Preparation method of 6063 aluminum alloy self-sealing micro-arc oxidation ceramic film layer

Abstract

The invention relates to the technical field of corrosion-resistant coatings, and discloses a preparation method of a 6063 aluminum alloy self-sealing micro-arc oxidation ceramic film layer. Comprising the following operation steps that 1, 6063 aluminum alloy is sequentially subjected to oil removal, acid pickling, washing and drying, and prefabricated 6063 aluminum alloy is obtained; 2, the prefabricated 6063 aluminum alloy serves as an anode, a stainless steel container with a cooling system serves as a cathode, the prefabricated 6063 aluminum alloy and the stainless steel container are immersed in the electrolyte, a constant-current mode is adopted, micro-arc oxidation is conducted for 15-25 min, and a self-sealing micro-arc oxidation ceramic film layer test piece is obtained; 3, (1) carrying out hydrothermal treatment on the self-sealing micro-arc oxidation ceramic film layer test piece and carbonate precursor hydrotalcite at 115-120 DEG C for 20-24 hours to obtain a sample containing an LDH coating; and (2) putting a sample containing the LDH coating into the modified hydroxyquinoline solution, soaking at 40-50 DEG C for 3-4 hours, taking out and drying to obtain a product.

Description

Technical Field

[0001] The invention relates to the technical field of corrosion-resistant coatings, and in particular to a method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film layer. Background Art

[0002] 6063 aluminum alloy belongs to Al-Mg-Si alloy, which is widely used in automobiles, aircraft, instruments and other fields, but its surface corrosion resistance is poor, so its application is limited in some occasions; in the prior art, surface treatment is performed by micro-arc oxidation to improve its surface hardness, corrosion resistance and other properties, thereby expanding the application of 6063 alloy; micro-arc oxidation (MAO), also known as plasma electrochemical oxidation (PEO), is a technology that uses high temperature and high pressure arc discharge to generate an oxide film on the surface of a metal material; it is widely used in the surface treatment of valve metals such as aluminum, magnesium, titanium and their alloys; this technology can significantly improve the corrosion resistance, wear resistance, hardness and surface smoothness of metal materials.

[0003] However, during the MAO process, micropores and cracks appear on the surface of the membrane layer. These defects usually weaken the corrosion resistance and mechanical properties of the coating. Researchers have found that certain electrolyte components will be deposited in the micropores, completing partial self-sealing. However, this self-sealing effect is often incomplete, and the presence of micropores and cracks may still become channels for the invasion of corrosive media. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film layer to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film layer, comprising the following steps: Step 1: Degreasing, pickling, washing and drying the 6063 aluminum alloy in sequence to obtain a prefabricated 6063 aluminum alloy; Step 2: Use the prefabricated 6063 aluminum alloy as the anode and the stainless steel container with a cooling system as the cathode, immerse them in the electrolyte, use the constant current mode, and micro-arc oxidation for 15 to 25 minutes to obtain a self-enclosed micro-arc oxidation ceramic film layer specimen; Step 3: (1) The self-sealed micro-arc oxidation ceramic film layer specimen and the carbonate precursor hydrotalcite are hydrothermally treated at 115-120°C for 20-24 hours to obtain a sample containing an LDH coating; (2) The sample containing the LDH coating is placed in a modified hydroxyquinoline solution, immersed at 40-50°C for 3-4 hours, taken out and dried to obtain a product.

[0006] More preferably, the raw materials of the electrolyte include the following components: 5-15 g / L of Na 2 SiO 3 , 1~4g / L KOH, 1~3g / L NaF, 4~8ml / L phytic acid (C 6 H 18 O 24 P 6 )、2~6g / L MoS 2 , 2~5g / L ethanol.

[0007] More preferably, the raw materials of the electrolyte include the following components: 8-10 g / L of Na 2 SiO 3 , 2~3g / L KOH, 1.5~2.5g / L NaF, 5~7g / L phytic acid (C 6 H 18 O 24 P 6 )、3~4g / L MoS 2 , 3~4g / L ethanol.

[0008] More optimally, the current of the micro-arc oxidation is 5-7A / dm 2 , the frequency of micro-arc oxidation is 200~500Hz.

[0009] The more optimized method for preparing the carbonate precursor hydrotalcite is as follows: 25-30 g / L zinc nitrate, ammonium nitrate and 160-180 g / L urea are uniformly mixed, heated at 90-100° C. for 18-20 hours under sealed conditions, filtered, washed and dried to obtain the carbonate precursor hydrotalcite.

[0010] More optimally, the raw materials of the carbonate precursor hydrotalcite include: 2-3 g / L zinc nitrate, 3-5 g / L ammonium nitrate, and 16-18 g / L urea.

[0011] More optimally, the concentration of the modified hydroxyquinoline solution is 0.5-0.8 g / L, and the pH of the modified hydroxyquinoline solution is adjusted to 10-12.

[0012] More optimally, in the modified hydroxyquinoline solution, the preparation method of the modified hydroxyquinoline is: 8-hydroxyquinoline-2-carboxaldehyde and glutamic acid are added to methanol and mixed evenly, and the mixture is heated to 70-75° C. and reacted for 10-14 hours to obtain the modified hydroxyquinoline.

[0013] More optimally, the molar ratio of 8-hydroxyquinoline-2-carboxaldehyde to glutamic acid is 1:(1-1.5).

[0014] Compared with the prior art, the present invention has the following beneficial effects: the present invention adds phytic acid (C 6 H 18 O 24 P 6 ) and molybdenum disulfide (MoS 2 ); Among them, phytic acid is a water-soluble organic weak acid with a chemical name of cyclohexanol hexaphosphate. It has six negatively charged phosphate groups and is easy to react with metal cations to form water-insoluble compound precipitations, mainly combining with ions such as iron, zinc, magnesium, and calcium; phytic acid is added to the electrolyte, and after ionization in the aqueous solution, it carries a negative charge and forms precipitations with other ions, increasing the voltage in the micro-arc oxidation process under constant current mode, and is conducive to the efficient participation of aluminum ions in the micro-arc oxidation film layer in the micro-arc oxidation reaction, thereby increasing the thickness and density of the film layer; in addition, molybdenum disulfide can enter the micropores and microcracks of the film layer during the micro-arc oxidation process, thereby producing a self-sealing effect, sealing the micropores and cracks of the film layer, and greatly enhancing the corrosion resistance of the aluminum alloy; molybdenum disulfide also has the characteristics of high hardness and self-lubrication, thereby significantly enhancing the wear resistance of the alloy.

[0015] In the scheme, by adding the LDH layer, the porosity of the self-sealed micro-arc oxidation ceramic layer can be effectively reduced, the sealing performance can be further improved, and the poor self-sealing caused by the pores can be reduced; thereby improving the corrosion resistance of the micro-arc oxidation ceramic layer.

[0016] In the scheme, zinc nitrate, ammonium nitrate and urea are made into carbonate precursor hydrotalcite; then it is heat-treated with the micro-arc oxidation ceramic layer specimen to obtain the LDH layer containing carbonate; wherein, hydrotalcite is a layered double hydroxide with strong adsorption and sealing ability, which can effectively fill the tiny pores in the oxide film; it is composed of alternating stacks of metal hydroxide layers and negatively charged anion layers, and can form a dense protective layer on the surface and inside the pores of the micro-arc oxidation ceramic layer through interaction with the micro-arc oxidation ceramic layer; due to the larger size and better thermal stability of carbonate ions, it helps CO 3 2- -LDH forms a more stable and dense coating, thereby closing micropores and cracks and enhancing the self-sealing barrier effect.

[0017] In order to enhance the corrosion inhibition of aluminum alloy, modified hydroxyquinoline is intercalated into the LDH layer by ion exchange, making the interlayer structure of LDH more stable and further improving its compactness. In the scheme, the aldehyde group on 8-hydroxyquinoline-2-carboxaldehyde reacts with the amino group on glutamic acid under certain conditions to obtain modified hydroxyquinoline. Among them, 8-hydroxyquinoline-2-carboxaldehyde provides more reaction sites through additional formaldehyde groups to form more stable complexing effects. When the coating is physically damaged and the metal substrate is exposed to the corrosive medium, the nitrogen atoms and oxygen atoms on 8-hydroxyquinoline-2-carboxaldehyde can interact with metal ions to form chelates, thereby hindering the penetration of the corrosive medium and improving the corrosion resistance of the coating. By modifying 8-hydroxyquinoline-2-carboxaldehyde with glutamic acid, the anions on glutamic acid increase its complexing ability with metal cations, thereby improving the structural stability and intercalation effect, and improving the corrosion inhibition of the aluminum alloy. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] In this embodiment, it should be noted that the purchase manufacturers of all raw materials involved in the present invention are not subject to any special restrictions, and exemplary include: Na2SiO3 has a CAS number of 6834-92-0; KOH has a CAS number of 1310-58-3; NaF has a CAS number of 7681-49-4; phytic acid (C6H18O24P6) has a CAS number of 83-86-3, purchased from Shanghai Yuanye Biotechnology Co., Ltd.; MoS2 has a CAS number of S30491, purchased from Shanghai Yuanye Biotechnology Co., Ltd.; ethanol has a CAS number of The CAS number of urea is S30375, purchased from Shanghai Yuanye Biotechnology Co., Ltd.; the CAS number of 8-hydroxyquinoline-2-carboxaldehyde is 14510-06-6; the CAS number of glutamic acid is S20035, purchased from Shanghai Yuanye Biotechnology Co., Ltd.; the CAS number of methanol is 67-56-1; the CAS number of 8-hydroxyquinoline is 148-24-3, purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0020] Example 1: A method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film layer; Step 1: The 6063 aluminum alloy is polished, degreased in acetone for 30 minutes, ultrasonically pickled at a frequency of 55KHz (the volume ratio of nitric acid to hydrogen peroxide is 3:1) for 3 minutes, washed, and dried to obtain a prefabricated 6063 aluminum alloy; Step 2: The prefabricated 6063 aluminum alloy was used as the anode and the stainless steel container with a cooling system was used as the cathode. They were immersed in the electrolyte and the constant current mode was adopted at a current of 7A / dm 2 , micro-arc oxidation was performed for 20 minutes at a frequency of 500 Hz to obtain a self-enclosed micro-arc oxidation ceramic film layer specimen, which was used as the product; The electrolyte includes: 6g / L Na 2 SiO 3 , 4g / L KOH, 2g / L NaF, 4ml / L phytic acid (C 6 H 18 O 24 P 6 )、3g / L MoS 2 , 3g / L ethanol.

[0021] Example 2: A method for preparing a self-enclosed micro-arc oxidation ceramic film layer of 6063 aluminum alloy; Step 1: The 6063 aluminum alloy is polished, degreased in acetone for 30 minutes, ultrasonically pickled at a frequency of 55KHz (the volume ratio of nitric acid to hydrogen peroxide is 3:1) for 3 minutes, washed, and dried to obtain a prefabricated 6063 aluminum alloy; Step 2: The prefabricated 6063 aluminum alloy was used as the anode and the stainless steel container with a cooling system was used as the cathode. They were immersed in the electrolyte and the constant current mode was adopted at a current of 7A / dm 2 , micro-arc oxidation was performed for 20 minutes at a frequency of 500 Hz to obtain a self-enclosed micro-arc oxidation ceramic film layer specimen, which was used as the product; The electrolyte includes: 10g / L Na 2 SiO 3 , 4g / L KOH, 2g / L NaF, 6ml / L phytic acid (C 6 H 18 O 24 P 6 )、3g / L MoS 2 , 4g / L ethanol.

[0022] Example 3: A method for preparing a self-enclosed micro-arc oxidation ceramic film layer of 6063 aluminum alloy; Step 1: The 6063 aluminum alloy is polished, degreased in acetone for 30 minutes, ultrasonically pickled at a frequency of 55KHz (the volume ratio of nitric acid to hydrogen peroxide is 3:1) for 3 minutes, washed, and dried to obtain a prefabricated 6063 aluminum alloy; Step 2: The prefabricated 6063 aluminum alloy was used as the anode and the stainless steel container with a cooling system was used as the cathode. They were immersed in the electrolyte and the constant current mode was adopted at a current of 7A / dm 2 , micro-arc oxidation was performed for 20 minutes at a frequency of 500 Hz to obtain a self-enclosed micro-arc oxidation ceramic film layer specimen, which was used as the product; The electrolyte includes: 15g / L Na 2 SiO 3 , 5g / L KOH, 2g / L NaF, 8ml / L phytic acid (C 6 H 18 O 24 P 6 )、4g / L MoS 2 , 4g / L ethanol.

[0023] Example 4 Based on Example 2, the 6063 aluminum alloy after micro-arc oxidation is further sealed; Step 1: The 6063 aluminum alloy is polished, degreased in acetone for 30 minutes, ultrasonically pickled at a frequency of 55KHz (the volume ratio of nitric acid to hydrogen peroxide is 3:1) for 3 minutes, washed, and dried to obtain a prefabricated 6063 aluminum alloy; Step 2: The prefabricated 6063 aluminum alloy was used as the anode and the stainless steel container with a cooling system was used as the cathode. They were immersed in the electrolyte and the constant current mode was adopted at a current of 7A / dm 2 , micro-arc oxidation was performed for 20 minutes at a frequency of 500 Hz to obtain a self-enclosed micro-arc oxidation ceramic film specimen; The electrolyte includes: 10g / L Na 2 SiO 3 , 4g / L KOH, 2g / L NaF, 6ml / L phytic acid (C 6 H 18 O 24 P 6 )、3g / L MoS 2 , 4g / L ethanol; Step 3: (1) The preparation method of carbonate precursor hydrotalcite is as follows: 2 g / L zinc nitrate, 3.2 g / L ammonium nitrate and 16.5 g / L urea are uniformly mixed, heated at 95°C for 18 hours under sealed conditions, filtered, washed and dried to obtain carbonate precursor hydrotalcite; (2) The self-sealed micro-arc oxidation ceramic film layer specimen and the carbonate precursor hydrotalcite are hydrothermally treated at 120°C for 20 hours to obtain a sample containing LDH coating; and the sample is used as the product; Example 5 Based on Example 4, the sample containing the LDH coating was intercalated; Step 1: The 6063 aluminum alloy is polished, degreased in acetone for 30 minutes, ultrasonically pickled at a frequency of 55KHz (the volume ratio of nitric acid to hydrogen peroxide is 3:1) for 3 minutes, washed, and dried to obtain a prefabricated 6063 aluminum alloy; Step 2: The prefabricated 6063 aluminum alloy was used as the anode and the stainless steel container with a cooling system was used as the cathode. They were immersed in the electrolyte and the constant current mode was adopted at a current of 7A / dm 2 , micro-arc oxidation was performed for 20 minutes at a frequency of 500 Hz to obtain a self-enclosed micro-arc oxidation ceramic film specimen; The electrolyte includes: 10g / L Na 2 SiO 3 , 4g / L KOH, 2g / L NaF, 6ml / L phytic acid (C 6 H 18 O 24 P 6 )、3g / L MoS 2 , 4g / L ethanol; Step 3: (1) 2 g / L zinc nitrate, 3.2 g / L ammonium nitrate and 16.5 g / L urea are uniformly mixed, heated at 95°C for 18 hours under sealed conditions, filtered, washed and dried to obtain carbonate precursor hydrotalcite; (2) The self-sealed micro-arc oxidation ceramic film layer specimen and the carbonate precursor hydrotalcite are hydrothermally treated at 120°C for 20 hours to obtain a sample containing LDH coating; (3) 8-Hydroxyquinoline-2-carboxaldehyde and glutamic acid were added to methanol and mixed evenly, and the mixture was heated to 70°C and reacted for 10 hours to obtain modified hydroxyquinoline; wherein the molar ratio of 8-hydroxyquinoline-2-carboxaldehyde to glutamic acid was 1:1; (4) The sample containing the LDH coating was placed in a 0.7 g / L modified hydroxyquinoline solution, the pH was adjusted to 10, and the solution was immersed at 45°C for 3 hours, taken out and dried to obtain the product.

[0024] Comparative Example 1 is based on Example 2, except that phytic acid is not added to the electrolyte; Step 1: The 6063 aluminum alloy is polished, degreased in acetone for 30 minutes, ultrasonically pickled at a frequency of 55KHz (the volume ratio of nitric acid to hydrogen peroxide is 3:1) for 3 minutes, washed, and dried to obtain a prefabricated 6063 aluminum alloy; Step 2: The prefabricated 6063 aluminum alloy was used as the anode and the stainless steel container with a cooling system was used as the cathode. They were immersed in the electrolyte and the constant current mode was adopted at a current of 7A / dm 2 , micro-arc oxidation was performed for 20 minutes at a frequency of 500 Hz to obtain a self-enclosed micro-arc oxidation ceramic film layer specimen, which was used as the product; The electrolyte includes: 10g / L Na 2 SiO3 , 4g / L KOH, 2g / L NaF, 3g / L MoS 2 , 4g / L ethanol.

[0025] Comparative Example 2 is based on Example 5, but 8-hydroxyquinoline-2-carboxaldehyde is not modified; Step 1: The 6063 aluminum alloy is polished, degreased in acetone for 30 minutes, ultrasonically pickled at a frequency of 55KHz (the volume ratio of nitric acid to hydrogen peroxide is 3:1) for 3 minutes, washed, and dried to obtain a prefabricated 6063 aluminum alloy; Step 2: The prefabricated 6063 aluminum alloy was used as the anode and the stainless steel container with a cooling system was used as the cathode. They were immersed in the electrolyte and the constant current mode was adopted at a current of 7A / dm 2 , micro-arc oxidation was performed for 20 minutes at a frequency of 500 Hz to obtain a self-enclosed micro-arc oxidation ceramic film specimen; The electrolyte includes: 10g / L Na 2 SiO 3 , 4g / L KOH, 2g / L NaF, 6ml / L phytic acid (C 6 H 18 O 24 P 6 )、3g / L MoS 2 , 4g / L ethanol; Step 3: (1) 2 g / L zinc nitrate, 3.2 g / L ammonium nitrate and 16.5 g / L urea are uniformly mixed, heated at 95°C for 18 hours under sealed conditions, filtered, washed and dried to obtain a carbonate precursor hydrotalcite; (2) The self-sealed micro-arc oxidation ceramic film layer specimen and the carbonate precursor hydrotalcite are hydrothermally treated at 120°C for 20 hours to obtain a sample containing LDH coating; (3) The sample containing LDH coating is placed in a 0.7 g / L 8-hydroxyquinoline-2-carboxaldehyde solution, the pH is adjusted to 10, immersed at 45°C for 3 hours, taken out and dried to obtain the product.

[0026] Comparative Example 3 is based on Example 5, except that molybdenum disulfide is not added to the electrolyte; Step 1: The 6063 aluminum alloy is polished, degreased in acetone for 30 minutes, ultrasonically pickled at a frequency of 55KHz (the volume ratio of nitric acid to hydrogen peroxide is 3:1) for 3 minutes, washed, and dried to obtain a prefabricated 6063 aluminum alloy; Step 2: The prefabricated 6063 aluminum alloy was used as the anode and the stainless steel container with a cooling system was used as the cathode. They were immersed in the electrolyte and the constant current mode was adopted at a current of 7A / dm 2 , micro-arc oxidation was performed for 20 minutes at a frequency of 500 Hz to obtain a self-enclosed micro-arc oxidation ceramic film specimen; The electrolyte includes: 10g / L Na 2 SiO 3 , 4g / L KOH, 2g / L NaF, 6ml / L phytic acid (C 6 H 18 O 24 P 6 ) 4g / L ethanol; Step 3: (1) The preparation method of carbonate precursor hydrotalcite is as follows: 2 g / L zinc nitrate, 3.2 g / L ammonium nitrate and 16.5 g / L urea are uniformly mixed, heated at 95°C for 18 hours under sealed conditions, filtered, washed and dried to obtain carbonate precursor hydrotalcite; (2) The self-sealed micro-arc oxidation ceramic film layer specimen and the carbonate precursor hydrotalcite are hydrothermally treated at 120°C for 20 hours to obtain a sample containing LDH coating; (3) The preparation method of modified hydroxyquinoline is as follows: 8-hydroxyquinoline-2-carboxaldehyde and glutamic acid are added to methanol and mixed evenly, and the mixture is heated to 70°C and reacted for 10 hours to obtain modified hydroxyquinoline; wherein the molar ratio of 8-hydroxyquinoline-2-carboxaldehyde to glutamic acid is 1:1; (4) The sample containing the LDH coating is placed in a 0.7 g / L modified hydroxyquinoline solution, the pH is adjusted to 10, and the solution is immersed at 45°C for 3 hours, taken out and dried to obtain the product.

[0027] Comparative Example 4 is based on Example 5, except that the modified cyanoquinoline is replaced by 8-hydroxyquinoline.

[0028] Step 1: The 6063 aluminum alloy is polished, degreased in acetone for 30 minutes, ultrasonically pickled at a frequency of 55KHz (the volume ratio of nitric acid to hydrogen peroxide is 3:1) for 3 minutes, washed, and dried to obtain a prefabricated 6063 aluminum alloy; Step 2: The prefabricated 6063 aluminum alloy was used as the anode and the stainless steel container with a cooling system was used as the cathode. They were immersed in the electrolyte and the constant current mode was adopted at a current of 7A / dm 2 , micro-arc oxidation was performed for 20 minutes at a frequency of 500 Hz to obtain a self-enclosed micro-arc oxidation ceramic film specimen; The electrolyte includes: 10g / L Na 2 SiO 3 , 4g / L KOH, 2g / L NaF, 6ml / L phytic acid (C 6 H 18 O 24 P 6 )、3g / L MoS 2 , 4g / L ethanol; Step 3: (1) The preparation method of carbonate precursor hydrotalcite is as follows: 2 g / L zinc nitrate, 3.2 g / L ammonium nitrate and 16.5 g / L urea are uniformly mixed, heated at 95°C for 18 hours under sealed conditions, filtered, washed and dried to obtain carbonate precursor hydrotalcite; (2) The self-sealed micro-arc oxidation ceramic film layer specimen and the carbonate precursor hydrotalcite are hydrothermally treated at 120°C for 20 hours to obtain a sample containing LDH coating; (3) The sample containing the LDH coating was placed in a 0.7 g / L 8-hydroxyquinoline solution, the pH was adjusted to 10, and it was immersed at 45° C. for 3 hours. The sample was taken out and dried to obtain a product.

[0029] Testing: (1) Take 6 samples of each of Examples 1 to 5 and Comparative Examples 1 to 4, and perform friction and wear tests on the prepared samples using a HT-600 high-temperature friction and wear testing machine. Record the mass before and after wear, and the difference between the mass before and after wear is the mass loss. Calculate the average mass loss. (2) Take 6 samples of each of Examples 1 to 5 and Comparative Examples 1 to 4, and test the average self-corrosion potential of the samples using a potentiodynamic polarization curve.

[0030] Table 1

[0031] Conclusion: It can be seen from Examples 1 to 3 that Example 2 is not the optimal solution; Example 4 is based on Example 2, and the 6063 aluminum alloy after micro-arc oxidation is further sealed; thereby reducing the average mass loss and increasing the average self-corrosion potential, thereby enhancing the corrosion resistance and wear resistance; Example 5 is based on Example 4, and the sample containing the LDH coating is intercalated; the intercalation treatment improves the density of the LDH layer, thereby reducing the average mass loss and significantly increasing the self-corrosion potential, thereby enhancing its corrosion resistance and wear resistance.

[0032] Comparative Example 1 is based on Example 2, but phytic acid is not added to the electrolyte; because phytic acid carries a negative charge after ionization in aqueous solution and reacts with Al 3+ Combined with, the size and number of pores are reduced; therefore, the film thickness and density of the micro-arc oxidation ceramic layer of comparative example 1 are reduced, the average mass loss is increased, and the self-corrosion points are reduced; comparative example 2 is based on example 5, and 8-hydroxyquinoline-2-carboxaldehyde is not modified; the intercalation effect is reduced, and glutamic acid also has a certain corrosion inhibition, which leads to a decrease in performance; comparative example 3 is based on example 5, and molybdenum disulfide is not added to the electrolyte; the sealing of the micro-arc oxidation ceramic layer is poor, and the pores are not effectively filled, resulting in a decrease in wear resistance and corrosion resistance; comparative example 4 is based on example 5, and the modified hydroxyquinoline is replaced with 8-hydroxyquinoline, thereby reducing the corrosion resistance of the aluminum alloy.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film layer, characterized in that: The steps include: Step 1: Degreasing, pickling, washing and drying the 6063 aluminum alloy in sequence to obtain a prefabricated 6063 aluminum alloy; Step 2: Use the prefabricated 6063 aluminum alloy as the anode and the stainless steel container with a cooling system as the cathode, immerse them in the electrolyte, use the constant current mode, and micro-arc oxidation for 15 to 25 minutes to obtain a self-enclosed micro-arc oxidation ceramic film layer specimen; Step 3: (1) The self-sealed micro-arc oxidation ceramic film layer specimen and the carbonate precursor hydrotalcite are hydrothermally treated at 115-120°C for 20-24 hours to obtain a sample containing an LDH coating; (2) The sample containing the LDH coating is placed in a modified hydroxyquinoline solution, immersed at 40-50°C for 3-4 hours, taken out and dried to obtain a product.

2. The method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film according to claim 1, characterized in that: The raw materials of the electrolyte include the following components: 5-15 g / L Na2SiO3, 1-4 g / L KOH, 1-3 g / L NaF, 4-8 ml / L phytic acid, 2-6 g / L MoS2, and 2-5 g / L ethanol.

3. The method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film layer according to claim 1, characterized in that: The current of the micro-arc oxidation is 5-7A / dm 2 , the frequency of micro-arc oxidation is 200~500Hz.

4. The method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film layer according to claim 1, characterized in that: The preparation method of the carbonate precursor hydrotalcite comprises: uniformly mixing zinc nitrate, ammonium nitrate and urea, heating at 90-100° C. for 18-20 hours under a sealed condition, filtering, washing and drying to obtain the carbonate precursor hydrotalcite.

5. The method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film according to claim 4, characterized in that: The raw materials of the carbonate precursor hydrotalcite include: 2-3 g / L zinc nitrate, 3-5 g / L ammonium nitrate, and 16-18 g / L urea.

6. The method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film according to claim 1, characterized in that: The concentration of the modified hydroxyquinoline solution is 0.5-0.8 g / L, and the pH of the modified hydroxyquinoline solution is adjusted to 10-12.

7. The method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film according to claim 1, characterized in that: In the modified hydroxyquinoline solution, the preparation method of the modified hydroxyquinoline is as follows: 8-hydroxyquinoline-2-carboxaldehyde and glutamic acid are added into methanol and mixed evenly, and the mixture is heated to 70-75° C. and reacted for 10-14 hours to obtain the modified hydroxyquinoline.

8. The method for preparing a 6063 aluminum alloy self-enclosed micro-arc oxidation ceramic film layer according to claim 7, characterized in that: The molar ratio of the 8-hydroxyquinoline-2-carboxaldehyde to glutamic acid is 1:(1-1.5).

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