CN103014804A - Aluminum alloy with army-green micro-arc oxidation ceramic membrane on surface and preparation method of aluminum alloy - Google Patents

Abstract

The invention discloses an aluminum alloy with a military green micro-arc oxidation ceramic film on the surface and a preparation method thereof, which mainly solves the problem that the color of the ceramic film processed by light metal micro-arc oxidation technology in the prior art is mostly off-white, white, black, etc. technical problem. The electrolyte solute of the present invention adopts: sodium phosphate, sodium silicate, sodium hexametaphosphate, sodium hydroxide, disodium edetate, potassium dichromate, sodium carbonate, sodium lauryl sulfate, hydrogen peroxide, The solvent is deionized water, which is configured into an alkaline electrolytic solution. After stirring and standing for 1 to 2 hours, the army green ceramic film is obtained by micro-arc oxidation treatment. The invention has the beneficial effects of simple preparation method, low cost and little environmental pollution. The prepared military green ceramic film has the advantages of high wear resistance, good corrosion resistance, uniform color, compactness, good stability, and not easy to fade, and is especially suitable for the camouflage needs of military products.

Description

Aluminum alloy with military green micro-arc oxidation ceramic film on surface and preparation method thereof

technical field

The invention relates to the technical field of light metal surface treatment, in particular to an aluminum alloy with a military green micro-arc oxidation ceramic film on the surface and a preparation method thereof.

Background technique

Aluminum alloy is well known for its light weight, high specific strength, high electrical conductivity, and good heat transfer, and has been widely used in the fields of machinery, electronics, aerospace, and aviation. However, due to its low hardness, poor corrosion resistance, and Low abrasiveness limits it. Therefore, improving the surface hardness, corrosion resistance, wear resistance and decorative properties of aluminum alloys has become a key issue in the development of aluminum alloys.

Micro-arc oxidation technology, also known as plasma micro-arc oxidation, is obtained by increasing the applied voltage on the basis of ordinary anodizing technology. The applied voltage of ordinary anodizing technology is relatively low, generally lower than 30V. As the applied voltage increases, the anodized film formed on the surface of the aluminum alloy will be broken down, holes will be formed, and eventually the local oxide film will fall off. Former Soviet scientists discovered in the late 1960s that continuing to increase the voltage would generate a new oxide film on the surface of light metals. Generally, this oxide film is called a ceramic film. The wear resistance, corrosion resistance and other surface properties of the ceramic layer obtained in this way are obviously higher than other surface strengthening treatment technologies, such as anodic oxidation and the like. The microhardness of the coated aluminum alloy ceramic layer is measured to be 2100HV, and the bonding strength is generally about 56MPa. This technique is simple and is a new technology for surface strengthening treatment of light metal materials. It has become one of the research hotspots in surface strengthening treatment of light metal materials in recent years.

With the continuous expansion of the application range of micro-arc oxidation, in addition to requiring the aluminum alloy treated by micro-arc oxidation to have high hardness, wear resistance, corrosion resistance, voltage insulation and other characteristics, it is also required that the surface of the treated aluminum alloy has some special properties. s color. For example, military products suitable for field operations, in addition to the above-mentioned performance, also require the surface of the product to be military green to facilitate camouflage. However, the current aluminum alloy micro-arc oxidation ceramic film is mostly white or gray, and the color is single. At present, there are many studies on the preparation of green ceramic membranes. The shortcomings are: (1) the solution contains strong corrosive substances, and the solution will volatilize toxic hydrogen fluoride during the micro-arc oxidation process, which is easy to cause harm to the experimenters (Pan Lihua, Rare Earth Magnesium alloy micro-arc oxidation green ceramic film preparation method, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences); (2) The color of the green ceramic film is too light; such as Geely University in Na ₂ SiO ₃ , NaoH, EDTA-Na ₂ , K ₂ Cr ₂ O ₇ in the electrolyte for 16 minutes to obtain a green ceramic film (Li Jiaqing, research on the preparation process of micro-arc oxidation ceramic film of different colors on the surface of aluminum alloy, 2009 Jilin University master's degree thesis); (3) The green ceramic film substrate produced has Dark spots and the surface green is very light, such as Lanzhou University of Technology with NaAlO ₂ , K ₂ Cr ₂ O ₇ , a small amount of NaOH and H ₂ O ₂ to prepare a green ceramic film on the surface of magnesium alloy (Yan Fengyun, micro-arc oxidation of magnesium alloy green ceramic film preparation).

Contents of the invention

The purpose of the present invention is to provide an aluminum alloy with a military green micro-arc oxidation ceramic film on the surface and a preparation method thereof for military products suitable for field operations that are not only wear-resistant, corrosion-resistant, but also easy to camouflage.

The technical scheme that realizes the object of the present invention is:

A method for preparing an aluminum alloy with a military-green micro-arc oxidation ceramic film on its surface, comprising the steps of preparing an electrolyte and performing micro-arc oxidation treatment with an AC pulse power supply, specifically:

(1) Inject the alkaline electrolyte mixed according to the specific composition and concentration into the PVC plastic tank, stir evenly at 10~20°C, and use it after standing for 1~2 hours;

The weight and total volume ratio of each component of the alkaline electrolyte is: sodium phosphate 15 ~ 45g/L, sodium silicate 20 ~ 40g/L, sodium hexametaphosphate 15 ~ 20g/L, sodium hydroxide 2 ~ 5g/L L, disodium edetate 3 ~10g/L, potassium dichromate 1 ~4g/L, sodium carbonate 2 ~10g/L, sodium lauryl sulfate 1 ~5g/L, hydrogen peroxide 2 ~ 8g/L, the pH value of the electrolyte is 12-14;

(2) Grinding the surface of the aluminum alloy substrate, ultrasonic cleaning in acetone and sodium hydroxide solution after grinding, cleaning with deionized water, and drying;

(3) Use the aluminum alloy substrate as the anode, take 2 stainless steel sheets as the cathode, fix the aluminum alloy substrate in the middle of the 2 stainless steel sheets with a clamp, and completely immerse in the alkaline electrolyte in step (1). Pulse power supply for micro-arc oxidation treatment, the forward voltage is 270~600V, the negative voltage is 10~100V, the current density is 10~20A/dm2, the frequency is 550~850Hz, and the duty cycle is 15%~45%. , Oxidation time is 5~60min;

(4) Place the aluminum alloy substrate after micro-arc oxidation treatment in deionized water with a pH value of 5.5 to 6.5 and 90 to 100°C for 40 to 50 minutes, take out the aluminum alloy substrate, wash it, and dry it to obtain Aluminum alloy with army green micro-arc oxidation ceramic film on the surface.

Another object of the present invention is to provide an aluminum alloy with army green micro-arc oxidation ceramic film on the surface prepared by the above method.

The thickness of the army green ceramic membrane is 20 μm-35 μm, and the hardness of the surface layer is 1700-1800 HV.

The beneficial effect of the present invention is: the preparation method is simple, the cost is low, the pollution to the environment is small, the application range is wide, and it is suitable for light metals. . The prepared military green ceramic film has the advantages of high wear resistance, good corrosion resistance, uniform color, compactness, good stability, and not easy to fade, and is especially suitable for the camouflage needs of military products.

Description of drawings

Fig. 1 is the cross-sectional structure schematic diagram of the aluminum alloy with military green micro-arc oxidation ceramic film on the surface of the present invention;

In the picture: 1. Aluminum alloy substrate 2. Army green ceramic film;

Fig. 2 is the scanning electron micrograph of embodiment 1 surface topography;

3 is a scanning electron microscope image of the cross-sectional morphology of Example 1.

Detailed ways

The content of the present invention will be further described below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited.

Example 1

Referring to FIG. 1 , an aluminum alloy with a military green micro-arc oxidation ceramic film on the surface of the present invention is composed of an aluminum alloy substrate 1 and a military green ceramic film 2 coated on the surface of the aluminum alloy substrate 1 .

Aluminum alloy substrate: 6061 aluminum alloy, size: 30mm×20mm×3mm.

The preparation method of the present invention is:

(1) Inject the alkaline electrolyte mixed according to the specific composition and concentration into the PVC plastic tank, stir evenly at 10~20°C, and use it after standing for 1~2 hours;

The weight of each component of the alkaline electrolyte and the total volume ratio of the electrolyte are: sodium phosphate 25g/L, sodium hexametaphosphate 15g/L, sodium hydroxide 4g/L, disodium edetate 3g/L, Potassium dichromate 3g/L, sodium carbonate 4g/L, sodium lauryl sulfate 2g/L, hydrogen peroxide 2g/L, pH value 12-14;

(2) Use 400#, 600#, 800#, and 1000# water-resistant sandpaper to polish the surface of the aluminum alloy substrate until the surface scratches are in the same direction. After polishing, perform ultrasonic cleaning in acetone and sodium hydroxide solution for 15 minutes, and then use Wash with deionized water and dry to remove oxides on the surface;

(3) Use the aluminum alloy substrate as the anode, take 2 stainless steel sheets as the cathode, fix the aluminum alloy substrate between the 2 stainless steel sheets with a clamp, and completely immerse in the alkaline electrolyte in step (1), and use AC pulse The power supply is subjected to micro-arc oxidation treatment. During the treatment, the forward voltage is 358~400V, the negative voltage is 25V, the current density is 20A/dm ² , the pulse frequency is 550Hz, the duty cycle is 15%, the number of positive pulses is 15, and the negative pulse number is 15. The number of pulses is 3, and the oxidation time is 60 minutes;

(4) Place the aluminum alloy substrate after micro-arc oxidation treatment in deionized water with a pH value of 5.5-6.5 and 90-100°C for 40-50 minutes, take out the aluminum alloy substrate, wash it with deionized water, and place it in distilled water. After soaking for 10 minutes and blowing dry, an aluminum alloy with a military green micro-arc oxidation ceramic film on the surface can be prepared.

Using a scanning electron microscope to observe the surface morphology of the army green ceramic membrane scanning electron microscope Figure 2, and the cross-sectional morphology scanning electron microscope Figure 3, the microhardness is 1800HV, and the thickness of the ceramic membrane is 33.9 μm measured by a film thickness gauge.

Example 2

Preparation of an aluminum alloy with a military green micro-arc oxidation ceramic film on the surface, the aluminum alloy substrate: 6061 aluminum alloy, size: 30mm×20mm×3mm.

The weight of each component of the alkaline electrolyte and the total volume ratio of the electrolyte are: sodium phosphate 30g/L, sodium silicate 30g/L, sodium hexametaphosphate 20g/L, sodium hydroxide 3g/L, ethylenediaminetetra Disodium acetate 4g/L, potassium dichromate 3.5g/L, sodium carbonate 4g/L, sodium lauryl sulfate 3g/L, hydrogen peroxide 2g/L; micro-arc oxidation time is 20min, current density is 10 A/dm ² , the rest of the preparation method is the same as in Example 1, the thickness of the prepared ceramic film is 20.2 μm, and the microhardness is 1700HV.

Example 3

Preparation of an aluminum alloy with a military green micro-arc oxidation ceramic film on the surface, the aluminum alloy substrate: 6061 aluminum alloy, size: 20mm×15mm×1mm.

The ratio of the weight of each component of the alkaline electrolyte to the total volume of the electrolyte is: sodium silicate 40g/L, sodium hexametaphosphate 18g/L, sodium hydroxide 4g/L, disodium edetate 2g/L , potassium dichromate 4g/L, sodium carbonate 10g/L, sodium lauryl sulfate 5g/L, hydrogen peroxide 2g/L; the micro-arc oxidation time is 45min, the current density is 10 A/dm ² , and the rest are prepared The method is the same as in Example 1, and the thickness of the prepared ceramic film is 21.4 μm, and the microhardness is 1700 HV.

Example 4

Preparation of an aluminum alloy with a military green micro-arc oxidation ceramic film on the surface, the aluminum alloy substrate: LY-type aluminum alloy, size: diameter 35mm, thickness 2mm.

The weight and total volume ratio of each component of the alkaline electrolyte is: sodium silicate 35g/L, sodium hexametaphosphate 16g/L, sodium hydroxide 2g/L, disodium edetate 8g/L, weight Potassium chromate is 2.7g/L, sodium carbonate is 10g/L, sodium lauryl sulfate is 3.5g/L, hydrogen peroxide is 5.5g/L; the micro-arc oxidation time is 30min, and the current density is 15 A/ ^dm2 , the rest of the preparation method is the same as in Example 1, the thickness of the prepared ceramic film is 25.7 μm, and the microhardness is 1750HV.

Claims (3)

1. A method for preparing an aluminum alloy with military green micro-arc oxidation ceramic film on the surface, comprising the preparation of electrolyte, adopting an AC pulse power supply to carry out the step of micro-arc oxidation treatment, characterized in that: (1) Inject the alkaline electrolyte mixed according to the specific composition and concentration into the PVC plastic tank, stir evenly at 10~20°C, and use it after standing for 1~2 hours; The weight ratio of each component of the alkaline electrolyte to the total volume of the electrolyte is: sodium phosphate 15 ~ 45g/L, sodium silicate 20 ~ 40g/L, sodium hexametaphosphate 15 ~ 20g/L, sodium hydroxide 2 ~ 5g/L, disodium edetate 3 ~10g/L, potassium dichromate 1 ~4g/L, sodium carbonate 2 ~10g/L, sodium lauryl sulfate 1 ~5g/L, hydrogen peroxide 2 ~8g/L, the pH value of the electrolyte is 12~14; (2) After polishing the surface of the aluminum alloy substrate, clean and dry it; (3) The aluminum alloy substrate is used as the anode, the stainless steel sheet is used as the cathode, immersed in the alkaline electrolyte in step (1), and the AC pulse power supply is used for micro-arc oxidation treatment. The forward voltage is 270~600V, and the negative The direct voltage is 10~100V, the current density is 10~20A/dm2, the frequency is 550~850Hz, the duty ratio is 15%~45%, and the oxidation time is 5~60min; (4) Place the aluminum alloy substrate after micro-arc oxidation treatment in deionized water with a pH value of 5.5 to 6.5 and 90 to 100°C for 40 to 50 minutes, take out the aluminum alloy substrate, wash it, and dry it to obtain Aluminum alloy with army green micro-arc oxidation ceramic film on the surface. 2. the aluminum alloy with military green micro-arc oxidation ceramic film on the surface prepared by the method claimed in claim 1. 3. The aluminum alloy with army green micro-arc oxidation ceramic film on the surface according to claim 2, characterized in that: the thickness of the army green ceramic film is 20-35 μm, and the surface hardness is 1700-1800 HV.

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