KR20110038981A - Method for electroless nikel coating of magnesiumalloy plate - Google Patents

Abstract

PURPOSE: An electroless nickel plating method of a magnesium-alloy plate is provided to enhance the decoration, corrosion resistance, abrasion resistance and high hardness of a magnesium plate. CONSTITUTION: An electroless nickel plating method of a magnesium-alloy plate is as follows. An ultrasonic degrease process, an etching process and a post etching process are performed on the magnesium-alloy plate(a). After first activation through the soak to activation solution, electroless nickel plating is done using reactive-gas inducing catalyst metal(b). After second activation through baking and then the soak to HCL solution or sulfuric acid solution, striking plating and electrical plating are successively done(c).

Description

Electroless nickel plating method of magnesium alloy plate {Method for electroless nikel coating of magnesiumalloy plate}

The present invention forms a uniform electroless nickel metal plated layer on the magnesium alloy sheet, and pretreatment such as degreasing, etching, post etching, etc. in order to increase the adhesion, and then surface treated using an electroless nickel plating method, the magnesium alloy sheet The present invention relates to an electroless nickel plating method of magnesium alloy sheet material characterized by having decorativeness, corrosion resistance, abrasion resistance and high strength.

In general, magnesium alloy is used in many industries because of the lightest of the metal materials. Although magnesium alloy has the above advantages, due to the weakness of acid and alkali, surface treatment is mainly performed by wet plating using strong acid and strong alkali chemicals. It is causing.

Therefore, various methods for surface treatment of magnesium alloy sheet material have been developed as a solution for solving the above problems. Looking at the contents of the patent application of the technologies developed in this way, Korean Patent Application Publication No. 2003-0073929 The double-electroless nickel plating method is known by performing the alkali degreasing, fluoride acid etching and alkali etching processes 2-3 times in the order of the magnesium alloy molded product, and then performing weakly acidic electroless nickel plating. And, in Korea Patent Publication No. 10-0881061, after washing the surface of the magnesium alloy sheet to remove the foreign matter, immersed in acidic acid and oxidized, and then immersed in the etching liquid to remove the adhesion product and then immersed in zinc replacement solution After zinc replacement, it is immersed in electrolytic solution. The plating method of magnesium alloy plate material is known, which is immersed in nickel electrolytic plating solution after electrolytic plating and then electroplated, followed by immersion in trivalent chromium electrolytic solution, and is also known in Korea. The surface of the magnesium alloy is degreased and washed with water, the oxide film on the surface of the magnesium alloy is removed and washed with water, followed by zinc plating on the surface of the magnesium alloy, followed by washing with water. The nickel plating method for a magnesium alloy is known, comprising the step of electrolytic nickel plating treatment to improve the hardness and wear resistance by treating the plating of any one selected from electroless nickel plating.

In the case of the above methods, the poor adhesion between the material and the metal coating layer and the resulting blister of the metal coating layer are still a problem, but nickel nucleation and growth on the magnesium die casting alloy (AZ91) surface are easy. The reaction takes place throughout the product. However, in the case of magnesium plate alloy (AZ31), since nucleation is hardly performed on the activated surface, plating is not performed by the electroless nickel plating method.

Therefore, the present invention is a pretreatment process for uniform formation and adhesion of the material layer of the magnesium alloy sheet and the electroless nickel metal layer through degreasing, etching, post etching, activation, electroless nickel plating and the like. An object of the present invention is to provide an electroless nickel plating method of a magnesium alloy sheet material which can improve decorative, corrosion resistance, wear resistance and high hardness properties.

In addition, the present invention uses the reaction-induced catalytic metal during electroless nickel plating to induce the formation and growth of electroless nickel nuclei on the activated magnesium alloy sheet during electroless plating, thereby bringing the nucleus into contact with the magnesium surface. Another object of the present invention is to provide an electroless nickel plating method of a magnesium alloy sheet, which is characterized by performing electroless nickel plating on the magnesium alloy sheet by inducing formation and growth.

In addition, the present invention improves the adhesion between the material and the plating layer during the baking process, which is a step of confirming the blister between the material and the coating due to the poor adhesion and the adhesion between the material and the metal coating layer during the process. Another object of the present invention is to provide an electroless nickel plating method of a magnesium alloy sheet material, which can reduce the defect rate of the surface treatment.

In the present invention for achieving the above object in the electroless nickel plating method of the magnesium alloy sheet,

The magnesium alloy sheet is subjected to an ultrasonic degreasing treatment and a pretreatment process of etching and post etching,

After immersion in the activating solution and the first activation treatment, after the electroless nickel plating process using the reaction gas-derived catalytic metal,

Solving the electroless nickel plating method of the magnesium alloy sheet, characterized in that the baking treatment and then immersed in an aqueous hydrochloric acid solution or sulfuric acid solution, and then subjected to a second activation treatment, followed by strike plating and electroplating. By means.

However, the present invention is a magnesium alloy using an etching solution adjusted to pH 2-3 using a mixed solution of 16 to 20% by weight of acetic acid, 3 to 5% by weight of sodium nitrate and 75 to 81% by weight of water. The board is immersed at room temperature for 20-50 seconds,

In the post etching, the magnesium alloy sheet material is immersed at room temperature for 20 to 60 seconds in a post etching solution of an oxalic acid aqueous solution in which 0.4 to 0.6% by weight of oxalic acid, 0.1 to 1.0% by weight of a wetting agent, and 98.4 to 99.5% by weight of water are mixed.

In the first activation treatment, magnesium alloy plate is immersed for 3 to 8 minutes at room temperature in an activation treatment solution containing 8 to 12 wt% of ammonium fluoride, 30 to 38 wt% of phosphoric acid, and 50 to 62 wt% of water, and the activation treatment is performed.

The electroless nickel plating process includes nickel carbonate 0.8-1.2 wt%, sodium hypophosphite 1.6-2.4 wt%, citric acid 0.4-0.6 wt%, ammonium fluoride 0.8-1.2 wt%, hydrofluoric acid 0.8-1.2 wt%, ammonia 0.2-0.3 An electroless nickel plating solution in which 0.05 to 0.20 parts by weight of an additive was mixed with 100 parts by weight of an aqueous solution composed of 93% to 95.4% by weight of water was set to pH 6-7, and then the reaction-induced catalyst metal and activated magnesium alloy sheet were After reaction at 75 ~ 85 ℃ for about 2 ~ 5 minutes, only reaction-induced catalyst metal is discharged, and only magnesium alloy plate is immersed in 15 ~ 25 minutes for electroless nickel plating.

The reaction induction catalyst metal is selected from one of metals reacting with the electroless nickel plating solution, such as iron, nickel, nickel plated metal,

The baking treatment heats the electroless nickel plated magnesium alloy sheet at 100 to 300 ° C. for 30 to 120 minutes,

And the electroplating is preferably coated with a general corrosion or decorative plating.

The present invention by the above-mentioned problem solving means significantly improves the unplated and poor adhesion by the pinhole and material processing, which has been a problem in the surface treatment on magnesium plate material through two etching processes, as well as It is possible to improve the corrosion resistance, strengthen the hardness and wear resistance, and also electroplating treatment using materials such as nickel, chromium or precious metal to improve the decorative, corrosion resistance, wear resistance and high hardness of magnesium plate , Information and communication products, leisure products, optical instruments, digital cameras. It can be applied to various purposes such as automobile, aircraft parts, construction materials, etc., and the demand is expected to increase significantly.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 1 to 5b, and the same reference numerals are used for components that perform the same function in FIGS. 1 to 5b. On the other hand, in the drawings and detailed description showing and referring to the configuration and operation that can be easily understood by those skilled in the art of electroless nickel plating in general, briefly or omitted. In particular, in the drawings and detailed description of the drawings, detailed descriptions and illustrations of specific technical configurations and operations of elements not directly related to the technical features of the present invention are omitted.

The technical idea according to the present invention will be described in detail below with reference to FIG. 1.

1 is a view attached to the present invention relates to a view showing a process for inducing the formation and growth of electroless nickel nuclei on the magnesium alloy plate activated during electroless plating on the magnesium alloy plate according to the present invention.

As shown in FIG. 1A, the reaction gas 30 generated from the reaction induction catalyst metal 10 during electroless nickel plating of the magnesium alloy sheet 20 using the reaction induction catalyst metal 10 is shown in FIG. ) By contacting the magnesium alloy plate 20 to the activated magnesium alloy plate 20 as shown in (b) of the electroless nickel core (30) by the gas induction reaction of the reaction induction catalyst metal (10) `) Is formed, and after 1 to 2 minutes after the electroless nickel plating is carried out, the electroless nickel nucleus 30 'is formed on the magnesium alloy sheet 20 as shown in FIG. By growing, the electroless nickel metal layer is formed uniformly in the material layer of the magnesium alloy plate material 20.

Hereinafter, the technical configuration of the present invention will be described in detail with reference to FIGS. 2 and 3, which are attached drawings.

2 is a view showing the process of nickel plating a magnesium alloy sheet as an embodiment according to the present invention, Figure 3 is a nickel plated magnesium alloy sheet according to the method of FIG. It is related with the figure which showed the cross section.

In the present invention, in the electroless nickel plating method of the magnesium alloy sheet as shown in Figure 2,

The magnesium alloy sheet is subjected to an ultrasonic degreasing treatment and a pretreatment process of etching and post etching,

After immersion in the activating solution and the first activation treatment, after the electroless nickel plating process using the reaction gas-derived catalytic metal,

After baking (baking) and then immersed in an aqueous hydrochloric acid solution or sulfuric acid aqueous solution to the secondary activation treatment is characterized in that the strike (Strike) plating and electroplating is performed sequentially.

As described above, the present invention relates to a wet plating treatment for ensuring decorativeness, corrosion resistance, abrasion resistance and high hardness by forming nickel metal or the like on the surface of a magnesium plate by using an electroless nickel plating method on a magnesium alloy plate.

In particular, the present invention is a method for forming a nickel metal or the like on a magnesium alloy sheet, a method for improving the uniform formation and adhesion of the material layer and the electroless nickel metal layer, such as degreasing, etching, post etching, etc. Characterized by passing through a pretreatment process.

In the present invention, in the degreasing treatment, in order to remove contaminants on the surface of the magnesium alloy sheet, the magnesium alloy sheet is immersed in the degreasing solution at 55 to 65 ° C., and then degreased using ultrasonic waves for 4 to 6 minutes. If the ultrasonic degreasing time is less than 4 minutes, contaminants on the surface of the magnesium alloy plate may not be removed properly, and if the ultrasonic degreasing time exceeds 6 minutes, the effect of exceeding the ultrasonic degreasing time is insignificant.

In this step, the magnesium alloy sheet material has a high corrosion resistance to the high alkaline degreasing solution, but dissolves in the degreasing solution of the aqueous alkali solution containing ammonium, amine salts, etc., so it is necessary to pay attention to the composition of the degreasing solution to be used.

Degreasing solution usable in the present invention is 3 to 5% by weight of sodium carbonate, 0.4 to 0.6% by weight of sodium hydroxide, 2 to 3% by weight of tribasic sodium phosphate, 0.1 to 0.3% by weight of nonionic surfactant, and 91.1 to 94.5% by weight of water. It is preferable that it is a mixed liquid of.

In the present invention, the etching process is a treatment process in which the magnesium alloy sheet material is immersed in the etching solution to remove the oxide film and organic contaminants, to obtain a temporarily uniform active surface, and also to perform a polishing function.

As the etching solution used in the present invention, it is preferable to use a mixed solution of 16 to 20% by weight of acetic acid, 3 to 5% by weight of sodium nitrate and 75 to 81% by weight of water.

In addition, the etching conditions are preferably adjusted by etching the etching solution to pH 2 to 3 and then immersed magnesium alloy plate material for 20 to 50 seconds at room temperature.

The etching solution requires attention to the composition ratio and pH control of the etching solution. In other words, if the content of sodium nitrate is increased, there is a possibility that the smut phenomenon occurs that the adhesion between magnesium alloy plate and nickel metal is poor during electroless nickel plating. If the content of acetic acid is increased, electroless nickel plating is caused by excessive etching. Since the appearance and poor adhesion will occur later, the etching treatment should be performed at pH 3 or less.

In the present invention, post etching is a treatment process for removing an oxide film not completely removed in the etching process.

The post etching solution used in this step is preferably an oxalic acid aqueous solution in which 0.4 to 0.6% by weight of oxalic acid, 0.1 to 1.0% by weight of wetting agent, and 98.4 to 99.5% by weight of water are mixed.

In the post etching condition, it is preferable to immerse the magnesium alloy sheet material in the post etching solution at room temperature for 20 to 60 seconds for post etching treatment.

In the post etching solution, a wetting agent is used as an additive, which can remove defects such as bubbles existing on the magnesium surface, prevent overetching, and obtain a uniform and active surface, and have an off-white appearance. When activation shows the best surface.

If the etching time is less than 20 seconds, the oxide film adhering to the surface of the magnesium alloy sheet may not be removed properly. If the etching time exceeds 60 seconds, grooves may be formed on the surface of the magnesium alloy sheet by overetching. There is a fear that the concave surface becomes uneven.

In the present invention, the primary activation treatment is a process of forming a fluoride film on the material while removing the peeled oxide film so as to provide an active surface on the material of the magnesium alloy sheet. The magnesium material surface after the activation treatment can have good results in nickel plating when it has an off-white clean appearance.

It is preferable to use the mixed solution of 8-12 weight% of ammonium fluoride, 30-38 weight% of phosphoric acid, and 50-62 weight% of water for the primary activation process liquid used at this process.

In the primary activation condition, the magnesium alloy sheet material is preferably immersed in the activation treatment liquid at room temperature for 3 to 8 minutes. If the primary activation time is less than 3 minutes, there is a fear that a fluoride film that provides an active surface to the material of the magnesium alloy sheet may not be properly formed, and if it exceeds 8 minutes, the material may be eroded.

In the present invention, the electroless nickel plating is a process for nickel plating the surface of the magnesium alloy sheet.

The process consists of 0.8-1.2 wt% nickel carbonate, 1.6-2.4 wt% sodium hypophosphite, 0.4-0.6 wt% citric acid, 0.8-1.2 wt% ammonium fluoride, 0.8-1.2 wt% hydrofluoric acid, 0.2-0.3 wt% ammonia and water The electroless nickel plating solution, in which 0.05 to 0.20 parts by weight of the additive is mixed with respect to 100 parts by weight of an aqueous solution of 93.1 to 95.4% by weight, is maintained such that pH 6 to 7 is maintained, and then the reaction induction catalyst metal and the activated magnesium alloy sheet are 75 to After the reaction at 85 ° C. for about 2 to 5 minutes, it is preferable to discharge the reaction-induced catalyst metal only and to immerse only magnesium alloy sheet for 15 to 25 minutes for electroless nickel plating.

In the present invention, when the electroless nickel plating condition is less than the range defined above, there is a concern that the nickel metal may not be uniformly plated on the surface of the magnesium alloy sheet material, and the electroless nickel plating condition exceeds the range defined above. In this case, the surface treatment is economical.

And since the material layer may be eroded from acid and alkali in the next process after electroless nickel plating, a minimum thickness of the electroless nickel plating layer is required to prevent the material erosion. Preferably, the thickness of the electroless nickel plating layer is 5 to 7 μm.

In addition, the electroless nickel plating additive is preferably 0.05 to 0.20 parts by weight based on 100 parts by weight of the aqueous solution, and as an additive, 0.03 to 0.10 parts by weight of an aqueous solution of thiourea (H ₂ NCSNH ₂ ), which is a stabilizer, and a wetting agent as an improving agent. (wetting agent-polyethylene glycol (PEG)) 0.02 to 0.10 parts by weight can be used.

In addition, the reaction induction catalyst metal may be selected from one of metals reacting with the electroless nickel plating solution, such as iron, nickel or nickel plated copper metal.

In the present invention, the baking process is a process performed to increase adhesion between the material of the magnesium alloy plate and the plating layer by using a metal diffusion phenomenon after the electroless nickel treatment. In addition, in case of poor adhesion due to corrosion of the material, the electroless nickel film is mainly generated by blister phenomenon at this stage, and thus it is also used for the purpose of defect screening. That is, the present invention provides a magnesium alloy sheet material by performing a baking process, which is a step of confirming blister between the material and the film due to poor adhesion and increasing adhesion between the material and the metal film layer during the process. It is characterized by improving adhesion between material and nickel plated layer and solving poor surface treatment at once.

In the baking treatment, it is preferable to heat-treat the electroless nickel plated magnesium alloy sheet at 100 to 300 ° C for 30 to 120 minutes. If the baking treatment condition falls below the range defined above, there is a risk of deterioration of adhesion between the material and the electroless nickel plating, and if the baking range exceeds the range defined above, it is formed during baking. There exists a possibility that the adhesive force of the electroless nickel plating layer and the plating layer of a post process may fall by the oxide layer which becomes.

In the present invention, the secondary activation treatment is a process for removing the oxide film formed on the surface of the magnesium alloy sheet during baking, and the magnesium alloy sheet in an aqueous solution of 5-15 v / v% hydrochloric acid or sulfuric acid at room temperature. It is preferable to activate by immersing for 1-3 minutes.

When the secondary activation condition is less than the above-defined range, there is a fear that the oxide film formed on the surface of the magnesium alloy sheet material may not be sufficiently removed, and when exceeding the above-mentioned range, the plating layer and the material by acid There is a risk of layer erosion.

In the present invention, the strike (strike) plating is a process for increasing the adhesion between the electroplating layer and the electroless nickel layer, which is a post-process, it is preferable to perform nickel or copper strike plating (strike).

Nickel or copper strike plating in this process is a common plating method.

And electroplating is carried out in the last step in the present invention. Electroplating is a process for electroless nickel plating on the surface of magnesium alloy plate to improve the corrosion resistance of the plated surface and to show decorativeness. Electroplating using materials such as nickel, chromium or precious metals It is a process to do it. Magnesium alloy sheet material having such a process is improved in physical properties such as decoration, corrosion resistance, wear resistance and high hardness.

And the thickness of the entire plating layer to be plated on the magnesium plate in the present invention is not particularly limited, it may be appropriately adjusted according to the use purpose and the user's needs.

As shown in FIG. 3, the cross-sectional structure of the magnesium alloy sheet subjected to the electroless nickel plating according to the present invention through the above process is an electroless nickel layer formed by the growth of the reaction gas on the outside of the magnesium alloy sheet 20. 40, the formation of the nickel or copper strike activation layer 50 on the outside thereof and the electroplating layer 60 using a material such as nickel, chromium or precious metal, thereby forming It is characterized by the surface treatment of magnesium alloy sheet.

And the center of the electroless nickel plating of the magnesium alloy sheet according to a preferred embodiment of the present invention will be described in detail with reference to Figures 4a to 5b of the accompanying drawings, the technical configuration of the present invention It is not necessarily limited to the embodiment of the.

1. Fabrication of specimens of electroless nickel plated magnesium alloy sheet

(Example 1)

As a step 1, a magnesium alloy sheet specimen prepared at a width of 60 mm x 80 mm x 1.0 mm in size was immersed in the degreasing solution, sonicated for 5 minutes, and then immersed in an etching solution adjusted to pH 2-3 to 40 at room temperature. After immersion for a second, the post etching solution was again immersed in a post etching solution at room temperature for 40 seconds, followed by post etching, and then the activation treatment solution was first activated by immersing at room temperature for 5 minutes. It is immersed in the electroless nickel plating solution set at pH 6 ~ 7 so that the nickel-plated copper metal, which is a reaction-induced catalytic metal, is placed at a certain distance below the specimen, and the reaction gas is easily contacted with the specimen at 80 ° C. After 2 minutes of reaction, the catalyst metal was removed and the electroless nickel plated was treated for 25 minutes.

In the second step, the electroless nickel plated magnesium alloy plate specimen was baked at 200 ° C. for 60 minutes for baking, and then the magnesium alloy plate was immersed in a 10v / v% hydrochloric acid solution at room temperature for 2 minutes to activate the secondary. After the nickel strike plating was performed to have a thickness of 0.5 μm, and electroplating was performed sequentially so that the thickness of the nickel plated was 30 μm, a specimen of an electroless nickel plated magnesium alloy plate was prepared.

However, the degreasing liquid in the above is composed of 3% by weight of sodium carbonate, 0.4% by weight of sodium hydroxide, 2% by weight of sodium triphosphate and 0.1% by weight of nonionic surfactant, and 94.5% by weight of water,

Etching solution is a mixture of 16% by weight of acetic acid, 3% by weight of sodium nitrate and 81% by weight of water,

As the post etching solution, a mixture of 0.4 wt% of oxalic acid, 0.1 wt% of a humectant, and 99.5 wt% of water was used.

Activation treatment liquid is a mixture of 8% by weight of ammonium fluoride, 30% by weight phosphoric acid and 62% by weight of water,

The electroless nickel plating solution is 100 parts by weight of an aqueous solution consisting of 0.8 wt% nickel carbonate, 1.6 wt% sodium hypophosphite, 0.4 wt% citric acid, 0.8 wt% ammonium fluoride, 0.8 wt% hydrofluoric acid, 0.2 wt% ammonia and 95.4 wt% water. As an additive, an electroless nickel plating solution having a pH of 6 to 7 was used as an electroless nickel plating solution in which 0.03 parts by weight of a thiourea (H ₂ NCSNH ₂ ) aqueous solution and 0.02 parts by weight of polyethylene glycol (PEG) were mixed.

(Example 2)

In the same manner as in the first step of Example 1, a specimen of an electroless nickel plated magnesium alloy plate was prepared, and as a second step, the electroless nickel plated magnesium alloy plate was heated at 200 ° C. for 60 minutes to be baked. Then, the magnesium alloy sheet was immersed in a 10v / v% sulfuric acid solution at room temperature for 2 minutes to activate the secondary, and the nickel strike plating was made to have a thickness of 0.5 μm, and the nickel plating was made to have a thickness of 30 μm. Plating was performed sequentially to prepare specimens of electroless nickel plated magnesium alloy sheet.

However, the degreasing liquid in the above is composed of 5% by weight of sodium carbonate, 0.6% by weight of sodium hydroxide, 3% by weight of tribasic sodium phosphate and 0.3% by weight of nonionic surfactant, and 91.1% by weight of water,

Etching solution using a mixed solution of 20% by weight of acetic acid, 5% by weight of sodium nitrate and 75% by weight of water,

As the post etching solution, a mixture of 0.6% by weight of oxalic acid, 1% by weight of a wetting agent, and 98.4% by weight of water was used.

Activation treatment liquid is a mixture of 12% by weight of ammonium fluoride, 38% by weight phosphoric acid and 50% by weight of water,

The electroless nickel plating solution is 100 parts by weight of an aqueous solution consisting of 1.2% by weight of nickel carbonate, 2.4% by weight of sodium hypophosphite, 0.6% by weight of citric acid, 1.2% by weight of ammonium fluoride, 1.2% by weight of hydrofluoric acid, 0.3% by weight of ammonia and 93.1% by weight of water. As an additive, an electroless nickel plating solution was used, in which an electroless nickel plating solution containing 0.1 parts by weight of a thiourea (H ₂ NCSNH ₂ ) aqueous solution and 0.1 parts by weight of polyethylene glycol (PEG) was set at a pH of 6 to 7.

(Comparative Example 1)

After performing the pretreatment process as in Example 1, no reaction induction catalyst metal was used in the electroless nickel plating process.

(Comparative Example 2)

In the same manner as in Example 1, the baking treatment was not performed in two steps after the electroless nickel plating process.

2. Evaluation of Specimens of Electroless Nickel Plated Magnesium Alloy Plates

The results of the coating degree, adhesion and corrosion resistance evaluation of the nickel film on the specimens of Examples 1 and 2 and Comparative Examples 1 and 2 are as shown in Table 1 below.

As a test method, the corrosion resistance test was confirmed based on the rating number after 48 hours by saturating 5% saline at 35 ° C according to KSD 9502 (Brine spray test method), and the adhesion test was based on KSD 0254 (plating test method for adhesion). According to the test method of adhesive tape, the area of adhesive force is% by tile cutting method.

Evaluation item Example Comparative example One 2 One 2 Corrosion Resistance Test (Rating Number) 10 10 - - Adhesion test (adhesive area%) 100 100 - 10

According to the contents of Table 1, in Examples 1 and 2, good test results were obtained in both the corrosion resistance test and the adhesion test, whereas in Comparative Example 1, the formation of electroless nickel nuclei was not formed on the specimen surface. Since the process of the step was not possible, the results were not measured in the corrosion resistance test. In Comparative Example 2, the material was eroded in the corrosion resistance test, and the physical properties of the corrosion resistance were lower than those of Examples 1 and 2. In the adhesion test, a phenomenon in which the nickel-plated coating film was stuck to the tape by about 80 to 90%, respectively, occurred.

This result is in the case of Examples 1 and 2 according to the present invention, the magnesium alloy plate subjected to the electroless nickel plating of the first step is again baked, the second activation process and the strike of the second step. By performing the plating and electroplating sequentially, the metal diffusion phenomenon after the electroless nickel treatment may be used to increase the adhesion between the material of the magnesium alloy sheet and the plating layer.

In addition, in Example 1 produced according to the present embodiment, it can be seen that an electroless nickel metal layer (nickel film) is uniformly formed on the material layer of the magnesium alloy sheet as shown in FIG. 4A, but in FIG. 4B of Comparative Example 1 As can be seen, it was confirmed that the electroless nickel metal layer (nickel coating) was not uniformly formed on the material layer of the specimen of the electroless nickel plated magnesium alloy sheet material and was formed nonuniformly.

As a result of photographing the results of the adhesion test on the specimens of Example 2 and Comparative Example 2 produced by the present embodiment, in the case of Example 2, as shown in Figure 5a, the electroless nickel-plated magnesium alloy It was confirmed that the nickel plated coating film was not peeled off at all on the tape in close contact with the specimen of the plate, and in Comparative Example 2, the nickel plated coating film was peeled off about 80 to 90% on the tape as shown in FIG. 5B. .

For reference, Figure 4a attached to the present invention is a view showing a state of Example 1 subjected to electroless nickel plating on a magnesium alloy plate specimen using a reaction-induced catalytic metal according to the present invention, Figure 4b is FIG. 5A is a view showing the state of Comparative Example 1 in which electroless nickel plating was performed on a magnesium alloy plate specimen without using a reaction-induced catalytic metal, and FIG. 5A illustrates a baking treatment of a magnesium alloy plate specimen according to the present invention. 5B is a view showing a state, and FIG. 5B relates to a view showing a state of Comparative Example 2 in which a magnesium alloy plate specimen is not baked in accordance with the present invention.

Therefore, the magnesium alloy sheet according to the electroless nickel plating method of the magnesium alloy sheet according to the present invention is very excellent in the corrosion resistance and adhesion of the surface-treated nickel plating, and also by using a material such as nickel, chromium or precious metals Information and communication products, leisure goods, optical equipment, digital cameras by plating to improve the decoration, corrosion resistance, abrasion resistance and high hardness of magnesium plate. It can be applied to various purposes such as automobile, aircraft parts, construction materials, etc., and the demand is expected to increase significantly.

As described above, the electroless nickel plating method of the magnesium alloy sheet according to the preferred embodiment of the present invention is shown in accordance with the above description and drawings, but this is only an example, and the scope does not depart from the spirit of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made therein.

1 is a view showing a process of inducing the formation and growth of electroless nickel nuclei on an activated magnesium alloy sheet during electroless plating on a magnesium alloy sheet according to the present invention;

2 is a view showing a process of nickel plating a magnesium alloy sheet as an embodiment according to the present invention;

3 is a cross-sectional view of the nickel-plated magnesium alloy sheet according to the method of FIG.

Figure 4a is a view showing a state of Example 1 subjected to electroless nickel plating on a magnesium alloy sheet specimen using a reaction-induced catalytic metal according to the present invention;

4b is a view showing a state of Comparative Example 1 in which electroless nickel plating was performed on a magnesium alloy sheet specimen without using a reaction induction catalyst metal according to the present invention;

Figure 5a is a view showing a state of Example 2 subjected to the baking treatment on the magnesium alloy sheet specimens according to the present invention;

Figure 5b relates to a view showing a state of Comparative Example 2 is not subjected to baking treatment on the magnesium alloy sheet specimens according to the present invention.

Explanation of symbols on the main parts of the drawings

10: reaction induction catalyst metal 20: magnesium alloy plate

30: reaction gas 30 ': electroless nickel core

40: electroless nickel layer 50: strike active layer

60: electroplating layer

Claims (8)

In the electroless nickel plating method of magnesium alloy sheet material, The magnesium alloy sheet is subjected to an ultrasonic degreasing treatment and a pretreatment process of etching and post etching, After immersion in the activating solution and the first activation treatment, after the electroless nickel plating process using the reaction gas-derived catalytic metal, A method of electroless nickel plating of a magnesium alloy sheet, characterized in that the baking treatment and the electroplating are performed sequentially after the baking treatment and then immersion in an aqueous hydrochloric acid solution or a sulfuric acid solution. The method of claim 1, The etching is performed by using an etching solution adjusted to pH 2-3 using a mixed solution of 16-20 wt% acetic acid, 3-5 wt% sodium nitrate, and 75-81 wt% water. An electroless nickel plating method of magnesium alloy sheet material, which is immersed for 50 seconds. The method of claim 1, The post etching is to immerse the magnesium alloy sheet in a post etching solution of oxalic acid solution mixed with 0.4 to 0.6% by weight of oxalic acid, 0.1 to 1.0% by weight of wetting agent and 98.4 to 99.5% by weight of water at room temperature for 20 to 60 seconds. Electroless nickel plating method of magnesium alloy sheet material characterized by. The method of claim 1, The primary activation treatment is to perform the activation treatment by immersing the magnesium alloy sheet material for 3 to 8 minutes at room temperature in an activation treatment solution containing 8 to 12% by weight of ammonium fluoride, 30 to 38% by weight of phosphoric acid and 50 to 62% by weight of water. Electroless nickel plating method of magnesium alloy sheet material characterized by. The method of claim 1, The electroless nickel plating process includes nickel carbonate 0.8-1.2 wt%, sodium hypophosphite 1.6-2.4 wt%, citric acid 0.4-0.6 wt%, ammonium fluoride 0.8-1.2 wt%, hydrofluoric acid 0.8-1.2 wt%, ammonia 0.2-0.3 An electroless nickel plating solution in which 0.05 to 0.20 parts by weight of an additive was mixed with 100 parts by weight of an aqueous solution composed of 93% to 95.4% by weight of water was set to pH 6-7, and then the reaction-induced catalyst metal and activated magnesium alloy sheet were A method of electroless nickel plating of magnesium alloy sheet, characterized in that after the reaction at 75-85 ° C. for about 2 to 5 minutes, only the reaction-induced catalyst metal is discharged, and only magnesium alloy sheet is immersed for 15 to 25 minutes to electroless nickel plating. The method of claim 1, The reaction induction catalyst metal is electroless nickel plating method of the magnesium alloy sheet, characterized in that one selected from the metal reacted with the electroless nickel plating solution, such as iron, nickel, nickel plated metal. The method of claim 1, The baking process is an electroless nickel plating method of a magnesium alloy plate material, characterized in that the electroless nickel plated magnesium alloy plate material is heated at 100 to 300 ℃ for 30 to 120 minutes. The method of claim 1, The electroplating method of electroless nickel plating of magnesium alloy sheet, characterized in that the general corrosion or decorative plating.

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