Copper-based alloy powders, their preparation methods and applications; copper-based alloy cladding layers containing chromium-rich precipitates, their preparation methods and applications.

Abstract

This invention belongs to the field of new materials and surface engineering, providing copper-based alloy powder, its preparation method and application, and a copper-based alloy cladding layer containing chromium-rich precipitates, its preparation method and application. The copper-based alloy powder provided by this invention comprises the following components by mass percentage: Cr 2-10%, Ni 0.2-3%, Mn 1-5%, Si 0.3-1%, P 0.1-0.5%, and Cu balance. The copper-based alloy cladding layer containing chromium-rich precipitates prepared using this copper-based alloy powder utilizes the chromium-rich precipitate effect. The chromium-rich precipitates and the copper-rich matrix phase form a micro-corrosion cell in situ. The chromium-rich precipitates, acting as the cathode, promote the corrosion and dissolution of the copper-rich matrix phase, acting as the anode, stably releasing copper ions. During the corrosion process, Cr2O3 particles formed in situ on the chromium-rich precipitates promote the exfoliation of Cu2(OH)3Cl, ensuring the long-term continuous release of copper ions, thereby achieving a long-term anti-fouling effect.

Description

Technical Field

[0001] This invention belongs to the field of new materials and surface engineering technology, and in particular relates to copper-based alloy powders and their preparation methods and applications, as well as copper-based alloy cladding layers containing chromium-rich precipitates and their preparation methods and applications. Background Technology

[0002] Marine fouling poses a significant threat to ships and underwater equipment, causing substantial economic losses and environmental threats.

[0003] In the 1960s, antifouling coatings using organotin compounds as antifouling agents were invented. However, these coatings suffered from drawbacks such as unstable leaching rates of toxic substances and high surface roughness, severely restricting their application and development. In the 1980s, TBT self-polishing antifouling coatings containing organotin were widely used for preventing ship pollution. However, organotin compounds severely impacted the growth and reproduction of marine life, leading to their death, and organotin-containing antifouling coatings were banned worldwide. Organotin-free antifouling coatings gradually became a research focus and development direction. The first generation of tin-free antifouling coatings used hydrolyzable base materials combined with low-toxicity cuprous oxide antifouling agents, but they were banned due to the significant harm caused to marine life by the added auxiliary toxic agents. The second generation of tin-free antifouling coatings are tin-free self-polishing antifouling coatings. The hydrolyzable side chains in the coating react with the large amounts of sodium, potassium, and calcium ions in seawater, causing the antifouling agents, pigments, and fillers in the coating to be released smoothly, keeping the coating surface smooth and exhibiting a good self-polishing effect.

[0004] Currently, antifouling coatings that release antifouling agents account for more than half of the global coatings market, among which self-polishing antifouling coatings are the most widely used. Antifouling coatings made from hydrating, hydrolytic, and hybrid Wuxi self-polishing antifouling coatings have service lives of 3 years, 5 years, and 3-5 years, respectively. However, self-polishing antifouling coatings still have the following problems: (1) The dissolution of the polymer chains after the side group hydrolysis in self-polishing antifouling coatings depends on the strong shearing action of the water flow. Therefore, under static conditions, the self-polishing rate is low and the antifouling effect is poor; (2) The antifouling agent in self-polishing antifouling coatings will have a burst release phenomenon in the early stage of application, resulting in the antifouling agent being released too quickly. As the application time is extended, the polishing rate will decrease significantly, making it difficult to achieve a long-term antifouling effect; (3) Most of the diluents in self-polishing antifouling coatings contain volatile organic compounds (VOCs). The large release of VOCs has caused serious harm to the atmospheric environment; (4) The main chain of the antifouling resin is a non-degradable carbon-carbon structure. After polishing, as the antifouling resin dissolves, it will form microplastics in the ocean and exist for a long time, posing a serious threat to marine ecology and human health.

[0005] Currently, there are different viewpoints both domestically and internationally regarding the antifouling mechanism of copper alloys. Efird proposed a toxic film mechanism, suggesting that the cuprous oxide film formed on the surface of copper alloys in seawater has an antifouling effect, but the antifouling effect decreases sharply when the cuprous oxide film is covered by basic copper chloride. Laque et al. proposed a cuprous ion desolvation mechanism, that is, the antifouling effect of copper alloys originates from the toxicity of cuprous ions dissolved from their surface. Studies have shown that when copper alloys corrode in seawater, the dissolved cuprous ions (Cu... + ) will react with chloride ions (Cl) adsorbed on its surface - The reaction forms CuCl2. - and with CuCl2 - The copper ion exists stably primarily in the form of complexes. An increase in these complexes leads to the formation of a cuprous ion layer on the copper alloy surface. This layer disrupts the biofilms of marine organisms, causing metalloprotein precipitation and ultimately killing the organisms. Therefore, when cuprous ions (CuCl2) are present on the surface of copper and copper alloys... - When a certain concentration is reached, it can effectively prevent marine organisms from adhering to and growing on the surface of metal components, thus achieving the purpose of antifouling. Currently, copper alloys are widely used in parts such as ship bottoms, propellers, sea locks, and torpedo launcher tracks.

[0006] Domestic scholars conducted marine plating tests on typical copper alloys in Zhanjiang Port and Qingdao. The results showed that the corrosion products on the surface of traditional copper alloys such as bronze and brass mainly consist of cuprous oxide, basic copper chloride, and basic copper carbonate. These alloys also exhibited a large number of bryozoans, calcareous worms, and barnacles, resulting in an antifouling effect of less than 12 months. Research revealed that the corrosion products of copper alloys in marine environments form a two-layer structure: an inner corrosion layer forms a Cu2O film, while an outer corrosion layer forms a film of CuO, CuCl2, Cu(OH)2, Cu2(OH)3Cl, or Cu2CO3(OH)2. The composition of the outer layer products is not entirely consistent during corrosion. When selective corrosion occurs (zinc removal in brass, aluminum removal in aluminum bronze, and nickel removal in cupronickel), the outer layer is easily covered by a low-copper product film (Cu2(OH)3Cl), shielding the copper and reducing the copper ion leaching rate, thus affecting the antifouling effect. In summary, existing copper alloys inevitably become covered by low-copper films (Cu2(OH)3Cl) or insoluble films (Cu2CO3(OH)2) during the corrosion process in marine environments, resulting in a sharp decrease in the release rate of copper ions and thus loss of antifouling properties. Figure 1 This image shows a copper alloy propeller hub cap that has suffered severe fouling in a marine environment due to loss of its antifouling function. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide copper-based alloy powder, its preparation method and application, and copper-based alloy cladding layer containing chromium-rich precipitates, its preparation method and application. In the copper-based alloy cladding layer containing chromium-rich precipitates prepared using the copper-based alloy powder provided by this invention, the chromium-rich precipitates and the copper-rich matrix phase form a micro-corrosion cell in situ. The chromium-rich precipitates, acting as the cathode, promote the corrosion and dissolution of the copper-rich matrix phase, acting as the anode, and stably release copper ions. During the corrosion process, the Cr2O3 particles formed in situ on the chromium-rich precipitates promote the exfoliation of Cu2(OH)3Cl, ensuring the continuous release of copper ions and providing long-term prevention of marine organism attachment.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0009] The present invention provides a copper-based alloy powder comprising the following components in weight percentage: Cr 2~10%, Ni 0.2~3%, Mn 1~5%, Si 0.3~1%, P 0.1~0.5%, and Cu balance.

[0010] Preferably, the particle size of the copper-based alloy powder is 200-400 mesh.

[0011] This invention provides a method for preparing the copper-based alloy powder described above, comprising the following steps:

[0012] Cr, Ni, Mn, Si, P and Cu are vacuum melted according to the composition of the copper-based alloy powder to obtain an alloy melt.

[0013] The alloy melt is atomized to produce copper-based alloy powder.

[0014] Preferably, the vacuum melting temperature is 1850~1950℃, and the holding time is 30~60min.

[0015] Preferably, the conditions for atomization powder production include: the atomization medium is nitrogen gas, and the flow rate of the alloy melt is 0.5~1 kg / min.

[0016] This invention provides a copper-based alloy cladding layer containing chromium-rich precipitates, comprising a metastable chromium-rich precipitate phase and a copper-rich matrix phase. The raw material for preparing the copper-based alloy cladding layer containing chromium-rich precipitates is the copper-based alloy powder described in the above technical solution or the copper-based alloy powder prepared by the preparation method described in the above technical solution.

[0017] Preferably, the average thickness of the copper-based alloy cladding layer containing chromium-rich precipitates is 300~1000μm.

[0018] This invention provides a method for preparing the copper-based alloy cladding layer containing chromium-rich precipitates as described above, comprising the following steps:

[0019] Remove the corrosion from the surface of the metal substrate to obtain a pretreated metal substrate;

[0020] Using copper-based alloy powder as raw material, laser cladding is performed on the surface of the pretreated metal substrate to obtain a copper-based alloy cladding layer containing chromium-rich precipitates.

[0021] Preferably, the working conditions for laser cladding include: powder feeding rate of 0.8~2kg / h, protective gas flow rate of 15~20L / min, laser power of 2~6kW, and relative motion speed between the laser spot and the workpiece of 10~25cm / s; for flat workpieces, the laser head stepping distance is 0.5~0.8mm.

[0022] This invention provides the application of the copper-based alloy powder described in the above-described technical solution, the copper-based alloy powder prepared by the preparation method described in the above-described technical solution, the copper-based alloy cladding layer containing chromium-rich precipitates described in the above-described technical solution, or the copper-based alloy cladding layer containing chromium-rich precipitates prepared by the preparation method described in the above-described technical solution in preventing marine biofouling.

[0023] This invention forms a copper-based alloy cladding layer containing chromium-rich precipitates by adding chromium, specifically by forming submicron-sized chromium-rich precipitates and copper-rich matrix phases (such as...) within the copper-based alloy cladding layer. Figure 2 As shown). Due to potential difference (such as... Figure 3 The presence of the chromium-rich precipitate (as shown) allows it to form a micro-corrosion cell with the copper-rich matrix phase. The chromium-rich precipitate, acting as the cathode, promotes the corrosion and dissolution of the copper-rich matrix phase, which acts as the anode, thus continuously and stably releasing copper ions. Analysis of the surface and cross-sectional electron microscopy images of the copper-based alloy cladding layer containing the chromium-rich precipitate after immersion in simulated seawater for 6 months reveals (…). Figures 4-5 As shown in the figure, the corrosion products exhibit a double-layer structure, with the inner layer primarily composed of Cu₂O and the outer layer primarily composed of Cu₂(OH)₃Cl. After corrosion, the surface of the chromium-rich precipitate is covered by a Cr₂O₃ film, forming Cr₂O₃ particles in situ and embedding them within the inner corrosion products. Because the formation of Cr₂O₃ particles creates an acidic local environment, the embedding of these particles promotes the dissolution of the inner corrosion product Cu₂O, forming Cu-rich particles and leaving numerous pores in the inner corrosion layer. Furthermore, the interface between the inner and outer corrosion product layers contains corrosion products with different coefficients of linear expansion, such as Cu₂O, Cr₂O₃, Cu, and Cu₂(OH)₃Cl. This results in a discontinuous distribution of Cu₂(OH)₃Cl in the outer product layer, increasing the internal stress between the corrosion product layers and promoting the exfoliation of Cu₂(OH)₃Cl.

[0024] Ni and Cu are infinitely soluble in solid solution, while Ni and Cr are partially soluble. At 1345℃, the solid solubility of Ni in Cr is 44 wt.%. Therefore, during rapid solidification, Ni can carry some of the dissolved Cr atoms into the copper-rich matrix, thereby reducing the number of Cr atoms in the Cr-rich melt. By adding Ni, the corrosion-promoting effect of chromium-rich precipitation in the cladding layer relative to the Cu-rich phase can be weakened, thus reducing the corrosion rate to a certain extent and consequently lowering the copper ion release rate within a certain range, preventing excessively high copper ion release rates.

[0025] Mn can be uniformly distributed in the chromium-rich precipitates and copper-rich matrix phases of copper-based alloy cladding layers (e.g.) Figure 6 As shown). (Mn) 2+ / Mn), (Cr 3+ / Cr) and (Cu 2+ The standard electrode potentials of / Cu are E 0 Mn =-1.18V (vs SHE); E 0 Cr =-0.74V (vs SHE); E 0 Cu =0.34V (vs SHE). Therefore, Mn atoms in the cladding layer have higher chemical activity and preferentially corrode and dissolve under the corrosive action of natural seawater, leaving vacancies at corresponding positions, forming micropore defects. This increases the contact area between the copper-rich matrix and seawater, further promoting the corrosion and dissolution of the copper-rich matrix phase. Since the micropore defects left on the surface of the cladding layer after the Mn atoms corrode and dissolve, they can effectively reduce the bonding strength between the corrosion products and the cladding layer surface, making the corrosion products easier to peel off.

[0026] Si has a deoxidizing and slag-forming effect, preventing alloying elements in the cladding layer from reacting with oxygen to form oxides. It also increases the fluidity of the molten pool and reduces surface roughness.

[0027] By adding phosphorus (P) to form Cu3P compounds in the Cu-rich phase of the cladding layer, the hardness and strength of the cladding layer can be improved.

[0028] This invention utilizes high-speed laser cladding technology to melt copper-based alloy powder (Cu-Cr-Mn-Ni-P-Si), preparing a copper-based alloy cladding layer containing metastable chromium-rich precipitates on a metal substrate. The chromium-rich precipitate effect ensures the continuous and stable release of copper ions, thus achieving a long-lasting anti-fouling effect. This invention utilizes the rapid solidification effect during laser cladding to form a metastable chromium-rich precipitate and a copper-rich matrix phase in the copper-based alloy cladding layer. The chromium-rich precipitate and the copper-rich matrix phase form a micro-corrosion cell in situ. The chromium-rich precipitate, acting as the cathode, promotes the corrosion and dissolution of the copper-rich matrix phase, acting as the anode, thus stably releasing copper ions. The corrosion products on the surface of the chromium-rich precipitate copper-based alloy cladding layer exhibit a bilayer structure: the inner layer corrosion products are mainly Cu2O, and the outer layer corrosion products are mainly Cu2(OH)3Cl. After corrosion, the surface of the chromium-rich precipitate is covered by a Cr2O3 film, forming Cr2O3 particles in situ and embedding them within the inner layer corrosion products. Because the formation of Cr2O3 particles creates an acidic local environment, the embedding of Cr2O3 particles promotes the dissolution of the inner corrosion product Cu2O, forming Cu-rich particles and leaving numerous pores in the inner corrosion layer. Furthermore, the interface between the inner and outer corrosion product layers contains corrosion products with different coefficients of linear expansion, such as Cu2O, Cr2O3, Cu, and Cu2(OH)3Cl. This results in a discontinuous distribution of Cu2(OH)3Cl in the outer layer, increasing the internal stress between the corrosion product layers and promoting the peeling off of Cu2(OH)3Cl, ensuring the continuous release of copper ions. The chromium-rich precipitated copper-based alloy cladding layer provided by this invention can be used for various structural components operating in harsh marine environments, such as shipboard below-water plates, propellers, sonar domes, seawater piping systems, steel structures in contact with seawater on offshore drilling platforms, and steel structures in contact with seawater in offshore wind turbines.

[0029] This invention also provides a method for preparing the copper-based alloy cladding layer containing chromium-rich precipitates as described in the above-mentioned technical solution. The preparation method provided by this invention uses laser cladding to prepare the antifouling cladding layer, resulting in a metallurgical bond between the copper-based alloy cladding layer containing chromium-rich precipitates and the metal substrate. This bond strength is high, allowing the copper-based alloy cladding layer containing chromium-rich precipitates to operate for a long time under harsh environments such as high stress, temperature changes, and alternating wet and dry corrosion. This avoids the disadvantages caused by the low bonding strength of coatings and thermal spray coatings, and has the advantages of long-lasting performance and environmental friendliness. Attached Figure Description

[0030] Figure 1 Image of a severely contaminated copper alloy propeller hub cap;

[0031] Figure 2 The image shows a scanning electron microscope (SEM) image of the surface of the copper-based alloy cladding layer containing chromium-rich precipitates prepared in Example 2, where 1 is the chromium-rich precipitate and 2 is the copper-rich matrix phase.

[0032] Figure 3The potential distribution curves on the surface of the copper-based alloy cladding layer containing chromium-rich precipitates prepared in Example 2 are shown. In this curve, 3 represents the copper-rich matrix phase, 4 represents the chromium-rich precipitate phase, 5 represents the potential of the chromium-rich precipitate phase, and 6 represents the potential of the copper-rich matrix phase.

[0033] Figure 4 The image shows a scanning electron microscope (SEM) image of the surface of the copper-based alloy cladding layer containing chromium-rich precipitates in Example 2 after immersion in a simulated seawater environment for 6 months. In the image, 7 represents Cu2(OH)3Cl, 8 represents Cu2O, 9 represents Cu-rich particles, and 10 represents Cr2O3 particles.

[0034] Figure 5 The image shows a scanning electron microscope (SEM) image of the cross-section of the copper-based alloy cladding layer containing chromium-rich precipitates in Example 2 after immersion in a simulated seawater environment for 6 months; 11 is Cu2(OH)3Cl, 12 is Cu2O, 13 is Cr2O3 particles, and 14 is Cu-rich particles.

[0035] Figure 6 The results of surface scanning analysis of the copper-based alloy cladding layer containing chromium-rich precipitates prepared in Example 2 are shown in Figure 15, where 15 represents the distribution of Cu, 16 represents the distribution of Cr, and 17 represents the distribution of Mn.

[0036] Figure 7 The copper ion release rate curve of the copper-based alloy cladding layer containing chromium-rich precipitates in Example 2 after immersion in a simulated seawater environment for 38 days;

[0037] Figure 8 This is a schematic diagram of the antifouling mechanism of a copper-based alloy cladding layer containing chromium-rich precipitates in a seawater environment. 18 represents vacancies left by preferential manganese corrosion, 19 represents the chromium-rich precipitates of the cladding layer, 20 represents the copper-rich matrix phase of the cladding layer, 21 represents the Cu2(OH)3Cl product layer, 22 represents Cu particles, 23 represents micropores, 24 represents Cr2O3 particles, 25 represents the Cu2O product layer, and 26 represents cracks formed during corrosion. Detailed Implementation

[0038] The present invention provides a copper-based alloy powder comprising the following components in weight percentage: Cr 2~10%, Ni 0.2~3%, Mn 1~5%, Si 0.3~1%, P 0.1~0.5%, and Cu balance.

[0039] The copper-based alloy powder provided by the present invention comprises 2-10% Cr, preferably 3-9%, more preferably 4-8%, further preferably 5-7%, and most preferably 6% by mass percentage.

[0040] The copper-based alloy powder provided by the present invention comprises 0.2-3% Ni, preferably 0.5-2.5%, more preferably 1-2%, and even more preferably 1.5% by mass percentage.

[0041] The copper-based alloy powder provided by the present invention comprises 1-5% Mn, preferably 1.5-4.5%, more preferably 2-4%, further preferably 2.5-3.5%, and most preferably 3% by mass percentage.

[0042] The copper-based alloy powder provided by the present invention comprises 0.3-1% Si, preferably 0.4-0.9%, more preferably 0.3-0.8%, further preferably 0.4-0.7%, and most preferably 0.5-0.6% by mass percentage.

[0043] The copper-based alloy powder provided by the present invention comprises P 0.1~0.5% by mass, preferably 0.15~0.45%, more preferably 0.2~0.4%, further preferably 0.25~0.35%, and most preferably 0.3%.

[0044] The copper-based alloy powder provided by this invention comprises Cu as the balance, based on mass percentage.

[0045] In this invention, the particle size of the copper-based alloy powder is preferably 200-400 mesh, more preferably 250-350 mesh.

[0046] This invention provides a method for preparing the copper-based alloy powder described above, comprising the following steps:

[0047] Cr, Ni, Mn, Si, P and Cu are vacuum melted according to the composition of the copper-based alloy powder to obtain an alloy melt.

[0048] The alloy melt is atomized to produce copper-based alloy powder.

[0049] Unless otherwise specified, all raw materials used in this invention are commercially available products.

[0050] This invention involves vacuum melting Cr, Ni, Mn, Si, P, and Cu according to the composition of the copper-based alloy powder to obtain an alloy melt. In this invention, Cr, Ni, Mn, Si, P, and Cu are preferably used in elemental form, and the purity of each metal (Cr, Ni, Mn, Cu) and non-metal (Si, P) element is preferably ≥99.9%. The melting point of Cu is 1084.87℃, and the melting point of Cr is 1863℃. The solid solubility of Cu and Cr is extremely low; the maximum solubility of Cr at 1076.6℃ is 0.89%, and the maximum solubility of Cu at 1150℃ is 0.085%. In this invention, the vacuum melting temperature is preferably 1850~1950℃, more preferably 1880~1920℃, and even more preferably 1900℃; the holding time of the vacuum melting is preferably 30~60min, more preferably 30~60min, and even more preferably 30~60min. The holding time of the vacuum melting begins when the raw material powder is evenly mixed and completely melted; the vacuum melting is preferably carried out in a vacuum medium-frequency induction melting furnace. Under the above conditions, the vacuum melting of this invention can avoid the segregation of elemental metal powder.

[0051] After obtaining the alloy melt, the present invention atomizes the alloy melt to obtain copper-based alloy powder. In the present invention, the atomization conditions include: the atomizing medium is preferably nitrogen; the flow rate of the alloy melt is preferably 0.5~1 kg / min, more preferably 0.6~0.9 kg / min, and even more preferably 0.7~0.8 kg / min; the atomization is preferably carried out in a crucible equipped with an atomization rapid condensation device.

[0052] After atomization and powdering, the present invention preferably further includes sieving the obtained atomized alloy powder to obtain copper-based alloy powder. The present invention does not have a special limitation on the sieving, as long as copper-based alloy powder with a particle size of 200-400 mesh can be obtained.

[0053] This invention provides a copper-based alloy cladding layer containing chromium-rich precipitates, comprising a metastable chromium-rich precipitate phase and a copper-rich matrix phase. The raw material for preparing the copper-based alloy cladding layer containing chromium-rich precipitates is the copper-based alloy powder described in the above-described technical solution or the copper-based alloy powder prepared by the preparation method described in the above-described technical solution. In this invention, the size of the metastable chromium-rich precipitate phase is preferably in the submicron range. In this invention, the average thickness of the copper-based alloy cladding layer containing chromium-rich precipitates is preferably 300~1200 μm, more preferably 500~1000 μm, and even more preferably 600~800 μm.

[0054] This invention provides a method for preparing a copper-based alloy cladding layer containing chromium-rich precipitates as described above, comprising the following steps:

[0055] Remove the corrosion from the surface of the metal substrate to obtain a pretreated metal substrate;

[0056] Using copper-based alloy powder as raw material, laser cladding is performed on the surface of the pretreated metal substrate to obtain a copper-based alloy cladding layer containing chromium-rich precipitates.

[0057] This invention removes corrosion from the surface of a metal substrate to obtain a pretreated metal substrate. In this invention, the metal substrate preferably includes a steel substrate, a copper alloy substrate, a titanium alloy substrate, and an aluminum alloy substrate. In this invention, the method for removing corrosion from the surface of the metal substrate preferably includes a mechanical method, which is preferably an electric grinding wheel and / or sandblasting.

[0058] After obtaining the pretreated metal substrate, the present invention uses copper-based alloy powder as raw material to perform laser cladding on the surface of the pretreated metal substrate to obtain a copper-based alloy cladding layer containing chromium-rich precipitates.

[0059] In this invention, the working conditions for laser cladding include: fixing the pretreated metal substrate workpiece on a cladding worktable before laser cladding; the preferred feed rate of the copper-based alloy powder is 0.8~2 kg / h, more preferably 1~1.8 kg / h, and even more preferably 1.2~1.5 kg / h; the preferred flow rate of the protective gas is 15~20 L / min, more preferably 16~19 L / min, and even more preferably 17~18 L / min, and the protective gas preferably includes argon; the preferred laser power is 2~6 kW, more preferably 3~5 kW, and even more preferably 4 kW; the preferred relative speed between the laser spot and the workpiece is 10~25 cm / s, more preferably 15~20 L / min, and even more preferably 15~20 L / min, and even more preferably 15~20 L / min, and even more preferably 15~20 L / min, and the preferred flow rate of the protective gas is 15~20 L / min, more preferably 16~19 L / min, and even more preferably 17~18 L / min, and the preferred flow rate of the protective gas is ... more preferably 16~19 L / min, and even more preferably 17~18 L / min, and the preferred flow rate of the protective gas is 15~20 L / min, more preferably 16~19 L / min, and even more preferably 17~ The preferred speed is 12~22cm / s, more preferably 15~20cm / s; for flat workpieces, laser cladding is preferably performed by the laser head making linear and stepping movements while the flat workpiece remains stationary; for cylindrical workpieces, laser cladding is preferably performed by the tube making spiral movements while the laser head remains stationary; for other complex-shaped workpieces, laser cladding is preferably performed by the component remaining stationary while the laser head is controlled by a robotic arm; for flat workpieces, the laser head stepping distance is preferably 0.5~0.8mm, more preferably 0.55~0.75mm, and more preferably 0.6~0.7mm; the laser is preferably a high-power fiber laser, and the use of a high-power fiber laser as the heat source for cladding in this invention can improve the cladding efficiency.

[0060] This invention provides the application of the copper-based alloy powder described in the above-described technical solution, the copper-based alloy powder prepared by the preparation method described in the above-described technical solution, the copper-based alloy cladding layer containing chromium-rich precipitates described in the above-described technical solution, or the copper-based alloy cladding layer containing chromium-rich precipitates prepared by the preparation method described in the above-described technical solution in preventing marine biofouling.

[0061] The following detailed descriptions, in conjunction with embodiments, illustrate the copper-based alloy powder, its preparation method, and its application, as well as the copper-based alloy cladding layer containing chromium-rich precipitates, its preparation method, and its application. However, these descriptions should not be construed as limiting the scope of protection of this invention.

[0062] In the following examples, elemental Cu, Cr, Mn, Ni, Si, and P are arranged as described above, with each metallic and non-metallic element having a purity ≥99.9%. The melting point of Cu is 1084.87℃, and the melting point of Cr is 1863℃. Cu and Cr have extremely low melting point solubility; the maximum solubility of Cr at 1076.6℃ is 0.89%, and the maximum solubility of Cu at 1150℃ is 0.085%. Simulated seawater was prepared according to the artificial seawater formula specified in Appendix A of GB / T7790-1996, using 23g sodium oxide (NaCl), 8.9g sodium sulfate decahydrate (Na2SO4·10H2O), 9.8g magnesium chloride hexahydrate (MgCl2·6H2O), and 1.2g anhydrous calcium chloride (CaCl2) dissolved in deionized water and diluted to a total volume of 1L.

[0063] Example 1

[0064] A copper-based alloy cladding layer containing chromium-rich precipitates was prepared on the surface of marine steel AH36.

[0065] AH36 steel plate was selected as the base material for cladding, with a plate size of 16500 mm. 2500mm 12mm.

[0066] 1. Composition and preparation of copper-based alloy powder

[0067] The composition of the copper-based alloy powder, by mass percentage, is: Cr 5%, Ni 0.5%, Mn 1.5%, Si 0.5%, P 0.3%, Cu balance.

[0068] Preparation of copper-based alloy powder: Elemental Cu, Cr, Mn, Ni, Si and P are thoroughly mixed according to the above composition, placed in a vacuum medium-frequency induction melting furnace and heated to melt. The mixture is then held at 1900℃ for 55 min to obtain an alloy melt. The alloy melt is poured into a crucible equipped with an atomizing rapid condensation device, and then atomized and sieved using this device to obtain copper-based alloy powder with a particle size of 200~400 mesh. The atomizing medium is nitrogen gas, and the flow rate of the alloy melt is 0.6 kg / min.

[0069] 2. Preparation of copper-based alloy cladding layer containing chromium-rich precipitates

[0070] The specific steps for preparing a copper-based alloy cladding layer containing chromium-rich precipitates on the surface of AH36 steel plate are as follows:

[0071] Corrosion on the surface of AH36 steel plate was removed using an electric grinding wheel. The workpiece, after surface rust removal, was fixed on the cladding table. Copper-based alloy powder was loaded into the powder storage container of a pneumatic powder feeder. A robotic arm controlled the laser head to perform linear motion along the x-axis and stepping motion along the y-axis, while the workpiece remained fixed, to perform laser cladding on the AH36 steel plate surface, obtaining a 550μm thick copper-based alloy cladding layer containing chromium-rich precipitates. The main operating parameters for cladding were: a high-power fiber laser, a powder feed rate of 0.9 kg / h, a protective gas flow rate of 16 L / min, a laser power of 2.6 kW, a relative speed between the laser spot and the workpiece of 13 cm / s, and a laser head stepping distance of 0.6 mm.

[0072] Example 2

[0073] An antifouling copper-based alloy cladding layer containing chromium-rich precipitates was prepared on the surface of Q235B marine steel.

[0074] Q235B steel plate was selected as the base material for cladding, with a plate size of 16500mm. 2500mm 12mm.

[0075] 1. Composition and preparation of copper-based alloy powder

[0076] The composition of the copper-based alloy powder, by mass percentage, is: Cr 6%, Ni 0.8%, Mn 4%, Si 0.6%, P 0.4%, Cu balance.

[0077] Preparation of copper-based alloy powder: Elemental Cu, Cr, Mn, Ni, Si and P are thoroughly mixed according to the above composition, placed in a vacuum medium-frequency induction melting furnace and heated to melt. The mixture is then held at 1920℃ for 50 min to obtain an alloy melt. The alloy melt is poured into a crucible equipped with an atomizing rapid condensation device, and then atomized and sieved using this device to obtain copper-based alloy powder with a particle size of 200~400 mesh. The atomizing medium is nitrogen gas, and the flow rate of the alloy melt is 0.7 kg / min.

[0078] 2. Preparation of copper-based alloy cladding layer containing chromium-rich precipitates

[0079] The specific steps for preparing a copper-based alloy cladding layer containing chromium-rich precipitates on the surface of Q235B steel plate are as follows:

[0080] Corrosion on the surface of Q235B steel plate was removed using an electric grinding wheel. The workpiece, after surface rust removal, was fixed on the cladding table. Copper-based alloy powder was loaded into the powder storage container of a pneumatic powder feeder. A robotic arm controlled the laser head to perform linear motion along the x-axis and stepping motion along the y-axis, while the workpiece remained fixed, to perform laser cladding on the Q235B steel plate surface, obtaining a 700μm thick copper-based alloy cladding layer containing chromium-rich precipitates. The main operating parameters for cladding were: high-power fiber laser, powder feed rate of 1.2kg / h, protective gas flow rate of 17L / min, laser power of 2.8kW, relative speed between the laser spot and the workpiece of 14cm / s, and laser head stepping distance of 0.7mm.

[0081] Example 3

[0082] Preparation of an antifouling copper-based alloy cladding layer containing chromium-rich precipitates on aluminum alloy marine surfaces

[0083] 5083 aluminum alloy was selected as the base material for cladding, and the aluminum alloy plate size was 1600mm. 2500mm 10mm.

[0084] 1. Composition and preparation of copper-based alloy powder

[0085] The composition of the copper-based alloy powder, by mass percentage, is: Cr 9%, Ni 1.5%, Mn 5%, Si 0.8%, P 0.1%, Cu balance.

[0086] Preparation of copper-based alloy powder: Elemental Cu, Cr, Mn, Ni, Si and P are thoroughly mixed according to the above composition, placed in a vacuum medium-frequency induction melting furnace and heated to melt. The mixture is then held at 1950℃ for 40 min to obtain an alloy melt. The alloy melt is poured into a crucible equipped with an atomizing rapid condensation device, and then atomized and sieved using this device to obtain copper-based alloy powder with a particle size of 200~400 mesh. The atomizing medium is nitrogen gas, and the flow rate of the alloy melt is 0.8 kg / min.

[0087] 2. Preparation of copper-based alloy cladding layer containing chromium-rich precipitates

[0088] The specific steps for preparing a copper-based alloy cladding layer containing chromium-rich precipitates on the surface of 5083 aluminum alloy are as follows:

[0089] An electric grinding wheel was used to remove the oxide layer from the surface of 5083 aluminum alloy. The workpiece to be clad, after surface rust removal, was fixed on the cladding table. Copper-based alloy powder was loaded into the powder storage container of a pneumatic powder feeder. A robotic arm controlled the laser head to perform linear motion along the x-axis and stepping motion along the y-axis, while the workpiece was fixed in place, to perform laser cladding on the surface of the 5083 aluminum alloy, obtaining a copper-based alloy cladding layer with chromium-rich precipitates with a thickness of 850 μm. The main working parameters for cladding were: a high-power fiber laser, a powder feed rate of 1.4 kg / h, a protective gas flow rate of 18 L / min, a laser power of 3 kW, a relative speed between the laser spot and the workpiece of 10 cm / s, and a laser head stepping distance of 0.6 mm.

[0090] Figure 2 The image shows a scanning electron microscope (SEM) image of the surface of the copper-based alloy cladding layer containing chromium-rich precipitates prepared in Example 2. In this image, 1 represents the chromium-rich precipitate phase, and 2 represents the copper-rich matrix phase. The copper-based alloy cladding layer containing chromium-rich precipitates consists of a chromium-rich precipitate phase and a copper-rich matrix phase. The chromium-rich precipitate phase mainly contains Cr (59.2 wt.%), with the remaining elements including Cu and Mn. The copper-rich matrix phase mainly contains Cu (98.2 wt.%). Both the chromium-rich precipitate phase and the copper-rich matrix phase contain trace amounts of Mn (<2 wt.%). The cladding layer has a good morphology without obvious pores or cracks. Energy dispersive spectroscopy (EDS) elemental analysis (only Cu, Cr, Mn, O, and Cl were detected) is shown in Table 1.

[0091] Table 1. Energy dispersive spectroscopy (EDS) analysis results of different regions in the copper-based alloy cladding layer containing chromium-rich precipitates prepared in Example 2.

[0092]

[0093] Figure 3 The potential distribution curves on the surface of the copper-based alloy cladding layer containing chromium-rich precipitates prepared in Example 2 are shown. 3 represents the copper-rich matrix phase, 4 represents the chromium-rich precipitate phase, 5 represents the potential of the chromium-rich precipitate phase, and 6 represents the potential of the copper-rich matrix phase. Microscopic corrosion cells are formed in the cladding layer. The chromium-rich precipitate phase has a high potential and acts as the cathode, while the copper-rich matrix phase has a low potential and acts as the anode.

[0094] Figure 4 The image shows a scanning electron microscope (SEM) image of the copper-based alloy cladding layer containing chromium-rich precipitates in Example 2 after immersion in a simulated seawater environment for 6 months. In the image, 7 represents Cu₂(OH)₃Cl, 8 represents Cu₂O, 9 represents Cu-rich particles, and 10 represents Cr₂O₃ particles. Energy dispersive spectroscopy (EDS) elemental analysis (detecting only Cu, Cr, Mn, O, and Cl) is shown in Table 2.

[0095] Table 2. Energy dispersive spectroscopy (EDS) analysis results of the chromium-rich copper-based alloy cladding layer prepared in Example 2 after immersion in simulated seawater for 6 months.

[0096]

[0097] Depend on Figure 4 As shown in Table 2, a large amount of Cu2(OH)3Cl was peeled off from the surface of the copper-based alloy cladding layer containing chromium-rich precipitates. The corrosion products at the peeled-off sites consisted of Cu2O, Cr2O3, and Cu-rich particles. After corrosion, the surface of the chromium-rich precipitates was covered by a Cr2O3 film, forming Cr2O3 particles in situ and embedding them into the inner corrosion products. Since the formation of Cr2O3 particles creates an acidic local environment, the embedding of Cr2O3 particles promoted the dissolution of the inner corrosion product Cu2O, forming Cu-rich particles and leaving numerous pores in the inner corrosion layer.

[0098] Figure 5 The image shows a scanning electron microscope (SEM) image of the cross-section of the copper-based alloy cladding layer containing chromium-rich precipitates in Example 2 after immersion in a simulated seawater environment for 6 months. In this image, 11 represents Cu₂(OH)₃Cl, 12 represents Cu₂O, 13 represents Cr₂O₃ particles, and 14 represents Cu-rich particles. Energy dispersive spectroscopy (EDS) elemental analysis (detecting only Cu, Cr, Mn, O, and Cl) is shown in Table 3.

[0099] Table 3. Energy dispersive spectroscopy (EDS) analysis results of different regions of the copper-based alloy cladding layer containing chromium-rich precipitates prepared in Example 2 after immersion in simulated seawater for 6 months.

[0100]

[0101] Depend on Figure 5 As shown in Table 3, the copper-based alloy cladding layer containing chromium-rich precipitates forms a double-layer corrosion product. The inner layer consists of Cu₂O, Cr₂O₃, and Cu-rich particles, while the outer layer consists of loose and discontinuous Cu₂(OH)₃Cl. The interface between the inner and outer corrosion product layers contains corrosion products such as Cu₂O, Cr₂O₃, Cu-rich particles, and Cu₂(OH)₃Cl with different coefficients of linear expansion. This results in a discontinuous distribution of Cu₂(OH)₃Cl in the outer layer, increasing the internal stress between the corrosion product layers and causing Cu₂(OH)₃Cl to peel off.

[0102] Figure 6 The results of surface scanning analysis of the copper-based alloy cladding layer containing chromium-rich precipitates prepared in Example 2 are shown in Figure 15, where Cu is distributed, Cr is distributed, and Mn is distributed. As can be seen from the figure, Cr is concentrated in the chromium-rich precipitates, while Cu is mainly distributed in the copper-rich matrix phase, and Mn is evenly distributed in both the chromium-rich precipitates and the copper-rich matrix phase.

[0103] Determination of copper ion release rate in copper-based alloy cladding layers containing chromium-rich precipitates: The copper ion release rate in copper-based alloy cladding layers containing chromium-rich precipitates was calculated according to the national standard GB / T 6824-2008. The copper ion leakage rate was calculated from the copper ion concentration using the following formula:

[0104]

[0105] In the formula:

[0106] R—Copper ion leaching rate (μg∙cm⁻¹) -2 ∙d -1 );

[0107] ρ V —Copper ion concentration in exudate (μg∙L) -1 );

[0108] F—Correction factor for the exudate sample, F=1.01

[0109] ρ B —Copper ion concentration (μg∙L) in artificial seawater blank solution -1 );

[0110] V—Volume of simulated seawater solution in the seepage tank (1.4L);

[0111] t—Immersion time of the cladding sample in the exudation tank (1h);

[0112] A—Exposed surface area of ​​the sample (cm²) 2 );

[0113] Existing research has shown that for smooth, flat surfaces, the ion release rate can reach 40 μg∙cm⁻¹. -2 ∙d -1 In this way, it can protect against most marine organisms such as barnacles, algae, hydra, and jellyfish.

[0114] Figure 7 The figure shows the copper ion release rate curve of the copper-based alloy cladding layer containing chromium-rich precipitates in Example 2 after immersion in a simulated seawater environment for 38 days. As can be seen from the figure, the copper ion release rate is relatively high in the initial stage of immersion, and then decreases and gradually stabilizes over time. All release rate results are greater than 40 μg∙cm⁻¹. -2 ∙d -1 .

[0115] Figure 8This diagram illustrates the antifouling mechanism of a copper-based alloy cladding layer containing chromium-rich precipitates in a seawater environment. In the diagram, 18 represents vacancies left by preferential manganese corrosion, 19 represents the chromium-rich precipitates of the cladding layer, 20 represents the copper-rich matrix phase of the cladding layer, 21 represents the Cu₂(OH)₃Cl product layer, 22 represents Cu particles, 23 represents micropores, 24 represents Cr₂O₃ particles, 25 represents the Cu₂O product layer, and 26 represents cracks formed during corrosion. During corrosion, driven by a potential difference, the chromium-rich precipitates and the copper-rich matrix phase form a micro-corrosion cell. The chromium-rich precipitates, acting as the cathode, promote the corrosion and dissolution of the copper-rich matrix phase, which acts as the anode, continuously and stably releasing copper ions. Simultaneously, Mn preferentially corrodes and dissolves, leaving vacancies at corresponding locations, forming micropore defects. This increases the contact area between the copper-rich matrix phase and seawater, further promoting the corrosion and dissolution of the copper-rich matrix. The dissolved copper gradually reacts in seawater to form corrosion products that deposit on the surface of the cladding layer. These corrosion products exhibit a double-layer structure: the inner layer is primarily composed of Cu₂O, while the outer layer is mainly composed of Cu₂(OH)₃Cl. After corrosion, the chromium-rich precipitates are covered by a Cr₂O₃ film, forming Cr₂O₃ particles in situ and embedding them within the inner corrosion products. The formation of these Cr₂O₃ particles creates a localized acidic environment, promoting the dissolution of Cu₂O to form Cu-rich particles, leaving numerous pores in the inner corrosion layer. Furthermore, corrosion products with different coefficients of linear expansion (Cu₂O, Cr₂O₃, Cu, Cu₂(OH)₃Cl) are distributed at the product layer boundaries, increasing the internal stress between the corrosion product layers. This results in discontinuous distribution and flaking of Cu₂(OH)₃Cl in the outer product layer.

[0116] Based on the relationship between the stable release rate of copper ions (R) and the thickness of the cladding layer (y), the antifouling period (T) of the copper-based alloy cladding layer can be calculated. The formula for calculating the antifouling period (T) is as follows:

[0117]

[0118] In the formula:

[0119] T—Antifouling period (years);

[0120] y—Effective thickness of the cladding layer (μm);

[0121] ρ—Density of the cladding layer (g / cm³) 3 );

[0122] R—The stable value of the average release rate of copper ions per unit area (μg∙cm⁻¹) -2 ∙d -1 );

[0123] The stable value of copper ion release from the copper-based alloy cladding layer is 90 μg∙cm⁻¹ -2 ∙d-1 It can be concluded that when the effective thickness of the cladding layer is 800 μm, the antifouling period can reach more than 22 years.

[0124] In summary, the copper-based alloy cladding layer containing chromium-rich precipitates provided by this invention ensures the stable and continuous release of copper ions through the chromium-rich precipitate effect, thereby achieving a long-term anti-fouling effect and solving the problem that the anti-fouling effect of copper alloy surface is hindered by the coverage of a difficult-to-dissolve film (Cu2(OH)3Cl), which leads to a sharp decline in the anti-fouling effect in the short term. Among them, the chromium-rich precipitate effect mainly has the following two aspects: (1) The submicron-sized chromium-rich precipitates and the copper-rich matrix phase form a micro-corrosion cell in situ. The chromium-rich precipitates, as the cathode, promote the corrosion and dissolution of the copper-rich matrix phase, as the anode, ensuring the stable release of copper ions; (2) During the corrosion process, the Cr2O3 particles formed in situ on the chromium-rich precipitates promote the peeling off of Cu2(OH)3Cl, ensuring the continuous release of copper ions.

[0125] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A copper-based alloy cladding layer containing chromium-rich precipitate phase, comprising a metastable chromium-rich precipitate phase and a copper-rich matrix phase, wherein the copper-based alloy cladding layer is prepared from a copper-based alloy powder. The copper-based alloy powder comprises the following components by mass percentage: Cr 2-10%, Ni 0.2-3%, Mn 1-5%, Si 0.3-1%, P 0.1-0.5%, and Cu the balance.

2. The copper-based alloy cladding layer containing a chromium-rich precipitate phase according to claim 1, characterized in that, The particle size of the copper-based alloy powder is 200-400 mesh.

3. The copper-based alloy cladding layer containing a chromium-rich precipitate phase according to claim 1 or 2, characterized in that, The preparation method of the copper-based alloy powder comprises the following steps: vacuum smelting Cr, Ni, Mn, Si, P and Cu according to the composition of the copper-based alloy powder to obtain an alloy melt; atomizing the alloy melt to obtain a copper-based alloy powder.

4. The copper-based alloy cladding layer containing a chromium-rich precipitate phase according to claim 3, characterized in that, The vacuum smelting temperature is 1850-1950℃, and the holding time is 30-60 min.

5. The copper-based alloy cladding layer containing a chromium-rich precipitate phase according to claim 3, characterized in that, The atomizing conditions include: nitrogen as the atomizing medium, and the flow rate of the alloy melt is 0.5-1 kg / min.

6. The copper-based alloy cladding layer containing a chromium-rich precipitate phase according to claim 1, 2, 4 or 5, characterized in that, The average thickness of the copper-based alloy cladding layer containing chromium-rich precipitate phase is 300-1000 μm. 7.A method for preparing the copper-based alloy cladding layer containing chromium-rich precipitate phase according to any one of claims 1-6, comprising the following steps: removing corrosion products from the surface of a metal substrate to obtain a pretreated metal substrate; laser cladding on the surface of the pretreated metal substrate using the copper-based alloy powder as the raw material to obtain the copper-based alloy cladding layer containing chromium-rich precipitate phase.

8. The preparation method according to claim 7, characterized in that, The working conditions of the laser cladding include: the powder feeding amount is 0.8-2 kg / h, the flow rate of the protective gas is 15-20 L / min, the laser power is 2-6 kW, and the relative movement speed between the laser spot and the workpiece is 10-25 cm / s; for a flat plate-shaped workpiece, the step distance of the laser head is 0.5-0.8 mm. 9.Use of the copper-based alloy cladding layer containing chromium-rich precipitate phase according to any one of claims 1-6 or prepared by the method according to any one of claims 7-8 in preventing marine biofouling.

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