Aluminum-nickel-bronze grounding material and preparation method thereof

Abstract

The application provides an aluminum-nickel-bronze grounding material and a preparation method thereof, and the method comprises the following steps: S1, melting copper, nickel, iron and a second modified element combination in a vacuum or a protective atmosphere, adding aluminum, manganese and silicon after the combination is completely melted and uniformly distributed, and refining by temperature rising; S2, adjusting the temperature of the melt to 1120 DEG C-1180 DEG C, and sending a preheated composite core wire containing a first modified element combination and phosphorus into the bottom of the melt pool by adopting an inert gas blowing method; S3, pouring the refined melt into a copper crystallizer with cooling water, applying a steady-state strong magnetic field parallel to the direction of gravity to the melt, and the magnetic field strength is 1.0 T-1.3 T, so that an ingot with an axial orientation columnar crystal organization is obtained; and S4, performing multi-stage coupled heat treatment on the ingot. The aluminum-nickel-bronze grounding material prepared by the application has good conductivity, strength, corrosion resistance and long-term stability.

Description

Technical Field

[0001] This invention relates to the field of grounding material preparation technology, and in particular to an aluminum-nickel bronze grounding material and its preparation method. Background Technology

[0002] Grounding materials are key components for ensuring the safe operation of power systems and building facilities. Their performance must balance high conductivity, excellent mechanical strength, and long-term corrosion resistance in harsh soil environments. Traditional copper-based grounding materials (such as pure copper and copper-clad steel) have good conductivity, but suffer from insufficient strength and limited corrosion resistance (especially against pitting and electrochemical migration). While common aluminum bronze or simple aluminum-nickel bronze materials offer improved strength, their conductivity and corrosion resistance are often difficult to optimize synergistically, and their service stability in complex and polluted soils is insufficient. These materials cannot meet the increasing demands for comprehensive material performance and lifespan in high-reliability applications such as ultra-high voltage power transmission and offshore platforms.

[0003] To address the aforementioned issues, existing technologies often improve AlNi bronze by adding single or small amounts of elements (such as trace amounts of rare earth elements or chromium). However, such improvements often compromise other aspects, making it difficult to systematically and simultaneously control the material's conductive network, reinforcing phase, and corrosion-resistant interface. Furthermore, conventional casting processes tend to result in coarse microstructures and component segregation, hindering the formation of a uniform, stable, and high-performance microstructure. Therefore, there is an urgent need to develop a novel AlNi bronze grounding material with a more refined and synergistic composition design and a more targeted preparation process to achieve a breakthrough balance and improvement in conductivity, strength, corrosion resistance, and long-term stability. Summary of the Invention

[0004] The purpose of this invention is to provide an aluminum-nickel bronze grounding material and its preparation method, aiming to develop a new type of aluminum-nickel bronze grounding material with more refined and synergistic composition design and more targeted preparation process, so as to achieve a breakthrough balance and improvement in properties such as conductivity, strength, corrosion resistance and long-term stability.

[0005] In a first aspect, the present invention provides an aluminum-nickel bronze grounding material, comprising, by weight percentage:

[0006] 8.5%-10.0% aluminum, 4.0%-5.5% nickel, 3.0%-4.5% iron, 0.8%-1.8% manganese, 0.1%-0.4% silicon, 0.01%-0.08% phosphorus, 0.05%-0.5% first modifying element combination, 0.3%-1.2% second modifying element combination, balance copper.

[0007] In some embodiments, the first combination of modifying elements includes at least one of yttrium, lanthanum, and cerium, and the second combination of modifying elements includes at least one of chromium, molybdenum, and tungsten.

[0008] In some embodiments, the mass percentage of chromium in the second combination of modifying elements is 0.15%-0.6%, the mass percentage of molybdenum is 0.1%-0.5%, and the mass percentage of tungsten is 0.05%-0.3%.

[0009] In some embodiments, the mass percentage of yttrium in the first modified element combination is 0.02%-0.15%, the mass percentage of lanthanum is 0.01%-0.2%, the mass percentage of cerium is 0.02%-0.25%, and the ratio of the total content of the three elements to the content of phosphorus is between 4:1 and 12:1.

[0010] Secondly, the present invention provides a method for preparing an aluminum-nickel bronze grounding material, for preparing the above-mentioned aluminum-nickel bronze grounding material, the preparation method comprising:

[0011] Step S1: Under vacuum or protective atmosphere, first melt the combination of copper, nickel, iron and the second modified element. After they are completely melted and homogeneous, add aluminum, manganese and silicon, and heat to 1220℃-1280℃ for refining.

[0012] Step S2: Adjust the melt temperature to 1120℃-1180℃, and use an inert gas blowing method to send the preheated composite cored wire containing the first modified element combination and phosphorus into the bottom of the molten pool to allow it to react fully.

[0013] Step S3: Pour the refined melt into a copper crystallizer with cooling water. During the pouring and solidification process, apply a steady-state strong magnetic field parallel to the direction of gravity to the melt. The magnetic field strength is 1.0T-1.3T to obtain an ingot with an axially oriented columnar crystal structure.

[0014] Step S4: Perform multi-stage coupled heat treatment on the ingot.

[0015] In some embodiments, in step S3, the cooling rate of the cooling water is 80-150 K / s, the average width of the obtained columnar crystals is 150-300 micrometers, and the angle between their growth direction and the axis of the final grounding electrode product is not greater than 10 degrees.

[0016] In some embodiments, step S4 includes:

[0017] Primary treatment: The ingot is held at 720-750℃ for 10-14 hours to allow for element diffusion and framework bridging.

[0018] Secondary treatment: Rapidly heat to 960-985℃, hold for 45-75 minutes, then water quench;

[0019] Level 3 treatment: Aging at 470-500℃ for 4-7 hours, followed by air cooling.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] This invention achieves a breakthrough improvement in the comprehensive performance of AlNi bronze grounding materials through a proprietary process of precise multi-element synergistic design and directional solidification-coupled heat treatment. In terms of composition, a conductive and corrosion-resistant framework is constructed by introducing specific proportions of elements such as chromium, molybdenum, and tungsten, and grain boundary purification and interface stabilization are achieved using a precise ratio of rare earth elements and phosphorus. In terms of process, directional solidification under a strong magnetic field confinement is used to obtain an axial columnar crystal structure, followed by multi-stage heat treatment to regulate the phase structure. The final material possesses high conductivity (≥24% IACS), high strength (tensile strength ≥800 MPa), excellent corrosion resistance (corrosion rate under acidic salt spray <0.003 mm / year), and unique electrochemical self-healing capabilities, overcoming the bottleneck of traditional materials' inability to achieve synergistic performance and meeting the application requirements of high-reliability grounding environments. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but does not exclude other elements or objects.

[0023] Example 1

[0024] Composition design: 9.25% aluminum, 4.75% nickel, 3.75% iron, 1.35% manganese, 0.25% silicon, 0.035% phosphorus, 0.08% yttrium, 0.12% cerium, 0.42% chromium, 0.28% molybdenum, 0.15% tungsten, balance copper.

[0025] Preparation process:

[0026] Step S1: Under vacuum or protective atmosphere, first melt the combination of copper, nickel, iron and the second modified element. After they are completely melted and homogeneous, add aluminum, manganese and silicon, and heat to 1250℃ for refining.

[0027] Step S2: Adjust the melt temperature to 1150℃, and use an inert gas blowing method to send the preheated composite cored wire containing the first modified element combination and phosphorus into the bottom of the molten pool to allow it to react fully.

[0028] Step S3: The refined melt is poured into a copper crystallizer with cooling water. During the pouring and solidification process, a steady-state strong magnetic field parallel to the direction of gravity is applied to the melt with a magnetic field strength of 1.15 T to obtain a Φ60×250 mm ingot with an axially oriented columnar crystal structure. The cooling rate of the cooling water is 125 K / s, and the average width of the obtained columnar crystals is 220 micrometers. The angle between the growth direction and the axis of the final grounding electrode product is no more than 8 degrees.

[0029] Step S4: Perform multi-stage coupled heat treatment on the ingot, specifically: First stage treatment: Hold the ingot at 735℃ for 12 hours to allow element diffusion and bridging of the framework.

[0030] Secondary treatment: Rapidly heat to 975℃, hold for 60 minutes, then water quench;

[0031] Level 3 treatment: Aging at 485℃ for 6 hours, followed by air cooling.

[0032] The performance of the AlNi bronze grounding material prepared in Example 1 was tested:

[0033] (1) Test process: The resistivity was measured in an environment of 20±1℃ using the four-terminal method. The sample was a Φ5×100mm cylinder with the surface polished to Ra 0.8μm. A ZJ-7 DC resistance tester was used with a constant current source output of 10A. Each sample was measured 5 times and the average value was taken.

[0034] Test results: Conductivity 25.2±0.3% IACS, resistivity 6.85±0.05×10⁻ 8 Ω·m.

[0035] (2) Testing procedure: Tensile specimens with a gauge length of 50 mm and a diameter of 10 mm were prepared according to GB / T 228.1 and tested on an Instron 5985 universal testing machine at a loading rate of 2 mm / min. The Brinell hardness test load was 187.5 kg and the indenter diameter was 2.5 mm. The Charpy V-notch specimen was used to test the impact toughness.

[0036] Test results: tensile strength 828±12 MPa, yield strength 675±8 MPa, elongation 14.2±0.5%, Brinell hardness 218±5 HB, impact energy 42.5±2.1 J.

[0037] (3) Test procedure: The acidic salt spray test was conducted according to ASTM G85 standard, in a 5% NaCl solution with pH=3.5, at 35±1℃ for 1000 hours. The electrochemical test was conducted using a Gamry Interface 1010E electrochemical workstation, in a soil simulation solution (pH=5.5) with a potential polarization scan at a scan rate of 0.5mV / s.

[0038] Test results: The average corrosion rate of acidic salt spray was 0.0025±0.0002 mm / year; the self-corrosion potential was -85±5 mV (vs. SCE), the pitting potential was +315±15 mV (vs. SCE), and the corrosion current density was 0.15±0.03 μA / cm².

[0039] (4) Test procedure: A 100 μm wide and 50 μm deep artificial scratch was made with a diamond engraving tool. The sample was immersed in a soil simulation solution with pH=6.0. The potential change and electrochemical impedance spectroscopy of the scratch area were monitored in situ using a Gamry potentiostat.

[0040] Test results: The initial potential of the scratch was -325 mV, which recovered to -12 mV after 36 hours. The impedance modulus recovered from 850 Ω·cm² to 18200 Ω·cm², with a potential recovery rate of 93.8%.

[0041] (5) Testing process: The microstructure was characterized using a Leica DM2700M metallurgical microscope, a FEI Nova NanoSEM 450 scanning electron microscope, a FEI Tecnai F20 transmission electron microscope and an Oxford Symmetry EBSD detector.

[0042] Test results: In the α-Cu matrix (78.5%), κII precipitates (35-65 nm) are dispersedly distributed (8.2%), forming a continuous framework phase (11.8%, continuity index 93%) along the columnar grain boundaries. YPO / Ce-PO composite inclusions (80-150 nm) are distributed at the framework / matrix interface. The average width of the columnar crystals is 220±15 μm, and the axial orientation deviation is 7±2°.

[0043] Example 2

[0044] Composition design: 9.9% aluminum, 5.4% nickel, 4.4% iron, 1.75% manganese, 0.38% silicon, 0.075% phosphorus, 0.14% yttrium, 0.1% lanthanum, 0.58% chromium, 0.48% molybdenum, 0.12% tungsten, balance copper.

[0045] Preparation process: The preparation process of this embodiment is basically the same as that of Example 1, except that the refining temperature in step S1 is adjusted to 1275℃, the melt temperature in step S2 is adjusted to 1175℃, the magnetic field strength in step S3 is 1.28 T, the cooling rate is 145K / s, the columnar crystal width is 155μm, and the axial angle is 6°; the heat treatment in step S4 is: first stage 740℃×10h, second stage 980℃×50min, and third stage 490℃×5h.

[0046] The performance of the AlNi bronze grounding material prepared in Example 2 was tested:

[0047] (1) Conductivity test: conductivity 24.6±0.3% IACS, resistivity 7.00±0.05×10 -8 Ω·m.

[0048] (2) Mechanical properties test: tensile strength 838±12 MPa, yield strength 685±8 MPa, elongation 13.0±0.5%, Brinell hardness 222±5 HB, impact energy 40.8±2.1 J.

[0049] (3) Corrosion resistance test: average corrosion rate of acidic salt spray 0.0028±0.0002 mm / year; self-corrosion potential -88±5 mV, pitting potential +305±15 mV, corrosion current density 0.18±0.03 μA / cm².

[0050] (4) Electrochemical self-healing performance test: The initial scratch potential was -330 mV, which recovered to -15 mV after 38 hours. The impedance modulus recovered to 17500 Ω·cm², and the potential recovery rate was 92.7%.

[0051] (5) Microstructure analysis: The size of the κII precipitate in the α-Cu matrix (77.8%) is 40-75 nm (8.5%), the continuity index of the framework phase is 90%, and the size of the inclusions is 90-180 nm.

[0052] Example 3

[0053] Composition design: 8.6% aluminum, 4.1% nickel, 3.1% iron, 0.85% manganese, 0.13% silicon, 0.012% phosphorus, 0.022% yttrium, 0.03% cerium, 0.16% chromium, 0.11% molybdenum, 0.06% tungsten, balance copper.

[0054] Preparation process: The preparation process of this embodiment is basically the same as that of Example 1. The difference is that the refining temperature in step S1 is adjusted to 1225℃, the melt temperature in step S2 is adjusted to 1125℃, the magnetic field strength in step S3 is 1.02 T, the cooling rate is 85K / s, the columnar crystal width is 290μm, the axial angle is 9.5°, and the heat treatment in step S4 is: first stage 725℃×13h, second stage 965℃×70min, and third stage 475℃×6.5h.

[0055] The performance of the AlNi bronze grounding material prepared in Example 2 was tested:

[0056] (1) Conductivity test: conductivity 23.6±0.3% IACS, resistivity 7.30±0.05×10 -8 Ω·m.

[0057] (2) Mechanical properties test: tensile strength 788±12 MPa, yield strength 638±8 MPa, elongation 14.8±0.5%, Brinell hardness 210±5 HB, impact energy 43.2±2.1 J.

[0058] (3) Corrosion resistance test: average corrosion rate of acidic salt spray 0.0034±0.0002 mm / year; self-corrosion potential -92±5 mV, pitting potential +295±15 mV, corrosion current density 0.22±0.03 μA / cm².

[0059] (4) Electrochemical self-healing performance test: The initial scratch potential was -340 mV, which recovered to -25 mV after 42 hours. The impedance modulus recovered to 16800 Ω·cm², and the potential recovery rate was 89.5%.

[0060] (5) Microstructure analysis: The size of the κII precipitate in the α-Cu matrix (79.2%) is 45-85nm (7.8%), the continuity index of the framework phase is 87%, and the size of the inclusions is 70-140nm.

[0061] Comparative Example 1

[0062] Composition design: 9.25% aluminum, 4.75% nickel, 3.75% iron, 1.35% manganese, 0.25% silicon, 0.035% phosphorus, 0.08% yttrium, 0.12% cerium, balance copper.

[0063] Preparation process: exactly the same as in Example 1.

[0064] The performance of the AlNi bronze grounding material prepared by Comparative Example 1 was tested:

[0065] (1) Conductivity test: conductivity 20.5±0.3% IACS, resistivity 8.41±0.05×10 -8 Ω·m.

[0066] (2) Mechanical properties test: tensile strength 640±12 MPa, yield strength 535±8 MPa, elongation 15.8±0.5%, Brinell hardness 195±5 HB, impact energy 38.5±2.1 J.

[0067] (3) Corrosion resistance test: average corrosion rate of acidic salt spray is 0.0090±0.0002 mm / year; self-corrosion potential is -125±5 mV, pitting potential is +185±15 mV, and corrosion current density is 0.85±0.03 μA / cm².

[0068] (4) Electrochemical self-healing performance test: The initial scratch potential was -380 mV, and after 72 hours it only recovered to -95 mV, the impedance modulus only recovered to 8500 Ω·cm², and the potential recovery rate was 68.8%.

[0069] (5) Microstructure analysis: There is no continuous framework phase in the α-Cu matrix (85.3%), the size of the coarse κ phase is 150-300nm (5.2%), and there are no interfacial composite inclusions.

[0070] Comparative Example 2

[0071] Composition design: 9.25% aluminum, 4.75% nickel, 3.75% iron, 1.35% manganese, 0.25% silicon, 0.08% phosphorus, 0.08% yttrium, 0.12% cerium, 0.42% chromium, 0.28% molybdenum, 0.15% tungsten, balance copper.

[0072] Preparation process: exactly the same as in Example 1.

[0073] The performance of the AlNi bronze grounding material prepared by Comparative Example 2 was tested:

[0074] (1) Conductivity test: conductivity 22.4±0.3% IACS, resistivity 7.69±0.05×10 -8 Ω·m.

[0075] (2) Mechanical properties test: tensile strength 735±12 MPa, yield strength 600±8 MPa, elongation 12.5±0.5%, Brinell hardness 205±5 HB, impact energy 36.8±2.1 J.

[0076] (3) Corrosion resistance test: average corrosion rate of acidic salt spray 0.0052±0.0002 mm / year; self-corrosion potential -105±5 mV, pitting potential +245±15 mV, corrosion current density 0.45±0.03 μA / cm².

[0077] (4) Electrochemical self-healing performance test: The initial scratch potential was -350 mV, which recovered to -65 mV after 58 hours. The impedance modulus recovered to 12500 Ω·cm², and the potential recovery rate was 77.8%.

[0078] (5) Microstructure analysis: A large number of rare earth phosphide particles with a size of 500-800 nm were found to be mixed in, the κII precipitate phase size was 60-120 nm, and the framework phase continuity index was 78%.

[0079] Comparative Example 3

[0080] Ingredient design: exactly the same as in Example 1.

[0081] Preparation process: The preparation process of this comparative example is basically the same as that of Example 1, except that step S3 is deleted: applying a steady-state strong magnetic field parallel to the direction of gravity to the melt, with a magnetic field strength of 1.15 T.

[0082] The performance of the AlNi bronze grounding material prepared by Comparative Example 3 was tested:

[0083] (1) Conductivity test: conductivity 23.0±0.3% IACS, resistivity 7.50±0.05×10 -8 Ω·m.

[0084] (2) Mechanical properties test: tensile strength 780±12 MPa, yield strength 625±8 MPa, elongation 14.5±0.5%, Brinell hardness 212±5 HB, impact energy 41.5±2.1 J.

[0085] (3) Corrosion resistance test: average corrosion rate of acidic salt spray 0.0040±0.0002 mm / year; self-corrosion potential -98±5 mV, pitting potential +275±15 mV, corrosion current density 0.32±0.03 μA / cm².

[0086] (4) Electrochemical self-healing performance test: The initial scratch potential was -335 mV, which recovered to -45 mV after 52 hours. The impedance modulus recovered to 14200 Ω·cm², and the potential recovery rate was 81.4%.

[0087] (5) Microstructure analysis: The skeleton phase is distributed in an island-like pattern with a continuity index of only 62%, and the κII precipitate phase is unevenly distributed.

[0088] Comparative Example 4

[0089] Ingredient design: exactly the same as in Example 1.

[0090] Preparation process: The preparation process of this comparative example is basically the same as that of Example 1, except that the primary treatment in step S4 is deleted.

[0091] The performance of the AlNi bronze grounding material prepared by Comparative Example 4 was tested:

[0092] (1) Conductivity test: conductivity 23.7±0.3% IACS, resistivity 7.26±0.05×10 -8 Ω·m.

[0093] (2) Mechanical properties test: tensile strength 785±12 MPa, yield strength 635±8 MPa, elongation 14.0±0.5%, Brinell hardness 208±5 HB, impact energy 40.2±2.1 J.

[0094] (3) Corrosion resistance test: average corrosion rate of acidic salt spray 0.0048±0.0002 mm / year; self-corrosion potential -110±5 mV, pitting potential +255±15 mV, corrosion current density 0.40±0.03 μA / cm².

[0095] (4) Electrochemical self-healing performance test: The initial scratch potential was -345 mV, which recovered to -55 mV after 55 hours. The impedance modulus recovered to 13500 Ω·cm², and the potential recovery rate was 79.3%.

[0096] (5) Microstructure analysis: obvious component segregation, discontinuous skeletal phase (continuity index 70%), and uneven size of κII precipitate.

[0097] Conclusion and Analysis: Examples 1-3 demonstrate that the AlNi bronze grounding materials prepared using the composition and process described in this invention exhibit excellent comprehensive performance. Their conductivity (23.6%-25.2% IACS), tensile strength (788-838 MPa), and corrosion resistance (acidic salt spray corrosion rate 0.0025-0.0034 mm / year) are significantly superior to traditional materials, and they possess highly efficient electrochemical self-healing capabilities (recovery within 36-42 hours). Microstructural analysis reveals the source of their high performance: an axially oriented columnar crystal structure induced by a specific component ratio and magnetic field-directed solidification process, internally constructing a unique multiphase synergistic structure containing a continuous framework phase, nano-κII precipitates, and interfacial composite inclusions. Comparative Examples 1-4 showed systematic and significant deterioration in various properties by changing a single variable, such as the absence of the second modifying element, the disruption of the rare earth / phosphorus ratio, the elimination of magnetic field directional solidification, or the simplification of heat treatment. For example, the conductivity decreased, the corrosion rate increased several times, the self-healing ability deteriorated or was lost, and the continuity of the framework phase was destroyed.

[0098] It should be noted that the terms "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. The directional terms "inner" and "outer" refer to the inside or outside relative to the outline of each component itself. The exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0099] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0100] It should also be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this application refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0101] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0102] It should also be noted that the above are merely preferred embodiments of this application and do not limit the scope of patent protection of this application. Any equivalent structural or procedural changes made using the content of this application's specification, or any direct or indirect application in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. An aluminum-nickel bronze grounding material, characterized in that, By mass percentage, it includes: 8.5%-10.0% aluminum, 4.0%-5.5% nickel, 3.0%-4.5% iron, 0.8%-1.8% manganese, 0.1%-0.4% silicon, 0.01%-0.08% phosphorus, 0.05%-0.5% of the first modifying element combination, 0.3%-1.2% of the second modifying element combination, and the balance being copper.

2. The aluminum-nickel bronze grounding material according to claim 1, characterized in that, The first combination of modifying elements includes at least one of yttrium, lanthanum, and cerium, and the second combination of modifying elements includes at least one of chromium, molybdenum, and tungsten.

3. The aluminum-nickel bronze grounding material according to claim 2, characterized in that, The second combination of modifying elements contains 0.15%-0.6% chromium, 0.1%-0.5% molybdenum, and 0.05%-0.3% tungsten by mass.

4. The AlNi bronze grounding material according to claim 2, characterized in that, The mass percentage of yttrium in the first modified element combination is 0.02%-0.15%, the mass percentage of lanthanum is 0.01%-0.2%, the mass percentage of cerium is 0.02%-0.25%, and the ratio of the total content of the three elements to the content of phosphorus is between 4:1 and 12:

1.

5. A method for preparing an AlNi bronze grounding material, used to prepare the AlNi bronze grounding material as described in any one of claims 1-4, characterized in that, The preparation method includes: Step S1: Under vacuum or protective atmosphere, first melt the combination of copper, nickel, iron and the second modified element. After they are completely melted and homogeneous, add aluminum, manganese and silicon, and heat to 1220℃-1280℃ for refining. Step S2: Adjust the melt temperature to 1120℃-1180℃, and use an inert gas blowing method to send the preheated composite cored wire containing the first modified element combination and phosphorus into the bottom of the molten pool to allow it to react fully. Step S3: Pour the refined melt into a copper crystallizer with cooling water. During the pouring and solidification process, apply a steady-state strong magnetic field parallel to the direction of gravity to the melt. The magnetic field strength is 1.0T-1.3T to obtain an ingot with an axially oriented columnar crystal structure. Step S4: Perform multi-stage coupled heat treatment on the ingot.

6. The method for preparing the AlNi bronze grounding material according to claim 5, characterized in that, In step S3, the cooling rate of the cooling water is 80-150 K / s, the average width of the obtained columnar crystals is 150-300 micrometers, and the angle between their growth direction and the axis of the final grounding electrode product is no greater than 10 degrees.

7. The method for preparing the AlNi bronze grounding material according to claim 5, characterized in that, Step S4 includes: Primary treatment: The ingot is held at 720-750℃ for 10-14 hours to allow for element diffusion and framework bridging. Secondary treatment: Rapidly heat to 960-985℃, hold for 45-75 minutes, then water quench; Level 3 treatment: Aging at 470-500℃ for 4-7 hours, followed by air cooling.