TWI623651B - Dyeing method for micro-arc processing of metal workpiece - Google Patents

Abstract

The invention provides a method for dyeing a micro-arc metal workpiece, comprising the steps of: providing a micro-arc processing metal workpiece, a reaction tank and a dyeing tank. The micro-arc processed metal workpiece has a metal substrate and a micro-arc oxidation layer, the micro-arc processed metal workpiece having a first color. The present invention includes a method of causing a micro-arc oxidation layer to generate a charge path, and a micro-arc oxidation layer dyeing method to impart a second color to the micro-arc treated metal workpiece. Through these two methods, the dye can be attached to the micro-arc oxidation layer, that is, the anionic dye particles are adsorbed in the charge channel of the micro-arc oxidation layer to achieve the dyeing effect.

Description

Dyeing method for micro-arc processing of metal workpiece

The present invention relates to a dyeing method, and more particularly to a method of dyeing a micro-arc treated metal workpiece.

Micro-arc oxidation (MAO) is based on anodizing, using micro-arcing to produce micro-arc discharge on the surface of micro-arc metal workpieces, in the surface of passivated light metals such as aluminum, magnesium and titanium or alloys thereof. The surface of the metal formed by the micro-arc oxidation of the oxide film has high hardness and good corrosion resistance, and is an emerging electrochemical surface treatment technology. Countries have different cognitions for this technology, and thus have different names, such as Microarc discharge oxidation (MDO), Microplasma oxidation (MPO), Anodic spark deposition, and spark discharge anodes. Anodischen oxidation unter funkenentladung (ANOF-process), spark discharge oxidation and plasma electrolytic oxidation (PEO).

Although the mechanical properties of the oxide layer obtained by micro-arc oxidation, such as surface hardness, wear resistance and bonding force, are superior to those of the conventional anodic aluminum oxide (AAO), the micro-arc oxidation is far less than the decorative application. Conventional anodizing is mainly due to the fact that the pore size accompanying the micro-arc oxidation layer falls on the micrometer scale. If the micro-arc oxidation layer is colored by dye adsorption, these micro-scale pores do not allow the dye to adhere firmly to its surface. The oxide layer formed on the surface by the conventional anodizing treatment has a hexagonal hole packing structure. These nanometer-scale pores have good permeability, and the surface can be soaked in an organic or inorganic dye to penetrate into the capillary pores. Bright colors can be dyed directly on the aluminum alloy by dyes of different colors. In addition, titanium metal can pass through the color treatment. After the titanium metal is placed in some special electrolyte to apply a certain current or voltage, the surface of the titanium metal will be electrolytically oxidized to form a very thin film with interference light characteristics. The film itself is not colored, but when the light is irradiated thereon, as the light of certain wavelengths cancels each other, the reflected pupil causes the surface of the titanium metal to have a color, and as the thickness of the film increases, the color changes from red to blue. Green, produces different changes.

Metallic hair color is mainly decorative, and the metal surface obtained by the chromonic treatment does not have special protective properties. The oxide layer of micro-arc oxidation is mainly white, grayish white, taupe and black. Although the film has a beautiful appearance and good overall performance, the color type is limited, which greatly limits the appearance application of the light alloy, especially the alloy die-casting of the outer casing of the electronic product. Consumers have a variety of color requirements on the surface. If they can obtain ceramic films with uniform color and various colors, and at the same time have the excellent mechanical protection properties, the application of micro-arc oxidation technology will be rapidly promoted. To this end, all countries in the world have tried their best to pursue this color technology. Among them, the mainland has made considerable attempts in the coloring technology of micro-arc oxidation workpieces. In the mainstream of modulating electrolyte to achieve color development, vanadic acid is mainly used. The salt electrolyte is used for micro-arc oxidation, and the obtained ceramic film is mostly green in color. A certain amount of ammonium metavanadate (NH ₄ VO ₃ ) may be added to the electrolyte to prepare a black ceramic film layer. Although the film has uniform color and good appearance, the comprehensive performance of the film layer is not good. More importantly, the vanadate added in the electrolyte is discharged with the solution without special treatment, causing heavy metal pollution and seriously affecting the environment. . In addition, the above embodiment has its difficulty. Since the colorant is directly added to the electrolyte, it is necessary to replace the electrolyte or prepare a treatment tank every time a micro-arc process is to be replaced. Cost and other considerations, which do not meet the needs of mass production.

Another type of post-treatment coloring attempt can be found in Chinese Patent Publication No. CN101376973A and No. CN103203915A. The above two previous cases respectively proposed the technology of "vacuum sputtering combined with electrophoretic coating processing micro-arc oxidation workpiece process" and "aluminum alloy micro-arc electrophoresis composite film layer", the main implementation method is first in aluminum, magnesium or titanium. The passivated metal or its alloy is firstly prepared by micro-arc oxidation, and then the metal layer is plated on the micro-arc oxidation layer and then electrophoretic coating, or directly on the micro-arc oxidation layer, according to the workpiece The required color is used to select the electrophoretic coating of the corresponding color to improve the poor color forming effect of the conventional micro-arc oxidation layer. However, electrophoretic coating uses the principle of electroplating to cause the water-soluble ionized coating resin to precipitate on the electrode, thereby forming an insoluble coating and covering the micro-arc oxide layer. Although the color layer is added to the oxide layer, it is also lost. The ceramic texture of the micro-arc oxidation layer and superior mechanical properties. In addition, the color layer coated or sprayed by electrophoresis has a certain degree of adhesion, because the colored layer has a certain thickness, and if it is an appearance assembly, whether it will affect the precision or the degree of assembly, there is still considerable Doubt.

The invention provides a dyeing method for a micro-arc metal workpiece, which not only obtains a ceramic oxide film with uniform color and various colors, but also has the effect of having an excellent mechanical protection performance.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of dyeing a metal workpiece for micro-arcing comprising the steps of providing a micro-arc treated metal workpiece, a reaction vessel, and a dyeing tank. The micro-arc processed metal workpiece has a metal substrate and a micro-arc oxidation layer, the micro-arc processed metal workpiece has a first color, the reaction tank includes a pre-treatment solution, and the dyeing tank includes a dyeing solution, the dyeing The solution has a plurality of anionic dye particles. The microarc-treated metal workpiece is placed in the reaction vessel, and the micro-arc-treated metal workpiece is entirely located in the pre-treatment solution. Then connecting the reaction tank to the anode, and connecting the metal substrate to the cathode, forming a first loop of the reaction tank, the pretreatment solution and the microarc processed metal workpiece, and applying a reverse voltage to the first loop, The microarc oxidation layer is formed into a plurality of charge channels. Removing the micro-arc processed metal workpiece into a dyeing tank, and placing the micro-arc processed metal workpiece all in the dyeing solution, connecting the dyeing tank to the cathode, and connecting the metal substrate to the anode, so that the dyeing tank, The dyeing solution and the micro-arc processed metal workpiece form a second loop, and a forward voltage is applied to the second loop, and a positive electric field is formed at a boundary between the metal substrate and the micro-arc oxide layer. After the positive electric field attracts the anionic dye particles, the anionic dye particles are adsorbed in the charge channel of the micro-arc oxidation layer, and the micro-arc processed metal workpiece has a second color.

According to a preferred embodiment of the invention, wherein the reverse voltage is 10 to 30 volts and the forward voltage is 2 to 10 volts.

According to a preferred embodiment of the present invention, wherein the reverse voltage is applied to the first loop, it further comprises maintaining a reaction time of 5 to 15 seconds.

According to a preferred embodiment of the present invention, after applying the forward voltage to the second loop, it further comprises maintaining a dyeing time of 60 to 300 seconds.

According to a preferred embodiment of the present invention, after applying the forward voltage to the second loop, further comprising maintaining a predetermined temperature, the predetermined temperature being 20 to 60 degrees Celsius (° C.).

According to a preferred embodiment of the present invention, the pretreatment solution is an electrolyte solution, and the electrolyte solution is one of a soluble salt, an acid, and a base, or a combination thereof.

According to a preferred embodiment of the present invention, the temperature of the electrolyte solution is 15 to 40 degrees Celsius (° C.).

According to a preferred embodiment of the present invention, the electrolyte solution is a sodium chloride solution having a concentration of 0.01 to 0.1 mol (M).

According to a preferred embodiment of the invention, the dye solution has a concentration of from 3 to 15 grams per liter (g/L).

According to a preferred embodiment of the invention, the dyeing solution comprises an anionic organic dye.

The present invention will be described in more detail with reference to the preferred embodiments of the invention. However, the examples of any form used in this specification are for illustrative purposes only and are not intended to limit the invention. Rather, the embodiments are provided so that this disclosure will be more fully and fully described.

In order to avoid the defects caused by the prior art, and to make the metal workpiece after micro-arc processing more competitive and development, the present invention proposes a new micro-arc processing method for dyeing metal workpieces by micro-arc oxidation. a method of pre-dyeing treatment to obtain a micro-arc oxidation layer having an active surface layer and a large number of charge channels, and then using the dyeing method proposed in the present invention, the micro-arc oxidation layer can be used in organic or inorganic dyes of various colors. Dyeing, to obtain a variety of micro-arc oxidation layer with saturated color, and retaining the superior characteristics of micro-arc processing, so that the metal workpiece can still have both functional and aesthetic use after micro-arc processing technology, further expanding micro-arc processing The application of technology to enhance the value of the overall industry.

Please refer to FIG. 1a to FIG. 1d, which are schematic diagrams of a preferred embodiment of a pre-dyeing treatment method for a micro-arc treated metal workpiece according to the present invention. The micro-arc processed metal workpiece 1 is composed of a metal substrate 12 and a micro-arc oxidation layer 11 obtained by micro-arc treatment, and has a first color, or uses other alloys as a metal substrate, but is not limited thereto. The micro-arc oxide layer 11 is a membranous structure belonging to an open and closed pore having a large number of micrometer scales. As shown in FIG. 1a, the pre-dyeing treatment method of the micro-arc-treated metal workpiece is performed by placing the micro-arc-treated metal workpiece 1 into the reaction tank 2, and the micro-arc-treated metal workpiece 1 is entirely located in the pre-treatment solution 21 Inside. Next, as shown in FIG. 1b, the reaction tank 2 is connected to the anode, and the metal substrate 12 is connected to the cathode, so that the reaction tank 2, the pretreatment solution 21 and the microarc treated metal workpiece 1 form a first loop. As shown in FIG. 1c and FIG. 1d, the interaction between the pretreatment solution 21 and the reverse voltage applied to the microarc treated metal workpiece 1 causes the open pores in the microarc oxidation layer 11 to be electrochemically dissolved. The structure of the charge channel 111. The formation of the charge channel 111 does not damage the metal substrate 12 and the micro-arc oxide layer 11, and retains the excellent essential characteristics of the micro-arc process.

Please refer to FIG. 2a to FIG. 2d, which are schematic diagrams showing a preferred implementation of the method for dyeing a micro-arc treated metal workpiece according to the present invention. When the entire micro-arc processed metal workpiece 1 is placed in a dyeing tank 3, and the micro-arc processed metal workpiece 1 is entirely located in the dyeing solution 31, the dyeing tank 3 is connected to the cathode, and the metal substrate 12 is connected to the anode. The dyeing tank 3, the dyeing solution 31 and the micro-arc treated metal workpiece 1 form a second loop and pass it to a forward voltage. At this time, a positive electric charge forms a positive electric field at the boundary between the metal substrate 12 and the micro-arc oxidation layer 11, and under the action of a positive electric field, the anionic dye particles 32 in the dyeing solution 31 are adsorbed to the opening having the charge channel 111. In the open pores, since the open pores having the charge channels 111 can efficiently attract the anionic dye particles 32 by the positive electric field, and the kinetic energy of the anionic dye particles 32 is adsorbed to the open pores having the charge channels 111, Therefore, there is a relatively good adhesion between the anionic dye particles 32 and the open pores having the charge channels 111, which have a second color. That is to say, the number of charge channels 111 formed and the time of dyeing can be controlled through different operation parameters, and then the amount of adsorbed anionic dye particles 32 can be controlled, and the color appearance after dyeing can be different according to the generated saturation. It will be different.

Embodiment 1

Figure 3 is a photograph showing the state of the micro-arc treated metal workpiece before dyeing in the preferred embodiment of the present invention. This embodiment performs dyeing of the micro-arc treated metal workpiece 1 with an aluminum alloy as the metal substrate 12. First, the micro-arc oxidation layer 11 is pre-dyed. In this embodiment, an aluminum alloy is used as the metal substrate 12, and the micro-arc processed metal workpiece 1 is placed in the reaction tank 2 of 304 SS stainless steel, and the reaction tank is used. 2 as a counter electrode, connected to the anode. The pretreatment solution 21 in the reaction tank 2 is an electrolyte solution including an electrolyte solution composed of most soluble salts, acids or bases. In the present embodiment, a sodium chloride solution having a concentration of 0.01 to 0.1 mol (M) is used, and the electrolyte solution is set between 15 and 40 degrees Celsius (° C.) by a temperature control system. The electrolyte solution was stirred. When a DC power source is used, the micro-arc processed metal workpiece 1 is set to a reverse voltage of 10 to 30 volts, and the reaction time is 5 to 15 seconds. Through the above steps, the surface layer of the micro-arc oxidation layer 11 is activated, and a large number of charge channels 111 are formed in the micro-arc oxidation layer 11. After the reaction is completed, the micro-arc treated metal workpiece 1 is taken out for washing, dehydrating, and drying.

Next, the dyeing work of the micro-arc oxidation layer 11 is performed in the dyeing solution. The composition of the dyeing solution 31 is a dye (non-pigment), and may be any kind of colored dye, such as an organic dye or an inorganic dye, etc., in this embodiment, 304 SS stainless steel. The tank is used as a dyeing tank 31 in which a red anionic organic dye is disposed at a concentration of 3 to 15 g/liter (g/L). The micro-arc processed metal workpiece 1 completed in the previous stage is placed in the dyeing tank 3, the dyeing tank 3 is connected to the cathode, and the metal substrate 12 is connected to the anode, and the micro-arc processed metal workpiece 1 is set as input. The forward voltage is 2 to 10 volts, the operating temperature is 20 to 60 degrees Celsius (°C), and the dyeing time is 60 to 300 seconds. After the dyeing is completed, the water is washed, dehydrated, and dried to complete the dyeing of the micro-arc oxidation layer 11, which is red as shown in FIG. 4 and Table 1. The dyeing effect can be identified by the colorimetric analysis test standard (CIE 1976 Lab). The Lab value of the undyed microarc oxidation layer is (L*a*b*)=(83.08, -0.58, 1.09), after the red dye. The chroma value after dyeing is (L*a*b*)=(65.54, 24.05, 11.32). Table I  <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> Chroma Value Example</td><td> L* </td><td> a* </td><td> b* </td></tr><tr><td> Micro-arc treated aluminum alloy metal substrate</td><td> 83.08 </td><td> -0.58 </td><td> 1.09 </td></tr><tr><td> Red anionic organic dye</td><td> 65.54 </td><td> 24.05 </td>< Td> 11.32 </td></tr><tr><td> green anionic organic dye</td><td> 75.93 </td><td> -2.59 </td><td> 35.63 </td ></tr><tr><td> Blue anionic organic dye</td><td> 52.48 </td><td> 2.98 </td><td> -36.48 </td></tr> </TBODY></TABLE>

Embodiment 2

In another embodiment, the green anionic organic dye is used, and the micro-arc metal workpiece is dyed according to the method of the first embodiment. The dyeing result is shown in FIG. 4 and Table 1. After the green dye is dyed, the chromaticity value (L) *a*b*)=(75.93, -2.59, 35.63).

Embodiment 3

In still another embodiment, the blue anionic organic dye is used, and the micro-arc metal workpiece is dyed according to the method of the first embodiment. The dyeing result is shown in FIG. 4 and Table 1. After the blue dye is dyed, the chromaticity value is obtained. Is (L*a*b*)=(52.48, 2.98, -36.48).

In summary, the present invention proposes a coloring technique for a micro-arc oxidation layer, and it is expected that the coloring technique provides a different thinking and practice for the industry in application. The technique of the present invention comprises a method for generating a charge channel by a micro-arc oxidation layer and a dyeing method for a micro-arc oxidation layer, and the two methods can effectively adhere the dye to the micro-arc oxidation layer to achieve the dyeing effect. .

The above is only the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto; therefore, the simple equivalent changes and modifications made by the scope of the present invention and the contents of the description of the invention, All remain within the scope of the invention patent.

1‧‧‧Micro-arc processing of metal workpieces
11‧‧‧Microarc Oxide
111‧‧‧Charge channel
12‧‧‧Metal substrate
2‧‧‧Reaction tank
21‧‧‧Pretreatment solution
3‧‧‧Dyeing tank
31‧‧‧Staining solution
32‧‧‧ Anionic dye particles

1a to 1d are schematic views showing a preferred embodiment of a pre-dyeing treatment method for a micro-arc treated metal workpiece according to the present invention. 2a to 2d are schematic views showing a preferred embodiment of a dyeing method for a micro-arc treated metal workpiece according to the present invention. Figure 3 is a photograph showing the state of the micro-arc treated metal workpiece before dyeing in the preferred embodiment of the present invention. Figure 4 is a photograph showing the results of dyeing a micro-arc treated metal workpiece in a preferred embodiment of the present invention.

Claims (10)

A micro-arc processing method for dyeing a metal workpiece comprises the steps of: providing a micro-arc processing metal workpiece, a reaction tank, and a dyeing tank, the micro-arc processing metal workpiece having a metal substrate and a micro-arc oxidation layer, The micro-arc processed metal workpiece has a first color, and the reaction tank comprises a pre-treatment solution, the dyeing tank includes a dyeing solution, the dyeing solution has a plurality of anionic dye particles; and the micro-arc processed metal workpiece is placed in the reaction In the tank, and the micro-arc metal workpiece is all located in the pre-treatment solution; connecting the reaction tank to the anode, and connecting the metal substrate to the cathode, the reaction tank, the pre-treatment solution and the micro-arc treatment metal The workpiece forms a first loop; applying a reverse voltage to the first loop to form the plurality of charge channels; and removing the micro-arc processed metal workpiece into a dyeing tank, and processing the micro-arc The metal workpiece is entirely located in the dyeing solution; the dyeing tank is connected to the cathode, and the metal substrate is connected to the anode to make the dyeing tank, the dyeing The liquid and the micro-arc processed metal workpiece form a second loop; applying a forward voltage to the second loop, and forming a positive electric field at a boundary between the metal substrate and the micro-arc oxidation layer; a positive electric field attracting the anionic dye Particles; Anionic dye particles are adsorbed in the charge channel of the micro-arc oxidation layer, and the micro-arc processed metal workpiece has a second color. A method of dyeing a micro-arc treated metal workpiece as described in claim 1, wherein the reverse voltage is 10 to 30 volts, and the forward voltage is 2 to 10 volts. The method for dyeing a micro-arc treated metal workpiece according to claim 1, wherein the applying the reverse voltage to the first circuit further comprises maintaining a reaction time of 5 to 15 seconds. The method for dyeing a micro-arc-treated metal workpiece according to claim 1, wherein the applying the forward voltage to the second circuit further comprises maintaining a dyeing time of 60 to 300 seconds. The method for dyeing a micro-arc processed metal workpiece according to claim 1, wherein the applying the forward voltage to the second circuit further comprises maintaining a predetermined temperature of 20 to 60 degrees Celsius ( °C). The method for dyeing a micro-arc treated metal workpiece according to claim 1, wherein the pre-treatment solution is an electrolyte solution, and the electrolyte solution is one of a soluble salt, an acid and a base, or a combination thereof. Made. The method of dyeing a micro-arc treated metal workpiece according to claim 6, wherein the temperature of the electrolyte solution is 15 to 40 degrees Celsius (° C.). The method for dyeing a micro-arc treated metal workpiece according to claim 6, wherein the electrolyte solution is a sodium chloride solution having a concentration of 0.01 to 0.1 mol (M). A method of dyeing a micro-arc treated metal workpiece as described in claim 1, wherein the dyeing solution has a concentration of 3 to 15 g/l (g/L). The method for dyeing a micro-arc treated metal workpiece according to claim 1, wherein the dyeing solution comprises an anionic organic dye.