TW200528584A - Anodization electrolyte and method for a magnesium metal - Google Patents

Abstract

An anodization electrolyte for a magnesium metal is disclosed. The anodization electrolyte for the magnesium metal comprises silicate and nitrate salts, wherein silicate salts can increase protectiveness of the anodized film to the magnesium metal, and nitrate salts can make the anodized film to be grown uniformly on the surface of the magnesium metal. The anodization electrolyte for the magnesium metal of the present invention not only increases protectiveness of the anodized film, but also mitigates the non-uniform anodized film due to sparking during anodizing the magnesium metal. In addition, a method of anodization for a magnesium metal is further disclosed, which is also suitable for processing the surface of the magnesium metal.

Description

200528584 发明. Description of the invention [Technical field to which the invention belongs] The present invention relates to an anodic oxidation treatment solution for magnesium metal, especially an anodic oxidation treatment solution suitable for magnesium metal surface treatment. [Previous technology] Under the demand for lightweight, the town and its alloys have received considerable attention. Because of its low density (about 1.7 g / cm2), high strength-to-weight ratio, and good electromagnetic shielding properties, the ballast alloy has been widely used in the automotive industry, leisure equipment, 3C products, etc., but it is used in magnesium alloys. In the development process and application fields, poor corrosion resistance has always been the biggest fatal injury of magnesium alloys. Therefore, magnesium alloy car fathers are rarely used in structural or corrosive environments. In order to cover the corrosion resistance properties of magnesium alloys, expand the application fields of magnesium alloys, and extend the life span and consideration of women's integrity, corrosion resistance treatment is an important step. Surface treatment is one of the important and effective methods. The alloy-related surface = etching treatment has been the subject of scholars' research. Among them, the anodized protective film has better abrasion resistance and protection, which is quite suitable for the surface residual treatment of lock alloys. The anodizing treatment uses the local high temperature generated during sparking to promote the formation of a sintered ceramic-like oxide layer on the surface of the magnesium alloy, that is, the anode film is achieved by the anode film's good protective protection of the magnesium alloy substrate. The effect of increasing button resistance. Compared with other surface treatments, the anodizing treatment has better abrasion resistance, and the adhesion of coating I is also good. It is quite suitable for the surface corrosion treatment of ballast alloys. One. -Generally speaking, the anodizing technology is mainly formed on the surface of the town alloy: a layer of anodic film, this anodic film layer must be evenly covered on the surface, so as to avoid impotence defects after anodizing, but accelerate the destruction of the substrate, at the same time The grown anode film must also provide excellent protection to achieve the effect of Baoyingzhen alloy substrate. Therefore, the uniformity, composition and structure of the anode film are all critical factors that determine the protection of the anode film. Furthermore, to increase the growth rate and protect the anode film layer of the magnesium alloy from the external environmental impact of rotten rice, the key lies in the electrolyte used in the anodizing process, and the composition of the electrolyte and its The results of the polar oxidation treatment of the additive and the properties of the anode film. "The anodic oxidation treatment liquids of the genus, magnesium and their alloys are mainly chromate-based, but in recent years, environmental awareness has risen. Chromate-based anodizing treatment liquids or chemical treatment (Conversion coating) electrolytes It has been gradually eliminated, and low-pollution and environmental-friendly anodizing treatment fluids have become mainstream. This type of anodizing treatment fluids include fluorides, phosphates, sulfates, potassium oxide (κ〇 ^, sodium hydroxide (Na0H) ), Etc. Adding phosphate to the anodizing solution can reduce the pores caused by spark discharge on the anode film, and adding fluoride to the anodizing solution can enhance the scratch resistance of the anode film. Although the protective film obtained by anodizing treatment has better abrasion resistance and dull f-phase ^ is suitable for the treatment of worms on the surface of lock alloys, but because its technology has not yet become hot, it is applied in the anodizing treatment of magnesium alloy industry Still limited. For example, during the anodizing process of Die Casting AZ91D magnesium alloy containing hydrogen 200528584 oxidized bell gasification bell and anodizing solution of sodium phosphate, The phenomenon of spark discharge concentration results in uneven growth of the anode film. In order to meet the future needs of magnesium alloys, 'it is necessary to change the composition of the electrolyte to improve the phenomenon of spark discharge concentration' in order to obtain a uniform sentence & lt Anode film, and improve the tolerance of towns and town alloys. [Summary]-Therefore, one of the purposes of the present invention is to disclose an anodic oxidation treatment solution of magnesium metal, the anodic oxidation treatment solution of magnesium metal contains at least Silicic acid I and nitrate, among which oxalate can improve the protection of the anode film to magnesium metal, and nitrate can make the anode film grow uniformly on the surface of magnesium metal. Another object of the present invention is to disclose a magnesium metal Anodizing treatment method. This anodizing treatment method uses the anodizing treatment solution of magnesium metal of the present invention to perform anodizing treatment on the surface of magnesium metal in this electrolyte. In this way, the protection of the anode film of magnesium metal can be improved. It also improves the problem of uneven anode film caused by spark discharge during the anodizing process of magnesium metal. For the above purpose, an anodic oxidation treatment solution for magnesium metal is proposed, which contains at least: 0.01 mol concentration (] ^) to 2 M silicate; 0.01 M to 2 M nitrate; 0.1 M to 5 M potassium hydroxide 0. ^ M to 1 M gasification unloading, 0. 1 M to 1 M sodium phosphate; and deionized water. According to a preferred embodiment of the present invention, the above silicate may be, for example, sodium oxalate (Na2Si03), sodium tetrasilicate (Na2Si409), or a combination thereof. 200528584 According to a preferred embodiment of the present invention, the above-mentioned nitrate is selected from the group consisting of aluminum nitrate, potassium nitrate, sodium nitrate, or the above. According to the above-mentioned object of the present invention, a method for anodizing an magnesium metal is further provided. The method includes at least: first, providing a ballast metal, wherein the ballast metal may be a ballast or a ball alloy; In the oxidation treatment solution, a constant current and a constant voltage are sequentially applied to the magnesium metal to form an anode film on the surface of the magnesium metal. The anode gasification treatment liquid contains at least: 0.0 to 2% of silicate; 〇〇11 ^ To 21 ^ of the stone Xiaoxizhi salt, 0.1 Of potassium hydroxide to 5 Μ; 〇1. 1 to M of the M potassium Dunhua; ο · 1 M of sodium phosphate as well. 1; and deionized water. Because the anodizing treatment solution of magnesium metal contains silicates and nitrates, among them, Shixiu acid can be used to protect the polar membrane, and nitrate is: good spark discharge The concentration phenomenon makes the anode film grow on the surface of the town metal and improves the button resistance of the magnesium metal. [Embodiment] The present invention discloses a magnesium metallization treatment system which uses deionized water to dissolve at least anodic oxygen, 0.1 to 1M, fluorinated bell, 0.1Mi5M to remove hydrogen hydroxide, mix well with white turban helmet, and sodium phosphate. Wait, stir + sentence to become an aqueous solution, and then chemical treatment. Anodizing is performed on the surface of the metal. In the present invention-a preferred embodiment, 1 acid 0.5M is preferred; nitric acid is preferably 0.1M to 0C and 0.1M to 0.5M is preferred, 10 200528584 argon oxidation The concentration of potassium is preferably from M to 3 M, the concentration of potassium fluoride is from 0.5 M to 1 M, and the concentration of sodium phosphate is from 0.1 M to 0.5 M. In a more preferred embodiment of the present invention, the concentration of potassium hydroxide is more preferably about 3M, the concentration of potassium fluoride is more preferably about 0.6M, and the concentration of sodium phosphate is about 0.21M. Better. According to a preferred embodiment of the present invention, the aforementioned silicate may be, for example, sodium silicate, sodium tetrasilicate, or a combination thereof. According to a preferred embodiment of the present invention, the aforementioned nitrate may be, for example, sodium nitrate, potassium nitrate, sodium nitrate, or a combination thereof. According to a preferred embodiment of the present invention, the above-mentioned magnesium metal may be, for example, pure magnesium or a magnesium alloy, wherein the magnesium alloy may be, for example, a magnesium-aluminum-zinc series magnesium alloy, and the forming method of the magnesium metal may be, for example, by die casting, casting, or forging. Method. Compared with the anodic oxidation treatment liquid phase of the magnesium metal of the present invention, adding silicate to the conventional anodic oxidation treatment solution containing potassium hydroxide, potassium fluoride and sodium phosphate can increase the corrosion resistance of the anode film, but still There is uneven spark discharge. Because the unevenness of the discharge prevents the anode film from uniformly covering the surface of the magnesium metal, the protection of the anode film cannot be greatly improved by adding silicate alone. However, the addition of nitrate to the conventional anodizing solution has been found to reduce the phenomenon of uneven growth of the anode film due to the concentration of spark discharge during the anodizing process. Therefore, combining the results obtained from the above two kinds of additives, the anodic oxidation treatment solution of the present invention simultaneously adds nitrate and silicate, which complement each other and can greatly improve the corrosion resistance of magnesium metal. As mentioned above, the present invention further discloses an anodic oxidation treatment of magnesium metal. 11 200528584 The method is suitable for the surface treatment of magnesium metal. The following are several examples and are provided with the diagrams of Figs. 1 to 11 to further disclose the anodic oxidation treatment method of magnesium metal of the present invention, but it is not intended to limit the present invention to anyone skilled in the art Without departing from the spirit of the present invention, it can be used as a slight modification and retouching. The magnesium metal used in the first to eleventh embodiments of the present invention is, for example, a die-cast AZ9 1D magnesium alloy, and the pretreatment is performed in the following manner. First, the die-cast AZ91D magnesium alloy was cut into 15 mm long, 15 mm wide, and 1.5 mm thick, and then the magnesium alloy was connected to a copper wire. Next, after "embedding with epoxy resin (EpOxy) into a test piece with a diameter of 30 mm", it was ground with silicon carbide sandpaper to # 丨 〇〇〇. Then, the test piece was washed with deionized water, and the surface of the test piece was washed with ultrasonic vibration. After that, the anode oxidation treatment step is performed. When performing the anodizing step, the voltage is first increased by a constant current method, and after the voltage reaches a preset voltage, the anodization is performed by a constant voltage method. According to a preferred embodiment of the present invention, the current density is set between 1 and 15 milliamperes (mA / cm2) per square centimeter, and the set voltage is between 80 and 100 volts (Volt; V). . In the first to fourth embodiments of the present invention, the current density is set to 5 mA / Cm2, and the voltage is set to 80V. In the fifth to eleventh embodiments of the present invention, the current density is set to 10 mA / cm2, and the voltage is set to 90 V. The anode oxidation treatment time of the first to eleventh embodiments described above is 20 minutes, and the cathode used for the anodization treatment is a ballast steel sheet. 12 200528584 The conventional anodizing treatment solution contains potassium hydroxide, potassium fluoride, and sodium phosphate, and the present invention uses the conventional anodizing treatment solution, and then uses different additives to form three different anodizing treatment solutions. One kind of anodizing treatment liquid is added to the conventional anodizing treatment liquid with ggi to 2 m aluminum nitrate, and the second type of anodizing treatment liquid is added to the conventional anodizing treatment liquid with G.G1 Μ to 2 Μ. It is expected that the third anodizing treatment solution is added to the conventional anodizing treatment solution, and sodium silicate and aluminum nitrate of 0.1 μm to 2 μm are added simultaneously. In the above embodiments, the anodizing conditions of the three anodizing treatment liquids are all the same, and the third anodizing treatment liquid only changes the concentration of sodium silicate. The surface microstructures of the first embodiment to the eleventh embodiment of the present invention are developed using an optical microscope (Optica), MicrOscope; 0M) and a scanning electron microscope (Scanning Electron Microscope; SEM). 4 亍 Observe. The electrochemical properties were tested at 3.5 weight percent (... ❺ 丨 钟 言

Percent; wt ° / 0) in aqueous sodium chloride (NaCl). Refer to Fig. 1 (a) to Fig. 1 (b) ', which shows the surface microstructure of the pressed AZ91D magnesium alloy. A preferred embodiment of the present invention uses a die-cast AZ91D magnesium alloy. The die-cast AZ91D magnesium alloy is a two-phase alloy including an α phase of a solid solution and a point phase of a magnesium aluminum alloy, as shown in Section 1 (b). Alpha and stone are shown in the figure. Please refer to Fig. 2 (a) to Fig. 2 (e), which show the die-cast AZ91D magnesium alloy after grinding (Fig. 2 (a)) and the first to fourth embodiments according to the present invention ( Figures 2 (b) to 2 (e)) are macroscopic photographs of the surface of the die-cast AZ91D magnesium alloy that has been anodized. Among them, the present invention is a control group, that is, a conventional anodizing treatment solution is used to perform an isolation oxidation treatment. The second embodiment to the fourth embodiment are on the upper surface: the anodizing treatment liquid is anodized, and the first anodizing treatment liquid contains 0.1M, 0.15μ, and 025M tellurate inscriptions, so as to understand nitric acid The effect of aluminum to reduce discharge. Please refer to the second figure. After the die-casting AZ9m town alloy was ground with #esand paper, the surface of the test piece had obvious scratches. However, when die-casting AZ91D town alloy is anodized in the conventional anodic oxygen, the surface will be covered with a layer of anode film. Due to the concentration of spark discharge, the resulting anode film structure is uneven and has poor protection. As shown in Figure 2 (b), in the · T, the white area is the area of concentrated discharge. Compared with the white area, the thinner anode film is formed. This is due to the phenomenon that the uniformity of the% electrode film is not good due to the phenomenon of current collection. 矣; the anode film formed in the white area is thicker; the anode film formed in the remaining area is thinner; Occurs, so the magnesium alloy substrate cannot be effectively protected. Reference: f 2 Figure, compared with the anode of the anode film of the first embodiment, the anode has been more uniform, so its protection is better. Please refer to FIG. 2 (b). The phenomenon of concentrated discharge in the third embodiment is significantly reduced, and the anode film is more uniform after the anodic oxidation process of the present invention. The anode film of the second embodiment is more uniform than that of the first embodiment. -Yindi has always known that the anode anode is thicker, so it has better health. Please refer to Fig. 2 (Fig. 2), the phenomenon of concentrated discharge in the third embodiment, which is rarely experienced, and therefore the resulting anode film is very uniform. Jian Luzhi's observation results from the first example $ ^^ to the fourth example can be 200528584. With the increase of the concentration of the acid I, the less uneven growth of the anode film caused by concentrated discharge, that is, concentrated The area of discharge decreases, as shown in Figures 2 (b) to 2 (e).

Please refer to FIGS. 3 (a) to 3 (c), which show the current in the anodizing step of the first embodiment, the fourth embodiment, and the first to fourth embodiments according to the present invention. A plot of density versus time. Please refer to Figure 3 (a), which shows that the current will oscillate during the anodizing process, which is a normal phenomenon in the spark discharge process. In the first embodiment, without the addition of aluminum nitrate, the current density does not decrease with the progress of the anodizing process, which shows that the anode film has not grown very completely, as shown in Figure 3 (a). As shown. Please refer to FIG. 3 (13), which is a diagram showing the relationship between the current degree of desire and time in the fourth embodiment. It can be clearly seen that the amplitude of the current oscillation is significantly reduced, and the current density will be significantly reduced. At this time, because the concentration of spark discharge is reduced, the anode film is more completely covered on the surface of the substrate. Please refer to FIG. 3 (c), which is a graph showing the relative relationship between current density and time in the anodizing step according to the first to fourth embodiments of the present invention. To avoid confusion, the oscillating part in the figure is flat. = Value to represent. It can be seen from the figure that when an appropriate amount of aluminum nitrate is added, such as the third embodiment and the fourth embodiment, the current density value is significantly reduced, showing that a uniform anode film is formed on the surface of the AZ91D magnesium alloy. According to the simple electrical principle, the surface resistance due to the anode film is 9 knives early, and the current value tends to decrease only when the potential is constant. However, it is also shown in Figure 3 (c) that the final current value of each group decreases with the increase of aluminum nitrate content, and the minimum value can reach about 0.3 mA / cm2. -15 200528584 凊 Refer to Figures 4 (a) to 4 (C), which show the surface size of anodized die-cast AZ9 1 D magnesium alloy according to the fifth to seventh embodiments of the present invention. View photos. Among them, the fifth embodiment to the seventh embodiment are performed by using the above-mentioned second anodizing treatment solution for anodization, wherein the second anodizing treatment solution contains 0.05M,

〇 1M and 〇15M sodium silicate to understand the effect of sodium silicate on the corrosion resistance of the anode. From the macroscopic photos of the surface in Figures 4 (a) to 4 (c), it can be seen that the second anodizing treatment with only sodium silicate added: the film has poor uniformity, and there is still a phenomenon of ten discharges. occur. However, due to the concentration of sodium silicate and the concentration of sodium silicate, during the anodizing process, a concentration of fire t discharge will still occur. Reference is made to Figs. 5 (a) to 5 (d), which are macroscopic photographs showing the surface of anodized die-casting magnesium alloy according to the eighth embodiment to the eleventh embodiment of the present invention. Among them, the eighth embodiment to the first embodiment are anodized using the third anodizing treatment solution described above: M: φ 盛-# t

/ 、 The two kinds of middle polar oxidation treatment solution contain 0.15 M nitric acid: solution with the addition of aluminum nitrate and sodium silicate to anodic oxidation treatment to acid = phase: as shown in Figure 4 (a) to Figure 4 The result is clear in the same wonderfulness; the uniformity and effect on the anode film after the improvement of the nitrate inscription of = 15. What is the concentration of sodium silicate that is not added, the test results show that the surface is more stable. 矣 π magnesium: 矣 strains are significantly reduced, and the anode 臈 can be evenly covered with ϋ 4, as shown in Figure 5 (a) to 5 (d). Please refer to FIG. 6 to FIG. 6, which show the surface microstructures of the anodized AZ91D magnesium alloy that has been anodized according to the eighth embodiment to the eleventh embodiment of the present invention. From Fig. 6 to Fig. 6, it can be seen that the 'anodic film has a porous structure, which is a characteristic of spark discharge. Please refer to Figs. 7 (a) to f 7 (d) ', which show cross-sectional structures of anodized die-cast AMD magnesium alloys according to the present invention < the eighth embodiment to the eleventh embodiment. As can be seen from Figs. 7 to 7 (d), the thickness of the anode film is about 6 / zm to 9 / zm. The composition of the anode film is also the key to determine the money-resistant effect of the anode film. Generally speaking, the anode film is an oxide film composed of an oxide. Please refer to FIG. 8, which shows X-ray diffraction (x_Ray Diffraction; xrd) patterns according to the eighth embodiment to the eleventh embodiment of the present invention. It can be seen from Fig. 8 that 'magnesium oxide (Mg0) is the main component of the anode film, as shown by the diffraction peak 0 in the figure, and contains a small amount of A12 (Si〇4). As shown in Fig. A, the anodization The treatment is to prevent external corrosive substances through the anode film, thereby protecting the substrate and reducing the occurrence of corrosion. The figure also contains a magnesium solid solution and an intermetallic compound (Mg ^ Al! 2), as shown in this figure and shown in the figure. Please refer to FIG. 9, which shows the electrochemical AC impedance test results according to the first to fourth embodiments of the present invention. It can be seen from Figure 9 that as the aluminum nitrate concentration increases, the impedance value also increases. This is because the phenomenon of concentrated discharge is reduced, the anode film will uniformly cover the surface of the magnesium alloy, and it has better protection for the magnesium alloy substrate, and its polarization resistance is also good. The electrification of the first to fourth embodiments is as follows: The AC impedance value is as shown in the table below. 17 17 028 584 Table 1 shows the first, second, and third numbered embodiments. Example Embodiments Polarization Impedance --- Two Bursts' J (Ω _cm2) 6954 5702 13783 Fourth 12054 The electrochemical AC impedance test results in Table 1 show that the increase in aluminum concentration and the increase in impedance value also indicate that the corrosion resistance of the anode film is evenly affected by the acidity of the anode film. As for the AC value of the first and second example of Yuyangbu W Guanyuan, this is because the addition of aluminum nitrate can remove the centralized discharge. However, the plutonium discharge time is shortened. At this time, the thickness of the anode film will be slightly reduced. There is also a limit concentration of the amount of aluminum added. Please refer to FIG. 10, which shows the results of the electrochemical AC impedance test according to the fifth embodiment to the seventh embodiment of the present day. " ι〇 It can be seen that as the concentration of sodium oxalate increases, the impedance value also increases, showing that the addition of sodium oxalate helps to increase the protection of the anode film, and the magnesium alloy substrate is not susceptible to external rotten silver. & attack. The electrochemical AC impedance values of the fifth to seventh embodiments are shown in Table 2. Table 2

Example No. ----- --- Polarization impedance (Ω -cm2) 18 200528584 According to the electrochemical AC impedance test results in Table 2, as the concentration of sodium silicate increases, the AC impedance value also increases, and the anode film The impedance value can be increased by three times compared to the first case. Reference is made to Fig. 11 which shows the results of the electrochemical AC impedance test according to the eighth embodiment to the eleventh embodiment of the present invention. From the results of the first to fourth embodiments, it can be seen that the addition of aluminum nitrate can reduce the concentration discharge effect, and the fifth to seventh embodiments show that sodium silicate can improve the protection of the anode film. Therefore, in the case where sodium silicate and aluminum nitrate are added simultaneously in the eighth embodiment to the eleventh embodiment, the polarization resistance value of the test piece is greatly increased, which is about 200 times that of the magnesium alloy substrate, which is also relatively Adding sodium silicate or aluminum nitrate alone increases the resistance by about ten times. Therefore, in the anodizing treatment solution of the present invention, aluminum nitrate and silicate steel complement each other, which greatly improves the uniformity and corrosion resistance of the anode film. The electrochemical AC impedance values of the eighth to eleventh embodiments are shown in Table 3. Table 3 r— ~ — number of the embodiment --- eighth embodiment ninth embodiment tenth embodiment eleventh embodiment polarization impedance Ω -cm2) 58480 119840 88690 ----- w 1 / J 93670 by The results of the electrochemical parent flow impedance test results in Table 3 show that the addition of nitric acid to reduce the concentration of spark discharges makes the anode film grow uniformly, and the increase in sodium concentration in Shixi 200528584 increases the corrosion resistance of the anode film and greatly improves the AC. The impedance value, in which the polarization impedance value of the ninth embodiment is about 17 times of that of the first embodiment, compared with the addition of sodium nitrate or sodium oxalate alone, the corrosion resistance of the anode film is more significantly improved. It is known from the results that the simultaneous addition of sodium silicate and nitric acid can greatly improve the corrosion resistance of the anode film. However, in the tenth embodiment, the polarization resistance value has a slight downward trend. This is because the formulas in the anodizing solution react with each other, and there are transparent reaction products in the solution, resulting in the polarization resistance of the test piece after the anodizing treatment. decline. The elliptic impedance value of the eleventh embodiment is quite close to that of the tenth embodiment, in which the reaction of the anodic oxidation treatment solution is increased and the products are also increased. It can be known from the foregoing preferred embodiments of the present invention that one of the advantages of applying the anodic oxidation treatment solution of the town metal of the present invention is that the anodic oxidation treatment solution of the magnesium metal includes at least silicate and nitrate, among which silicate can be improved The protective effect of the anode film on magnesium metal, nitrate can make the anode film grow evenly on the surface of magnesium metal. According to the above-mentioned preferred embodiments of the present invention, another advantage of applying the anodic oxidation treatment method of the magnesium metal of the present invention is that the anodic oxidation treatment method of the magnesium metal is to use the anodic oxidation treatment solution of the magnesium metal of the present invention to treat the magnesium. The surface of the metal is anodized. In this way, the protection of magnesium metal = polar film can be improved, and the problem of non-uniformity of the anode film caused by spark discharge during the anodic oxidation process of the ballast metal is improved. Although the present invention has been disclosed in the preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and decorations within the spirit and scope of the present invention. The scope of protection of the present invention 20 200528584 shall be determined by the scope of the attached patent application. [Schematic description] Figures 1 (a) to 1 (b) show the surface microstructure of the die-cast AZ91D magnesium alloy; Figure 2 (a) shows the surface giant of the die-cast AZ91D magnesium alloy after grinding Viewing photos; Figures 2 (b) to 2 (e) are macroscopic photos of the surface of the die-cast az9 丨 D magnesium alloy that has been anodized according to the first to fourth embodiments of the present invention; Figure 3 (a) is a graph showing the relative relationship between current density and time in the anodizing step according to the first embodiment of the present invention; Figure 3 (b) is a graph showing the anodization according to the fourth embodiment of the present invention Figure 3 (c) shows the relative relationship between current density and time in the processing step; Figure 3 (c) shows the relative relationship between current density and time in the anodizing step according to the first to fourth embodiments of the present invention.

Fig. 4 (a) shows a macroscopic photo of the surface of the AZ91D magnesium alloy which has been anodized according to the fifth embodiment of the present invention; Fig. 4 (b) shows a photo according to the present invention A macro photo of the surface of the anodized AZ91D magnesium alloy in the sixth embodiment; FIG. 4 (c) is a diagram showing the surface of the anodized magnesium alloy in the eight positions according to the seventh embodiment of the present invention Macro view photo; No. 5 (magic picture shows the surface of the anode 21 200528584 oxidation treated ^ AZ91D town alloy according to the eighth embodiment of the present invention, macro view picture; No. 5 (b) shows a photo according to the present invention A macro view of the surface of the anodized AZ91D town alloy after the anodizing treatment in the ninth embodiment; FIG. 5 (c) is a diagram showing the pressure of the anodizing treatment according to the tenth embodiment of the present invention. View photos

Figure 5 (d) shows a macroscopic photo of the surface of the die-cast AZ91D magnesium alloy that has been anodized according to the tenth embodiment of the present invention; 〃 Figure 6 (a) shows an eighth implementation according to the present invention Example of the surface microstructure of anodized die-cast AZ91D magnesium alloy; Figure 6 (b) shows the surface microstructure of anodized die-cast AZ91D town alloy according to the ninth embodiment of the present invention; A sixth (c) diagram shows the surface microstructure of a die-cast AZ91D magnesium alloy that has been anodized according to the tenth embodiment of the present invention; a sixth (d) diagram shows the eleventh according to the present invention Surface microstructure of die-casting AZ9 丨 D magnesium alloy after anodic oxidation treatment in the embodiment;

^ Figure 7 (a) shows the cross-sectional structure of anodized die-cast AZ91D magnesium alloy according to the eighth embodiment of the present invention; " Figure 7 (b) shows the ninth embodiment according to the present invention Anodized cross-sectional structure of die-cast AZ9 丨 D magnesium alloy; a seventh (c) diagram shows the cross-sectional structure of anodized die-cast AZ91D magnesium alloy according to the tenth embodiment of the present invention; 7 (d) shows the cross-sectional structure of anodized die-cast AZ91D · alloy according to the eleventh embodiment of the present invention; FIG. 8 shows the eighth embodiment to the eleventh embodiment according to the present invention 22 200528584 Example of x-ray diffraction pattern; FIG. 9 shows the results of the electrochemical AC impedance test according to the first embodiment to the fourth embodiment of the present invention; FIG. 10 shows the fifth embodiment of the present invention. The electrochemical AC impedance test results of the embodiment to the seventh embodiment; and FIG. 11 is a graph showing the electrochemical AC impedance test results of the eighth embodiment to the eleventh embodiment of the present invention.

twenty three

Claims (1)

200528584 Patent application scope 1. Anodizing treatment solution of magnesium metal, at least: 0.01 Molar concentration (M) to 2 IV [one silicate; 〇. 〇1 Μ to 2 Μ nitric acid Salt; 0.1 M to 5 M potassium hydroxide; 0.1 M to 1 M potassium fluoride; 0.1 M to 1 M sodium scale; and deionized water. 2_ The anodic oxidation treatment solution for magnesium metal according to item 1 of the scope of the patent application, wherein the concentration of the silicate is between M and 0.05 M. 3. The anodic oxidation treatment solution for magnesium metal according to item 1 of the scope of the patent application, wherein the concentration of the nitrate is between M and 0.5 M. 4. The anodic oxidation treatment solution for magnesium metal according to item 1 of the scope of the patent application, wherein the silicate is selected from the group consisting of sodium silicate (Na2Si〇3), sodium tetralithium sulfate (Na; zSi4〇9 ) And a combination of the above. 5. The anodic oxidation treatment solution for magnesium metal according to item 1 of the scope of patent application, wherein the nitrate is selected from the group consisting of aluminum nitrate, potassium nitrate, sodium nitrate and combinations thereof. 6. Anodizing of magnesium metal as described in item 1 of the scope of patent application 24 200528584, wherein the magnesium metal forms a group. It is selected from the group consisting of a pure magnesium and a magnesium alloy. 7. Anodizing treatment solution of magnesium metal as described in item 6 of the scope of the patent application, wherein the magnesium alloy is a zinc alloy series ballast alloy. 8. The anodic oxidation treatment solution of magnesium metal according to item 6 of the scope of the patent application, wherein the method of forming the magnesium metal is to use a group selected from the group consisting of die casting, casting, and forging. 9. An anodizing method for magnesium metal, at least comprising: providing the magnesium metal, wherein the magnesium metal is selected from the group consisting of a pure magnesium and a magnesium alloy; and performing an anodizing step, The magnesium metal was sequentially applied in an anodizing treatment solution with a current density between 15 mA / cm2 per millimeter and milliamperes, and a current between 100 volts (Volt; 乂) and 100 v. A voltage between the two is used to form an anodic film on one of the surfaces of the magnesium metal; wherein the anodic oxidation treatment system contains at least one materate of 0.001 M to 2 M and one of 0.001 M to 2 M Nitrate. 10. The anodic oxidation treatment method for magnesium metal according to item 9 of the scope of the patent application, wherein the silicate is selected from the group consisting of sodium silicate, sodium tetrasilicate, and a combination thereof. 25 200528584 Π · The method for anodizing an magnesium metal as described in item 9 of the scope of patent application, wherein the nitrate is selected from the group consisting of aluminum nitrate, potassium nitrate, sodium nitrate, and combinations thereof Ethnic group. 12. The anodic oxidation treatment method for magnesium metal as described in item 9 of the scope of the patent application, wherein the magnesium alloy is a magnesium-aluminum alloy. 13. The anodic oxidation treatment method for magnesium metal according to item 9 of the scope of the patent application, wherein one of the magnesium metal forming methods utilizes a group selected from the group consisting of pressing, casting and forging. 14_ The anodic oxidation treatment method for magnesium metal as described in item 9 of the scope of the patent application, wherein the concentration of the silicate is between 0.01 and Q.5M. 15. Anodizing treatment method for magnesium metal as described in item 9 of the scope of patent application, wherein the concentration of the nitrate is between 0.01 and Q.5 M. 16_ As described in item 9 of the scope of patent application An anodizing method for magnesium metal, wherein the anodizing treatment liquid further includes at least: 1M to 3M potassium hydroxide; 0.5 M to 1 μ potassium fluoride; 〇_1 M to 0.5 M disk Sodium acid; and the deionized water.