Preparation process of high-performance composite coating through oxidation electrophoresis plasma spraying

Abstract

The invention discloses a preparation process of a high-performance composite coating for oxidation electrophoresis plasma spraying, which comprises the following steps: pretreatment: soaking an aluminum alloy window frame in an alkaline degreasing fluid, subsequently cleaning the aluminum alloy window frame with deionized water, soaking the aluminum alloy window frame in a mixed acid solution, washing the aluminum alloy window frame with deionized water, and blow-drying the aluminum alloy window frame; anodic oxidation: putting the pretreated aluminum alloy window frame into an electrolytic bath as an anode, taking a tantalum-niobium alloy plate as a cathode, putting into a compound electrolyte, and electrifying to form an oxidation film on the surface of the aluminum alloy window frame; the aluminum alloy window frame is put into deionized water to be subjected to ultrasonic cleaning for multiple times; electrophoretic coating is conducted, specifically, the workpiece is immersed in electrophoretic paint liquid with charges, and circulation of tank liquid is ensured; and plasma nanometer spraying is conducted, specifically, the aluminum alloy window frame obtained after electrophoretic coating is completed is heated, and the nanometer ceramic powder paint enables a nanometer ceramic coating to be deposited on the surface of the aluminum alloy window frame through plasma spraying equipment. The method has the advantage that the overall wear resistance and corrosion resistance of the aluminum alloy window frame are improved.

Description

Technical Field

[0001] The present invention relates to the technical fields of materials science and surface engineering, and particularly relates to a preparation process for a high-performance composite coating by oxidation electrophoresis plasma spraying. Background Art

[0002] With the continuous development of industrial automation technology, the post-treatment process of aluminum alloy window frames has been significantly improved, especially in the automation of the cleaning process. Modern production lines can achieve automatic cleaning, thus eliminating the need for manual intervention. This not only reduces labor costs but also ensures the consistency and reliability of the cleaning process. This progress is crucial for improving the efficiency of the entire post-treatment process.

[0003] Meanwhile, the booming development of the construction industry has led to a continuous increase in the demand for aluminum alloy doors and windows. The increase in the completed housing area indicates that the demand for aluminum alloy window frames will also rise accordingly, which provides impetus for the progress and innovation of post-treatment technologies. The changing market demand has prompted the industry to continuously seek more effective, more economical, and more environmentally friendly post-treatment methods.

[0004] In addition, the emergence of new materials and new processes has brought new opportunities to the post-treatment technology of aluminum alloy window frames. With the increase in scientific research investment and the in-depth study of technologies, it is expected that more advanced post-treatment technologies will emerge in the future, which will further improve product performance and reduce production costs.

[0005] With the continuous development of industrial technologies, the requirements for the protective and decorative properties of material surfaces are increasing day by day, and traditional single-coating technologies are difficult to meet high-performance requirements. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation process for a high-performance composite coating by oxidation electrophoresis plasma spraying to enhance the overall wear resistance and corrosion resistance of aluminum alloy window frames.

[0007] The above technical purpose of the present invention is achieved through the following technical solutions:

[0008] A preparation process for a high-performance composite coating by oxidation electrophoresis plasma spraying, characterized by comprising the following steps:

[0009] Pretreatment: Immerse the aluminum alloy window frame in an alkaline degreasing solution, then clean it thoroughly with deionized water, soak it in a mixed acid solution, and blow it dry after rinsing with deionized water;

[0010] Anodic oxidation: Place the pretreated aluminum alloy window frame in an electrolytic cell as the anode, use a tantalum-niobium alloy plate as the cathode, place both in a compound electrolyte, and energize the electrolytic cell to form an oxide film on the surface of the aluminum alloy window frame;

[0011] Cleaning: After anodizing, the aluminum alloy window frame is placed in deionized water for ultrasonic cleaning multiple times;

[0012] Electrophoretic coating: The aluminum alloy window frame is immersed in an electrophoretic paint solution with an electric charge, ensuring the circulation of the bath solution to make the electrophoretic paint solution evenly adhere to the aluminum alloy window frame;

[0013] Plasma nano spraying: The aluminum alloy window frame after electrophoretic coating is heated up, and nano-ceramic powder coating is selected. Through a plasma spraying device, the nano-ceramic coating is deposited on the surface of the aluminum alloy window frame, thereby realizing the preparation of the composite coating.

[0014] Preferably, the concentrations of the components in the alkaline degreasing solution are: 10 - 15 g / L of sodium hydroxide, 5 - 8 g / L of sodium carbonate, and 3 - 5 g / L of the surfactant sodium dodecylbenzenesulfonate. The immersion temperature of the alkaline degreasing solution is 50 - 60 °C, and the immersion time is 10 - 15 min.

[0015] Preferably, the mixed acid solution includes: 8 - 12% by mass of sulfuric acid, 2 - 4% by mass of nitric acid, and the balance of deionized water. The immersion time of the mixed acid solution is 3 - 5 min.

[0016] Preferably, the compound electrolyte is a sulfuric acid solution added with a compound additive. The concentration of the sulfuric acid solution is 60 - 180 g / L, the addition amount of the compound additive is 0.5 - 1%, and the compound additive includes 40 - 60% by mass of citric acid and the balance of nickel sulfate.

[0017] Preferably, the electrolysis time of the anodizing is 15 - 25 min, the temperature is 23 - 27 °C, and the current density is 1.5 - 2.5 A / dm 2 .

[0018] Preferably, the ultrasonic cleaning time is 5 - 8 min, and the ultrasonic frequency is 30 - 40 kHz.

[0019] Preferably, the epoxy resin content in the electrophoretic paint solution is 30 - 35%, the curing agent toluene diisocyanate content is 14 - 16%, the pigment content is 8 - 12%, the nano-titanium dioxide particle content is 2 - 5%, and the balance is deionized water. The electrophoresis time is set to 8 - 12 min, the first-stage voltage is set to 150 V, the second-stage voltage is set to 260 V, and the electrophoresis temperature is 28 - 32 °C.

[0020] Preferably, the nano-ceramic powder coating is Al 2 O 3 -13% TiO 2, with a particle size of 200 - 300 mesh, the aluminum alloy window frame is heated to 150 °C for plasma spraying. The specific parameters of plasma spraying are: arc voltage 70 - 80 V, arc current 500 A, spraying power 35 - 40 kW, powder feeding gas flow rate 3 - 6 L / min, spraying distance 80 - 150 mm, spray gun moving speed 6 - 8 m / min, Ar ion gas flow rate 70 - 80 L / min, H 2 ion gas flow rate 100 - 150 L / min.

[0021] Preferably, the thickness of the oxide film formed by anodic oxidation is 10 - 15 μm, the thickness of the electrophoretic coating film is 22 - 25 μm, and the thickness of the plasma spraying coating is 80 - 100 μm.

[0022] In summary, the present invention has the following beneficial effects:

[0023] 1. Strong bonding force: The oxide film formed by anodic oxidation treatment has good bonding force with the substrate, and at the same time, good bonding can also be formed between the electrophoretic coating and the powder coating, ensuring the overall bonding force of the composite coating.

[0024] 2. High corrosion resistance: Both the anodic oxidation film and the electrophoretic coating have good anti-corrosion properties, which can effectively prevent the substrate from being corroded.

[0025] 3. Excellent anti-aging performance: The composite coating after curing treatment has good weather resistance and anti-aging performance, and can maintain the performance stability of the coating for a long time.

[0026] 4. Optimized steps: Through the basic high temperature of plasma spraying, while realizing the curing of the electrophoretic coating film, the spraying of nano-ceramic powder can be completed, and the bonding force between the two is also higher, reducing the separate curing step of the electrophoretic coating film, and at the same time reducing the step of the nano-ceramic powder requiring an intermediate bonding layer.

[0027] 5. The bonding strength of the nano-ceramic powder by plasma spraying is higher, and the nano-structure can achieve good toughening effect and wear resistance. Specific embodiments

[0028] The following further describes the specific embodiments of the present invention. This embodiment does not constitute a limitation to the present invention.

[0029] Example 1

[0030] A preparation process of a high-performance composite coating by anodic oxidation electrophoretic plasma spraying, including the following steps:

[0031] Pretreatment: Immerse the aluminum alloy window frame in an alkaline degreasing solution. The concentrations of each component in the alkaline degreasing solution are: 10 g / L of sodium hydroxide, 8 g / L of sodium carbonate, and 3 g / L of the surfactant sodium dodecylbenzenesulfonate. The immersion temperature of the alkaline degreasing solution is 50 - 60 °C, and the immersion time is 10 - 15 min. Subsequently, wash it thoroughly with deionized water, and then immerse it in a mixed acid solution. The mixed acid solution includes: 8% sulfuric acid by mass fraction, 4% nitric acid by mass fraction, and the balance deionized water. The immersion time of the mixed acid solution is 5 min. After rinsing with deionized water, blow it dry;

[0032] Anodic oxidation: Place the pretreated aluminum alloy window frame in the electrolytic cell as the anode, use a tantalum-niobium alloy plate as the cathode, and place both in a compound electrolyte. The compound electrolyte is a sulfuric acid solution added with a compound additive. The concentration of the sulfuric acid solution is 60 g / L, and the addition amount of the compound additive is 0.5%. The compound additive includes 40% citric acid by mass fraction and the balance nickel sulfate. Then, energize the electrolytic cell, and an oxide film is formed on the surface of the aluminum alloy window frame. The electrolysis time is 25 min, the temperature is 23 °C, and the current density is 2.5 A / dm 2 ;

[0033] Cleaning: After anodic oxidation, put the aluminum alloy window frame into deionized water for multiple ultrasonic cleanings. The ultrasonic cleaning time is 5 min, and the ultrasonic frequency is 40 kHz;

[0034] Electrophoretic coating: Immerse the aluminum alloy window frame in an electrophoretic paint solution with an electric charge. The epoxy resin content in the electrophoretic paint solution is 35%, the content of the curing agent toluene diisocyanate is 14%, the pigment content is 12%, the content of nano-titanium dioxide particles is 5%, and the balance is deionized water. The electrophoresis time is set to 12 min, the first-stage voltage is set to 150 V, the second-stage voltage is set to 260 V, and the electrophoresis temperature is 28 °C. Ensure the circulation of the bath solution to make the electrophoretic paint solution evenly adhere to the aluminum alloy window frame;

[0035] Plasma nano-spraying: Heat the aluminum alloy window frame after electrophoretic coating to 150 °C, and select nano-ceramic powder coating Al with a particle size of 200 mesh 2 O 3 -13% TiO 2 , through the plasma spraying equipment, deposit the nano-ceramic coating on the surface of the aluminum alloy window frame. The arc voltage is 80 V, the arc current is 500 A, the spraying power is 35 kW, the powder feeding gas flow rate is 6 L / min, the spraying distance is 150 mm, the spray gun moving speed is 8 m / min, the Ar ion gas flow rate is 70 L / min, and the H 2 ion gas flow rate is 100 L / min. Finally, the thickness of the oxide film formed by anodic oxidation is 10 μm, the thickness of the electrophoretic coating film is 25 μm, and the thickness of the plasma spraying coating is 80 μm, thus realizing the preparation of the composite coating.

[0036] Example 2

[0037] A preparation process of a high-performance composite coating by oxidative electrophoretic plasma spraying, comprising the following steps:

[0038] Pretreatment: Immerse the aluminum alloy window frame in an alkaline degreasing solution. The concentrations of each component in the alkaline degreasing solution are: 12 g / L of sodium hydroxide, 6 g / L of sodium carbonate, and 4 g / L of the surfactant sodium dodecylbenzenesulfonate. The immersion temperature of the alkaline degreasing solution is 55 °C, and the immersion time is 14 min. Subsequently, rinse it clean with deionized water, and then immerse it in a mixed acid solution. The mixed acid solution includes: 9% by mass of sulfuric acid, 3% by mass of nitric acid, and the balance of deionized water. The immersion time of the mixed acid solution is 4 min, and after rinsing with deionized water, blow it dry;

[0039] Anodic oxidation: Place the pretreated aluminum alloy window frame in an electrolytic cell as the anode, use a tantalum-niobium alloy plate as the cathode, and place both in a compound electrolyte. The compound electrolyte is a sulfuric acid solution added with a compound additive. The concentration of the sulfuric acid solution is 100 g / L, and the addition amount of the compound additive is 1%. The compound additive includes 50% by mass of citric acid and the balance of nickel sulfate. Then, energize the electrolytic cell to form an oxide film on the surface of the aluminum alloy window frame. The electrolysis time is 20 min, the temperature is 25 °C, and the current density is 2.5 A / dm 2 ;

[0040] Cleaning: After anodic oxidation, put the aluminum alloy window frame into deionized water for multiple ultrasonic cleanings. The ultrasonic cleaning time is 6 min, and the ultrasonic frequency is 35 kHz;

[0041] Electrophoretic coating: Immerse the aluminum alloy window frame in an electrophoretic paint solution with an electric charge. The epoxy resin content in the electrophoretic paint solution is 32%, the curing agent toluene diisocyanate content is 15%, the pigment content is 10%, the nano-titanium dioxide particle content is 3%, and the balance is deionized water. The electrophoresis time is set to 9 min, the first-stage voltage is set to 150 V, the second-stage voltage is set to 260 V, and the electrophoresis temperature is 30 °C. Ensure the circulation of the bath solution to make the electrophoretic paint solution evenly adhere to the aluminum alloy window frame;

[0042] Plasma nano-spraying: Heat the aluminum alloy window frame after electrophoretic coating to 150 °C, and select nano-ceramic powder coating Al with a particle size of 250 mesh 2 O 3 -13% TiO 2 , through a plasma spraying device, deposit the nano-ceramic coating on the surface of the aluminum alloy window frame. The arc voltage is 75 V, the arc current is 500 A, the spraying power is 35 kW, the powder feeding gas flow rate is 4 L / min, the spraying distance is 100 mm, the gun moving speed is 7 m / min, and the Ar ion gas flow rate is 75 L / min, H 2The flow rate of the ion gas is 120 L / min, the thickness of the oxide film finally formed by anodic oxidation is 12 μm, the thickness of the paint film by electrophoretic coating is 23 μm, and the thickness of the coating by plasma spraying is 90 μm, thereby realizing the preparation of the composite coating.

[0043] Example 3

[0044] A preparation process for a high-performance composite coating by anodic oxidation, electrophoretic coating, and plasma spraying, comprising the following steps:

[0045] Pretreatment: Immerse the aluminum alloy window frame in an alkaline degreasing solution. The concentrations of the components in the alkaline degreasing solution are: 15 g / L of sodium hydroxide, 8 g / L of sodium carbonate, and 5 g / L of the surfactant sodium dodecylbenzenesulfonate. The immersion temperature of the alkaline degreasing solution is 50 °C, the immersion time is 10 min, and then it is cleaned thoroughly with deionized water and then immersed in a mixed acid solution. The mixed acid solution includes: 12% by mass of sulfuric acid, 4% by mass of nitric acid, and the balance of deionized water. The immersion time of the mixed acid solution is 3 min, and it is rinsed with deionized water and then dried.

[0046] Anodic oxidation: Place the pretreated aluminum alloy window frame in an electrolytic cell as the anode, use a tantalum-niobium alloy plate as the cathode, and place both in a compound electrolyte. The compound electrolyte is a sulfuric acid solution added with a compound additive. The concentration of the sulfuric acid solution is 180 g / L, the addition amount of the compound additive is 0.5%, the compound additive includes 60% by mass of citric acid and the balance of nickel sulfate, and the electrolytic cell is electrified. An oxide film is formed on the surface of the aluminum alloy window frame. The electrolysis time is 25 min, the temperature is 23 °C, and the current density is 1.5 A / dm 2 ;

[0047] Cleaning: After anodic oxidation, put the aluminum alloy window frame into deionized water for ultrasonic cleaning multiple times. The ultrasonic cleaning time is 8 min, and the ultrasonic frequency is 30 kHz.

[0048] Electrophoretic coating: Immerse the aluminum alloy window frame in an electrophoretic paint solution with an electric charge. The epoxy resin content in the electrophoretic paint solution is 30%, the curing agent toluene diisocyanate content is 16%, the pigment content is 12%, the nano-titanium dioxide particle content is 5%, and the balance is deionized water. The electrophoretic time is set to 12 min, the first-stage voltage is set to 150 V, the second-stage voltage is set to 260 V, and the electrophoretic temperature is 32 °C. Ensure the circulation of the bath solution to make the electrophoretic paint solution evenly adhere to the aluminum alloy window frame.

[0049] Plasma nano-spraying: Heat the aluminum alloy window frame after electrophoretic coating to 150 °C, and select nano-ceramic powder coating Al with a particle size of 300 mesh 2 O 3 -13% TiO 2, through a plasma spraying device, deposit a nano-ceramic coating on the surface of the aluminum alloy window frame. The arc voltage is 80V, the arc current is 500A, the spraying power is 40kW, the powder feeding gas flow rate is 6L / min, the spraying distance is 150mm, the gun moving speed is 8m / min, the Ar ion gas flow rate is 80L / min, and the H 2 ion gas flow rate is 150L / min. Finally, an anodic oxidation film with a thickness of 15μm is formed, the paint film thickness of electrophoretic coating is 25μm, and the coating thickness of plasma spraying is 100μm, thus realizing the preparation of the composite coating.

[0050] Take the aluminum alloy window frames made in Examples 1 to 3 and the ordinary aluminum alloy window frames purchased externally as the comparative example. According to the provisions of GB / T 10125-2012 "Artificial Atmosphere Corrosion Test - Salt Spray Test", conduct corrosion resistance detection on the coated test pieces, use neutral NaCl solution, and carry out accelerated corrosion by continuous spraying and testing; according to GB / T 23988-2009 "Determination of Coating Abrasion Resistance - Falling Sand Method", test the abrasion resistance of the coating, use 1000-mesh SiC sandpaper to conduct cyclic friction on the superhydrophobic coating sample under a load of 200g, and the moving distance of each cycle is 10cm. The specific test data are shown in Table 1 below.

[0051] Table 1 Performance test data of each example and comparative example

[0052] Wear resistance Corrosion resistance Example 1 155.6 Excellent Example 2 159.3 Excellent Example 3 152.4 Excellent Comparative example 141.2 Good

[0053] As can be seen from Table 1 above, the aluminum alloy window frame with the high-performance composite coating of the present invention has stronger corrosion resistance and abrasion resistance than the ordinary aluminum alloy window frame. The advantages of the present invention are:

[0054] Strong bonding force: The anodic oxidation film formed by anodic oxidation treatment has good bonding force with the substrate, and at the same time, good bonding can also be formed between the electrophoretic coating and the powder coating, ensuring the overall bonding force of the composite coating.

[0055] High corrosion resistance: Both the anodic oxidation film and the electrophoretic coating have good anti-corrosion performance, which can effectively prevent the substrate from being corroded.

[0056] Excellent anti-aging performance: The composite coating treated by curing has good weather resistance and anti-aging performance, and can maintain the performance stability of the coating for a long time.

[0057] Optimization steps: Through the basic high temperature of plasma spraying, while realizing the curing of the paint film of electrophoretic coating, the spraying of nano-ceramic powder can be completed, and the bonding force between the two is also higher, reducing the separate curing step of the paint film of electrophoretic coating, and at the same time reducing the step that the nano-ceramic powder needs an intermediate bonding layer.

[0058] The plasma-sprayed nano-ceramic powder has a higher bonding strength, and the nano-structure can achieve good toughening effect and wear resistance.

[0059] The above are only the preferred embodiments of the present invention, and are not used to limit the present invention. Those skilled in the art can make various modifications or equivalent replacements to the present invention within the essence and protection scope of the present invention. Such modifications or equivalent replacements should also be regarded as falling within the protection scope of the technical solution of the present invention.

Claims

1. A high-performance composite coating preparation process by oxidation electrophoresis plasma spraying, characterized in that: The steps include: Pretreatment: Soak the aluminum alloy window frame in alkaline degreasing solution, then clean it with deionized water, then soak it in mixed acid solution, rinse it with deionized water and blow it dry; Anodic oxidation: The pretreated aluminum alloy window frame is placed in an electrolytic cell as the anode, and the tantalum-niobium alloy plate is used as the cathode. The two are placed in a composite electrolyte, and the electrolytic cell is powered to form an oxide film on the surface of the aluminum alloy window frame; Cleaning: After anodizing, the aluminum alloy window frame is placed in deionized water for multiple ultrasonic cleanings; Electrophoretic coating: immerse the aluminum alloy window frame in the electrophoretic paint liquid with charge, ensure the tank liquid circulation, and make the electrophoretic paint liquid evenly adhere to the aluminum alloy window frame; Plasma nano-spraying: Heat up the aluminum alloy window frame after electrophoretic coating, select nano-ceramic powder coating, and use plasma spraying equipment to deposit the nano-ceramic coating on the surface of the aluminum alloy window frame, thereby realizing the preparation of the composite coating.

2. The high-performance composite coating preparation process of oxidation electrophoresis plasma spraying according to claim 1 is characterized in that: The concentrations of the components in the alkaline degreasing liquid are: 10-15 g / L sodium hydroxide, 5-8 g / L sodium carbonate and 3-5 g / L surfactant sodium dodecylbenzene sulfonate. The soaking temperature of the alkaline degreasing liquid is 50-60° C. and the soaking time is 10-15 min.

3. The process for preparing a high-performance composite coating by oxidation electrophoresis plasma spraying according to claim 1, characterized in that: The mixed acid solution includes: 8-12% by mass sulfuric acid, 2-4% by mass nitric acid and the balance of deionized water. The immersion time of the mixed acid solution is 3-5 minutes.

4. The process for preparing a high-performance composite coating by oxidation electrophoresis plasma spraying according to claim 1, characterized in that: The compound electrolyte is a sulfuric acid solution with a compound additive added, the concentration of the sulfuric acid solution is 60-180 g / L, the amount of the compound additive added is 0.5-1%, and the compound additive includes 40-60% by weight of citric acid and the balance of nickel sulfate.

5. The process for preparing a high-performance composite coating by oxidation electrophoresis plasma spraying according to claim 1, characterized in that: The electrolysis time of the anodizing is 15-25 minutes, the temperature is 23-27° C., and the current intensity is 1.5-2.5 A / dm².

6. The process for preparing a high-performance composite coating by oxidation electrophoresis plasma spraying according to claim 1, characterized in that: The ultrasonic cleaning time is 5-8 minutes, and the ultrasonic frequency is 30-40 kHz.

7. The process for preparing a high-performance composite coating by oxidation electrophoresis plasma spraying according to claim 1, characterized in that: The electrophoretic paint liquid has an epoxy resin content of 30-35%, a curing agent toluene diisocyanate content of 14-16%, a pigment content of 8-12%, a nano titanium dioxide particle content of 2-5%, and the balance of deionized water. The electrophoresis time is set to 8-12 minutes, the first stage voltage is set to 150V, the second stage voltage is set to 260V, and the electrophoresis temperature is 28-32°C.

8. The process for preparing a high-performance composite coating by oxidation electrophoresis plasma spraying according to claim 1, characterized in that: The nano ceramic powder coating is Al2O3-13%TiO2 with a particle size of 200-300 meshes. The aluminum alloy window frame is heated to 150°C for plasma spraying. The specific parameters of plasma spraying are: arc voltage 70-80V, arc current 500A, spraying power 35-40kW, powder feeding gas flow 3-6L / min, spraying distance 80-150mm, spray gun moving speed 6-8m / min, Ar ion gas flow 70-80L / min, and H2 ion gas flow 100-150L / min.

9. The process for preparing a high-performance composite coating by oxidation electrophoresis plasma spraying according to claim 1, characterized in that: The thickness of the oxide film generated by the anodic oxidation is 10-15 μm, the thickness of the paint film generated by the electrophoretic coating is 22-25 μm, and the thickness of the coating generated by the plasma spraying is 80-100 μm.