Preparation method of aluminum alloy electroplated ni-ptfe@pda corrosion-resistant coating layer

Abstract

The application discloses a preparation method of an aluminum alloy electroplated Ni-PTFE@PDA corrosion-resistant coating, and comprises the following steps: adding PTFE nanoparticles into anhydrous ethanol, adding polyethylene glycol monolaurate, uniformly mixing, centrifuging after the particles are preliminarily hydrophilized, and reserving; adding the preliminarily hydrophilized PTFE nanoparticles into deionized water, ultrasonic dispersing, adding dopamine hydrochloride, tris-hydroxymethyl aminomethane and polyethylene glycol monolaurate, uniformly mixing, adjusting pH, adding appropriate temperature and stirring, centrifuging, cleaning and drying after polymerization in a dark environment, and obtaining PTFE@PDA particles; putting a pretreated aluminum alloy substrate into a Watts plating solution containing the PTFE@PDA particles to perform electroplating, and obtaining the Ni-PTFE@PDA corrosion-resistant coating. The corrosion rate of the prepared Ni-PTFE@PDA corrosion-resistant coating is far lower than the corrosion rate of the aluminum alloy, the corrosion resistance is obviously improved, and the preparation method has simple preparation process and high reliability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of surface protection, and particularly relates to a preparation method of an aluminum alloy electroplated Ni-PTFE@PDA corrosion-resistant coating. BACKGROUND

[0002] Aluminum and its alloy materials are applied in more and more fields due to their superior physicochemical properties, but aluminum alloy has a very low corrosion potential, and is prone to corrosion on the surface of the aluminum alloy in a humid environment containing Cl-, which causes damage to the aluminum alloy and related equipment, reduces the service life of the equipment, and causes certain economic losses.

[0003] PTFE particles have good corrosion resistance, and the addition of the PTFE particles to the coating can effectively improve the corrosion resistance of the coating, but the PTFE particles have a very low surface energy and are difficult to be directly added to the plating solution for electroplating, and the low amount of the PTFE particles compounded in the electroplated coating also limits the improvement of the performance of the composite coating. The traditional plasma treatment, irradiation method, emulsion method and other treatment processes are complex, require expensive equipment, and are difficult to achieve an ideal dispersion state, and therefore it is necessary to propose a new method for modifying the PTFE particles to improve the dispersion stability of the PTFE particles in water, so as to stably disperse in the plating solution and improve the content of the PTFE particles in the coating, so as to improve the corrosion resistance of the aluminum alloy. The modification of the PTFE by hydrochloric acid dopamine (DA) can solve the problem of stable dispersion of the PTFE in the plating solution, and can improve the particle content in the coating and the corrosion resistance of the coating. The method has the advantages of simplicity, economy, easy operation and high reliability. SUMMARY

[0004] An object of the present application is to solve at least the above problems and / or drawbacks, and to provide at least the advantages stated hereinafter.

[0005] In order to solve the above problems, the present application provides a new PTFE particle modification method, the PTFE is modified by DA, the particle surface is coated with a layer of PDA, the hydrophilic groups such as hydroxyl and amino contained in the PDA realize the stable dispersion of the particles in water, and the catechol group contained in the PDA adsorbs the metal Ni 2+ to form a complex, and the PTFE@PDA is coated in the coating together with the reduced metal Ni2+, so as to improve the content of the particles in the coating and increase the corrosion resistance of the aluminum alloy.

[0006] In order to achieve these objects and other advantages according to the present application, a preparation method of an aluminum alloy electroplated Ni-PTFE@PDA corrosion-resistant coating is provided, which comprises the following steps:

[0007] Step one, add PTFE nanoparticles into anhydrous ethanol, add polyethylene glycol monolaurate and mix well, make the particles preliminarily hydrophilic, then centrifuge and reserve;

[0008] Step two, add the preliminarily hydrophilic PTFE nanoparticles into deionized water and ultrasonic dispersion, add dopamine hydrochloride, tris-hydroxymethyl aminomethane and polyethylene glycol monolaurate, mix well, adjust pH, add appropriate temperature and stirring, polymerize in dark environment, then centrifuge, wash and dry to obtain PTFE@PDA particles;

[0009] Step three, put the pretreated aluminum alloy substrate into the Watts plating solution containing PTFE@PDA particles to perform electroplating, and obtain Ni-PTFE@PDA corrosion-resistant plating layer.

[0010] Preferably, in step one, after mixing well, the concentration of PTFE nanoparticles is 20-30 g / L, and the concentration of polyethylene glycol monolaurate is 4-8 g / L.

[0011] Preferably, in step two, after mixing well, the concentration of preliminarily hydrophilic PTFE nanoparticles is 10-15 g / L, the concentration of dopamine hydrochloride is 1-3 g / L, the concentration of tris-hydroxymethyl aminomethane is 10-20 g / L, and the concentration of polyethylene glycol monolaurate is 1-3 g / L.

[0012] Preferably, in step two, adjust pH to 8.5, appropriate temperature is 30-40℃, stirring speed is 100-300 r / min; polymerize for 12-36 hours in dark environment.

[0013] Preferably, the Watts plating solution is: NiSO4·6H2O 100-300 g / L, NiCl2·6H2O 30-50 g / L, H3BO3 20-40 g / L, sodium saccharin 0.01-0.03 g / L; the concentration of PTFE@PDA particles is 7-8 g / L, the current density for electroplating is 0.01-0.08 A / cm2, the temperature is 40-50℃, the stirring speed is 100-300 r / min, and the time is 1-2 h. -1 Preferably, the preparation method of the pretreated aluminum alloy substrate comprises sandpaper polishing, oil removal, acid etching, DA activation and chemical plating of Ni-P.

[0014] Preferably, the preparation method of the pretreated aluminum alloy substrate comprises sandpaper polishing, oil removal, acid etching, DA activation and chemical plating of Ni-P.

[0015] Preferably, the formula of DA activation is: dopamine hydrochloride 1-3 g / L, tris-hydroxymethyl aminomethane 10-20 g / L; the temperature of DA activation is 30-40℃, the time is 12-36 h, and pH is 8.5.

[0016] Preferably, the electroless plating Ni-P formula is: NiSO4 20-30 g / L, NaH2PO2 10-30 g / L, Na3C6H5O7 40-50 g / L, temperature 85-95 DEG C, time 20-60 min.

[0017] The application further provides a Ni-PTFE@PDA corrosion-resistant coating prepared according to the preparation method.

[0018] The application further provides application of the Ni-PTFE@PDA corrosion-resistant coating prepared according to the preparation method in corrosion resistance of aluminum alloy.

[0019] The application at least has the following beneficial effects:

[0020] (1) The PTFE particle modification method adopted in the application increases the dispersion stability of PTFE particles in water, so that the PTFE particles are stably dispersed in the plating solution, and composite plating is possible. In addition, the catechol groups on the surface of the modified PTFE@PDA particles adsorb metal ions in the plating solution to form a complex, so that more particles are coated in the coating during composite plating, thereby improving the corrosion resistance of aluminum alloy. Compared with traditional plasma and irradiation methods, the method has the advantages of simple operation, economic environmental protection, high reliability, etc., and can overcome the low content of electroplated particles, greatly exert the original physicochemical properties of the particles, improve the performance of the coating, and improve the protection of the substrate. In addition, the method can be analogized to other particle materials, and the particle content in the coating can be improved by electroplating, electroless plating and other methods after the particles are wrapped with PDA.

[0021] (2) The modified PTFE@PDA particles successfully realize the dispersion stability in water, the water contact angle reaches 30 DEG, the PTFE content in the coating is increased, and the volume fraction reaches 54%. In order to detect the corrosion resistance of the coating, the potentiodynamic polarization curve analysis, electrochemical impedance spectroscopy (EIS) analysis and full immersion experiment are carried out on the coating. The potentiodynamic polarization curve analysis result shows that the self-corrosion potential of the Ni-PTFE@PDA coating reaches-0.22E / V, which is positively shifted by 0.58E / V and 1.04E / V compared with the aluminum alloy substrate and the Ni-P coating respectively, and the corrosion current density is decreased by 1 and 3 orders of magnitude respectively. The EIS analysis result shows that the film resistance of the composite coating in the corrosion medium is higher. The full immersion experiment result shows that the corrosion rate of the composite coating is much lower than that of the aluminum alloy. In summary, the Ni-PTFE@PDA coating has good corrosion resistance.

[0022] Other advantages, objects, and features of the application will be apparent from the following specification, and will be appreciated by those skilled in the art. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Potentiodynamic polarization curve of Ni-PTFE@PDA coating prepared for Example 1;

[0024] Figure 2 Electrochemical impedance spectrogram of Ni-PTFE@PDA coating prepared for Example 1;

[0025] Figure 3 Electrochemical impedance spectrogram (partial amplification) of Ni-PTFE@PDA coating prepared for Example 1;

[0026] Figure 4 Comparison chart of 72-hour full immersion experiment of Ni-PTFE@PDA coating prepared for the application. DETAILED DESCRIPTION

[0027] The application will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement the application according to the description and the drawings.

[0028] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0029] The application Figure 1 and Figure 2 Corrosion resistance test: The potentiodynamic polarization scanning test is carried out by using a PGSTAT30 electrochemical workstation, a saturated calomel electrode (SCE) is used as a reference electrode, a platinum electrode is used as an auxiliary electrode, and the aluminum alloy after plating (the working surface is 10mmx10mm) is used as a working electrode. The test medium is a 3.5wt% NaCl solution, and the test is started after the open circuit potential is stable, and the scanning rate is 0.02mV / s. The test range of the electrochemical impedance spectrogram is 100Hz-0.01Hz, and the alternating current potential disturbance is 5mV.

[0030] The application simulates the corrosion resistance of the composite coating in the marine environment by using the full immersion experiment, the test solution is a 5% NaCl solution by mass fraction, the immersion time is 48 hours, and the corrosion resistance of the coating is analyzed by observing the change of the surface of the composite coating after immersion and calculating the corrosion rate of the composite coating by the weight loss method. Figure 4 The appearance morphology chart of the surface of the composite coating before and after immersion in the 5% NaCl solution by mass fraction for 48 hours, and the corrosion rate is calculated by the mass before and after corrosion.

[0031] Example 1:

[0032] A preparation method of an aluminum alloy electroplated Ni-PTFE@PDA corrosion-resistant coating, comprising the following steps:

[0033] Step 1: Cut commercially available aluminum alloy into rectangular blocks of 30mm×10mm×2mm. Grind, degrease, and acid-etch the aluminum alloy. After cleaning, place it in anhydrous ethanol to prevent the surface of the aluminum alloy from being oxidized again. Replace the traditional aluminum alloy zinc immersion process with dopamine hydrochloride activation. Put the treated aluminum alloy into the prepared dopamine hydrochloride activation formula (dopamine hydrochloride (DA) 2g / L, tris(hydroxymethyl)aminomethane (tris) 15g / L, temperature 35℃, time 24h, pH 8.5) for polymerization for 24 hours, then take it out, clean it and blow it dry.

[0034] Step 2: Place the activated aluminum alloy into a plating solution containing 25 g / L NiSO4, 20 g / L NaH2PO2, and 45 g / L Na3C6H5O7. Perform chemical Ni-P plating in the plating solution at 90°C. After 30 minutes, remove the alloy, clean it, and dry it for later use.

[0035] Step 3: Weigh and mix PTFE particles with anhydrous ethanol, add polyethylene glycol monolaurate, and mix thoroughly (after thorough mixing, the concentration of PTFE nanoparticles is 24 g / L, and the concentration of polyethylene glycol monolaurate is 6 g / L) to make the particles initially hydrophilic; add the initially hydrophilic PTFE nanoparticles to deionized water and ultrasonically disperse them, then add dopamine hydrochloride, tris(hydroxymethylaminomethane), and polyethylene glycol monolaurate, and mix thoroughly (after thorough mixing, the concentration of the initially hydrophilic PTFE nanoparticles is 12 g / L, the concentration of dopamine hydrochloride is 2 g / L, the concentration of tris(hydroxymethylaminomethane) is 15 g / L, and the concentration of polyethylene glycol monolaurate is 2 g / L), adjust the pH to 8.5, maintain the temperature at 35℃, and the stirring speed at 200 r / min. After polymerization in the dark for 24 hours, centrifuge, wash, and dry.

[0036] Step 4: Place the treated aluminum alloy into a Watt plating bath containing PTFE@PDA particles (NiSO4·6H2O 200g / L, NiCl2·6H2O 40g / L, H3BO3 30g / L, sodium saccharin 0.01g / L, PTFE@PDA particle concentration 7.5g / L) for electroplating (current density 0.05A / cm²). -1 The temperature was 45℃, the stirring speed was 200 r / min, and the time was 1.5 h, resulting in a Ni-PTFE@PDA corrosion-resistant coating with a corrosion rate of 0.052 g·h. -1 ·m -2 .

[0037] like Figure 1 The self-corrosion potential of the Ni-PTFE@PDA coating shown is -0.22E / V, which is 0.58E / V and 1.04E / V higher than that of the aluminum alloy substrate and Ni-P coating, respectively, and the corrosion current density is reduced by 1 and 3 orders of magnitude, respectively.

[0038] As Figure 2 EIS analysis results show that the composite coating has higher film resistance in the corrosion medium;

[0039] Example 2:

[0040] A preparation method of an aluminum alloy electroplated Ni-PTFE@PDA corrosion-resistant coating, comprising the following steps:

[0041] Step one, commercially available aluminum alloy is cut into a cuboid block of 30mm x 10mm x 2mm, the aluminum alloy is polished, degreased, and etched, and then placed in anhydrous ethanol to prevent the aluminum alloy surface from being oxidized again; the traditional zinc immersion process for aluminum alloy is replaced by a dopamine hydrochloride activation method, and the treated aluminum alloy is placed in a prepared dopamine hydrochloride activation formula (dopamine hydrochloride (DA) 2g / L, tris 15g / L, temperature 35℃, time 24h, pH 8.5) for polymerization for 24 hours, then taken out, washed and dried;

[0042] Step two, the activated aluminum alloy is placed in a plating solution of NiSO4 25g / L, NaH2PO2 20g / L, and Na3C6H5O7 45g / L, and chemical plating Ni-P is carried out in the plating solution at a temperature of 90℃, and after 30 minutes, it is taken out, washed and dried for standby use;

[0043] Step three, PTFE particles are mixed with anhydrous ethanol, and polyethylene glycol monolaurate is added, and mixed uniformly (after mixing uniformly, the concentration of PTFE nanoparticles is 24g / L, and the concentration of polyethylene glycol monolaurate is 6g / L), so that the particles are initially hydrophilic; the initially hydrophilic PTFE nanoparticles are added to deionized water and ultrasonically dispersed, and then dopamine hydrochloride, tris, and polyethylene glycol monolaurate are added and mixed uniformly (after mixing uniformly, the concentration of the initially hydrophilic PTFE nanoparticles is 12g / L, the concentration of dopamine hydrochloride is 2g / L, the concentration of tris is 15g / L, and the concentration of polyethylene glycol monolaurate is 2g / L), the pH is adjusted to 8.5, the temperature is 25℃, the stirring speed is 200r / min, and after polymerization in a dark environment for 24 hours, centrifugation, washing, and drying are carried out;

[0044] Step four, the treated aluminum alloy is placed in a Watt plating solution containing PTFE@PDA particles (NiSO4·6H2O 200g / L, NiCl2·6H2O 40g / L, H3BO3 30g / L, sodium saccharin 0.01g / L, PTFE@PDA particle concentration 7.5g / L) for electroplating (the current density is 0.05A / cm -1, the temperature is 45 DEG C, the stirring speed is 200 r / min, and the time is 1.5 h, to obtain the Ni-PTFE@PDA corrosion-resistant coating, and the corrosion rate is 0.061 g.h -1 ·m -2 .

[0045] The water contact angle of the Ni-PTFE@PDA corrosion-resistant coating prepared in the embodiment is 46.311 DEG.

[0046] Example 3:

[0047] A preparation method of an aluminum alloy plated with a Ni-PTFE@PDA corrosion-resistant coating, comprising the following steps:

[0048] Step one, commercially available aluminum alloy is cut into a cuboid block with a size of 30 mm x 10 mm x 2 mm, the aluminum alloy is polished, degreased, and acid-etched, and then placed in anhydrous ethanol to prevent the surface of the aluminum alloy from being oxidized again; a dopamine hydrochloride activation method is used to replace the traditional zinc immersion process of the aluminum alloy, and the treated aluminum alloy is placed in a prepared dopamine hydrochloride activation formula (dopamine hydrochloride (DA) 2 g / L, tris 15 g / L, temperature 35 DEG C, time 24 h, pH 8.5) to polymerize for 24 hours, and then taken out, washed and dried;

[0049] Step two, the activated aluminum alloy is placed in a plating solution containing NiSO4 25 g / L, NaH2PO2 20 g / L, and Na3C6H5O7 45 g / L, and chemical Ni-P plating is performed in the plating solution at a temperature of 90 DEG C, and the aluminum alloy is taken out after 30 min, washed and dried for standby use;

[0050] Step three, PTFE particles are mixed with anhydrous ethanol, and polyethylene glycol monolaurate is added, and the mixture is uniformly mixed (after uniform mixing, the concentration of the PTFE nanoparticles is 24 g / L, and the concentration of the polyethylene glycol monolaurate is 6 g / L), so that the particles are initially hydrophilic; the initially hydrophilic PTFE nanoparticles are added to deionized water and ultrasonically dispersed, and then dopamine hydrochloride, tris, and polyethylene glycol monolaurate are added, and the mixture is uniformly mixed (after uniform mixing, the concentration of the initially hydrophilic PTFE nanoparticles is 12 g / L, the concentration of the dopamine hydrochloride is 2 g / L, the concentration of the tris is 15 g / L, and the concentration of the polyethylene glycol monolaurate is 2 g / L), the pH is adjusted to 8.5, the temperature is 45 DEG C, the stirring speed is 200 r / min, and the mixture is polymerized in a dark environment for 24 hours, and then centrifuged, washed, and dried;

[0051] Step four, put the treated aluminum alloy into the Watt plating solution containing PTFE@PDA particles (NiSO4·6H2O 200 g / L, NiCl2·6H2O 40 g / L, H3BO3 30 g / L, sodium saccharin 0.01 g / L, PTFE@PDA particle concentration 7.5 g / L) for electroplating (current density 0.05 A / cm -1 , temperature 45℃, stirring speed 200 r / min, time 1.5 h) to obtain a Ni-PTFE@PDA corrosion-resistant coating, and the corrosion rate is 0.154 g·h -1 ·m -2 .

[0052] The water contact angle of the Ni-PTFE@PDA corrosion-resistant coating prepared in this example is 67.865°.

[0053] Example 4:

[0054] A preparation method of an aluminum alloy electroplated with a Ni-PTFE@PDA corrosion-resistant coating, comprising the following steps:

[0055] Step one, cut commercially available aluminum alloy into a cuboid block with a size of 30 mm x 10 mm x 2 mm, polish, degrease, and etch the aluminum alloy, and then put it into anhydrous ethanol to prevent the surface of the aluminum alloy from being oxidized again; replace the traditional zinc immersion process of aluminum alloy with a dopamine hydrochloride activation method, put the treated aluminum alloy into a prepared dopamine hydrochloride activation formula (dopamine hydrochloride (DA) 2 g / L, tris 15 g / L, temperature 35℃, time 24 h, pH 8.5) for polymerization for 24 hours, then take it out, wash and dry;

[0056] Step two, put the activated aluminum alloy into a plating solution of NiSO4 25 g / L, NaH2PO2 20 g / L, and Na3C6H5O7 45 g / L, and perform chemical plating of Ni-P in the plating solution at a temperature of 90℃, take it out after 30 min, wash and dry for standby use;

[0057] Step 3: Weigh and mix PTFE particles with anhydrous ethanol, add polyethylene glycol monolaurate, and mix thoroughly (after thorough mixing, the concentration of PTFE nanoparticles is 24 g / L, and the concentration of polyethylene glycol monolaurate is 6 g / L) to make the particles initially hydrophilic; add the initially hydrophilic PTFE nanoparticles to deionized water and ultrasonically disperse them, then add dopamine hydrochloride, tris(hydroxymethylaminomethane), and polyethylene glycol monolaurate, and mix thoroughly (after thorough mixing, the concentration of the initially hydrophilic PTFE nanoparticles is 12 g / L, the concentration of dopamine hydrochloride is 2 g / L, the concentration of tris(hydroxymethylaminomethane) is 15 g / L, and the concentration of polyethylene glycol monolaurate is 2 g / L), adjust the pH to 8.5, maintain the temperature at 35℃, and the stirring speed at 200 r / min. After polymerization in the dark for 24 hours, centrifuge, wash, and dry.

[0058] Step 4: Place the treated aluminum alloy into a Watt plating bath containing PTFE@PDA particles (NiSO4·6H2O 200g / L, NiCl2·6H2O 40g / L, H3BO3 30g / L, sodium saccharin 0.01g / L, PTFE@PDA particle concentration 7.5g / L) for electroplating (current density 0.07A / cm²). -1 The Ni-PTFE@PDA corrosion-resistant coating was obtained by stirring at 45℃ for 200 r / min for 2 h.

[0059] like Figure 4 The experimental results shown in Table 1 indicate that aluminum alloy ( Figure 4 The corrosion rate of the sample on the left reached 2.207 g·h. -1 ·m -2 The Ni-PTFE@PDA corrosion-resistant coating prepared in this embodiment ( Figure 4 The corrosion rate of the sample on the right is 0.074 g·h. -1 ·m -2 In summary, the Ni-PTFE@PDA coating exhibits good corrosion resistance.

[0060] Table 1

[0061]

[0062] Example 5:

[0063] A method for preparing a Ni-PTFE@PDA corrosion-resistant coating on aluminum alloy by electroplating includes the following steps:

[0064] Step one, cut the commercially available aluminum alloy into 30mm x 10mm x 2mm cuboid, polish, degrease, acid etch, clean and then put into anhydrous ethanol to prevent the aluminum alloy surface from being oxidized again; replace the traditional zinc immersion process of aluminum alloy with the dopa hydrochloride activation method, put the treated aluminum alloy into the prepared dopa hydrochloride activation formula (dopa hydrochloride (DA) 2g / L, tris 15g / L, temperature 35℃, time 24h, pH 8.5) and polymerize for 24 hours, then take out, clean and dry;

[0065] Step two, put the activated aluminum alloy into a plating solution containing NiSO4 25g / L, NaH2PO2 20g / L and Na3C6H5O7 45g / L, and perform chemical plating of Ni-P in the plating solution at a temperature of 90℃, take out after 30min, clean and dry for standby use;

[0066] Step three, mix PTFE particles with anhydrous ethanol and add polyethylene glycol monolaurate, mix uniformly (after mixing uniformly, the concentration of PTFE nanoparticles is 24g / L and the concentration of polyethylene glycol monolaurate is 6g / L), to make the particles preliminarily hydrophilic; add the preliminarily hydrophilic PTFE nanoparticles to deionized water and ultrasonic dispersion, then add dopa hydrochloride, tris and polyethylene glycol monolaurate, mix uniformly (after mixing uniformly, the concentration of preliminarily hydrophilic PTFE nanoparticles is 12g / L, the concentration of dopa hydrochloride is 2g / L, the concentration of tris is 15g / L and the concentration of polyethylene glycol monolaurate is 2g / L), adjust the pH to 8.5, the temperature to 35℃ and the stirring speed to 200r / min, and polymerize in a dark environment for 24 hours, then centrifuge, clean and dry;

[0067] Step four, put the treated aluminum alloy into a Watt plating solution containing PTFE@PDA particles (NiSO4·6H2O 200g / L, NiCl2·6H2O 40g / L, H3BO3 30g / L, sodium saccharin 0.01g / L, PTFE@PDA particle concentration 10g / L) to perform electroplating (current density 0.08A / cm -1 , temperature 45℃, stirring speed 200r / min, time 1.5h), to obtain a Ni-PTFE@PDA corrosion-resistant plating layer.

[0068] The corrosion rate of the Ni-PTFE@PDA corrosion-resistant plating layer prepared in this example is 0.075g·h -1 ·m -2 .

[0069] While embodiments of the application have been disclosed in connection with the above specification and drawings this description is not intended to limit the scope of the application and many modifications, enhancements, alternatives, and variations will become apparent to those skilled in the art from this disclosure. Accordingly, it is intended that the application not be limited to the described embodiments, but that it include all variations falling within the scope of the claims, and their equivalents.

Claims

1. A method for preparing an electroplated Ni-PTFE@PDA corrosion-resistant coating on an aluminum alloy, characterized in that, The preparation method comprises the following steps: Step one, adding PTFE nanoparticles into anhydrous ethanol, adding polyethylene glycol monolaurate to mix uniformly, making the particles preliminarily hydrophilic, and then centrifuging for standby; Step two, adding the preliminarily hydrophilic PTFE nanoparticles into deionized water, ultrasonic dispersing, adding dopamine hydrochloride, tris-hydroxymethyl aminomethane and polyethylene glycol monolaurate to mix uniformly, adjusting pH, and polymerizing under appropriate temperature and stirring in a dark environment, and then centrifuging, washing and drying to obtain PTFE@PDA particles; Step three, placing the pretreated aluminum alloy substrate into a Watts plating solution containing PTFE@PDA particles to perform electroplating, and obtaining a Ni-PTFE@PDA corrosion-resistant plating layer; The preparation method of the pretreated aluminum alloy substrate comprises sandpaper polishing, oil removal, acid etching, DA activation and chemical plating of Ni-P; The formula of the DA activation is: dopamine hydrochloride 1-3 g / L, tris-hydroxymethyl aminomethane 10-20 g / L; the temperature of the DA activation is 30-40 ℃, the time is 12-36 h, and the pH is 8.

5.

2. The preparation method of the aluminum alloy electroplated Ni-PTFE@PDA corrosion-resistant coating layer according to claim 1, characterized in that, In step one, after mixing uniformly, the concentration of the PTFE nanoparticles is 20-30 g / L, and the concentration of the polyethylene glycol monolaurate is 4-8 g / L.

3. The preparation method of the aluminum alloy electroplated Ni-PTFE@PDA corrosion-resistant coating layer according to claim 1, characterized in that, In step two, after mixing uniformly, the concentration of the preliminarily hydrophilic PTFE nanoparticles is 10-15 g / L, the concentration of the dopamine hydrochloride is 1-3 g / L, the concentration of the tris-hydroxymethyl aminomethane is 10-20 g / L, and the concentration of the polyethylene glycol monolaurate is 1-3 g / L.

4. The preparation method of the aluminum alloy electroplated Ni-PTFE@PDA corrosion-resistant coating layer according to claim 1, characterized in that, In step two, the pH is adjusted to 8.5, the appropriate temperature is 30-40 ℃, the stirring speed is 100-300 r / min, and the polymerization is performed in a dark environment for 12-36 h.

5. The preparation method of the aluminum alloy electroplated Ni-PTFE@PDA corrosion-resistant coating layer according to claim 1, characterized in that, The watt plating solution is: NiSO4·6H2O 100-300 g / L, NiCl2·6H2O 30-50 g / L, H3BO3 20-40 g / L, sodium saccharin 0.01-0.03 g / L; the PTFE@PDA particle concentration is 7-8 g / L, the current density for electroplating is 0.01-0.08 A / cm -1 , the temperature is 40-50 DEG C, the stirring speed is 100-300 r / min, and the time is 1-2 h.

6. The preparation method of the aluminum alloy electroplated Ni-PTFE@PDA corrosion-resistant coating layer according to claim 1, characterized in that, The formula of the chemical plating of Ni-P is: NiSO4 20-30 g / L, NaH2PO2 10-30 g / L, Na3C6H5O7 40-50 g / L, the temperature is 85-95 ℃, and the time is 20-60 min.

7. A Ni-PTFE@PDA corrosion-resistant plating layer prepared by the preparation method according to any one of claims 1-6.

8. Application of a Ni-PTFE@PDA corrosion-resistant plating layer prepared by the preparation method according to any one of claims 1-6 in corrosion resistance of an aluminum alloy.

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