing a Cu or Ni plating process on the surface of the magnesium alloy material (S-16); After the step (S-16) to perform the Ag plating process (S-17); characterized in that the.

As described above, the corrosion-resistant surface treatment coating method of the magnesium die-casting alloy according to the present invention, high corrosion resistance by forming the Mg-Al intermetallic compound layer by Al sputtering coating and diffusion heat treatment before the NCP process step and the coating process It can be secured, and it is possible to maintain the gloss of various colors without discoloration due to aging of the color after a certain time, and to reduce the weight and processing cost.

1 is a view showing a highly corrosion-resistant surface treatment coating method of magnesium die casting alloy according to a first embodiment of the present invention.
2 is a view for explaining the characteristics of the high corrosion resistance surface treatment coating method of the magnesium die casting alloy shown in FIG.
Figure 3 is a view showing the test results by the salt mist spray test (SST) of a high corrosion resistance surface treatment coated magnesium die casting alloy according to the present invention.

Description of the present invention is only an embodiment for structural or functional description, the scope of the present invention should not be construed as limited by the embodiments described in the text. That is, since the embodiments may be variously modified and may have various forms, the scope of the present invention should be understood to include equivalents capable of realizing the technical idea.

On the other hand, the meaning of the terms described in the present invention will be understood as follows.

Terms such as "first" and "second" are intended to distinguish one component from another component, and the scope of rights should not be limited by these terms. For example, the first component may be named a second component, and similarly, the second component may also be named a first component.

When a component is referred to as being "connected" to another component, it should be understood that there may be other components in between, although it may be directly connected to the other component. On the other hand, when a component is said to be "directly connected" to another component, it should be understood that there is no other component in between. On the other hand, other expressions describing the relationship between the components, such as "between" and "immediately between" or "neighboring to" and "directly neighboring to", should be interpreted as well.

Singular expressions should be understood to include plural expressions unless the context clearly indicates otherwise, and terms such as "include" or "have" refer to features, numbers, steps, operations, components, parts, or parts thereof described. It is to be understood that the combination is intended to be present and does not exclude in advance the possibility of the presence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof.

In each step, an identification code (e.g., a, b, c, etc.) is used for convenience of description, and the identification code does not describe the order of the steps, and each step clearly indicates a specific order in context. Unless stated otherwise, they may occur out of the order noted. That is, each step may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. Generally, the terms defined in the dictionary used are to be interpreted to coincide with the meanings in the context of the related art, and should not be interpreted as having ideal or excessively formal meanings unless clearly defined in the present invention.

In order to achieve a high corrosion resistance surface treatment coating method of magnesium die casting alloy according to the present invention, the present invention comprises the steps of: (a): casting and post-cast treatment step of magnesium alloy material; (b) step: forming an Al coating and Mg-Al intermetallic compound on the magnesium alloy material after performing step (a); Step (c): after performing step (b), performing painting pretreatment and painting on the magnesium alloy material; And (d) step: plating the magnesium alloy material after performing step (c).

More specifically, the high corrosion resistance surface treatment coating method of the magnesium die casting alloy is the step (a), the casting and post-casting process step of the magnesium alloy material, the (S-1) step of casting the magnesium alloy material After the step (S-1), the step (S-1) and the post-treatment step of the casting, after the casting process to remove the foreign matter (release material) and impurities (organic matter) on the surface of the magnesium alloy material In order to clean the surface of metal materials such as the grinding process of grinding the surface and casting magnesium alloy material (S-3) in order to clean the surface, casting sand and oxide film which are foreign substances remaining on the surface of the metal material Sand blast (Sand Blast) step to remove the (S-4) step of the milling process includes a machining (Machining) step.

The step (b) is to form an Al coating and an intermetallic compound on the magnesium alloy material after performing the step (a), the thin film deposition coating Al on the magnesium alloy material (S-5) step A sputtering coating step using Al and a diffusion heat treatment step are performed to form an Mg-Al intermetallic compound, which is an Al-coated Mg metal material (S-6).

Step (c) is a step of performing pre-painting and painting after the step (b) is processed. First of all, the pre-painting step is a non-chromium coating treatment on the surface before painting as a step before performing the painting. NCP (Non Chromate Plating, forming Al oxide film)) is formed to perform the coating process after coating the surface prior to painting, and then coating. In more detail, the process steps may include a non-chromic plate (NCP) process step of coating with non-chromium (S-7) and a heat treatment step of (S-8).

In the step (c), after performing all the coating pretreatment process, a coating step is performed to enhance corrosion resistance. More specifically, in order to prevent corrosion on the metal surface, the masking treatment step (S-9) and the liquid coating as the (S-10) step are carried out to enhance the corrosion resistance (Primer Coating). ), And (S-11) heat treatment step, (S-12) step to perform the powder coating to coat (Top Coating) step to increase the plastering, functionality and corrosion resistance, and (S- 13) the heat treatment step, and (S-14) comprises a masking removal step, and a series of coating steps in this way to prevent corrosion by performing a coating so as not to rust the entire surface of the metal. After applying the coating as described above, the coated product is generated as in step (S-15).

The step (d) is a plated process step in which the coated metal product may exhibit more improved electrical properties, the (S-16) step Cu or Ni plating step, and (S-17 A) Ag plating step.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view sequentially showing the overall process steps of a method for coating a highly corrosion resistant surface treatment of magnesium die casting alloy according to a first embodiment of the present invention.

As shown in the figure, the method of coating a highly corrosion-resistant surface treatment of magnesium (Mg) die casting alloy according to the first embodiment of the present invention, as the step (a), the casting and post-casting process step of the magnesium alloy material Is done.

As shown in the drawing, first, a magnesium alloy material is cast as a casting treatment step ((S-1)).

As a grinding step performed after the step (S-1) of casting the magnesium alloy material, the surface is polished to remove foreign matters (releasing material) and impurities (organic matter) from the surface of the magnesium alloy material. (S-2).

In addition, the sand blast (Sand Blast) step is performed after the (S-2) step of polishing the magnesium alloy material surface, a process of cleanly finishing the surface of the metal material, such as cast magnesium alloy material, the surface of the metal material Remove the foundry sand and the oxide film remaining in the foreign matter (S-3).

The step (S-3) may be performed by any one of metal or ceramic blades, sandpaper or brush. This is done by repeated movements on the surface of the magnesium alloy material.

A machining process step is performed as a milling process performed after the step (S-3) of removing the casting sand and the oxide film, which are foreign substances remaining on the surface of the magnesium alloy material (S-4).

As such, step (a), which is a casting and post-casting treatment step of the magnesium alloy material, is to remove foreign substances and oxide films on the surface of the cast magnesium alloy material.

Next, step (b) is performed after removing the oxide film, which is a foreign matter remaining on the surface of the metal material, such as the magnesium alloy material of the casting process (a), Al coating and To produce an intermetallic compound.

 More specifically, after removing the oxide film, which is a foreign substance remaining on the surface of the metal material, such as cast magnesium alloy material, Al sputtering coating for thin film deposition coating of Al on the magnesium alloy material to prevent corrosion and enhance corrosion resistance ( Al Sputtering Coating) step (S-5).

The reason why the sputtering coating to deposit a thin film by Al on the surface of the magnesium alloy material is that when the scratch occurs in the magnesium alloy material, the magnesium alloy material has a chemical reaction with Cl ^- or So ₄ ^{2 +} in the air. In the process of swelling, swelling may occur and erosion may occur. As a result, the amount of magnesium alloy material may be eroded and the amount thereof may gradually decrease, thereby preventing sputtering by Al. Prevents the occurrence of erosion by forming a coating layer to enhance the corrosion resistance

In addition, after the step (S-5) of sputtering coating of Al on the magnesium alloy material, a diffusion heat treatment step is performed to form an intermetallic compound on Mg-Al, which is an Al-coated magnesium alloy material (S- 6).

This allows the intermetallic compound to be produced by heat treatment diffusion between the magnesium alloy material and the sputtered coating Al material.

More specifically, since the plating process itself is impossible when it is performed by the wet plating method of Al, according to the present invention, Al is sputtered by the plating process on the surface of the magnesium alloy material by dry plating. After the heat treatment process, Mg ₁₇ Al ₁₂ on the surface of the magnesium alloy material And Mg ₂ Al ₃ phosphorus An intermetallic compound is formed to form a magnesium metal alloy layer that enhances corrosion resistance.

On the other hand, there is a method to enhance the corrosion resistance by adding a special element to the PEO (Plasma Electrolytic Oxidation) coating or magnesium alloy material as a conventional method to enhance the corrosion resistance, but in the case of PEO coating is not conductive, plating after Al conductive coating It is not applicable to the process, and since the method of adding a special element to the magnesium alloy material is still technically immature stage, therefore, in the present invention Al conductive sputtering coating on the surface of the magnesium alloy material as described above to enhance the corrosion resistance Mg ₁₇ Al ₁₂ by Post Heat Treatment Diffusion And after forming the intermetallic compound layer of Mg ₂ Al ₃ , Cu or Ni plating and Ag plating are performed.

Next, as step (c), after the Al conductive sputtering coating on the surface of the magnesium alloy material of step (b) Mg ₁₇ Al ₁₂ by heat treatment diffusion And after performing the step of forming the intermetallic compound layer of Mg ₂ Al ₃ , after the step (b) is a step of pre-painting and painting.

First of all, the painting pretreatment process is a step before coating, and after coating, the surface is coated before the painting by forming NCP (Non Chromate Plating). do. In more detail, the process steps

Mg ₁₇ Al ₁₂ and Mg ₂ Al _{3 as} intermetallic compound layers Before coating the layer is subjected to non chromium coating non-chromic plate (NCP) process step (S-7).

After performing the step (S-7), which is the non chromium coating process (NCP (Non Chromate Plate) process), and performing a heat treatment step of drying the non-chromium coated magnesium alloy surface as a drying process (S-8).

In the step (c), after performing both the NCP process step (S-7) step (S-8) step and the heat treatment step (S-8) step is a coating (Coating) step to enhance the corrosion resistance .

More specifically, in the painting step, in order to perform a coating process for preventing corrosion on the metal surface, first, a masking treatment is performed to attach a mask to the surface of the magnesium alloy material which has been pre-painted (S-9).

Primer coating is applied to the masked magnesium alloy material to improve the corrosion resistance (S-10).

A heat treatment step is performed to dry the magnesium alloy material subjected to the undercoat (S-11).

Magnesium alloy material dried by the heat treatment is subjected to a top coating (Top Coating) which is a powder coating to increase the plastering, functionality and corrosion protection (S-12).

A heat treatment step is performed to dry the magnesium alloy material subjected to the top coat (S-13).

The masking removal step of removing the mask from the magnesium alloy material after the heat treatment step (S-13) is performed (S-14).

In this way, the entire surface of the metal is prevented from being rusted by a series of painting pretreatment and painting steps to prevent corrosion.

As described above, after the pretreatment and coating in step (c), the coated magnesium alloy is produced (S-15).

Step (d) is a plating process step in which the coated magnesium metal alloy is exhibited to exhibit improved electrical characteristics.

The plating process step includes performing a Cu or Ni plating process (S--16) and performing an Ag plating process (S-17).

2 is a view for explaining the characteristics of the highly corrosion-resistant surface treatment coating of the magnesium die casting alloy shown in FIG.

As shown, (a) is a view showing the characteristics of each layer (layer) for the normal magnesium alloy material, (b) is an intermetallic compound layer (Mg ₁₇ Al ₁₂ And Mg ₂ Al) is a view showing the layer (layer) characteristics for the magnesium alloy material formed.

As shown in (b), an intermetallic compound layer (Mg ₁₇ Al _{12) is} formed on the upper surface layer of the magnesium alloy material. And it can be seen that the Mg ₂ Al ₃ ) layer is formed, the corrosion resistance is enhanced by the intermetallic compound layer formed in this way, even if a scratch occurs in the magnesium alloy material has the effect of preventing corrosion by preventing corrosion.

Figure 3 is a view showing the test results by the salt mist spray test (SST) of a high corrosion resistance surface treatment coated magnesium die casting alloy according to the present invention.

As shown, the SST test was performed by cross-cutting a magnesium alloy material on which the Mg ₁₇ Al ₁₂ intermetallic compound formed by performing the steps (S-1) to (S-6) was performed. As a case, it is a figure which shows the erosion state of the cross-cut site | part after 720 hours of about 30 days (4weeks) by giving chlorine spray to the cross-cut magnesium alloy material.

In the case of the normal magnesium alloy material on the right side as shown in Figure 3, the erosion occurred in the cross-cut site, in the case of the Al-coated magnesium alloy material on the left side it can be confirmed that the erosion hardly occurs. Same as Mg ₁₇ Al ₁₂ And Mg ₂ Al ₃ And Mg ₂ Al ₃ a can be found that it is possible to suppress corrosion by forming the intermetallic compound layer.

Therefore, the corrosion-resistant surface treatment coating method of the magnesium die casting alloy according to the present invention, Mg ₁₇ Al ₁₂ Mg-Al intermetallic compound layer And Mg ₂ Al ₃ layer to ensure high corrosion resistance, and can maintain the gloss of various colors without discoloration due to aging of the color after a certain time to reduce the weight and processing cost There is.

The present invention has been described in detail so far, but the embodiments mentioned in the process are merely exemplary and are not limitative, and the present invention is provided by the following claims. Within the scope of not departing from the scope of the present invention, changes in components to such an extent as to cope with evenly fall within the scope of the present invention.

Step (a): casting and post-casting process
Step (b): Al sputtering coating and intermetallic compound layer forming process
(c) step: painting pretreatment and painting process
(d) step: plating process

Claims (7)

Casting and post-cast post-processing step of magnesium alloy material (Sa);
Forming an Al coating and an intermetallic compound on the magnesium alloy material after performing step (Sa) (Sb);
Performing a painting pretreatment and painting on the magnesium alloy material after performing the step (Sb) (Sc); And
Plating the magnesium alloy material after performing the step (Sc) (Sd);
High corrosion resistance surface treatment coating method of magnesium die casting alloy comprising a.
The method according to claim 1, wherein (Sb) step,
Sputtering coating step by Al for thin film deposition coating Al on magnesium alloy material,
The high corrosion resistance surface treatment coating method of the magnesium die casting alloy, characterized in that the diffusion heat treatment step to form an intermetallic compound on the Al-coated magnesium alloy material.
The method according to claim 1 or 2,
The intermetallic compound formed on the magnesium alloy material is Mg ₁₇ Al ₁₂ And Mg ₂ Al ₃ , a highly corrosion-resistant surface treatment coating method of magnesium die casting alloy.
The method of claim 1, wherein the casting and post-casting process step of the magnesium alloy material,
Casting treatment of the magnesium alloy material as a casting treatment step (S-1);
A finishing step (S-2) of polishing the surface of the magnesium alloy material to remove foreign substances and impurities after the step (S-1) of casting the magnesium alloy material;
A sand blasting step (S-3) for removing an oxide film which is a foreign matter remaining on the surface of the magnesium alloy material cast after the step of polishing the magnesium alloy material surface (S-2);
Machining step (S-4) performed after the step (S-3) of removing the oxide film remaining on the surface of the magnesium alloy material;
High corrosion resistance surface treatment coating method of magnesium die casting alloy, characterized in that.
The method of claim 1 or 4, wherein the forming Al coating and the intermetallic compound on the magnesium alloy material,
Sputtering coating step (S-5) by Al for thin film deposition coating Al on magnesium alloy material;
A diffusion heat treatment step (S-6) to form an intermetallic compound in the Al-coated magnesium alloy material by the step (S-5);
High corrosion resistance surface treatment coating method of magnesium die casting alloy, characterized in that.
The method of claim 5, wherein the coating pretreatment and painting are performed on the magnesium alloy material.
NCP process step (S-7) of coating with non-chromium;
A heat treatment step of drying the non-chromium coated magnesium alloy surface (S-8);
A masking treatment step (S-9) of attaching a mask to the magnesium alloy surface to perform painting;
A coating step for strengthening corrosion resistance by performing liquid coating after the mask is attached (S-10);
A heat treatment step of drying the undercoated magnesium alloy (S-11);
A phase coating step (S-12) to increase the plastering and corrosion resistance of the powder coating on the surface of the magnesium alloy subjected to the undercoating;
A heat treatment step of drying the top coat coated magnesium alloy (S-13);
Removing the mask of the magnesium alloy surface of which the painting is completed (S-14);
High corrosion resistance surface treatment coating method of magnesium die casting alloy, characterized in that.
The method of claim 6, wherein the plating on the surface of the magnesium alloy material,
Performing a Cu or Ni plating process on the surface of the magnesium alloy material (S-16);
Performing an Ag plating process after the step (S-16) (S-17);
High corrosion resistance surface treatment coating method of magnesium die casting alloy, characterized in that.

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