Corrosion-resistant self-cleaning light reflection ceramic coating and preparation method thereof

Abstract

The invention discloses a corrosion-resistant self-cleaning light reflection ceramic coating and a preparation method thereof, and belongs to the technical field of surface treatment.The corrosion-resistant self-cleaning light reflection ceramic coating is formed by attaching a coating solution to a substrate material through a blade coating method; the coating solution comprises silica sol, a silane coupling agent, a wetting agent, tetrafluoroethylene particles, formic acid and titanium dioxide nanoparticles, and the content of the titanium dioxide nanoparticles is 12 wt.%-30 wt.%. The light reflection ceramic coating provided by the invention is a high-performance light reflection ceramic coating, can be used as a cooling coating of a building, can effectively improve the light reflection capability of a base material, so that the surface temperature is remarkably reduced, the heat radiation absorption is reduced, and the light reflection ceramic coating is particularly suitable for heat management of an outer wall and a window of the building and achieves a good energy-saving and cooling effect.

Description

Technical Field

[0001] The invention belongs to the technical field of surface treatment, and in particular is a corrosion-resistant self-cleaning light-reflecting ceramic coating and a preparation method thereof. Background Art

[0002] As global climate change and energy shortage become increasingly serious, building energy conservation has become a focus of social attention. Traditional building cooling methods mainly rely on mechanical equipment such as air conditioners, which not only consume a lot of energy, but also emit a lot of greenhouse gases, further exacerbating climate change. Therefore, it is particularly important to develop new energy-saving materials to reduce the energy consumption of buildings.

[0003] Light reflection cooling technology is a green solution for passive cooling. It reduces heat accumulation and lowers indoor temperature by efficiently reflecting solar radiation on the coating surface. Most existing reflective coatings are made of polymer materials, but these materials are easily degraded by ultraviolet radiation, resulting in reduced reflective performance and durability, making it difficult to meet the needs of long-term use. In contrast, ceramic-based coatings have attracted widespread attention for their excellent weather resistance and chemical stability. Among them, titanium dioxide (TiO2), as a highly efficient light reflective material, not only has excellent reflective properties, but also can withstand high temperatures and ultraviolet radiation, showing great potential in the field of building energy conservation. However, the existing TiO2 coatings still have problems in practical applications, such as insufficient adhesion, easy shedding, and limited corrosion resistance, which restricts their promotion and application. Summary of the invention

[0004] In order to solve the problems of TiO2 coating in the prior art, the present invention provides a corrosion-resistant self-cleaning light-reflecting ceramic coating and a preparation method thereof.

[0005] Technical solution: A method for preparing a corrosion-resistant self-cleaning light-reflecting ceramic coating, wherein a coating solution is attached to a base material by a scraping method to form a corrosion-resistant self-cleaning light-reflecting ceramic coating; the coating solution includes silica sol, a silane coupling agent, a wetting agent, tetrafluoroethylene particles, formic acid and titanium dioxide nanoparticles.

[0006] Preferably, in the coating solution, the content of titanium dioxide nanoparticles is 12wt.%-30wt.%.

[0007] Preferably, in the coating solution, the content of each component is as follows:

[0008] Silane coupling agent, 24.5wt.% to 42.5wt.%;

[0009] Silica sol, 40wt.%;

[0010] Wetting agent, 0.1-0.3%;

[0011] Polytetrafluoroethylene particles, 5wt.%;

[0012] Formic acid, 0.3wt.%;

[0013] Titanium dioxide nanoparticles, 12wt.%-30wt.%.

[0014] Preferably, the silane coupling agent is methyltrimethoxysilane; the wetting agent is BYK-310; and the titanium dioxide nanoparticles are rutile titanium dioxide, a nanomaterial with a particle size of about 250 nm.

[0015] Preferably, the method for preparing the corrosion-resistant self-cleaning light-reflecting ceramic coating comprises the following steps:

[0016] Step 1: Add silane coupling agent, silica sol, wetting agent, polytetrafluoroethylene particles and formic acid into a reagent bottle, and mix them evenly on an oscillator at a speed of 3000 rpm to obtain a basic solution;

[0017] Step 2: adding titanium dioxide nanoparticles of different concentrations to the base solution, stirring at room temperature for 1 hour to ensure that the nanoparticles are evenly dispersed to obtain a coating solution;

[0018] Step 3: evenly apply the coating solution to the surface of the base material, and adjust the coating thickness by using a scraping technique;

[0019] Step 4: Bake the coated substrate at 120° C. for 30 minutes to complete the coating curing and form a light-reflective ceramic coating.

[0020] Preferably, in step three, the coating thickness is 74 μm, and the coating thickness is achieved by adjusting the gap of the scraper.

[0021] Preferably, the substrate material is any one of glass, wood and steel.

[0022] In the present invention, methyltrimethoxysilane is used to enhance the adhesion between the coating and the substrate, silica sol is used to improve the hardness and corrosion resistance of the coating, PTFE particles help to form a hydrophobic surface and improve the self-cleaning property of the coating; and the wetting agent BYK-310 is used to improve the dispersibility of the coating. The addition of titanium dioxide nanoparticles effectively improves the light reflection performance of the coating. Titanium dioxide itself has good ultraviolet absorption capacity and self-cleaning properties, which can enhance the pollution resistance of the coating. The use of scraping technology can ensure uniform coating thickness, thereby ensuring the uniformity and functionality of the coating; baking helps to further improve the stability and corrosion resistance of the coating, so that the coating can maintain its function for a long time under high temperature and harsh environmental conditions. The ratio of methyltrimethoxysilane to silica sol is adjusted to enhance the adhesion and weather resistance of the coating, and the performance of the light-reflecting ceramic coating is changed by adjusting the ratio of titanium dioxide to silica sol. The solar reflectivity of the coating surface prepared by the present invention is not less than 80%, and the substrate temperature can be reduced by up to 13°C.

[0023] Beneficial effects:

[0024] 1) The light-reflective ceramic coating of the present invention is a high-performance light-reflective ceramic coating, which can be used as a cooling coating for buildings. It has excellent solar reflectivity, strong adhesion and durability, and can effectively improve the light-reflecting ability of the substrate, thereby significantly reducing the surface temperature and reducing the absorption of thermal radiation. It is particularly suitable for thermal management of building exterior walls and windows, achieving good energy-saving and cooling effects.

[0025] Compared with traditional polymer-based coatings, the ceramic coating of the present invention has stronger UV stability, corrosion resistance and mechanical properties, can effectively reduce indoor temperature, reduce the burden of air conditioning, and improve the energy efficiency of buildings.

[0026] 2) The ceramic coating prepared by the present invention adopts ceramic materials, which are made of titanium dioxide (TiO2) nanoparticles, silane coupling agent and silica sol, and attached to a glass substrate. The coating is prepared by an improved low-temperature curing process (120°C), which ensures high adhesion, high reflectivity and excellent weather resistance. The preparation process is simple, low-cost, can be prepared at low temperatures, has a wide range of application prospects, and is particularly suitable for areas with high solar radiation.

[0027] 3) The titanium dioxide nanoparticles in the light-reflective ceramic coating of the present invention not only improve the light-reflective performance, but also have excellent corrosion resistance, which can effectively extend the service life of the coating.

[0028] 4) The ceramic coating prepared by the present invention not only has high light reflection and excellent corrosion resistance, but also has good self-cleaning effect, and is suitable for various surfaces that require durable protection, especially in the fields of construction, automobiles, electronic equipment, etc. The PTFE particles added to the light-reflective ceramic coating of the present invention give the coating excellent self-cleaning properties, which can effectively avoid the adhesion of pollutants, maintain the long-term stability of the coating, and reduce maintenance costs; the coating can maintain its efficient reflection and self-cleaning functions even in a humid or dusty environment, thereby improving the use value of the building material. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 1 and 2. Fourier transform infrared spectra of the light reflective ceramic coating (0% TiO2) and the light reflective ceramic coating (24% TiO2) in Examples 1 and 4, as well as pure TiO2 powder.

[0030] Figure 2 This is a scanning electron microscope image of the light-reflective ceramic coating (24% TiO2) in Example 4.

[0031] Figure 3 The scanning electron microscope (SEM) image, coating cross-section image and energy dispersive spectrum analysis (EDS) image of the light reflective ceramic coating (24% TiO2) glass in Example 4 are shown.

[0032] Figure 4 This is a macroscopic comparison of light-reflective ceramic coatings (24% TiO2) under different test conditions.

[0033] Figure 5 Schematic diagram of the indoor simulated house cooling experiment results.

[0034] Figure 6 Temperature curves of glass and glass with light-reflective ceramic coating (24% TiO2) for 6 hours under the same ambient lighting conditions to simulate a house cooling experiment.

[0035] Figure 7 The middle graph shows the test results of three days of outdoor cooling experiments.

[0036] Figure 8 Diagram of the cooling power device for light-reflecting ceramic-coated (24% TiO2) glass.

[0037] Fig. 9 This is the electrochemical corrosion test result diagram.

[0038] Fig.10 Schematic diagram of the contact angle of the light-reflective ceramic coating (24% TiO2).

[0039] Fig.11This is a before and after comparison of the self-cleaning effect of the light-reflecting ceramic coating (24% TiO2). DETAILED DESCRIPTION

[0040] The technical solution of the present invention is described in detail below through embodiments, but the protection scope of the present invention is not limited to the embodiments.

[0041] In the following examples, for substances with uncertain fixed structures or fixed component parameters, such as silica sol, wetting agent BYK-310, titanium dioxide nanoparticles (R902), and polytetrafluoroethylene (PTFE) particles, please provide the name of the manufacturer or purchaser. Methyltrimethoxysilane (MTMS, 98%), silica sol (alkaline, 30%), and formic acid (98%) were all from Alibaba. Titanium dioxide nanoparticles (R902) were obtained from Chemours, USA. Polytetrafluoroethylene (PTFE) powder was purchased from Nanjing Tianshi New Material Technology Co., Ltd. The silicon-based surface additive (BYK-310) was provided by BYK (Wesel, Germany).

[0042] Example 1: Preparation of light-reflective ceramic coating (0% TiO2)

[0043] The preparation method of the light reflective ceramic coating (0% TiO2) comprises the following steps:

[0044] (1) 54.5 wt.% of methyltrimethoxysilane, 40 wt.% of silica sol, 0.2 wt.% of wetting agent BYK-310, 5 wt.% of polytetrafluoroethylene (PTFE) particles and 0.3 wt.% of formic acid were added to a 15 mL reagent bottle and mixed evenly on an oscillator at a speed of 3000 rpm to obtain a base solution.

[0045] (2) uniformly coating the base solution on the surface of the glass substrate, and adjusting the coating thickness by using a doctor blade coating technique;

[0046] (3) The coated substrate was baked at 120° C. for 30 minutes to complete the coating curing and form a ceramic coating (0% TiO2).

[0047] Example 2: Preparation of light-reflective ceramic coating (12% TiO2)

[0048] The preparation method of the light reflective ceramic coating (12% TiO2) comprises the following steps:

[0049] (1) 42.5 wt.% of methyltrimethoxysilane, 40 wt.% of silica sol, 0.2 wt.% of wetting agent BYK-310, 5 wt.% of polytetrafluoroethylene (PTFE) particles and 0.3 wt.% of formic acid were added to a 15 mL reagent bottle and mixed evenly on an oscillator at a speed of 3000 rpm to obtain a base solution.

[0050] (2) adding 12 wt.% of titanium dioxide nanoparticles (R902) to the base solution and stirring at room temperature for 1 hour to ensure that the nanoparticles are evenly dispersed to obtain a coating solution;

[0051] (3) uniformly coating the coating solution on the surface of the glass substrate, and adjusting the coating thickness by using a doctor blade coating technique;

[0052] (4) The coated substrate was baked at 120° C. for 30 minutes to complete the curing of the coating and form a ceramic coating (12% TiO2).

[0053] Example 3: Preparation of light-reflective ceramic coating (18% TiO2)

[0054] The preparation method of the light reflective ceramic coating (18% TiO2) comprises the following steps:

[0055] (1) 36.5 wt.% of methyltrimethoxysilane, 40 wt.% of silica sol, 0.2 wt.% of wetting agent BYK-310, 5 wt.% of polytetrafluoroethylene (PTFE) particles and 0.3 wt.% of formic acid were added to a 15 mL reagent bottle and mixed evenly on an oscillator at a speed of 3000 rpm to obtain a base solution.

[0056] (2) adding 18 wt.% of titanium dioxide nanoparticles (R902) to the base solution and stirring at room temperature for 1 hour to ensure that the nanoparticles are evenly dispersed to obtain a coating solution;

[0057] (3) applying the coating solution evenly to the surface of the substrate and adjusting the coating thickness by using a scraping technique;

[0058] (4) The coated substrate was baked at 120° C. for 30 minutes to complete the curing of the coating and form a ceramic coating (18% TiO2).

[0059] Example 4: Preparation of light-reflecting ceramic coating (24% TiO2)

[0060] The preparation method of the light reflective ceramic coating (24% TiO2) comprises the following steps:

[0061] (1) 30.5 wt.% of methyltrimethoxysilane, 40 wt.% of silica sol, 0.2 wt.% of wetting agent BYK-310, 5 wt.% of polytetrafluoroethylene (PTFE) particles and 0.3 wt.% of formic acid were added to a 15 mL reagent bottle and mixed evenly on an oscillator at a speed of 3000 rpm to obtain a base solution.

[0062] (2) adding 24 wt.% of titanium dioxide nanoparticles (R902) to the base solution and stirring at room temperature for 1 hour to ensure that the nanoparticles are evenly dispersed to obtain a coating solution;

[0063] (3) uniformly coating the coating solution on the surface of the glass substrate, and adjusting the coating thickness by using a doctor blade coating technique;

[0064] (4) The coated substrate was baked at 120° C. for 30 minutes to complete the curing of the coating and form a ceramic coating (24% TiO2).

[0065] Example 5: Preparation of light-reflective ceramic coating (30% TiO2)

[0066] The preparation method of the light reflective ceramic coating (30% TiO2) comprises the following steps:

[0067] (1) 24.5 wt.% of methyltrimethoxysilane, 40 wt.% of silica sol, 0.2 wt.% of wetting agent BYK-310, 5 wt.% of polytetrafluoroethylene (PTFE) particles and 0.3 wt.% of formic acid were added to a 15 mL reagent bottle and mixed evenly on an oscillator at a speed of 3000 rpm to obtain a base solution.

[0068] (2) adding 30 wt.% of titanium dioxide nanoparticles (R902) to the base solution and stirring at room temperature for 1 hour to ensure that the nanoparticles are evenly dispersed to obtain a coating solution;

[0069] (3) uniformly coating the coating solution on the surface of the glass substrate, and adjusting the coating thickness by using a doctor blade coating technique;

[0070] (4) The coated substrate was baked at 120° C. for 30 minutes to complete the curing of the coating and form a ceramic coating (30% TiO2).

[0071] The ceramic coatings prepared in Examples 1-5 were characterized and tested, and the results are as follows:

[0072] 1) Figure 1 The Fourier transform infrared (FTIR) spectra of the ceramic coating (24% TiO2) are shown, including the ceramic coating (24% TiO2) glass of Example 4, the ceramic coating (0% TiO2) glass of Example 1, and pure TiO2. The FTIR spectrum is at 1090 cm -1 and 1000cm -1Characteristic absorption peaks appear at , corresponding to the stretching vibrations of Si-O-Si and Si-OH, which indicate the presence of silicon in the composite material and the formation of Si-O-Si bonds on the glass surface. These results verify that the introduction of methyltrimethoxysilane, a known silane coupling agent, can enhance the interfacial adhesion between the coating and the substrate.

[0073] 2) Figure 2 This is a scanning electron microscope image of the ceramic coating (24% TiO2) glass in Example 4. Figure 2 Figure a shows that the size distribution of TiO2 nanoparticles is uniform. Figure 2 As shown in Figure b, the average diameter of TiO2 nanoparticles is about 250±52nm. To verify the uniform distribution of TiO2 nanoparticles in the ceramic coating, the microstructure of the light-reflecting ceramic coating was further analyzed by scanning electron microscopy. Figure 2 As shown in Figure c, TiO2 nanoparticles are evenly distributed in the coating, verifying their good incorporation effect.

[0074] 3) Figure 3 The scanning electron microscope (SEM) images of the ceramic coating (24% TiO2) glass in Example 4 are shown, wherein a is a magnified electron microscope scanning image of the coating surface, b is a cross-sectional image of the coating, and cf is an energy dispersive spectrum analysis (EDS) image of a. Figure 3 As can be seen in the figure, the thickness of the light-reflective ceramic coating is about 74 μm. The magnified SEM image shows that the layers of the coating have a close connection interface, verifying the compactness of the coating. cf further shows that the uniform distribution of Ti, Si, O, and C in the coating confirms the successful combination of TiO2 nanoparticles in the ceramic matrix, forming a uniform morphology and element distribution. In addition, the SEM image also shows that the reflective coating is firmly attached to the glass substrate, verifying the adhesion and stability of the coating.

[0075] 4) Figure 4 Shows macroscopic comparison of light-reflective ceramic coating (24% TiO2) under different test conditions. Figure 4 Figures ab are macroscopic images of the coating before and after boiling in 100°C water for 10 hours. Figure 4 cd are macro images of the cross-section and peeling test of the boiled coating using 3M 600 tape, c is a macro image of the ceramic coating after 100 times of tape peeling; d is a macro image of the ceramic coating after the scratch test after 100 times of tape peeling; Figure 4 As can be seen from Figures ad, the light-reflecting ceramic coating (24% TiO2) coated on the glass remains intact without obvious damage after being boiled in 100°C water for 10 hours and subjected to 100 tape peeling tests. Figure 4Figure e is a macroscopic image of the pull-out force test of the ceramic coating. Figure e further shows that the light-reflective ceramic coating (24% TiO2) can withstand a tensile force of 5 MPa, demonstrating its good durability and adhesion.

[0076] 5) Indoor simulated house cooling experiment

[0077] Test method: In order to demonstrate the effect of ceramic coating (24% TiO2) in mitigating the greenhouse effect, glass and ceramic coated glass with different TiO2 concentrations were installed on the same expanded polystyrene (EPS) box as light irradiation windows. In order to simulate actual applications, the light intensity was fixed at 1 sun, and a thermocouple was inserted in the middle of each house to measure the temperature in the box. A transparent nail-free adhesive was used to ensure good thermal contact between the glass layer and the roof. The ambient temperature was controlled at 25°C, and the solar simulator was vertically injected into the house and the temperature in the two boxes was monitored in real time. The device is shown in the figure below. Figure 5 As shown in c.

[0078] Test results and conclusions: The results are as follows Figure 5 As shown, Figure 5 Herein, ab are transmission and absorption diagrams of glass, pure TiO2, and the light-reflecting ceramic coating (24% TiO2) glass in Example 4 in the ultraviolet-visible-near infrared region of 200-2500nm; c is a diagram of an indoor simulated house cooling device; d is a temperature rise curve of a glass box and a glass box with a ceramic coating (24% TiO2) in Example 4 over time at 25°C under one sun.

[0079] from Figure 5 In figure d, we can see that the average temperature difference of the box at the beginning and 1 hour is about 13℃, which confirms the cooling effect of the ceramic coating (24% TiO2). Figure 6 As shown, it was found that the temperature difference between the box containing ceramic coating (24% TiO2) glass and the box containing ordinary glass was also about 13°C, verifying that the ceramic coating (24% TiO2) glass was the best sample.

[0080] 6) Outdoor cooling experiment

[0081] Test method: In order to verify the actual effectiveness of ceramic coated glass in cooling applications, an outdoor cooling experiment was conducted. Two model houses were used, each of which used polystyrene foam as the surrounding environment and foundation, with a thickness of 2cm to reduce heat conduction. The slopes of the model houses were covered with glass and ceramic coatings respectively. These model houses were placed on a one-meter-high table to reduce the impact of ground radiation, and the solar irradiance was quantified using an optical power meter. K-type thermocouples were used to measure the temperature inside and around the model house, and an anemometer with a hygrometer was used to monitor the outdoor wind speed and ambient humidity. During the entire experiment, the solar irradiance in the model house, the wind speed, humidity, temperature of the ceramic coated (24% TiO2) glass model house, and the temperature and ambient temperature of the glass model house were monitored in real time.

[0082] Test results and conclusions: Figure 7 The figure below shows the test results of the three-day outdoor cooling experiment, where a is the outdoor light intensity change diagram for three days, b is the humidity change diagram, c is the wind speed change diagram, and d is the outdoor temperature (corresponding to the environment in the figure), the temperature of the small house with glass (corresponding to the glass in the figure), and the temperature of the small house with glass containing light-reflecting ceramic coating (24% TiO2). Figure 7 It can be seen that due to its excellent thermal insulation performance, the temperature inside the glass box is significantly higher than the ambient temperature, especially under strong light, and due to the greenhouse effect, it rises by an average of about 17°C in three days. In contrast, the average temperature inside the glass box with ceramic coating (24% TiO2) is 17°C lower than the average temperature inside the glass box, which has a significant cooling effect.

[0083] 7) Cooling power test of ceramic coated (24% TiO2) glass

[0084] Test method: Heating efficiency (η) of a ceramic rod (power 5W): The efficiency of the heating rod is calculated by heating water using the heating rod. Water (80g) is placed in a glass bottle wrapped with insulating foam to prevent heat dissipation. The temperature of the water rises from 19°C to 100°C in 30 minutes. The power supply voltage is recorded as 7.5V and the current is 2.15A. Therefore, the thermal efficiency (η) of the ceramic rod can be calculated using the following formula:

[0085]

[0086] In the formula, C p is the specific heat of water (4.18 J g -1 K -1 ), m is the mass of water (80g), ΔT is the temperature difference before and after heating (81), A and I are the power supply voltage (7.5V) and current (2.15A), and t is the heating time (30min). The heating efficiency η of the ceramic rod is calculated to be 93.3%.

[0087] like Figure 8Installation diagram, temperature controlled at 25°C, glass and ceramic coated (24% TiO2) glass are installed on two identical expanded polystyrene (EPS) boxes as light irradiation windows. Use transparent nail-free adhesive to ensure good thermal contact between the glass layer and the roof. The light intensity is fixed at 1 sun, and a thermocouple is inserted in the middle of each house to measure the temperature in the box. In addition, a ceramic heating rod is inserted into the box containing ceramic coating (24% TiO2). The current and voltage of the mobile power supply are adjusted to make the temperature in the two polystyrene foam boxes consistent. Therefore, the calculation formula of the cooling power P is:

[0088]

[0089] Where A and I are the power supply voltage and current, and S is the surface area of ​​the ceramic-coated glass.

[0090] Test results and conclusions: Through calculation, the passive cooling power of the room with ceramic coated glass was determined to be 182Wm -2 After taking into account the efficiency of the heating rods, the effective cooling power of the house with coated glass is about 169.8W m -2 .

[0091] 8) Electrochemical corrosion test

[0092] The ceramic coating was immersed in 3.5wt% NaCl solution, and the corrosion resistance of the ceramic coating was evaluated using an electrochemical workstation (Gamry Reference3000). The corrosive medium was 3.5wt% NaCl solution, and the working electrode was exposed to an area of ​​1cm 2 The platinum sheet was used as the counter electrode and the Ag / AgCl electrode was used as the reference electrode. -2 EIS was measured in the frequency range of 10 Hz, and polarization curves were obtained in the range of -0.25-0.25 V relative to the open circuit potential at a scan rate of 1 mV / s. The open circuit potential was measured 30 minutes before the test to ensure that the system was stable.

[0093] The test results are as follows Fig. 9 As shown, a is the Tafel curve of ordinary iron sheet and iron sheet with ceramic coating (24% TiO2), b is the Nyquist diagram of ordinary iron sheet, c is the Nyquist diagram of iron sheet coated with reflective ceramic coating (24% TiO2), d is the Bode diagram of ordinary iron sheet and iron sheet with light reflective ceramic coating (24% TiO2);

[0094] Fig. 9As shown in a, the anode slope of the ceramic coating is large and the cathode slope is small, indicating that the circuit density changes slowly with the increase of the cathode branch potential. Table 1 shows the Tafel data parameters of the ceramic coating (24% TiO2), as follows:

[0095] Table 1: Tafel data parameters of ordinary iron sheets and coated iron sheets

[0096]

[0097] From the data in Table 1, we can see that the i of the coated iron sheet corr 4.890×10 -8 A cm -2 , much lower than that of ordinary iron sheets corr , indicating that the coating can effectively reduce the probability of corrosion and corrosion. For ordinary iron sheets, its EIS spectrum shows a concave semicircle at high frequencies, which represents the charge transfer resistance at the electrode / electrolyte interface. Therefore, the equivalent circuit model shown is used for fitting, which consists of a modified Randles circuit. Among them, Rs represents the solution resistance, Rct represents the charge transfer resistance at the electrode / electrolyte interface, and CPE (constant phase element) is used to simulate the behavior of non-ideal capacitors, such as Fig. 9 As shown in Figs. b, c, they are schematic diagrams of equivalent circuit models for fitting the impedance data of ordinary iron sheets and iron sheets coated with ceramic coatings, respectively. The fitting results are shown in Table 2.

[0098] Table 2: EIS data fitting results of ordinary iron sheet and coated iron sheet

[0099]

[0100] From the data in Table 2, we can see that the capacitance loop diameter of the ceramic coated iron sheet is larger than that of the iron sheet, which indicates that the charge transfer resistance has increased due to the presence of a protective layer at the metal-solution interface. The Rf and Rct of the coated iron sheet are higher than those of the ordinary iron sheet, and the CPEdl of the coated iron sheet is 5 orders of magnitude lower than that of the ordinary iron sheet. The higher Rct and lower CPEdl indicate that the ceramic coating has better anti-corrosion performance. Fig. 9 (d) is the Bode diagram of ordinary iron sheet and coated iron sheet. Compared with ordinary iron sheet, coated iron sheet shows higher impedance at all frequencies. The impedance modulus |Z| of the coated sample reaches 2.023×10 6 Ωcm 2 , significantly higher than that of ordinary iron sheets, further indicating that its corrosion resistance is enhanced. EIS analysis shows that compared with ordinary iron sheets (CPEdl = 1.670 × 10 -3 F s(1-a)cm -2 ) compared to the double layer capacitance of the coating sample (CPEdl = 1.793 × 10 -9F s(1-a)cm -2 ) is significantly reduced, reflecting the development of a compact and strong protective barrier. This dense layer reduces the active sites for corrosion reactions and increases the stability of the coating in a corrosive environment. The contact angle of the coating of the present invention is greater than 90° ( Fig.10 ), has good hydrophobic properties. Fig.11 As shown in ab, ab is a before and after comparison of the self-cleaning effect of the light-reflecting ceramic coating (24% TiO2). When river bottom silt is used on the surface of the ceramic coating, the coating surface can self-clean.

[0101] In summary, the light-reflecting ceramic coating prepared by the present invention is a titanium dioxide-enhanced ceramic coating with excellent light-reflecting performance, which can effectively improve the passive cooling effect of buildings and significantly reduce energy consumption. The coating not only has excellent solar reflectivity, UV stability and corrosion resistance, but also has high-strength adhesion, excellent wear resistance and self-cleaning function, and can maintain excellent performance under long-term ultraviolet irradiation and harsh outdoor environments. By optimizing the concentration of titanium dioxide, the present invention can maintain good adhesion and durability on a variety of substrates such as metal, wood and glass, and has significant anti-yellowing properties, and can still maintain its aesthetics after long-term use. Therefore, the ceramic coating of the present invention is not only suitable for various types of building materials, but also has broad application prospects in improving the energy efficiency of buildings and reducing energy consumption. The present invention has strong market application potential and can provide a sustainable, environmentally friendly and efficient passive cooling solution for the construction field.

[0102] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to the form and details without departing from the spirit and scope of the present invention.

Claims

1. A method for preparing a corrosion-resistant self-cleaning light-reflecting ceramic coating, characterized in that: The coating solution is attached to the base material by a doctor blade coating method to form a corrosion-resistant, self-cleaning, light-reflective ceramic coating; The coating solution comprises silica sol, silane coupling agent, wetting agent, tetrafluoroethylene particles, formic acid and titanium dioxide nanoparticles.

2. The preparation method according to claim 1, characterized in that: In the coating solution, the content of titanium dioxide nanoparticles is 12wt.%-30wt.%.

3. The preparation method according to claim 1, characterized in that: In the coating solution, the content of each component is as follows: Silane coupling agent, 24.5wt.% to 42.5wt.%; Silica sol, 40wt.%; Wetting agent, 0.1-0.3%; Polytetrafluoroethylene particles, 5wt.%; Formic acid, 0.3wt.%; Titanium dioxide nanoparticles, 12wt.%-30wt.%.

4. The preparation method according to claim 1, characterized in that: The silane coupling agent is methyltrimethoxysilane; the wetting agent is BYK-310; the titanium dioxide nanoparticles are rutile titanium dioxide with a particle size of 250nm.

5. The preparation method according to claim 1, characterized in that: The preparation method comprises the following steps: Step 1: Add silane coupling agent, silica sol, wetting agent, polytetrafluoroethylene particles and formic acid into a reagent bottle, and mix them evenly on an oscillator at a speed of 3000 rpm to obtain a basic solution; Step 2: adding titanium dioxide nanoparticles of different concentrations to the base solution, stirring at room temperature for 1 hour to ensure that the nanoparticles are evenly dispersed to obtain a coating solution; Step 3: evenly apply the coating solution to the surface of the base material, and adjust the coating thickness by using a scraping technique; Step 4: Bake the coated substrate at 120° C. for 30 minutes to complete the coating curing and form a light-reflective ceramic coating.

6. The preparation method according to claim 5, characterized in that: In step three, the coating thickness is 74 μm, and the coating thickness is achieved by adjusting the gap of the scraper.

7. The preparation method according to claim 5, characterized in that: The base material is any one of glass, wood and steel.

8. A corrosion-resistant, self-cleaning, light-reflecting ceramic coating obtained according to any one of the preparation methods described in claims 1-7.

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