A ZnO / CuO porous coating, its preparation method and application

Abstract

This invention discloses a ZnO / CuO porous coating, its preparation method, and its application, belonging to the field of semiconductor material preparation technology. The ZnO / CuO porous coating is prepared according to the following steps: using zinc powder as raw material, copper is electrolessly plated onto the surface of the zinc powder to obtain Zn@Cu core-shell powder; using an atmospheric plasma spraying system with argon and hydrogen as driving gases, the Zn@Cu core-shell powder is fed into the plasma jet as the spraying material to prepare the ZnO / CuO porous coating. This invention utilizes high-melting-point Cu to encapsulate Zn powder, employs atmospheric plasma spraying to evaporate Zn, and then vapor-deposits ZnO, thereby efficiently preparing a nanoporous ZnO / CuO coating.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material preparation technology, and more specifically to a ZnO / CuO porous coating, its preparation method, and its application. Background Technology

[0002] ZnO has three main crystal structures: hexagonal wurtzite, cubic zincblende, and tetragonal rock salt. Under natural conditions, ZnO typically exhibits the hexagonal wurtzite structure. ZnO is a common amphoteric oxide, soluble in both acids and alkalis. It is usually a white powder, non-toxic, odorless, and environmentally friendly. ZnO is an excellent semiconductor material with applications in catalysis, antibacterial applications, and sensors. As a functional material, its specific surface area is often a crucial factor affecting its performance. Nano-sized porous ZnO coatings have a large specific surface area and exhibit superior performance compared to ordinary ZnO coatings.

[0003] Traditional porous nano-ZnO coatings are mainly produced using liquid-phase methods such as solution precipitation and hydrothermal synthesis, and vapor-phase deposition methods such as thermal evaporation deposition and PVD. Currently, liquid-phase deposition methods generally suffer from wastewater pollution. Traditional vapor-phase deposition methods, on the other hand, are characterized by low preparation efficiency, high cost, and limitations on workpiece size.

[0004] Plasma spraying is a thermal spraying technology that often uses Ar-H2 plasma jets as a heat source. It can be used to effectively prepare various metal and ceramic coatings. It involves using a DC-driven plasma arc as a heat source to heat ceramics, alloys, metals, etc., to a molten or semi-molten state, and then spraying it at high speed onto the pre-treated workpiece surface to form a firmly adhered surface layer. However, because ZnO's boiling point is lower than its melting point, ZnO sublimates upon heating, making it difficult to obtain a ZnO coating normally using plasma spraying of ZnO powder.

[0005] The applicant's preliminary research indicated that using atmospheric plasma jets as a heat source and Zn powder as a raw material could vaporize Zn and simultaneously react with air to generate nano-ZnO. However, due to the non-uniform temperature distribution of the plasma jet and the instantaneous nature of the heating, Zn could not be completely vaporized and converted into ZnO. Therefore, the deposited coating still consisted mainly of Zn, with ZnO accounting for only a small amount. Summary of the Invention

[0006] To address the above problems, this invention provides a ZnO / CuO porous coating, its preparation method, and its application. The method utilizes high-melting-point Cu to encapsulate Zn powder, employs atmospheric plasma spraying to evaporate Zn, and then vapor-deposits ZnO, thereby efficiently preparing a nanoporous ZnO / CuO coating.

[0007] The first objective of this invention is to provide a method for preparing a ZnO / CuO porous coating, which is prepared according to the following steps:

[0008] Step 1: Using zinc powder as raw material, copper is electrolessly plated onto the surface of the zinc powder to obtain Zn@Cu core-shell powder;

[0009] Step 2: Using an atmospheric plasma spraying system, with argon and hydrogen as driving gases, Zn@Cu core-shell powder is fed into the plasma jet to prepare a ZnO / CuO porous coating.

[0010] Preferably, in step 1, the chemical plating process is as follows: zinc powder is added to the copper plating solution, stirred until the solution becomes colorless, allowed to stand to obtain a precipitate, and then the residual salt solution on the surface of the powder is removed, and then dried, ground and pulverized to obtain Zn@Cu core-shell powder.

[0011] Preferably, the ratio of zinc powder to copper plating solution is 0.3125-10g:100mL.

[0012] Preferably, in step 2, the spraying current is 400-700A and the spraying voltage is 61-66V.

[0013] Preferably, in step 2, the argon flow rate is 2000 L / h and the hydrogen flow rate is 70-130 L / h.

[0014] Preferably, in step 2, the spraying distance is 60-100mm.

[0015] The second objective of this invention is to provide a ZnO / CuO porous coating prepared by the above-described preparation method.

[0016] A third objective of this invention is to provide the application of the aforementioned ZnO / CuO porous coating in the preparation of antibacterial agents.

[0017] A fourth objective of this invention is to provide the application of the above-mentioned ZnO / CuO porous coating in the degradation of organic matter.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention proposes a highly efficient, large-scale, and low-pollution method for preparing nano-ZnO / CuO porous coatings. A spherical shell Zn@Cu powder is prepared by electroless plating of Cu onto the Zn surface. Taking advantage of the higher melting point of Cu compared to the boiling point of Zn, plasma spraying of the Zn@Cu core-shell powder avoids liquid Zn deposition, allowing only chemical (oxidative) vapor deposition of the Zn powder. This results in more Zn being converted into ZnO, thereby preparing ZnO / CuO porous thin film materials.

[0020] This method offers advantages such as high deposition efficiency, low cost, fine ZnO grains, and a large specific surface area due to its porous structure, thus solving the problem of efficient and large-scale preparation of ZnO / CuO porous thin film materials. The prepared ZnO / CuO porous coating exhibits excellent antibacterial and photocatalytic degradation properties. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the principle of plasma spraying-chemical vapor deposition of the present invention;

[0022] Figure 2 Here is a SEM backscattered electron image of the polished cross-section of Zn@Cu powder, where, Figure 2 The 1-6 in the diagram are Zn@Cu powders prepared by adding 0.3125g, 0.625g, 1.25g, 2.5g, 5g, and 10g of zinc powder to 100mL of copper plating solution, respectively.

[0023] Figure 3 The effect of the ratio of zinc powder to copper plating solution on the copper plating thickness of Zn@Cu powder;

[0024] Figure 4 Here is a surface SEM image of Zn@Cu core-shell powder, where... Figure 4 The 1-6 in the diagram are Zn@Cu powders prepared by adding 0.3125g, 0.625g, 1.25g, 2.5g, 5g, and 10g of zinc powder to 100mL of copper plating solution, respectively.

[0025] Figure 5 Here is the EDS energy spectrum of Zn@Cu core-shell powder, where, Figure 5 a is a polished cross-sectional view of the Zn@Cu core-shell powder prepared in Example 2. Figure 5 b、 Figure 5 c and Figure 5 d are the elemental distribution diagrams of O, Zn, and Cu in the Zn@Cu core-shell powder prepared in Example 2; Figure 5 e is a polished cross-sectional view of the Zn@Cu core-shell powder prepared in Example 4. Figure 5 f、 Figure 5 g and Figure 5 h are the elemental distribution diagrams of O, Zn, and Cu in the Zn@Cu core-shell powder prepared in Example 4;

[0026] Figure 6 XRD patterns of coatings prepared from different raw materials. Figure 6 (a) uses pure Zn powder as raw material. Figure 6 (b) uses Zn@Cu core-shell powder as raw material;

[0027] Figure 7 SEM surface morphology of the nano-ZnO / CuO porous coating;

[0028] Figure 8 A trend diagram showing the relationship between spraying power and grain size of nano-ZnO / CuO porous coating;

[0029] Figure 9 The nano-ZnO-CuO porous coating forms an inhibition zone against Staphylococcus aureus;

[0030] Figure 10 The degradation of methyl orange solution by nano-ZnO / CuO porous coatings at different degradation times under ultraviolet light is shown. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This invention first employs a chemical plating method to plate copper onto the surface of zinc powder, forming a shell-like structure: copper encapsulating zinc, i.e., Zn@Cu core-shell powder as the spraying raw material. Then, using an atmospheric plasma spraying system with Ar-H2 as the driving gas, the prepared Zn@Cu core-shell powder is poured into a powder feeder and fed into the plasma jet as the spraying raw material. This yields a porous nano-ZnO / CuO coating.

[0033] The specific schematic diagram is as follows: Figure 1 As shown. Zinc has a boiling point of 907℃, while copper has a melting point of 1083.4℃, which is higher than zinc's boiling point. During the spraying process, as the powder enters the plasma jet, its temperature is gradually heated by the jet over time. When the powder reaches zinc's boiling point, the nucleus-zinc at the center of the powder boils first. As the temperature continues to rise, the copper shell melts when it reaches copper's melting point. At this point, the gaseous zinc inside breaks out of the shell and combines with surrounding oxygen atoms to form zinc oxide. Since ZnO's sublimation point (1800-1949.9℃) is much higher than Zn's boiling point, the generated ZnO is supersaturated in the gas phase and grows efficiently on the substrate through vapor deposition. Due to the relatively low ambient temperature, the supercooling is significant, resulting in a high nucleation rate and very fine ZnO grains. Furthermore, because the ambient air temperature is low and the temperature gradient is negative, ZnO grows into an approximately dendritic structure, forming a porous thin film material.

[0034] The copper shell serves to prevent the powder, which has not reached the boiling point of zinc and the melting point of copper, from depositing and being deflected during impact with the substrate.

[0035] Example 1

[0036] This embodiment provides a method for preparing Zn@Cu core-shell powder, and the specific steps are as follows:

[0037] First, weigh 1.5g of copper sulfate pentahydrate and pour it into a beaker containing 80mL of deionized water. Stir the solution with a glass rod until it is completely dissolved. Then, weigh out 2.5g of potassium sodium tartrate, 1.3g of EDTA, 10g of NaOH, 0.7g of NaH2PO2, 1.5mg of bipyridine, and 1mg of potassium ferrocyanide in sequence. After each chemical is added to the solution, stir with a glass rod until it is completely dissolved before adding the next chemical. This process prepares the copper plating solution for later use.

[0038] Weigh 0.3125 g of zinc powder with an average particle size of 3-5 μm using an electronic balance and add it to 100 mL of copper plating solution. Stir magnetically until the solution turns colorless, then stop stirring and let it stand for 5 minutes before discarding the supernatant. Add sufficient deionized water and stir the powder mixture with a glass rod. Let it stand for another 3 minutes and then discard the waste liquid. Repeat this step 5 times to remove any residual salt solution from the powder surface. Place the powder in a dryer and dry at 120°C for 2 hours. After the powder is dried, pour the lumpy powder from the beaker into a mortar and grind it thoroughly, then sieve it through a 300-mesh sieve.

[0039] Example 2

[0040] This embodiment provides a method for preparing Zn@Cu core-shell powder, which is the same as in Example 1, except that:

[0041] In this embodiment, 0.625g of zinc powder with an average particle size of 3-5μm was weighed and added to 100mL of copper plating solution.

[0042] Example 3

[0043] This embodiment provides a method for preparing Zn@Cu core-shell powder, which is the same as in Example 1, except that:

[0044] In this embodiment, 1.25g of zinc powder with an average particle size of 3-5μm was weighed and added to 100mL of copper plating solution.

[0045] Example 4

[0046] This embodiment provides a method for preparing Zn@Cu core-shell powder, which is the same as in Example 1, except that:

[0047] In this embodiment, 2.5g of zinc powder with an average particle size of 3-5μm was weighed and added to 100mL of copper plating solution.

[0048] Example 5

[0049] This embodiment provides a method for preparing Zn@Cu core-shell powder, which is the same as in Example 1, except that:

[0050] In this embodiment, 5g of zinc powder with an average particle size of 3-5μm was weighed and added to 100mL of copper plating solution.

[0051] Example 6

[0052] This embodiment provides a method for preparing Zn@Cu core-shell powder, which is the same as in Example 1, except that 10g of zinc powder with an average particle size of 3-5μm is weighed and added to 100mL of copper plating solution.

[0053] According to the principle of plasma spraying-chemical vapor deposition for ZnO preparation designed in this invention, the copper plating layer must completely encapsulate the zinc powder. Figure 2 and Figure 4 The images show SEM backscattered electron images of the polished cross-section and surface of zinc powder after electroless copper plating, respectively. The images show that the zinc powder surface is covered with a plating layer.

[0054] Figure 5 This is the EDS energy spectrum of Zn@Cu core-shell powder, where, Figure 5 a is a polished cross-sectional view of Zn@Cu core-shell powder (Example 2) prepared by adding 0.625g of zinc powder to 100mL of copper plating solution. Figure 5 b、 Figure 5 c and Figure 5 d are the elemental distribution diagrams of O, Zn, and Cu in Zn@Cu core-shell powder (Example 2) prepared by adding 0.625g of zinc powder to 100mL of copper plating solution; Figure 5 e is a polished cross-sectional view of Zn@Cu core-shell powder (Example 4) prepared by adding 2.5g of zinc powder to 100mL of copper plating solution. Figure 5 f、 Figure 5 g and Figure 5 h are the elemental distribution diagrams of O, Zn, and Cu in Zn@Cu core-shell powder (Example 4) prepared by adding 2.5g of zinc powder to 100mL of copper plating solution;

[0055] Depend on Figure 2 and Figure 4 It can be seen that when the ratio of zinc powder to plating solution is 10g:100mL, a layer of fine copper grains is deposited on the surface of zinc powder, but the coating is uneven and not smooth; when the ratio of zinc powder to plating solution is 5g:100mL, the copper coating on the surface can uniformly cover the zinc powder, and the surface is smooth.

[0056] In addition, the thickness of the coating can be measured using polished cross-sectional images. Figure 3It can be seen that the smaller the amount of zinc powder added, the thicker the copper plating layer. An excessively thick copper plating layer will hinder the escape of Zn vapor during plasma spraying, thus reducing the deposition efficiency of ZnO. Furthermore, too small a zinc powder ratio also wastes the copper plating solution. Therefore, while ensuring a uniform and complete plating layer, a higher ratio of zinc powder to plating solution is more advantageous.

[0057] The results above indicate that the optimal ratio of zinc powder to copper plating solution is 5g-10g:100mL. A ratio of 7.5g:100mL was selected for subsequent experiments.

[0058] Example 7

[0059] Step 1: Zn@Cu core-shell powder prepared by chemical plating is used as the coating material; the specific steps are the same as in Example 1, except that...

[0060] In this embodiment, 7.5g of zinc powder with an average particle size of 3-5μm was weighed and added to 100mL of copper plating solution.

[0061] Step 2: Prepare a nano-ZnO / CuO porous coating using an atmospheric plasma spraying system. The specific steps are as follows:

[0062] A stainless steel sample with dimensions of 50mm × 10mm × 2mm was selected as the substrate for the plasma spraying. The substrate was sandblasted with 250μm silica sand to remove impurities from the sample surface and increase its surface roughness. The plasma spraying current was 400A, the spraying voltage was 61V, the hydrogen flow rate was 70L / h, the argon flow rate was 2000L / h, and the powder feed rate was 500mm. 3 The powder delivery air flow rate was 250 L / h, the spraying distance was 100 mm, and the lateral movement speed of the spray gun was 350 mm / min. The preparation parameters are shown in Table 1. A coating A with a thickness of approximately 170 μm was prepared.

[0063] Example 8

[0064] Step 1: Zn@Cu core-shell powder prepared by chemical plating is used as the coating material; the preparation method is the same as that used in Example 7.

[0065] Step 2: Prepare a nano-ZnO / CuO porous coating using an atmospheric plasma spraying system. The specific steps are as follows:

[0066] A stainless steel sample with dimensions of 50mm × 10mm × 2mm was selected as the substrate for spraying, and the substrate was sandblasted with quartz sand with a particle size of 250μm. The spraying current was increased to 500A, the voltage to 62V, and the hydrogen flow rate to 90L / h, while other preparation parameters remained unchanged. The spraying distance was 100mm, the argon flow rate was 2000L / h, and the powder feeding rate was 500mm.3 The powder feeding air flow rate was 250 L / h, the lateral movement speed of the spray gun was 350 mm / min, and the preparation parameters are shown in Table 1. A coating B with a thickness of about 150 μm was prepared.

[0067] Example 9

[0068] Step 1: Zn@Cu core-shell powder prepared by chemical plating is used as the coating material; the preparation method is the same as that used in Example 7.

[0069] Step 2: Prepare a nano-ZnO / CuO porous coating using an atmospheric plasma spraying system. The specific steps are as follows:

[0070] A stainless steel sample with dimensions of 50mm × 10mm × 2mm was selected as the substrate for spraying, and the substrate was sandblasted with quartz sand with a particle size of 250μm. The spraying current was further increased to 600A, the voltage to 64V, and the hydrogen flow rate to 110L / h, while other preparation parameters remained unchanged: spraying distance of 100mm, argon flow rate of 2000L / h, and powder feeding rate of 500mm. 3 The powder feeding air flow rate was 250 L / h, the lateral movement speed of the spray gun was 350 mm / min, and the preparation parameters are shown in Table 1. A coating C with a thickness of approximately 140 μm was prepared.

[0071] Example 10

[0072] Step 1: Zn@Cu core-shell powder prepared by chemical plating is used as the coating material; the preparation method is the same as that used in Example 7.

[0073] Step 2: Prepare a nano-ZnO / CuO porous coating using an atmospheric plasma spraying system. The specific steps are as follows:

[0074] A stainless steel sample with dimensions of 50mm × 10mm × 2mm was selected as the substrate for spraying. The substrate was sandblasted with 250μm silica sand to remove impurities from the sample surface and increase its surface roughness. The plasma spraying current was 600A, the spraying voltage was 64V, the hydrogen flow rate was 110L / h, the argon flow rate was 2000L / h, and the powder feed rate was 500mm. 3 With a powder delivery airflow rate of 250 L / h, a spraying distance of 80 mm, and a lateral movement speed of 350 mm / min, a coating D with a thickness of approximately 130 μm was prepared.

[0075] Example 11

[0076] Step 1: Zn@Cu core-shell powder prepared by chemical plating is used as the coating material; the preparation method is the same as that used in Example 7.

[0077] Step 2: Prepare a nano-ZnO / CuO porous coating using an atmospheric plasma spraying system. The specific steps are as follows:

[0078] A stainless steel sample with dimensions of 50mm × 10mm × 2mm was selected as the substrate for spraying. The substrate was sandblasted with 250μm silica sand to remove impurities from the sample surface and increase its surface roughness. The plasma spraying current was 600A, the spraying voltage was 64V, the hydrogen flow rate was 110L / h, the argon flow rate was 2000L / h, and the powder feed rate was 500mm. 3 With a powder delivery airflow rate of 250 L / h, a spraying distance of 60 mm, and a lateral movement speed of 350 mm / min, a coating E with a thickness of approximately 160 μm was prepared.

[0079] Example 12

[0080] Step 1: Zn@Cu core-shell powder prepared by chemical plating is used as the coating material; the preparation method is the same as that used in Example 7.

[0081] Step 2: Prepare a nano-ZnO / CuO porous coating using an atmospheric plasma spraying system. The specific steps are as follows:

[0082] A stainless steel sample with dimensions of 50mm × 10mm × 2mm was selected as the substrate for spraying, and the substrate was sandblasted with quartz sand with a particle size of 250μm. The spraying current was further increased to 700A, the voltage to 66V, and the hydrogen flow rate to 130L / h, while other preparation parameters remained unchanged: spraying distance of 100mm, argon flow rate of 2000L / h, and powder feeding rate of 500mm. 3 The powder feeding air flow rate was 250 L / h, the lateral movement speed of the spray gun was 350 mm / min, and the preparation parameters are shown in Table 1. A coating F with a thickness of approximately 160 μm was prepared.

[0083] Table 1. Parameters for preparing ZnO / CuO porous coatings

[0084]

[0085] Comparative Example 1

[0086] Nano-sized ZnO / Zn porous coatings were prepared using Zn powder with an original average particle size of 3-5 μm as the coating material and an atmospheric plasma spraying system. A stainless steel sample with dimensions of 50 mm × 10 mm × 2 mm was selected as the coating substrate, and the substrate was sandblasted with quartz sand with a particle size of 250 μm. The plasma spraying current was 250 A, the spraying voltage was 59 V, the hydrogen flow rate was 40 L / h, the argon flow rate was 2000 L / h, and the powder feed rate was 500 mm / h. 3 The powder delivery air flow rate was 250 L / h, the spraying distance was 100 mm, and the lateral movement speed of the spray gun was 350 mm / min. A coating Z0 was prepared.

[0087] Comparative Example 2

[0088] Nano-sized ZnO / Zn porous coatings were prepared using Zn powder with an original average particle size of 3-5 μm as the coating material and an atmospheric plasma spraying system. A stainless steel sample with dimensions of 50 mm × 10 mm × 2 mm was selected as the coating substrate, and the substrate was sandblasted with quartz sand with a particle size of 250 μm. The plasma spraying current was increased to 300 A, the spraying voltage to 60 V, and the hydrogen flow rate to 50 L / h, while other parameters remained constant. The argon flow rate was 2000 L / h, and the powder feed rate was 500 mm / h. 3 The powder delivery air flow rate was 250 L / h, the spraying distance was 100 mm, and the lateral movement speed of the spray gun was 350 mm / min. Coating Z1 was prepared.

[0089] Comparative Example 3

[0090] Nano-sized ZnO / Zn porous coatings were prepared using Zn powder with an original average particle size of 3-5 μm as the coating material and an atmospheric plasma spraying system. A stainless steel sample with dimensions of 50 mm × 10 mm × 2 mm was selected as the coating substrate, and the substrate was sandblasted with quartz sand with a particle size of 250 μm. The plasma spraying current was increased to 350 A, the spraying voltage to 61 V, and the hydrogen flow rate to 60 L / h, while other parameters remained unchanged. The argon flow rate was 2000 L / h, and the powder feed rate was 500 mm / h. 3 The powder delivery air flow rate was 250 L / h, the spraying distance was 100 mm, and the lateral movement speed of the spray gun was 350 mm / min. Coating Z2 was prepared.

[0091] Comparative Example 4

[0092] Nano-sized ZnO / Zn porous coatings were prepared using Zn powder with an original average particle size of 3-5 μm as the coating material and an atmospheric plasma spraying system. A stainless steel sample with dimensions of 50 mm × 10 mm × 2 mm was selected as the coating substrate, and the substrate was sandblasted with quartz sand with a particle size of 250 μm. The plasma spraying current was increased to 400 A, the spraying voltage to 62 V, and the hydrogen flow rate to 70 L / h, while other parameters remained unchanged. The argon flow rate was 2000 L / h, and the powder feed rate was 500 mm / h. 3 The powder delivery air flow rate was 250 L / h, the spraying distance was 100 mm, and the lateral movement speed of the spray gun was 350 mm / min. Coating Z3 was prepared.

[0093] Comparative Example 5

[0094] Nano-sized ZnO / Zn porous coatings were prepared using Zn powder with an original average particle size of 3-5 μm as the coating material and an atmospheric plasma spraying system. A stainless steel sample with dimensions of 50 mm × 10 mm × 2 mm was selected as the coating substrate, and the substrate was sandblasted with quartz sand with a particle size of 250 μm. The plasma spraying current was increased to 450 A, the spraying voltage to 63 V, and the hydrogen flow rate to 80 L / h, while other parameters remained unchanged. The argon flow rate was 2000 L / h, and the powder feed rate was 500 mm / h. 3 The powder delivery air flow rate was 250 L / h, the spraying distance was 100 mm, and the lateral movement speed of the spray gun was 350 mm / min. Coating Z4 was prepared.

[0095] Table 2. Comparative ZnO / Zn porous coating preparation parameters

[0096]

[0097] The ZnO / CuO coatings prepared by plasma spraying-chemical vapor deposition in Examples 7-10 were characterized by XRD, such as... Figure 6 As shown.

[0098] Figure 6 The XRD pattern in (b) shows that the coating prepared with Zn@Cu powder contains only ZnO and CuO as the identifiable substances, and no Zn was found. Figure 6(a) The control group Z0-Z4 coatings showed the highest ZnO content, reaching 25%. However, with increasing spraying power parameters, the ZnO content in the Z4 coating was actually lower than that in the Z3 coating, indicating that the ZnO content could not be further increased. This demonstrates that coatings prepared by electroless copper plating with a zinc core-shell powder coating can obtain more ZnO, confirming that the Cu shell can prevent Zn from depositing in elemental form. The intensity and number of diffraction peaks corresponding to ZnO in several coating groups exceeded those of CuO. This further indicates that Zn and Cu in the electroless copper-plated Zn@Cu powder deposit as ZnO and CuO under high-temperature conditions.

[0099] Figure 7 The images show a comparison of the surface microstructure of the ZnO / CuO porous coatings under different spraying powers. A, B, C, and F represent the surface microstructures of the ZnO / CuO porous coatings prepared in Examples 7-10, respectively. Figure 7 The numbers 1, 2, and 3 in each horizontal row represent the surface microstructure of the ZnO / CuO porous coating at different scales (i.e., different magnifications). Figure 7 It can be seen that the ZnO / CuO coating surface is very porous, composed of finely dispersed particles. This is because, under the ultra-high temperature conditions of plasma spraying, the powder is directly vaporized and deposited unevenly onto the substrate. At lower spraying power, such as coating A, the particles are relatively fine, with many gaps and pores between them, resulting in a dendritic morphology similar to pine needles. This is because when the spraying power is low, the surrounding air temperature is low during ZnO deposition, creating a negative temperature gradient, causing ZnO to grow in a dendritic form. As the spraying power increases, the coating particles become larger and more tightly packed, resulting in a coral-like or even cauliflower-like surface. This is because the increased spraying power causes a significant rise in the surrounding air temperature, gradually turning the temperature gradient positive, causing ZnO to gradually transform into planar growth, and the dendritic morphology to gradually disappear.

[0100] Figure 8 The average grain size of ZnO in the coatings prepared under different power levels in Examples 7-10 was measured using image analysis. As the spraying power decreased, the grain size on the surface of the ZnO / CuO thin film gradually decreased, while the surface roughness increased. Higher spraying power resulted in a smoother surface morphology, lower sample roughness, and larger grain size observed in the microstructure.

[0101] Taking Staphylococcus aureus as an example, the antibacterial properties of the coating powders prepared in Example 7 (Group A, ZnO / CuO-A) and Example 10 (Group F, ZnO / CuO-F) were tested. The experimental results are as follows: Figure 9 As shown in the figure, a transparent ring appears around the prepared coating powder, indicating that the prepared ZnO / CuO porous coating has a certain antibacterial effect.

[0102] Using the nano-sized ZnO-CuO porous coating A from Example 7 as a catalyst and an 8W UV lamp as a light source, 5 mL of a 10 mg / L methyl orange solution was degraded from a 10 mm × 10 mm coating. Figure 10 The UV-Vis light absorption curves of methyl orange solution under different UV lamp irradiation times show that the characteristic absorption peak of methyl orange solution at 465 nm decreases significantly with increasing time, indicating that the coating can effectively degrade organic matter. When the irradiation time reaches 160 min, the degradation efficiency of methyl orange solution by the nano-ZnO-CuO porous coating exceeds 80%.

[0103] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0104] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a ZnO / CuO porous coating, characterized in that, The following steps were followed to prepare the following: Step 1: Using zinc powder as raw material, copper is electrolessly plated onto the surface of the zinc powder to obtain Zn@Cu core-shell powder; Step 2: Using an atmospheric plasma spraying system, with argon and hydrogen as driving gases, Zn@Cu core-shell powder is fed into the plasma jet to prepare a ZnO / CuO porous coating. The spraying current is 400-700A, the spraying voltage is 61-66V, the argon flow rate is 2000L / h, the hydrogen flow rate is 70-130L / h, and the spraying distance is 60-100mm.

2. The method for preparing a ZnO / CuO porous coating according to claim 1, characterized in that, In step 1, the chemical plating process is as follows: zinc powder is added to the copper plating solution, stirred until the solution becomes colorless, and then allowed to stand to obtain a precipitate. After removing the residual salt solution from the surface of the powder, it is dried, ground, and pulverized to obtain Zn@Cu core-shell powder.

3. The method for preparing a ZnO / CuO porous coating according to claim 2, characterized in that, The ratio of zinc powder to copper plating solution is 0.3125-10g:100mL.

4. A ZnO / CuO porous coating prepared by the preparation method according to any one of claims 1-3.

5. The application of the ZnO / CuO porous coating according to claim 4 in the preparation of antibacterial agents.

6. The application of the ZnO / CuO porous coating of claim 4 in the degradation of organic matter.

Images