High-performance aluminum alloy sacrificial anode material for seawater corrosion prevention and preparation method thereof

Abstract

The application belongs to the technical field of metal corrosion and protection of seawater cooling system of nuclear power plant, and aims to solve the problem of low comprehensive performance of the sacrificial anode used in the seawater cooling system of nuclear power plant, and discloses a preparation method of high-performance aluminum alloy sacrificial anode material for seawater corrosion prevention, which heats an electric furnace to 725 DEG C ~ 750 DEG C, takes pure aluminum ingot, pure zinc ingot, pure indium ingot, pure magnesium ingot, pure silver particle and aluminum-titanium intermediate alloy containing 5% titanium as raw materials, carries out batching according to the set alloy composition, puts the pure aluminum ingot and the alloy elements into a crucible for refining and degassing under the protection of argon, pours into a preheated iron mold, and obtains the aluminum alloy sacrificial anode material after cooling and solidification; the prepared material has the component composition of zinc 5.5%, indium 0.02%~0.04%, magnesium 1%, titanium 0.04%~0.10%, silver 0.02%~0.08%, and the balance of aluminum. The prepared material has the advantages of stable working potential, low polarization rate, high current efficiency, uniform dissolution and easy falling off of corrosion products.

Description

Technical Field

[0001] This application belongs to the field of metal corrosion and protection technology for seawater cooling systems in nuclear power plants, and particularly relates to a high-performance aluminum alloy sacrificial anode material for seawater corrosion protection and its preparation method. Background Technology

[0002] Coastal nuclear power plants typically use circulating seawater as a cooling medium to effectively remove waste heat from steam generated after equipment operation and heat generated by conventional island equipment operation. However, pipe materials, primarily made of steel, are highly susceptible to corrosion in seawater environments. Therefore, cathodic protection is commonly used to protect the pipes from corrosion, with sacrificial anode cathodic protection being the most frequently employed method.

[0003] The sacrificial anode method is an electrochemical protection technique that directly connects the metal to be protected as the cathode to a metal with a more negative potential, forming a galvanic cell current loop. The protected material then undergoes cathodic polarization. In this way, the potential of the protected metal shifts negatively in the electrolyte environment, reaching a corrosion-resistant potential, thus effectively preventing metal corrosion.

[0004] The sacrificial anode materials commonly used in engineering fall into three main categories: magnesium and magnesium alloys, zinc and zinc alloys, and aluminum alloys. Compared with magnesium and zinc alloys, aluminum alloy sacrificial anode materials have advantages such as high theoretical capacitance, low price, and simple manufacturing process, making them the most commonly used sacrificial anode materials.

[0005] Currently, the most widely used aluminum alloy sacrificial anodes include aluminum-zinc-mercury, aluminum-zinc-tin, and aluminum-zinc-indium alloys. Aluminum-zinc-mercury sacrificial anodes contain mercury, which has adverse effects on human health and the environment; aluminum-zinc-tin sacrificial anodes have relatively low current efficiency and require heat treatment to achieve better electrochemical performance; aluminum-zinc-indium sacrificial anodes, due to their more negative potential, lower polarizability, and larger theoretical capacitance, have become the widely used and researched aluminum alloy sacrificial anode material.

[0006] The national standard GB / T4948-2002, "Aluminum-Zinc-Indium Alloy Anodes," recommends five types of aluminum-zinc-indium sacrificial anodes: aluminum-zinc-indium-cadmium alloy sacrificial anodes, aluminum-zinc-indium-tin alloy sacrificial anodes, aluminum-zinc-indium-silicon alloy sacrificial anodes, aluminum-zinc-indium-tin-magnesium alloy sacrificial anodes, and aluminum-zinc-indium-magnesium-titanium alloy sacrificial anodes. However, in actual production, aluminum alloy sacrificial anodes with the alloy compositions recommended by the national standard still suffer from problems such as low anodic current efficiency, severe and uneven corrosion, and shorter-than-expected lifespan, making it difficult to meet the high-performance requirements of sacrificial anodes used in seawater cooling systems of coastal nuclear power plants. Summary of the Invention

[0007] The purpose of this application is to provide a high-performance aluminum alloy sacrificial anode material for seawater corrosion protection and its preparation method, thereby solving the problem of low overall performance of sacrificial anodes used in seawater cooling systems of nuclear power plants.

[0008] To achieve the above objectives, this application provides the following technical solution: In a first aspect, this application provides a method for preparing a high-performance aluminum alloy sacrificial anode material for seawater corrosion protection, comprising: Step 1: Heat the electric furnace and control the temperature to 725℃~750℃; Step 2: Using pure aluminum ingots, pure zinc ingots, pure indium ingots, pure magnesium ingots, pure silver granules, and an aluminum-titanium master alloy containing 5% titanium as raw materials, the ingredients are prepared according to the set alloy composition. Step 3: Under argon protection, pure aluminum ingots and alloying elements are successively placed in a crucible for refining and degassing; Step 4: Cast the aluminum alloy sacrificial anode material using a preheated iron mold, and after cooling and solidification, obtain the material.

[0009] As one feasible approach, the alloy composition is set as follows: 5.5% zinc, 0.02%~0.04% indium, 1% magnesium, 0.04%~0.10% titanium, 0.02%~0.08% silver, with the balance being aluminum.

[0010] As one feasible method, the electric furnace is heated to 750°C, and the alloy composition used is 5.5% zinc, 0.02% indium, 1% magnesium, 0.05% titanium, 0.08% silver, and the balance is aluminum.

[0011] As one feasible method, the electric furnace is heated to 745°C, and the alloy composition used is 5.5% zinc, 0.03% indium, 1% magnesium, 0.05% titanium, 0.05% silver, and the balance is aluminum.

[0012] As one feasible approach, the electric furnace is heated to 740°C, using an alloy composition of 5.5% zinc, 0.03% indium, 1% magnesium, 0.10% titanium, 0.02% silver, with the balance being aluminum.

[0013] As one feasible method, the electric furnace is heated to 735°C, and the alloy composition used is 5.5% zinc, 0.04% indium, 1% magnesium, 0.10% titanium, 0.08% silver, and the balance is aluminum.

[0014] As an feasible approach, an electric furnace using medium-frequency induction furnaces is employed.

[0015] As one feasible approach, a graphite crucible is used.

[0016] As one feasible approach, an iron mold preheated to 400°C is used.

[0017] Secondly, this application provides a high-performance aluminum alloy sacrificial anode material for seawater corrosion protection prepared by the above method, wherein the composition by mass percentage is: zinc 5.5%, indium 0.02%~0.04%, magnesium 1%, titanium 0.04%~0.10%, silver 0.02%~0.08%, and the balance is aluminum.

[0018] Compared with the prior art, the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection and its preparation method provided in this application have the following advantages: The aluminum alloy sacrificial anode material prepared by this method has an open-circuit potential of -1.14V and an operating potential of -0.96V to -1.14V in a simulated seawater environment (3.5% NaCl solution), with a current efficiency of 89.30%. It exhibits good dissolution morphology and appropriately sized and uniform corrosion pits. Compared with traditional aluminum alloy sacrificial anode materials, it has the advantages of stable operating potential, low polarization, high current efficiency, uniform dissolution, and easy removal of corrosion products. Its comprehensive performance is excellent and meets the performance requirements of sacrificial anodes in seawater cooling systems of nuclear power plants.

[0019] This method reduces the cooling rate during the forming of aluminum alloy sacrificial anode materials, resulting in more alloying elements dissolved in the matrix, leading to stronger activity during discharge. It also reduces current efficiency loss caused by the shedding of the second phase and grains, thus improving discharge performance. Furthermore, the preparation method is simple, suitable for large-scale industrial production, and can be used to prepare sacrificial anode materials for seawater cooling systems in nuclear power plants. Attached Figure Description

[0020] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the technical description will be briefly introduced below.

[0021] Figure 1 A flowchart illustrating the preparation method of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection provided in this application; Figure 2 This is a scanning electron microscope (SEM) image of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection provided in Example 1 of this application. Figure 3 This is a scanning electron microscope (SEM) image of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection provided in Example 2 of this application. Figure 4 This is a scanning electron microscope (SEM) image of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection provided in Example 3 of this application. Figure 5 This is a scanning electron microscope (SEM) image of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection provided in Example 4 of this application. Figure 6The surface dissolution morphology of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection provided in Example 1 of this application after discharge performance testing; Figure 7 This is a surface dissolution morphology image of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection provided in Example 2 of this application after discharge performance testing. Figure 8 This is a surface dissolution morphology image of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection provided in Example 3 of this application after discharge performance testing. Figure 9 The image shows the surface dissolution morphology of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection provided in Example 4 of this application after discharge performance testing. Detailed Implementation

[0022] The following detailed description provides further details on specific implementation methods.

[0023] like Figure 1 As shown, this application provides a method for preparing a high-performance aluminum alloy sacrificial anode material for seawater corrosion protection, comprising the following steps: Step 1: Heat the medium-frequency induction furnace and control the temperature to 725℃~750℃; Step 2: Using pure aluminum ingots, pure zinc ingots, pure indium ingots, pure magnesium ingots, pure silver granules, and an aluminum-titanium master alloy containing 5% titanium as raw materials, the materials are prepared according to the designed alloy composition (zinc 5.5%, indium 0.02%~0.04%, magnesium 1%, titanium 0.04%~0.10%, silver 0.02%~0.08%, balance aluminum); Step 3: Under argon protection, pure aluminum ingots and alloying elements are successively placed into a graphite crucible for refining and degassing; Step 4: Cast the aluminum alloy sacrificial anode material by pouring it into an iron mold preheated to 400°C and allowing it to cool and solidify.

[0024] This application employs an alloying method, effectively solving the passivation problem of pure aluminum by adding activating elements.

[0025] In this method, zinc is the main alloying element of aluminum alloy sacrificial anode material. It can shift the anode potential negatively, increase the driving voltage, enhance its current output capability, make the anode dissolve evenly, and help the corrosion products to fall off.

[0026] In this method, indium can effectively activate the alloy, making the anodic potential more negative, and can slow down the rate of aluminum anodic pitting corrosion and increase the uniformity of the corroded surface.

[0027] In this method, magnesium can significantly refine grains, making the distribution of intermetallic compounds more uniform, while reducing corrosion potential. It also enhances activation performance through synergistic effects with the second phase, promotes matrix dissolution, and improves sacrificial anode efficiency.

[0028] The silver element in this method can improve the corrosion resistance of aluminum alloys and reduce the current efficiency loss caused by self-corrosion, thereby improving the sacrificial anode current efficiency.

[0029] The titanium element in this method can reduce segregation, make the alloying elements dissolve more uniformly, enhance activation performance, and reduce intergranular corrosion.

[0030] This method uses a 400℃ iron mold for casting and cooling, which reduces the cooling rate, allowing more alloying elements to dissolve in the aluminum alloy sacrificial anode matrix, enhancing discharge activity, and reducing current efficiency loss caused by the shedding of the second phase and grains, thus improving overall performance.

[0031] In addition, a high-performance aluminum alloy sacrificial anode material for seawater corrosion protection was prepared according to the method. The composition of the material by mass percentage is: zinc 5.5%, indium 0.02%~0.04%, magnesium 1%, titanium 0.04%~0.10%, silver 0.02%~0.08%, and the balance being aluminum.

[0032] Example 1 The preparation method of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection in this embodiment includes the following steps: Step 1: Heat the medium-frequency induction furnace and control the temperature to 750℃; Step 2: Combine pure aluminum ingots, pure zinc ingots, pure indium ingots, pure magnesium ingots, pure silver granules, and an aluminum-titanium master alloy containing 5% titanium according to the mass percentage of the alloy composition. The purity of the aluminum in the raw materials must meet the requirements of Al 99.999 in YS / T275-2018, the purity of zinc must meet the requirements of Zn 99.995 in GB / T470-2008, the purity of indium must meet the requirements of In 99.995 in YS / T257-2009, the purity of magnesium must meet the requirements of Mg 99.98 in GB / T 3499-2023, and the purity of silver must meet the requirements of Ag 99.995 in GB / T 39810-2021. The alloy composition is 5.5% zinc, 0.02% indium, 1% magnesium, 0.05% titanium, 0.08% silver, with the balance being aluminum. Step 3: Under argon protection, pure aluminum ingots and alloying elements are successively placed into a graphite crucible for refining and degassing; Step 4: Cast the aluminum alloy sacrificial anode material by pouring it into an iron mold preheated to 400°C and allowing it to cool and solidify.

[0033] According to the above method, this embodiment provides a high-performance aluminum alloy sacrificial anode material for seawater corrosion protection, with the following composition by mass percentage: zinc 5.5%, indium 0.02%, magnesium 1%, titanium 0.05%, silver 0.08%, and the balance being aluminum.

[0034] Example 2 The preparation method of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection in this embodiment includes the following steps: Step 1: Heat the medium-frequency induction furnace and control the temperature to 745℃; Step 2: Combine pure aluminum ingots, pure zinc ingots, pure indium ingots, pure magnesium ingots, pure silver granules, and an aluminum-titanium master alloy containing 5% titanium according to the mass percentage of the alloy composition. The purity of aluminum in the raw materials must meet the requirements of Al 99.999 in YS / T275-2018, zinc 99.995 in Zn in GB / T470-2008, indium 99.995 in YS / T257-2009, magnesium 99.98 in Mg in GB / T 3499-2023, and silver 99.995 in Ag in GB / T 39810-2021. The alloy composition is 5.5% zinc, 0.03% indium, 1% magnesium, 0.05% titanium, 0.05% silver, with the balance being aluminum. Step 3: Under argon protection, pure aluminum ingots and alloying elements are successively placed into a graphite crucible for refining and degassing; Step 4: Cast the aluminum alloy sacrificial anode material by pouring it into an iron mold preheated to 400°C and allowing it to cool and solidify.

[0035] According to the above method, this embodiment provides a high-performance aluminum alloy sacrificial anode material for seawater corrosion protection, with the following composition by mass percentage: zinc 5.5%, indium 0.03%, magnesium 1%, titanium 0.05%, silver 0.05%, and the balance being aluminum.

[0036] Example 3 The preparation method of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection in this embodiment includes the following steps: Step 1: Heat the medium-frequency induction furnace and control the temperature to 740℃; Step 2: Combine pure aluminum ingots, pure zinc ingots, pure indium ingots, pure magnesium ingots, pure silver granules, and an aluminum-titanium master alloy containing 5% titanium according to the mass percentage of the alloy composition. The purity of aluminum in the raw materials must meet the requirements of Al 99.999 in YS / T275-2018, zinc 99.995 in Zn in GB / T470-2008, indium 99.995 in YS / T257-2009, magnesium 99.98 in Mg in GB / T 3499-2023, and silver 99.995 in Ag in GB / T 39810-2021. The alloy composition is 5.5% zinc, 0.03% indium, 1% magnesium, 0.10% titanium, 0.02% silver, with the balance being aluminum. Step 3: Under argon protection, pure aluminum ingots and alloying elements are successively placed into a graphite crucible for refining and degassing; Step 4: Cast the aluminum alloy sacrificial anode material by pouring it into an iron mold preheated to 400°C and allowing it to cool and solidify.

[0037] According to the above method, this embodiment provides a high-performance aluminum alloy sacrificial anode material for seawater corrosion protection, with the following composition by mass percentage: zinc 5.5%, indium 0.03%, magnesium 1%, titanium 0.10%, silver 0.02%, and the balance being aluminum.

[0038] Example 4 The preparation method of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection in this embodiment includes the following steps: Step 1: Heat the medium-frequency induction furnace and control the temperature to 735℃; Step 2: Combine pure aluminum ingots, pure zinc ingots, pure indium ingots, pure magnesium ingots, pure silver granules, and an aluminum-titanium master alloy containing 5% titanium according to the mass percentage of the alloy composition. The purity of the aluminum in the raw materials must meet the requirements of Al 99.999 in YS / T275-2018, the purity of zinc must meet the requirements of Zn 99.995 in GB / T470-2008, the purity of indium must meet the requirements of In 99.995 in YS / T257-2009, the purity of magnesium must meet the requirements of Mg 99.98 in GB / T 3499-2023, and the purity of silver must meet the requirements of Ag 99.995 in GB / T 39810-2021. The alloy composition is 5.5% zinc, 0.04% indium, 1% magnesium, 0.10% titanium, 0.08% silver, with the balance being aluminum. Step 3: Under argon protection, pure aluminum ingots and alloying elements are successively placed into a graphite crucible for refining and degassing; Step 4: Cast the aluminum alloy sacrificial anode material by pouring it into an iron mold preheated to 400°C and allowing it to cool and solidify.

[0039] According to the above method, this embodiment provides a high-performance aluminum alloy sacrificial anode material for seawater corrosion protection, with the following composition by mass percentage: zinc 5.5%, indium 0.04%, magnesium 1%, titanium 0.10%, silver 0.08%, and the balance being aluminum.

[0040] Based on the above four embodiments, the composition of the high-performance aluminum alloy sacrificial anode material for seawater corrosion protection is shown in Table 1: Table 1. Composition (mass percentage) of high-performance aluminum alloy sacrificial anode material for seawater corrosion protection Examples 1-4 were tested according to the electrochemical performance testing standard for aluminum sacrificial anodes (GB / T 17848-1999), and the working potential, actual capacitance, and current efficiency of the sacrificial anodes are shown in Table 2. Table 2. Current efficiency test results of high-performance aluminum alloy sacrificial anode materials for seawater corrosion protection Compared with traditional aluminum alloy sacrificial anode materials, the material prepared by this method has the advantages of stable working potential, low polarization, high current efficiency, uniform dissolution and easy removal of corrosion products. It has good comprehensive performance and meets the performance requirements of sacrificial anodes in seawater cooling systems of nuclear power plants.

[0041] The above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. A method for preparing a high-performance aluminum alloy sacrificial anode material for seawater corrosion protection, characterized in that, include: Step 1: Heat the electric furnace and control the temperature to 725℃~750℃; Step 2: Using pure aluminum ingots, pure zinc ingots, pure indium ingots, pure magnesium ingots, pure silver granules, and an aluminum-titanium master alloy containing 5% titanium as raw materials, the ingredients are prepared according to the set alloy composition. Step 3: Under argon protection, pure aluminum ingots and alloying elements are successively placed in a crucible for refining and degassing; Step 4: Cast the aluminum alloy sacrificial anode material using a preheated iron mold, and after cooling and solidification, obtain the material.

2. The method for preparing high-performance aluminum alloy sacrificial anode material for seawater corrosion protection according to claim 1, characterized in that, The alloy composition is set as follows: 5.5% zinc, 0.02%~0.04% indium, 1% magnesium, 0.04%~0.10% titanium, 0.02%~0.08% silver, and the balance is aluminum.

3. The method for preparing high-performance aluminum alloy sacrificial anode material for seawater corrosion protection according to claim 1, characterized in that, The electric furnace is heated to 750℃. The alloy composition used is 5.5% zinc, 0.02% indium, 1% magnesium, 0.05% titanium, 0.08% silver, and the balance is aluminum.

4. The method for preparing high-performance aluminum alloy sacrificial anode material for seawater corrosion protection according to claim 1, characterized in that, The electric furnace is heated to 745℃. The alloy composition used is 5.5% zinc, 0.03% indium, 1% magnesium, 0.05% titanium, 0.05% silver, and the balance is aluminum.

5. The method for preparing high-performance aluminum alloy sacrificial anode material for seawater corrosion protection according to claim 1, characterized in that, The electric furnace is heated to 740℃. The alloy composition used is 5.5% zinc, 0.03% indium, 1% magnesium, 0.10% titanium, 0.02% silver, and the balance is aluminum.

6. The method for preparing high-performance aluminum alloy sacrificial anode material for seawater corrosion protection according to claim 1, characterized in that, The electric furnace is heated to 735℃. The alloy composition used is 5.5% zinc, 0.04% indium, 1% magnesium, 0.10% titanium, 0.08% silver, and the balance is aluminum.

7. The method for preparing high-performance aluminum alloy sacrificial anode material for seawater corrosion protection according to claim 1, characterized in that, In step 1, a medium-frequency induction furnace is used.

8. The method for preparing high-performance aluminum alloy sacrificial anode material for seawater corrosion protection according to claim 1, characterized in that, In step 3, a graphite crucible is used.

9. The method for preparing high-performance aluminum alloy sacrificial anode material for seawater corrosion protection according to claim 1, characterized in that, In step 4, an iron mold preheated to 400°C is used.

10. A high-performance aluminum alloy sacrificial anode material for seawater corrosion protection prepared by the method according to any one of claims 1 to 9, characterized in that, The composition by mass percentage is: zinc 5.5%, indium 0.02%~0.04%, magnesium 1%, titanium 0.04%~0.10%, silver 0.02%~0.08%, with the balance being aluminum.

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