Low driving potential aluminum alloy sacrificial anode for seawater cooling water system and preparation method thereof

Abstract

The application discloses a low-driving-potential aluminum alloy sacrificial anode for a seawater cooling water system, which comprises a sacrificial anode body and a core, the core is wrapped in the sacrificial anode body, the sacrificial anode body is mainly composed of aluminum, and gallium, tin, antimony and copper are added, the weight percentage of each component is as follows: 0.3-0.5% of gallium, 0.01-0.1% of tin, 0.005-0.02% of antimony, 0.01-0.1% of copper, less than or equal to 0.06% of impurity iron, and the balance of aluminum. The working potential of the low-driving-potential aluminum alloy sacrificial anode for the seawater cooling water system is-0.75V to-0.90V (relative to a saturated calomel electrode), the electric capacity is greater than or equal to 2300 Ah / kg, the sacrificial anode surface dissolves uniformly, the corrosion product is easy to fall off, and the low-driving-potential aluminum alloy sacrificial anode is suitable for cathode protection of high-strength steel, titanium-steel composite structure, stainless steel and other materials in a seawater environment. The application further discloses a preparation method of the low-driving-potential aluminum alloy sacrificial anode for the seawater cooling water system.

Description

Technical Field

[0001] This invention belongs to the field of corrosion and protection technology of metallic materials, and in particular relates to a low-drive-potential aluminum alloy sacrificial anode for seawater cooling water systems and its preparation method. Background Technology

[0002] Electrochemical protection is a material protection method that relies on the inflow of an external current to change the metal's potential, thereby reducing the metal's corrosion rate. Cathodic protection involves passing a sufficient cathodic current through the metal surface to reduce the anodic dissolution rate, thus preventing corrosion. Cathodic protection is an effective means of preventing steel structure corrosion in marine and soil environments. Cathodic protection includes impressed current cathodic protection and sacrificial anode protection. Sacrificial anode cathodic protection connects a metal with a more negative potential to the metal being protected, placing them in the same electrolyte. The current generated by the continuous corrosion and dissolution of the negatively charged metal protects the metal being protected, ensuring that the entire protected metal is at a relatively negative and uniform potential.

[0003] Aluminum alloy sacrificial anodes have been widely used in offshore oil equipment, subsea pipelines, offshore structures, and coastal power plants due to their advantages such as light weight, excellent electrochemical performance, and low cost. For a long time, researchers have been committed to developing sacrificial anodes with open-circuit potentials and operating potentials negative than -1.0V (relative to saturated calomel electrodes, the same below) and high current efficiency. Currently, sacrificial anodes suitable for seawater environments are mainly Al-Zn-In, Al-Zn-Sn, and Al-Zn-Hg system sacrificial anodes, with operating potentials all around -1.05V.

[0004] In 1980, researchers discovered that hydrogen embrittlement induced by cathodic protection caused the failure of UNS G43406 high-strength steel, thus raising awareness of the hydrogen embrittlement problem caused by traditional sacrificial anode materials. Some coastal power plants in China use titanium-steel composite structures for their cooling water condensers. Due to the difference in natural potential between titanium alloys and stainless steel, galvanic corrosion occurs, leading to preferential dissolution of stainless steel components. Cathodic protection technology is needed to reduce the corrosion rate of the condenser. Because titanium alloys are sensitive to hydrogen embrittlement, when implementing combined cathodic protection for stainless steel and titanium alloy structural components in seawater, the cathodic protection potential needs to be strictly controlled to prevent galvanic corrosion and hydrogen embrittlement. Therefore, it is necessary to develop low-drive-potential sacrificial anodes with an operating potential between -0.75 and -0.90 V (relative to a saturated calomel electrode).

[0005] In 1996, Le Guyader et al. pioneered two low-drive-potential aluminum anodes with Al-Ga and Al-Cd formulations (US Patent 5547560), with an operating potential range of -0.770V to -0.870V. While this anode's potential met the cathodic protection requirements of high-strength steel and titanium-steel composite structures, it suffered from low current efficiency and uneven anode dissolution. Based on this formulation, the 725th Research Institute of China Shipbuilding Industry Corporation developed the Al-Zn-Ga-Si low-drive-potential sacrificial anode (CN101445936A); Qingdao Shuangrui Marine Environmental Engineering Co., Ltd. developed the Al-Ga-Si-Mg-Ti low-drive-potential sacrificial anode (CN106222567A). Although these anode formulations showed some improvement in current efficiency and dissolution morphology compared to Al-Ga anodes, they still lagged significantly behind conventional Al-Zn-In anodes. Summary of the Invention

[0006] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this invention is to provide a low-drive-potential aluminum alloy sacrificial anode for seawater cooling water systems, which is suitable for cathodic protection of hydrogen embrittlement-sensitive materials such as high-strength steel, stainless steel, and titanium alloys. While preventing material corrosion, it avoids material failure and damage caused by hydrogen embrittlement, and ensures the long-term safe service of the protected body.

[0007] This invention provides a low-drive-potential aluminum alloy sacrificial anode for seawater cooling systems, comprising a sacrificial anode body and a core. The core is encapsulated within the sacrificial anode body. The sacrificial anode body is primarily composed of aluminum, with added gallium, tin, antimony, and copper. The weight percentages of each component are: gallium 0.3%–0.5%, tin 0.01%–0.1%, antimony 0.005%–0.02%, copper 0.01%–0.1%, iron impurities ≤0.06%, and the balance being aluminum.

[0008] Furthermore, the weight ratio of tin to antimony in the sacrificial anode body is 2:1 to 5:1.

[0009] Furthermore, the operating potential of the low-drive-potential aluminum alloy sacrificial anode used in the seawater cooling system is -0.75V to -0.90V (relative to a saturated calomel electrode), and the capacitance is ≥2300Ah / kg.

[0010] Furthermore, the core is an iron core, and the iron core is made of 316L stainless steel.

[0011] This invention provides a method for preparing a low-drive-potential aluminum alloy sacrificial anode for a seawater cooling water system, comprising the following steps:

[0012] The aluminum ingots are heated in a furnace to a first temperature and completely melted into aluminum solution;

[0013] Gallium ingots, tin ingots, antimony ingots, and copper ingots are added to the aluminum solution according to the formula ratio and then melted.

[0014] Maintain the temperature in the heating furnace at the second temperature, and stir the heating furnace to ensure that the components are mixed evenly;

[0015] The core is placed in the mold beforehand and heated to the third temperature. The mixed solution prepared above is then poured into the mold after slag removal and quenching.

[0016] The cooled sacrificial anode blank was placed in a heat treatment furnace and held at the fourth temperature for 2-4 hours, and then cooled to room temperature at a rate of 15-50℃ / h to obtain the low driving potential aluminum alloy sacrificial anode for the seawater cooling water system.

[0017] Furthermore, the first temperature is ≥820℃.

[0018] Furthermore, the second temperature is 820℃~880℃.

[0019] Furthermore, the third temperature is 120℃~200℃.

[0020] Furthermore, the fourth temperature is 200℃~300℃.

[0021] Furthermore, the purity of the aluminum ingot is not less than 99.85%, and the purity of the gallium ingot, tin ingot, antimony ingot, and copper ingot is not less than 99.99%.

[0022] The sacrificial anode body of the low-drive-potential aluminum alloy sacrificial anode for seawater cooling systems of the present invention is mainly composed of aluminum (Al), with gallium (Ga), tin (Sn), antimony (Sb) and copper (Cu) added in proportion, and the content of impurity iron (Fe) strictly controlled. This results in the working potential of the low-drive-potential aluminum alloy sacrificial anode for seawater cooling systems being -0.75V to -0.90V (relative to a saturated calomel electrode), a capacitance ≥2300Ah / kg, uniform dissolution on the sacrificial anode surface, and easy removal of corrosion products. It is suitable for cathodic protection of high-strength steel, titanium-steel composite structures, stainless steel, and other materials in seawater environments. At the same time, the production process is simple and the production cost is low. Attached Figure Description

[0023] Figure 1 Metallographic microstructure of the Sb-free Al-Ga-Sn-Cu anode of the present invention;

[0024] Figure 2 The metallographic microstructure of the Al-Ga-Sn-Sb-Cu anode with a Sb content of 0.01% according to the present invention is shown. Detailed Implementation

[0025] Specific embodiments of the present invention will now be described in detail. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of them. Based on the description of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention.

[0026] The terms "first," "second," "third," etc., used in the specification and claims of this invention are merely for distinguishing similar objects and do not indicate or imply relative importance or a specific order.

[0027] The terms “comprising,” “including,” or any other variations thereof used in the specification and claims of this invention are intended to cover a non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0028] This invention provides a low-drive-potential aluminum alloy sacrificial anode (Al-Ga-Sn-Sb-Cu) for seawater cooling systems, comprising a sacrificial anode body and a core. The core is encapsulated within the sacrificial anode body. The sacrificial anode body is primarily composed of aluminum, with added gallium, tin, antimony, and copper. The weight percentages of each component are as follows: gallium 0.3%–0.5%, tin 0.01%–0.1%, antimony 0.005%–0.02%, copper 0.01%–0.1%, iron impurities ≤0.06%, and the balance being aluminum.

[0029] In this embodiment, increasing the gallium content to 0.3%–0.5% increases the number of activation points on the sacrificial anode, resulting in more uniform corrosion. To suppress the negative shift in the sacrificial anode's operating potential due to increased gallium content, copper is added. Adding a small amount of copper (0.01%–0.1%) controls the negative shift in the anode potential, preventing excessively negative operating potential without significantly affecting the anode's dissolution morphology. To further improve the dissolution performance of the low-drive-potential anode, tin and antimony alloying elements are added. Sn can refine the grains and improve the activity of the anode surface; the combined effect of Sn and Sb can more effectively prevent the segregation of impurity elements and improve the sacrificial anode current efficiency.

[0030] Furthermore, in this embodiment, the weight ratio of tin to antimony in the sacrificial anode body is 2:1 to 5:1.

[0031] Furthermore, in this embodiment, the working potential of the low-drive-potential aluminum alloy sacrificial anode used in the seawater cooling water system is -0.75V to -0.90V (relative to a saturated calomel electrode), and the capacitance is ≥2300Ah / kg.

[0032] Furthermore, in this embodiment, the core is an iron core, and the iron core is made of 316L stainless steel. Ordinary carbon steel requires a cathodic protection potential negative 0.8V (relative to a silver / silver chloride / seawater electrode) in seawater to avoid corrosion, while the cathodic protection potential of 316L stainless steel is negative 0.5V (relative to a silver / silver chloride / seawater electrode). Therefore, 316L stainless steel is selected as the low-drive-potential anode core to avoid corrosion of the iron core. Simultaneously, 316L stainless steel requires a low cathodic protection current density, which can improve the actual current efficiency of the sacrificial anode.

[0033] This invention also provides a method for preparing a low-drive-potential aluminum alloy sacrificial anode for a seawater cooling water system, comprising the following steps:

[0034] The aluminum ingots are heated in a furnace to a first temperature and completely melted into aluminum solution;

[0035] Gallium ingots, tin ingots, antimony ingots, and copper ingots are added to the aluminum solution according to the formula ratio and then melted.

[0036] Maintain the temperature in the heating furnace at the second temperature, and stir the heating furnace to ensure that the components are mixed evenly;

[0037] The core is placed in the mold beforehand and heated to the third temperature. The mixed solution prepared above is then poured into the mold after slag removal and quenching.

[0038] The cooled sacrificial anode blank was placed in a heat treatment furnace and held at the fourth temperature for 2-4 hours. Then it was cooled to room temperature at a rate of 15-50℃ / h to obtain a low-drive potential aluminum alloy sacrificial anode for seawater cooling water systems.

[0039] Furthermore, in this embodiment, the first temperature is ≥820°C.

[0040] Furthermore, in this embodiment, the second temperature is 820°C to 880°C.

[0041] Furthermore, in this embodiment, the third temperature is 120°C to 200°C.

[0042] Furthermore, in this embodiment, the fourth temperature is 200℃~300℃.

[0043] Specifically, in this embodiment, the preparation process of the low-drive-potential aluminum alloy sacrificial anode for the seawater cooling system of the present invention adopts the melting and casting method. The heating furnace is selected from crucibles, but is not limited to this. Stirring is done with a carbon rod, but is not limited to this. During melting, aluminum ingots are first heated in a crucible to above 820°C to melt into an aluminum solution. Then, alloying elements are added to the aluminum solution according to the formula ratio, and then gently stirred with a carbon rod to ensure uniform mixing and sufficient diffusion of the alloying elements during solidification. The temperature of the aluminum liquid is maintained between 820°C and 880°C throughout the refining process to ensure that the alloying elements form an effective solid solution with the base aluminum. During casting, the iron core is pre-placed in a cast iron mold and heated to between 120°C and 200°C. After slag removal, the uniformly mixed aluminum alloy solution is poured into the cast iron mold and immediately quenched and cooled to room temperature. This step can reduce the residence time of the 316L stainless steel iron core in the temperature range of 450°C to 800°C, avoiding the increased tendency for intergranular corrosion caused by stainless steel sensitization. The quenched and cooled aluminum alloy sacrificial anode blank is held in a heat treatment furnace at 200℃~300℃ for 2-4 hours, and then cooled to room temperature at a rate of 15~50℃ / h to obtain a low-drive-potential aluminum alloy sacrificial anode for seawater cooling systems. Holding in the heat treatment furnace for 2-4 hours and then cooling to room temperature at a rate of 15~50℃ / h can eliminate the segregation of alloying elements, improve the uniformity of the sacrificial anode composition, and improve the anode's dissolution morphology.

[0044] Furthermore, in this embodiment, the purity of the aluminum ingot is not less than 99.85%, and the purity of the gallium ingot, tin ingot, antimony ingot and copper ingot is not less than 99.99%.

[0045] This invention uses high-purity aluminum as the main raw material. By optimizing the types and content ranges of alloying elements and strictly controlling the content of impurity elements, the invention controls the melting process parameters such as temperature and alloying element addition methods during the anode melting process, and adjusts the distribution state of alloying elements in the alloy to achieve effective activation of the anode. At the same time, it controls the negative shift of the anode potential to obtain a low-drive potential aluminum alloy sacrificial anode for seawater cooling water systems. The anode has a uniform dissolution morphology and the corrosion products are easy to detach. It can be used as a cathodic protection sacrificial anode for hydrogen embrittlement sensitive materials such as high-strength steel.

[0046] The beneficial effects of this invention are as follows:

[0047] (1) By increasing the gallium content to 0.3% to 0.5%, the number of activation points of the low-drive potential aluminum alloy sacrificial anode in the seawater cooling system increases, and the corrosion becomes more uniform.

[0048] (2) To suppress the excessively negative working potential of the low-drive-potential aluminum alloy sacrificial anode used in seawater cooling systems due to the increase in gallium content, copper is added. Copper has a high electrode potential, and in conventional Al-Zn-In anodes, a high copper content will change the working potential of the anode, so it is considered an impurity element. However, in low-drive-potential anodes, adding a small amount of copper (0.01% to 0.1%) can avoid the anode's working potential from becoming too negative, and at the same time, it will not have a significant impact on the anode's dissolution morphology.

[0049] (3) To further improve the dissolution performance of the low-drive-potential aluminum alloy sacrificial anode for seawater cooling systems, tin and antimony alloying elements were added. Tin can refine the grains and improve the activity of the anode surface; the combined effect of tin and antimony can more effectively prevent the segregation of impurity elements and improve the current efficiency of the sacrificial anode.

[0050] The present invention will be further described in detail below with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0051] The following description is based on specific embodiments:

[0052] Example 1:

[0053] The formulation of the sacrificial anode body of the low-drive-potential aluminum alloy sacrificial anode for seawater cooling systems is (by weight percentage): Ga 0.3%, Sn 0.01%, Sb 0.005%, Cu 0.01%, Fe 0.06% (impurity element), and the balance being Al.

[0054] Aluminum ingots with an aluminum content ≥99.85% are heated in a furnace to above 850℃ until completely melted, or until no solid aluminum ingots are visually visible. Then, gallium ingots, tin ingots, antimony ingots, and copper ingots with a purity of not less than 99.99% are added according to the formula and melted. The mixture is gently stirred with a carbon rod to ensure uniform mixing, and the temperature of the molten aluminum is maintained between 820℃ and 850℃.

[0055] The iron core is pre-placed in a cast iron mold and heated to 200°C. After slag removal, the uniformly mixed aluminum alloy solution is poured into the cast iron mold and immediately quenched and cooled to room temperature. The quenched and cooled aluminum alloy sacrificial anode is held in a 200°C heat treatment furnace for 4 hours, and then cooled to room temperature at a rate of 50°C / h to obtain a low-drive-potential aluminum alloy sacrificial anode.

[0056] The electrochemical performance of the low-drive-potential aluminum alloy sacrificial anode used in the seawater cooling system obtained in Example 1 was tested according to the standard test method specified in GB / T 17848-1999. The test medium was natural seawater from the coastal area of ​​Qingdao, and the reference electrode was a saturated calomel electrode (SCE). The specific experimental results are shown in Table 1. The open-circuit potential was between -0.95V and -1.10V, the operating potential was between -0.77V and -0.85V, and the capacitance was 2493Ah / kg. Furthermore, the surface of the low-drive-potential aluminum alloy sacrificial anode used in this seawater cooling system was uniformly dissolved, and the corrosion products were easily detached.

[0057] Example 2:

[0058] The formulation of the sacrificial anode body of the low-drive-potential aluminum alloy sacrificial anode for seawater cooling water systems is (by weight percentage): Ga 0.5%, Sn 0.1%, Sb 0.02%, Cu 0.1%, Fe 0.04% (impurity element), with the balance being Al.

[0059] Aluminum ingots with an aluminum content ≥99.85% are heated in a furnace to above 820℃ until completely melted, or until no solid aluminum ingots are visually visible. Then, gallium ingots, tin ingots, antimony ingots, and copper ingots with a purity of not less than 99.99% are added according to the formula and melted. The mixture is gently stirred with a carbon rod to ensure uniform mixing, and the temperature of the molten aluminum is maintained between 820℃ and 850℃.

[0060] The iron core is pre-placed in a cast iron mold and heated to around 120°C. After slag removal, the uniformly mixed aluminum alloy solution is poured into the cast iron mold and immediately quenched and cooled to room temperature. The quenched and cooled aluminum alloy sacrificial anode is held in a 300°C heat treatment furnace for 2 hours, and then cooled to room temperature at a rate of 15°C / h to obtain the low-drive-potential aluminum alloy sacrificial anode.

[0061] The electrochemical performance of the low-drive-potential aluminum alloy sacrificial anode used in the seawater cooling system obtained in Example 2 was tested according to the standard test method specified in GB / T 17848-1999. The test medium was natural seawater from the Qingdao coastal area, and the reference electrode was a saturated calomel electrode (SCE). Specific experimental results are shown in Table 1. The open-circuit potential was between -0.90V and -1.10V, the operating potential was between -0.75V and -0.80V, the capacitance was 2331Ah / kg, the sacrificial anode surface showed uniform dissolution, and corrosion products were easily detached.

[0062] Example 3:

[0063] The formulation of the sacrificial anode body of the low-drive-potential aluminum alloy sacrificial anode for seawater cooling systems is (by weight percentage): Ga 0.4%, Sn 0.05%, Sb 0.02%, Cu 0.04%, Fe 0.05% (impurity element), and the balance being Al.

[0064] Aluminum ingots with an aluminum content ≥99.85% are heated to 850℃ in a furnace until completely melted, or until no solid aluminum ingots are visually visible. Then, gallium ingots, tin ingots, antimony ingots, and copper ingots with a purity of not less than 99.99% are added according to the formula and melted. The mixture is gently stirred with a carbon rod to ensure uniform mixing, and the temperature of the molten aluminum is maintained between 850℃ and 880℃.

[0065] The iron core is pre-placed in a cast iron mold and heated to 150°C. After slag removal, the uniformly mixed aluminum alloy solution is poured into the cast iron mold and immediately quenched and cooled to room temperature. The quenched and cooled aluminum alloy sacrificial anode is held in a 260°C heat treatment furnace for 3 hours, and then cooled to room temperature at a rate of 30°C / h to obtain the low-drive-potential aluminum alloy sacrificial anode.

[0066] The electrochemical performance of the low-drive-potential aluminum alloy sacrificial anode used in the seawater cooling system obtained in Example 3 was tested according to the standard test method specified in GB / T 17848-1999. The test medium was natural seawater from the Qingdao coastal area, and the reference electrode was a saturated calomel electrode (SCE). Specific experimental results are shown in Table 1. The open-circuit potential was between -0.95V and -1.05V, the operating potential was between -0.78V and -0.83V, the capacitance was 2478 Ah / kg, the sacrificial anode surface showed uniform dissolution, and corrosion products were easily detached.

[0067] Table 1 Electrochemical performance of low-drive-potential aluminum alloy sacrificial anodes

[0068]

[0069] Based on the experimental results of the above embodiments, it can be seen that in a natural seawater environment, the open circuit potential of the low driving potential aluminum alloy sacrificial anode prepared by the present invention is -0.90V to -1.10V, the working potential is -0.75V to -0.90V, the working potential is stable, the capacitance is ≥2300Ah / kg, the activation is complete, the corrosion is very uniform, the corrosion products are easy to detach, and it has excellent comprehensive performance.

[0070] Furthermore, in order to verify the effect of Cu on the electrochemical performance of the low-drive potential aluminum alloy sacrificial anode (Al-Ga-Sn-Sb-Cu) for seawater cooling water systems, the effects of adding different copper contents on the electrochemical performance of the four groups of low-drive potential aluminum alloy sacrificial anodes (Al-Ga-Sn-Sb-Cu) for seawater cooling water systems were tested. The core of each comparative sample was made of 316L stainless steel, and the content of each component of the sacrificial anode body is shown in Table 2.

[0071] Table 2. Composition (%) of each component in the comparative sample of the sacrificial anode body.

[0072]

[0073] The electrochemical performance of low-drive-potential aluminum alloy sacrificial anodes for seawater cooling water systems was tested using the GB / T 17848 method for testing the electrochemical performance of sacrificial anodes. The results are shown in Table 3.

[0074] Table 3 Electrochemical performance of low-driving-potential aluminum alloy sacrificial anodes

[0075]

[0076] As shown in Table 3, when the copper content of sample 1 is low (less than 0.005%), the working potential of the anode is around -1.0V, which does not meet the requirement of -0.75V to -0.90V for low-drive-potential aluminum alloy sacrificial anodes used in seawater cooling systems. This fails to meet the cathodic protection requirements of high-strength steel, leading to problems such as hydrogen embrittlement. With increasing copper content, the working potential of the anode gradually shifts positively, reaching the working potential range of low-potential anodes, and the capacitance stabilizes above 2300Ag / kg. Therefore, it can be seen that adding a small amount of copper (0.01%–0.1%) to a low-drive-potential anode can prevent the working potential from becoming too negative, effectively preventing galvanic corrosion and hydrogen embrittlement, without significantly affecting the anode's dissolution morphology.

[0077] Furthermore, to demonstrate the synergistic effect of Sn and Sb in low-drive-potential aluminum alloy anodes, the effect of adding Sb on the electrochemical performance of low-drive-potential aluminum alloy sacrificial anodes (Al-Ga-Sn-Sb-Cu) for seawater cooling systems was tested. The components are shown in Table 4.

[0078] Table 4. Composition (%) of each component in the sacrificial anode bulk comparison sample.

[0079]

[0080] Figure 1 The metallographic morphology of the Al-Ga-Sn-Cu anode without added Sb is shown. Figure 2This is the metallographic microstructure of an Al-Ga-Sn-Sb-Cu anode with 0.01% Sb added. From... Figure 1 and Figure 2 The comparison shows that, under the synergistic effect of Sn and Sb, the grain size of the Al-Ga-Sn-Sb-Cu anode with added Sb is reduced, the segregation of impurity elements at the grain boundaries is significantly reduced, and the element distribution is more uniform, which has a significant effect on the uniform dissolution of the anode. Therefore, Sn can refine the grains and improve the activity of the anode surface; the combined effect of Sn and Sb can more effectively prevent the segregation of impurity elements and improve the sacrificial anode current efficiency.

[0081] In summary, the low-drive-potential aluminum alloy sacrificial anode for seawater cooling systems of this invention exhibits excellent performance and can be applied in the following fields: cathodic protection of titanium alloy and stainless steel hybrid structures in condensers and other equipment in coastal power plants or factories; and cathodic protection of high-strength steel with a minimum yield strength greater than 550 MPa. Copper alloy seawater pipeline systems in ships and coastal power plants primarily use ferroalloy sacrificial anodes for corrosion protection, but ferroalloys have relatively low capacitance, and traditional zinc alloy anodes dissolve too quickly and have a short lifespan due to their excessively negative potential. The low-potential anode avoids the disadvantages of both types of anodes. With the increasing demand for protection of high-strength steel and titanium steel composite structures, the application of low-potential anodes will become increasingly widespread. Successful application of these anodes can protect the safe operation of nuclear power plants, ships, and marine engineering equipment, resulting in significant social benefits.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content without departing from the scope of the technical solution of the present invention, which are equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the technical solution of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A low-drive-potential aluminum alloy sacrificial anode for a seawater cooling system, comprising a sacrificial anode body and a core, wherein the core is enclosed within the sacrificial anode body, characterized in that, The sacrificial anode body is mainly composed of aluminum, with added gallium, tin, antimony and copper. The weight percentages of each component are: gallium 0.3%~0.5%, tin 0.01%~0.1%, antimony 0.005%~0.02%, copper 0.01%~0.1%, iron impurities ≤0.06%, and the balance being aluminum. The method for preparing the low-drive-potential aluminum alloy sacrificial anode for the seawater cooling system includes the following steps: The aluminum ingots are heated in a heating furnace to a first temperature ≥820℃ and completely melted into aluminum solution; Gallium ingots, tin ingots, antimony ingots, and copper ingots are added to the aluminum solution according to the formula ratio and then melted. Maintain the temperature in the heating furnace at a second temperature of 820℃~880℃, and stir the heating furnace to ensure that the components are mixed evenly; The core is placed in the mold beforehand and heated to a third temperature of 120℃~200℃. The mixed solution obtained above is then poured into the mold after removing the slag and quenched and cooled. The cooled sacrificial anode blank was placed in a heat treatment furnace and held at a fourth temperature of 200℃~300℃ for 2-4 hours, and then cooled to room temperature at a rate of 15~50℃ / h to obtain the low driving potential aluminum alloy sacrificial anode for the seawater cooling water system.

2. The low-drive-potential aluminum alloy sacrificial anode for a seawater cooling water system as described in claim 1, characterized in that, The weight ratio of tin to antimony in the sacrificial anode body is 2:1 to 5:

1.

3. The low-drive-potential aluminum alloy sacrificial anode for a seawater cooling water system as described in claim 1, characterized in that, The operating potential of the low-drive-potential aluminum alloy sacrificial anode used in the seawater cooling system is -0.75V to -0.90V relative to the saturated calomel electrode, and the capacitance is ≥2300 Ah / kg.

4. The low-drive-potential aluminum alloy sacrificial anode for a seawater cooling water system as described in claim 1, characterized in that, The core is an iron core, and the iron core is made of 316L stainless steel.

5. The method for preparing a low-drive-potential aluminum alloy sacrificial anode for a seawater cooling water system as described in claim 1, characterized in that, The purity of the aluminum ingot is not less than 99.85%, and the purity of the gallium ingot, tin ingot, antimony ingot and copper ingot is not less than 99.99%.

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