Iron-cobalt alloy for use as a metal catalyst and method for producing the same

Abstract

The application discloses an iron-cobalt alloy used as a metal catalyst and a preparation method thereof, relates to the technical field of alloy materials, and comprises the following steps: configuring pure iron and pure cobalt raw materials according to proportions, and preparing electrode structural members through welding; the electrode and an ingot head are loaded into a vacuum electron beam melting and ingot drawing furnace, and vacuumizing is performed; first electron beam melting and ingot drawing is performed under the vacuum condition to form an iron-cobalt ingot; second electron beam melting and ingot drawing is performed on the first melted ingot to further purify and homogenize; and the final iron-cobalt ingot is cut and subjected to chemical component detection. The iron and cobalt contents in the iron-cobalt alloy are set in a specific proportion range, so that the alloy has a relatively narrow solid-liquid phase temperature difference and good fluidity while maintaining a suitable melting point; the component design can maintain a face-centered cubic structure under diamond synthesis conditions, and has a relatively high lattice matching degree, which is beneficial to reducing interface energy and promoting carbon atom diffusion and diamond nucleation.

Description

Technical Field

[0001] This invention belongs to the field of alloy materials technology, and in particular relates to an iron-cobalt alloy used as a metal catalyst and its preparation method. Background Technology

[0002] Diamond is the hardest natural material, possessing excellent semiconductor properties and superhardness, including an ultra-wide bandgap, high electron mobility, high breakdown electric field, and high thermal conductivity. It is an ideal material for manufacturing tools, abrasives, and high-frequency, high-power electronic devices. Diamonds can be classified according to the presence of nitrogen (N) and boron (B) in their internal crystal structure. Diamonds containing nitrogen impurities are generally called Type I diamonds, where nitrogen exists as isolated atoms replacing carbon atoms in the carbon crystal structure; these are called Type Ib diamonds, which are yellow, wood-orange, and brown. Diamonds where nitrogen atoms exist as two nitrogen atom pairs are classified as Type IaA diamonds, which are colorless, brown, green, and purple. Diamonds without significant nitrogen impurities are called Type II diamonds. Type II diamond is further divided into boron-free Type IIa diamonds, which are colorless, brown, pink, and green, and boron-containing Type IIb diamonds, which are blue and gray [Zhang Jiabao, Wang Jianpeng, Huo Zexuan, Huang Zejia, Wu Linjia. A review of diamond synthesis, modification technology, and cutting tool application in ultra-precision machining[J]. Materials & Design, 2024, 237: 112577]. In nature, diamonds are formed over a long period of time through the transformation of graphite under high temperature and pressure conditions in the Earth's crust. Therefore, the essence of synthetic diamond synthesis is to use ultra-high temperature and pressure technology to transform graphite into diamond through an allotropic phase transition. The use of metal catalysts such as iron (Fe), cobalt (Co), nickel (Ni), and manganese (Mn) and their alloys during the synthesis process helps to reduce the pressure and temperature parameters of the graphite-diamond transformation, and the overall catalytic ability to promote the transformation of graphite into diamond is ranked as Co>Fe>Mn>Ni. CN1467030A discloses an Fe-Ni-Co based catalyst for diamond synthesis, with a weight ratio of 20%–35% Ni, 10–25% Co, 0.05–0.5% Fe, but does not provide a preparation method. CN105624558A discloses an iron-cobalt alloy and its preparation method, containing a mass ratio of 26.80%–28.50% Co, 0–0.025% C, 0–0.35% Mn, 0–0.35% Si, 0–0.015% S, 0–0.015% P, 0–0.6% Cr, 0–0.65% Ni, 0–0.3% V, with the balance being Fe, and is prepared by vacuum melting and vacuum arc remelting combined with forging, hot rolling, cold rolling, and heat treatment.Currently, powdered catalysts on the market are mainly prepared through rapid solidification and atomization. Before atomization and powdering, the prepared metals need to be melted into an alloy. The content of nitrogen (N) and boron (B), sulfur (S), carbon (C) impurities, and other microalloying elements in the alloy all have varying degrees of influence on the grade of diamond. Therefore, in order to improve the quality of synthetic diamond, it is first necessary to prepare an iron-cobalt alloy with low impurity content for use as a metal catalyst. However, there is currently a lack of relevant preparation technologies both domestically and internationally.

[0003] Traditional alloy preparation processes face significant challenges in controlling boron content, making it difficult to consistently reduce it to extremely low levels. Furthermore, conventional methods struggle to ensure compositional uniformity, dimensional accuracy, and internal quality stability when producing high-purity alloy ingots of specific dimensions. Vacuum electron beam melting and drawing furnaces, with their high-vacuum environment and high-energy beam heating characteristics, offer new possibilities for preparing low-boron, precisely composed iron-cobalt alloy ingots. Therefore, preparing low-boron iron-cobalt alloys before synthesizing synthetic diamonds is crucial, and currently, better preparation technologies are lacking both domestically and internationally. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0005] This invention relates to an iron-cobalt alloy for use as a metal catalyst. The alloy, by mass percentage, comprises 55%–65% Fe, 35%–45% Co, and the balance being impurities. The impurities are: B ≤ 0.005 ppm, O ≤ 115 ppm, N ≤ 27 ppm, C ≤ 39 ppm, S ≤ 0.31 ppm, Cu ≤ 5 ppm, Mg ≤ 0.005 ppm, Ti ≤ 0.01 ppm, Cr ≤ 0.04 ppm, Si ≤ 0.11 ppm, Mo ≤ 0.35 ppm, and V ≤ 0.72 ppm.

[0006] Furthermore, by mass percentage, the alloy contains 58%–62% Fe and 38%–42% Co.

[0007] A method for preparing an iron-cobalt alloy for use as a metal catalyst includes the following steps:

[0008] Step S1: Preparation of iron-cobalt electrode: Pure iron and pure cobalt raw materials are prepared in proportion, and after surface treatment, they are welded into electrode structure by argon arc welding.

[0009] Step S2, Raw materials and ingot head loading: Load the iron-cobalt electrode and the pure iron ingot head into the corresponding positions of the vacuum electron beam melting ingot pulling furnace, close the furnace door and evacuate the furnace;

[0010] Step S3, First Vacuum Electron Beam Melting and Pulling: After reaching the set vacuum level, the electron gun is started to melt the ingot head to form a molten pool, and then the iron-cobalt electrode is scanned to melt and pull the ingot. After cooling, a first-melted ingot is obtained.

[0011] Step S4, Second Vacuum Electron Beam Melting and Pulling: After swapping the head and tail of the first-melting ingot, it is reloaded into the furnace, and the vacuum melting and pulling steps are repeated. After cooling, a second-melting ingot is obtained.

[0012] Step S5, Quality Inspection: Remove the ingot head and riser from the secondary smelting ingot, take samples to test the chemical composition, and if they pass the test, they are considered finished products.

[0013] Further, in step S1, the purity of the pure iron is better than 99.99%, and the specifications are Φ20~100mm×200~1700mm; the purity of the pure cobalt is better than 99.996%, and the specifications are 200~1700mm long×50~200mm wide×3~10mm thick; the specifications of the iron-cobalt electrode are 200~1700mm long×50~300mm wide×50~280mm thick.

[0014] Furthermore, in step S2, the specifications of the pure iron ingot head are Φ49~298mm×25~30cm; when loading the furnace, the ingot head is raised into the copper crystallizer with a diameter of Φ50~300mm, and is 2~3mm lower than the upper end of the crystallizer.

[0015] Furthermore, in step S3, the melting vacuum degree meets the following requirement: the vacuum degree inside the furnace is better than 5 × 10⁻⁶. -2 Pa, electron gun chamber vacuum degree better than 5×10 -3 Pa; the electron gun filament is preheated for 10 minutes, the initial emission current is set to 1.8–3A, and then increased to 3.5–4A; the electron beam scanning speed is 0.62–0.65 mm / s, the ingot pulling speed is 0.52–0.56 mm / s; the melting power is 55–220 kW, the cooling water flow rate is 55 L / min, the water temperature is ≤40℃, the molten pool holding time is 6–8 s, and the cooling time is 3–8 hours.

[0016] Furthermore, in step S4, after sawing off 25-30cm of the original ingot head of the primary smelting ingot, it is replaced and loaded into the furnace; the electron gun emission current is initially set to 2-3A, and then increased to 4-4.5A; the electron beam scanning speed is 0.6-0.7mm / s, the ingot pulling speed is 0.5-0.6mm / s; and the cooling time is 3-8 hours.

[0017] Furthermore, in steps S3 and S4, the electrode rotation speed during melting is 5 r / min, and the distance between the molten pool and the top of the copper crystallizer is controlled at 2-3 cm; the electron beam scanning pattern is circular and magnified to a distance of 1-2 cm from the inner wall of the crystallizer.

[0018] The present invention has the following beneficial effects:

[0019] 1. This invention sets the iron and cobalt content in the iron-cobalt alloy within a specific ratio range, enabling the alloy to maintain a suitable melting point while possessing a narrow solid-liquid phase temperature difference and good fluidity. This composition design can maintain a face-centered cubic structure under diamond synthesis conditions, with a high lattice matching degree, which is beneficial for reducing interfacial energy and promoting carbon atom diffusion and diamond nucleation. In addition, the alloy is mainly composed of iron with a relatively low cobalt content, which helps to reduce raw material costs. At the same time, the composition range retains a certain degree of adjustment space, which is convenient for adding other alloying elements to meet different catalyst requirements.

[0020] 2. This invention employs a vacuum electron beam melting and ingot-pulling process to prepare iron-cobalt alloys. Precise heating and melting with an electron beam under high vacuum effectively reduces metal volatilization and impurity introduction. Compared to traditional vacuum induction melting, this method eliminates furnace preparation and baking processes, shortening the production cycle and improving overall preparation efficiency. Furthermore, the melting process takes place in a water-cooled copper crystallizer, avoiding refractory material contamination and facilitating the production of alloy ingots with low levels of impurities such as oxygen, nitrogen, and boron, thus providing high-purity catalyst materials for subsequent diamond synthesis.

[0021] 3. This invention utilizes a vacuum electron beam melting and ingot pulling process combined with directional solidification in a water-cooled copper crystallizer. This enables the alloy melt to solidify smoothly from the outside in, resulting in an alloy ingot with uniform composition and fine grains. Adjustments to the pulling speed and cooling conditions further optimize the solidification microstructure. Real-time monitoring and feedback control of the ingot diameter and solidification temperature help improve product dimensional consistency, ensuring stable composition along the length of the ingot and meeting the microstructure and dimensional accuracy requirements of different specifications of metal catalysts.

[0022] 4. In the vacuum electron beam melting and drawing process of this invention, under high vacuum and high temperature conditions, low-boiling-point impurities in the raw materials are volatilized and extracted from the system. Through two melting processes, difficult-to-remove impurity elements such as boron are further promoted to precipitate in gaseous form, thereby reducing their residue in the alloy. This process can also decompose and float non-metallic inclusions such as oxides and nitrides for removal, thereby reducing the content of impurities such as oxygen, nitrogen, sulfur, and carbon in the alloy, improving the overall purity of the iron-cobalt alloy, and meeting the stringent requirements for catalyst impurity control in high-quality diamond synthesis.

[0023] 5. After two vacuum electron beam melting and ingot pulling processes, the iron-cobalt alloy obtained in this invention exhibits a stable main component distribution and maintains a low level of trace element content. The alloy possesses good structural uniformity and consistent solidification structure, providing a reliable performance basis for its use as a catalyst in diamond synthesis. This preparation process has good repeatability and is suitable for the production of alloy ingots of different scales and specifications. The obtained product can be used for subsequent powder preparation and other alloying treatments, providing a feasible technical approach for the mass production of metal catalysts for diamond synthesis.

[0024] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic flowchart of a method for preparing an iron-cobalt alloy used as a metal catalyst according to the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The present invention is an iron-cobalt alloy for use as a metal catalyst, containing 55% to 65% Fe and 45% to 35% Co by mass percentage;

[0029] Please see Figure 1 As shown, the preparation method of iron-cobalt alloy includes the following steps:

[0030] Step S1: Prepare iron-cobalt electrode

[0031] Alloy raw materials are prepared by mixing pure iron (55%–65% by mass) and pure cobalt (45%–35% by mass). The surface of the iron rod is polished with a shot blasting machine to remove impurities. The surface of the cobalt plate is ground with an angle grinder to remove dirt and impurities. The pure iron and pure cobalt are welded into an electrode structure using an argon arc welding process to complete the preparation of the iron-cobalt electrode.

[0032] The raw material for pure iron is pure iron bars with a purity of better than 99.99%, with specifications of Φ20~100mm×200~1700mm; the size of the pure iron bars is Φ30mm×1650mm;

[0033] Pure cobalt refers to cobalt plates with a purity better than 99.996%, with a length of 200–1700 mm, a width of 50–200 mm, and a thickness of 3–10 mm.

[0034] The cobalt plate has dimensions of 500mm x 120mm x 3mm (length x width x thickness).

[0035] The dimensions of the prepared iron-cobalt electrode are determined by the product weight, with a length of 200–1700 mm, a width of 50–300 mm, and a thickness of 50–280 mm.

[0036] Step S2: Loading raw materials and ingot head into the furnace.

[0037] After hoisting the iron-cobalt electrode prepared in step S1 to the center of the track in the vacuum electron beam melting ingot pulling furnace hopper and fixing it, the raw material loading is completed. After wiping the surface of the pure iron ingot head with a diameter of Φ49~298mm and a length of 25~30cm with alcohol, it is installed on the lower electrode copper clamp of the ingot pulling device in the vacuum electron beam melting ingot pulling furnace and fixed. Then, the pure iron ingot head is raised into the copper crystallizer with a diameter of Φ50~300mm and lowered by 2~3mm from the top. Then, the hopper door is closed, and the ingot head loading is completed. After closing the furnace door, the raw material and ingot head loading are completed. The vacuum system is started, and the furnace is evacuated.

[0038] Step S3: First vacuum electron beam melting and drawing of ingots

[0039] When the vacuum degree inside the vacuum electron beam melting ingot pulling furnace is better than 5×10 -2 At Pa, the vacuum level of the electron gun chamber is better than 5 × 10⁻⁶. -3At Pa, the main high voltage, negative high voltage, and filament current of the electron gun are turned on. After the filament preheats for 10 minutes, the electron beam is initiated. The electron beam is adjusted to the center of the ingot head, and the negative high voltage current is gradually increased. At the same time, the x and y positions of the scan are controlled to be 1 cm away from the edge of the crystallizer. After the entire upper surface of the ingot head is covered with molten metal and there are no visible impurities, the position of the electron beam is adjusted and focused, and the electron gun emission current is set to 1.8-3A. Then, the scanning pattern of the electron beam emitted with the center point of the copper crystallizer as the reference is adjusted, and the circular scanning pattern is enlarged to a position 1.2-2 cm away from the inner wall of the copper crystallizer, and the emission current is slowly increased to 3.5-4A. The upper 3.5-4.5 cm of the ingot head is melted into a molten pool, so that the molten metal completely binds with the copper. The inner wall of the crystallizer is brought into contact, and the rotating electrode is started. The electrode rotates at a speed of 5 r / min. After adjusting the distance between the molten pool and the top of the copper crystallizer to 2.2-3 cm, the electron beam power of the electron gun is adjusted to 55-220 kW, the water flow rate is 55 L / min, the water temperature is controlled below 40℃, and the molten pool is maintained for 6-8 s. Feeding begins, and melting starts from the front end of the hopper. The electron beam scans from the front end of the electrode to the tail end at a scanning speed of 0.62-0.65 mm / s. During the melting process, the height between the molten pool and the copper crystallizer is observed to remain unchanged, and the ingot is pulled at a speed of 0.52-0.56 mm / s until the tail end of the electrode, completing the first melting. After cooling in the furnace for 3-8 hours, the ingot is removed from the furnace, and the first vacuum electron beam melting and pulling ingot is obtained.

[0040] Step S4, Second Vacuum Electron Beam Melting and Pulling of Ingots

[0041] After cooling, the iron-cobalt ingot obtained in step S3 from the first vacuum electron beam melting and drawing process is removed from the copper crystallizer and a pure iron ingot head with a diameter of 49-298 mm and a length of 25-30 cm is inserted again and fixed on the lower electrode copper clamp of the drawing device in the vacuum electron beam melting and drawing furnace. After sawing off 25-30 cm of the original ingot head from the first melting process, the head of the iron-cobalt ingot becomes the tail, and it is inserted back into the center position of the track in the hopper and fixed with a clamp. The hopper door and the furnace door are closed in sequence, and the vacuum electron beam melting and drawing furnace is evacuated. When the vacuum degree in the furnace is better than 5×10 -2 At Pa, the vacuum level of the electron gun chamber is better than 5 × 10⁻⁶. -3At Pa, the main high voltage, negative high voltage, and filament current of the electron gun are turned on. After the filament is preheated for 10 minutes, the electron beam is drawn out and adjusted to the center of the ingot head. The negative high voltage current is gradually increased, while the scanning x and y positions are controlled to be 1 cm away from the edge of the copper crystallizer. After the entire surface of the ingot head is liquid and the liquid surface is free of impurities, the melting process is prepared. After the cathode (filament) is heated, the position of the focused electron beam is adjusted, and the emission current of the electron gun is adjusted to 2-3 A. The scanning pattern is then adjusted, and the scanning pattern of the electron beam emitted from the center point of the copper crystallizer is magnified from a circular scanning pattern to a distance of 1-2 cm from the inner wall of the copper crystallizer, while the emission current is slowly increased. At 4-4.5A, melt the top 3-5cm of the ingot head into a molten liquid and ensure the solution is in complete contact with the inner wall of the copper crystallizer. Instantly turn on the ingot transfer button. When the distance between the molten pool and the top of the copper crystallizer is observed to be 2-3cm, start feeding. Melt from the front end of the preparation electrode. The electron beam scans towards the tail end of the iron-cobalt ingot at a speed of 0.6-0.7mm / s. During the melting process, observe that the molten pool and the top of the copper crystallizer are kept at 2-3cm and pull the ingot at a speed of 0.5-0.6mm / s until the electron beam reaches the tail end of the iron-cobalt ingot in the feeding bin. The second melting ends. After the iron-cobalt ingot is slowly cooled in the furnace for 3-8 hours, the second vacuum electron beam melting and ingot pulling is completed.

[0042] Step S5: Quality Inspection of Iron-Cobalt Ingots

[0043] For the iron-cobalt ingot prepared in step S4, the 25-30cm high ingot head fused to the bottom of the iron-cobalt ingot is sawed off using a sawing machine. Then, the riser 1-3cm high at the top of the iron-cobalt ingot is sawed off. A 10mm×10mm×5mm block is cut from the upper part of the riser using wire cutting. The chemical composition is detected using instruments such as glow discharge mass spectrometer, inductively coupled plasma atomic emission spectrometer, oxygen and nitrogen analyzer, and carbon and sulfur analyzer.

[0044] The specific application of this embodiment is as follows:

[0045] Example 1

[0046] Step S1: Prepare iron-cobalt electrode

[0047] The alloy raw materials were prepared according to 94.2 kg of Fe and 62.8 kg of Co. The iron was made of pure iron rods with a purity of 99.99%, each measuring Φ30mm×1650mm, with approximately 10.3 rods in total. The surface of the iron rods was polished using a shot blasting machine to remove impurities. The cobalt was made of cobalt plates with a purity of 99.996%, each measuring 500mm×120mm×3mm, with approximately 39.2 plates in total. The surface of the cobalt plates was ground using an angle grinder to remove surface dirt and impurities. The pure iron rods and pure cobalt plates were then welded together using an argon arc welding process to form an electrode structure. The iron-cobalt electrode measures 1700×120mm×100mm, thus completing the preparation of the iron-cobalt electrode.

[0048] Step S2: Loading raw materials and ingot head into the furnace.

[0049] After hoisting the iron-cobalt electrode prepared in step S1 to the center of the track in the vacuum electron beam melting ingot pulling furnace hopper and fixing it, the raw material loading is completed. After wiping the surface of the pure iron ingot head with alcohol (116 mm in diameter and 30 cm in length), it is installed on the lower electrode copper clamp of the ingot pulling device in the vacuum electron beam melting ingot pulling furnace and fixed. Then, the pure iron ingot head is raised into the copper crystallizer with a diameter of 120 mm and 2 mm below the top. Then, the hopper door is closed, and the ingot head loading is completed. After closing the furnace door, the raw material and ingot head loading are completed. The vacuum system is started, and the furnace is evacuated.

[0050] Step S3: First vacuum electron beam melting and drawing of ingots

[0051] When the vacuum degree inside the furnace is better than 5×10 -2 Pa, electron gun chamber vacuum degree better than 5×10 -3At Pa, the main high voltage, negative high voltage, and filament current of the electron gun are turned on. After the filament is preheated for 10 minutes, the electron beam is started. The electron beam is adjusted to the center of the ingot head, and the negative high voltage current is gradually increased. At the same time, the x and y positions of the scan are controlled to be 1 cm away from the edge of the crystallizer. After the entire upper surface of the ingot head is covered with molten metal and there are no visible impurities, the position of the electron beam is adjusted and focused, and the electron gun emission current is set to 1.8 A. Then, the scanning pattern of the electron beam emitted with the center point of the copper crystallizer as the reference is adjusted, and the circular scanning pattern is enlarged to a position where its edge is about 1.5 cm away from the inner wall of the crystallizer, and the emission current is slowly increased to 3.5 A. The upper 4 cm of the ingot head is melted into a molten pool, and the outer edge of the formed molten pool is kept in contact with the inner wall of the copper crystallizer. The electrode is then started at 5 Rotating at a speed of r / min, adjusting the distance between the molten pool and the top of the crystallizer to 2.5cm, the electron beam melting power of the electron gun was set to 70kW, the cooling water flow rate to 55L / min, and the water temperature to be controlled below 39℃. After maintaining the molten pool for 7s, feeding began, and melting started from the front end of the hopper. The electron beam scanned from the front end of the electrode to the tail end at a scanning speed of 0.65mm / s. During the melting process, the height of the molten pool and the copper crystallizer was observed, and the ingot was pulled at a speed of 0.55mm / s until the tail end of the electrode was reached, completing the first melting. After cooling in the furnace for 5 hours, the ingot was removed from the furnace, yielding the first vacuum electron beam melting and pulling of the iron-cobalt ingot.

[0052] Step S4, Second Vacuum Electron Beam Melting and Pulling of Ingots

[0053] After cooling, the iron-cobalt ingot obtained in step S3 from the first vacuum electron beam melting and drawing process is removed from the copper crystallizer. A pure iron ingot head with a diameter of 116 mm and a length of 30 cm is then inserted and fixed onto the lower electrode copper clamp of the drawing device inside the vacuum electron beam melting and drawing furnace. After sawing off 25 cm of the original ingot head from the removed iron-cobalt ingot, the ends of the iron-cobalt ingot are reversed, and it is placed in the center of the track in the hopper and fixed with clamps. The hopper door and furnace door are closed sequentially, and vacuuming of the vacuum electron beam melting and drawing furnace begins. When the vacuum level inside the furnace is better than 5 × 10⁻⁶, the process is repeated. -2 At Pa, the vacuum level of the electron gun chamber is better than 5 × 10⁻⁶. -3At Pa, the main high voltage, negative high voltage, and filament current of the electron gun are turned on. After the filament is preheated for 10 minutes, the electron beam is drawn out and adjusted to the center of the ingot head. The negative high voltage current is gradually increased, while the scanning x and y positions are controlled to be 1 cm away from the edge of the copper crystallizer. After the entire surface of the ingot head is liquid and the liquid surface is free of impurities, melting is prepared. After the cathode (filament) is heated, the position of the focused electron beam is adjusted, the emission current of the electron gun is adjusted to 2A, and the scanning pattern is adjusted so that the scanning pattern of the electron beam emitted from the center point of the copper crystallizer is expanded from a circular scanning pattern. The electron beam is set to a distance of approximately 1 cm from the inner wall of the copper crystallizer, and the emission current is slowly increased to 4A. The top 3 cm of the ingot head is melted into a liquid and the solution is brought into complete contact with the inner wall of the crystallizer. The ingot transfer button is turned on instantly. When the distance between the molten pool and the top of the copper crystallizer is observed to be 2 cm, feeding begins. Melting is carried out from the front end of the preparation electrode. The electron beam scans towards the tail end of the electrode at a speed of 0.68 mm / s. The ingot pulling speed is maintained at 0.58 mm / s until the electron beam reaches the tail end of the iron-cobalt ingot in the feeding bin, ending the second melting process. The iron-cobalt ingot is then slowly cooled in the furnace for 6 hours, completing the second vacuum electron beam melting and ingot pulling process.

[0054] Step S5: Quality Inspection of Iron-Cobalt Ingots

[0055] For the iron-cobalt ingot prepared in step S4, the 30cm high ingot head fused to the bottom of the iron-cobalt ingot was sawed off with a saw, and the 2cm high riser at the top of the iron-cobalt ingot was sawed off. The resulting ingot has dimensions of Φ118mm×1675mm. A 10mm×10mm×5mm block was cut from the upper part of the riser using wire cutting. Co and Fe were detected using a Plasma 2000 inductively coupled plasma atomic emission spectrometer, and B, Cu, Mg, Ti, Cr, Si, Mo, V, and S were detected using an Element GD Plus glow discharge mass spectrometer. O and N were detected using an O-3000 oxygen-nitrogen analyzer, and C was detected using a CS-2800 carbon-sulfur analyzer. After the first vacuum electron beam melting and ingot pulling, the Co and Fe content in the alloy was: 41.23 wt% Co, 58.71 wt% Fe, and the content of other trace elements was (unit: ppm). The alloy content after the second vacuum electron beam melting and ingot pulling is as follows (wt%): B≤0.12, Cu≤36, Mg≤0.02, Ti≤0.09, Cr≤69, Si≤1.6, Mo≤2.9, V≤0.99, O≤399, N≤61, C≤49, S≤15; The Co and Fe contents in the alloy after the second vacuum electron beam melting and ingot pulling are: 40.24 wt% Co, 59.74 wt% Fe, and the contents of other trace elements (unit: ppm wt%) are: B≤0.005, Cu≤5, Mg≤0.005, Ti≤0.01, Cr≤0.04, Si≤0.11, Mo≤0.35, V≤0.72, O≤115, N≤27, C≤39, S≤0.31.

[0056] Example 2

[0057] Step S1: Prepare iron-cobalt electrode

[0058] The alloy raw materials were prepared according to 1.76 kg of Fe and 1.44 kg of Co. The iron was made of pure iron rods with a purity of 99.99%, each measuring Φ20mm×200mm, and 3.6 rods were prepared. The surface of the iron rods was polished using a shot blasting machine to remove impurities. The cobalt was made of cobalt plates with a purity of 99.996%, each measuring 200mm×50mm×3mm, and 5.4 plates were prepared. The pure iron and pure cobalt were welded into electrode structures using argon arc welding. The iron-cobalt electrode measured 200mm×50mm×50mm, thus completing the preparation of the iron-cobalt electrode.

[0059] Step S2: Loading raw materials and ingot head into the furnace.

[0060] After hoisting the iron-cobalt electrode prepared in step S1 to the center of the track in the vacuum electron beam melting ingot pulling furnace hopper and fixing it, the raw material loading is completed. After wiping the surface of the pure iron ingot head with alcohol (49 mm in diameter and 25 cm in length), it is installed on the lower electrode copper clamp of the ingot pulling device in the vacuum electron beam melting ingot pulling furnace and fixed. Then, the pure iron ingot head is raised into the copper crystallizer with a diameter of 50 mm and lowered by 2.5 mm from the top. Then, the hopper door is closed, and the ingot head loading is completed. After closing the furnace door, the raw material and ingot head loading are completed. The vacuum system is started, and the furnace is evacuated.

[0061] Step S3: First vacuum electron beam melting and drawing of ingots

[0062] When the vacuum degree inside the furnace is better than 5×10 -2 Pa, electron gun chamber vacuum degree better than 5×10 -3 At time Pa, the main high voltage, negative high voltage, and filament current of the electron gun are turned on. After the filament preheats for 10 minutes, the electron beam is initiated. The electron beam is adjusted to the center of the ingot head, and the negative high voltage current is gradually increased. At the same time, the x and y positions of the scan are controlled to be 1 cm away from the edge of the crystallizer. After the entire upper surface of the ingot head is covered with molten metal and there are no visible impurities, the position of the electron beam is adjusted and focused, and the electron gun emission current is set to 2.5 A. Then, the scanning pattern of the electron beam emitted with the center point of the copper crystallizer as the reference is adjusted, and the circular scanning pattern is enlarged to a position 1.2 cm away from the inner wall of the crystallizer. The emission current is slowly increased to 3.6 A. The upper 3.5 cm of the ingot head is melted into a molten pool. To ensure the molten metal fully contacts the inner wall of the copper crystallizer, the electrode is started to rotate at a speed of 5 r / min. After adjusting the distance between the molten pool and the top of the crystallizer to 2.2 cm, the electron beam melting power of the electron gun is set to 55 kW, the cooling water flow rate to 55 L / min, and the water temperature to be controlled below 36 ℃. After maintaining the molten pool for 6 seconds, feeding begins, starting from the front end of the hopper. The electron beam scans from the front end of the electrode to the rear end at a scanning speed of 0.62 mm / s. During the melting process, the height of the molten pool and the copper crystallizer is observed, and the ingot is pulled at a speed of 0.52 mm / s until it reaches the rear end of the electrode, completing the first melting. After cooling in the furnace for 3 hours, the ingot is removed from the furnace, yielding the first vacuum electron beam melted and pulled iron-cobalt ingot.

[0063] Step S4, Second Vacuum Electron Beam Melting and Pulling of Ingots

[0064] After cooling, the iron-cobalt ingot obtained in step S3 from the first vacuum electron beam melting and drawing process is removed from the copper crystallizer. A pure iron ingot head with a diameter of 49mm and a length of 25cm is then inserted and fixed onto the lower electrode copper clamp of the drawing device inside the vacuum electron beam melting and drawing furnace. After sawing off the original 25cm length of the removed iron-cobalt ingot head with a saw, the ends of the iron-cobalt ingot are reversed, and it is placed in the center of the track in the hopper and fixed with clamps. The hopper door and furnace door are closed sequentially, and vacuuming of the vacuum electron beam melting and drawing furnace begins. When the vacuum level inside the furnace is better than 5×10⁻⁶... -2 At Pa, the vacuum level of the electron gun chamber is better than 5 × 10⁻⁶. -3 At Pa, the main high voltage, negative high voltage, and filament current of the electron gun are turned on. After the filament is preheated for 10 minutes, the electron beam is drawn out and adjusted to the center of the ingot head. The negative high voltage current is gradually increased, while the scanning x and y positions are controlled to be 1 cm away from the edge of the copper crystallizer. After the entire surface of the ingot head is liquid and the liquid surface is free of impurities, melting is prepared. After the cathode (filament) is heated, the position of the focused electron beam is adjusted, the emission current of the electron gun is adjusted to 2.2A, and the scanning pattern is adjusted to enlarge the scanning pattern of the electron beam emitted from the center point of the copper crystallizer from a circular scanning pattern. The electron beam is moved to a position 1.2 cm from the inner wall of the copper crystallizer, and the emission current is slowly increased to 4.1 A. The top 3 cm of the ingot head is melted into a liquid and the solution is brought into complete contact with the inner wall of the crystallizer. The ingot transfer button is turned on instantly. When the distance between the molten pool and the top of the copper crystallizer is observed to be 2.7 cm, the feeding begins. Melting is carried out from the front end of the preparation electrode. The electron beam scans towards the tail end of the electrode at a speed of 0.6 mm / s. The ingot pulling speed is maintained at 0.5 mm / s until the electron beam reaches the tail end of the iron-cobalt ingot in the feeding bin, ending the second melting. The iron-cobalt ingot is then slowly cooled in the furnace for 3 hours, completing the second vacuum electron beam melting and ingot pulling.

[0065] Step S5: Quality Inspection of Iron-Cobalt Ingots

[0066] For the iron-cobalt ingot prepared in step S4, the 25cm high ingot head fused to the bottom of the iron-cobalt ingot was sawed off with a saw, and the 1cm high riser at the top of the iron-cobalt ingot was sawed off. The resulting ingot size was Φ48mm×195mm. A 10mm×10mm×5mm block was cut from the upper part of the riser using wire cutting. Co and Fe were detected using a Plasma 2000 inductively coupled plasma atomic emission spectrometer, and B, Cu, Mg, Ti, Cr, Si, Mo, V, and S were detected using an Element GD Plus glow discharge mass spectrometer. O and N were detected using an O-3000 oxygen-nitrogen analyzer, and C was detected using a CS-2800 carbon-sulfur analyzer. After the first vacuum electron beam melting and ingot pulling, the Co and Fe content in the alloy was: 43.78wt% Co, 56.16wt% Fe, and the content of other trace elements was (unit: ppm). The alloy content after the second vacuum electron beam melting and ingot pulling is as follows (wt%): B≤0.25, Cu≤23, Mg≤0.22, Ti≤2.6, Cr≤50, Si≤9.9, Mo≤6, V≤1.7, O≤406, N≤62, C≤52, S≤7.2. The Co and Fe contents in the alloy after the second vacuum electron beam melting and ingot pulling are: 45.56wt% Co, 54.4wt% Fe. The contents of other trace elements (unit: ppm wt%) are: B≤0.1, Cu≤7.7, Mg≤0.1, Ti≤1.6, Cr≤39, Si≤1.6, Mo≤3.9, V≤0.4, O≤255, N≤34, C≤35, S≤6.5.

[0067] Example 3

[0068] Step S1: Prepare iron-cobalt electrode

[0069] The alloy raw materials were prepared using 630.5 kg of Fe and 339.5 kg of Co. The iron was made from 99.99% pure iron bars, each measuring Φ100mm × 1700mm, approximately six in total. The surface of the iron bars was polished using a shot blasting machine to remove impurities. The cobalt was made from 99.996% pure cobalt plates, each measuring 1700mm × 200mm × 10mm, approximately 11.3 in total. Argon arc welding was used to ensure uniform distribution of the Fe and Co materials and to avoid localized component segregation. An inert gas (argon) was used throughout the welding process to prevent weld oxidation. The final weld formed an integral electrode structure with overall dimensions of 1700mm × 300mm × 280mm, completing the fabrication of the iron-cobalt electrode.

[0070] Step S2: Loading raw materials and ingot head into the furnace.

[0071] After hoisting the iron-cobalt electrode prepared in step S1 to the center of the track in the vacuum electron beam melting ingot pulling furnace hopper and fixing it, the raw material loading is completed. After wiping the surface of the pure iron ingot head with alcohol (298 mm in diameter and 28 cm in length), it is installed on the lower electrode copper clamp of the ingot pulling device in the vacuum electron beam melting ingot pulling furnace and fixed. Then, the pure iron ingot head is raised into the copper crystallizer with a diameter of 300 mm and 3 mm below the top. Then, the hopper door is closed, and the ingot head loading is completed. After closing the furnace door, the raw material and ingot head loading are completed. The vacuum system is started, and the furnace is evacuated.

[0072] Step S3: First vacuum electron beam melting and drawing of ingots

[0073] When the vacuum degree inside the furnace is better than 5×10 -2 Pa, electron gun chamber vacuum degree better than 5×10 -3 At Pa, the main high voltage, negative high voltage, and filament current of the electron gun are turned on. After the filament preheats for 15 minutes, the electron beam is induced. The electron beam is adjusted to the center of the ingot head, and the negative high voltage current is gradually increased. At the same time, the x and y positions of the scan are controlled to be 2 cm away from the edge of the crystallizer. After the entire upper surface of the ingot head is covered with molten metal and there are no visible impurities, the position of the electron beam is adjusted and focused, and the electron gun emission current is set to 3A. Then, the scanning pattern of the electron beam emitted with the center point of the copper crystallizer as the reference is adjusted, and the circular scanning pattern is enlarged to a position 2 cm away from the inner wall of the crystallizer, and the emission current is slowly increased to 4A. The upper 4.5 cm of the ingot head is melted into molten metal. The electrode was brought into full contact with the inner wall of the copper crystallizer. It was then started to rotate at a speed of 5 r / min. After adjusting the distance between the molten pool and the top of the crystallizer to 3 cm, the electron beam melting power of the electron gun was set to 220 kW, the cooling water flow rate to 55 L / min, and the water temperature to be controlled below 38 ℃. After the molten pool was maintained for 8 seconds, feeding began. Melting started from the front end of the hopper. The electron beam scanned from the front end of the electrode to the tail end at a scanning speed of 0.65 mm / s. During the melting process, the height of the molten pool and the copper crystallizer was observed, and the ingot was pulled at a speed of 0.56 mm / s until the tail end of the electrode was reached, completing the first melting. After cooling in the furnace for 8 hours, the ingot was removed from the furnace, resulting in the first vacuum electron beam melting and pulling of the iron-cobalt ingot.

[0074] Step S4, Second Vacuum Electron Beam Melting and Pulling of Ingots

[0075] After cooling, the iron-cobalt ingot obtained in step S3 from the first vacuum electron beam melting and drawing process is removed from the copper crystallizer, and a pure iron ingot head with a diameter of 298 mm and a length of 28 cm is inserted again and fixed on the lower electrode copper clamp of the drawing device in the vacuum electron beam melting and drawing furnace. After sawing off the original 28 cm length of the iron-cobalt ingot head with a saw, the ends of the iron-cobalt ingot are reversed, and it is placed in the center position of the track in the hopper and fixed with a clamp. The hopper door and the furnace door are closed in sequence, and the vacuum electron beam melting and drawing furnace is evacuated. When the vacuum degree in the furnace is better than 5 × 10⁻⁶, the ingot is drawn into place. -2 At Pa, the vacuum level of the electron gun chamber is better than 5 × 10⁻⁶. -3 At Pa, the main high voltage, negative high voltage, and filament current of the electron gun are turned on. After the filament is preheated for 15 minutes, the electron beam is drawn out and adjusted to the center of the ingot head. The negative high voltage current is gradually increased, while the scanning x and y positions are controlled to be 2 cm away from the edge of the copper crystallizer. After the entire surface of the ingot head is liquid and the liquid surface is free of impurities, melting is prepared. After the cathode (filament) is heated, the position of the focused electron beam is adjusted, the emission current of the electron gun is adjusted to 3A, and the scanning pattern is adjusted to enlarge the scanning pattern of the electron beam emitted from the center point of the copper crystallizer from a circular scanning pattern. The electron beam is moved to a position 2 cm from the inner wall of the copper crystallizer, and the emission current is slowly increased to 4.5 A. The top 4.5 cm of the ingot head is melted into a liquid and the solution is made to fully contact the inner wall of the crystallizer. The ingot transfer button is turned on instantly. When the distance between the molten pool and the top of the copper crystallizer is observed to be 3 cm, the feeding begins. Melting is carried out from the front end of the preparation electrode. The electron beam scans towards the tail end of the electrode at a speed of 0.7 mm / s. The ingot pulling speed is maintained at 0.6 mm / s until the electron beam reaches the tail end of the iron-cobalt ingot in the feeding bin, ending the second melting. The iron-cobalt ingot is then slowly cooled in the furnace for 8 hours, completing the second vacuum electron beam melting and ingot pulling.

[0076] Step S5: Quality Inspection of Iron-Cobalt Ingots

[0077] For the iron-cobalt ingot prepared in step S4, the 28cm high ingot head fused to the bottom of the iron-cobalt ingot was sawed off with a saw, and the 3cm high riser at the top of the iron-cobalt ingot was sawed off. The resulting ingot size was Φ297mm×1679mm. A 10mm×10mm×5mm block was cut from the upper part of the riser using wire cutting. Co and Fe were detected using a Plasma 2000 inductively coupled plasma atomic emission spectrometer, and B, Cu, Mg, Ti, Cr, Si, Mo, V, and S were detected using an Element GD Plus glow discharge mass spectrometer. O and N were detected using an O-3000 oxygen-nitrogen analyzer, and C was detected using a CS-2800 carbon-sulfur analyzer. After the first vacuum electron beam melting and ingot pulling, the Co and Fe content in the alloy was: 36.04 wt% Co, 63.90 wt% Fe, and the content of other trace elements was (unit: ppm). The alloy content after the second vacuum electron beam melting and ingot pulling is as follows (wt%): B≤0.21, Cu≤32, Mg≤0.25, Ti≤3.1, Cr≤74, Si≤8.2, Mo≤5.2, V≤2.1, O≤354, N≤50, C≤41, S≤5.8; The Co and Fe contents in the alloy after the second vacuum electron beam melting and ingot pulling are: 35.85wt% Co, 64.12wt% Fe, and the contents of other trace elements are (unit: ppm wt%): B≤0.12, Cu≤5.1, Mg≤0.18, Ti≤1.4, Cr≤58, Si≤4.6, Mo≤3.4, V≤0.8, O≤189, N≤38, C≤26, S≤4.1.

[0078] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0079] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing an iron-cobalt alloy for use as a metal catalyst, characterized in that, Includes the following steps: Step S1: Preparation of iron-cobalt electrode: Pure iron and pure cobalt raw materials are prepared in proportion, and after surface treatment, they are welded into electrode structure by argon arc welding; Step S2, Raw materials and ingot head loading: Load the iron-cobalt electrode and the pure iron ingot head into the corresponding positions of the vacuum electron beam melting ingot pulling furnace, close the furnace door and evacuate the furnace; Step S3, First Vacuum Electron Beam Melting and Pulling: After reaching the set vacuum level, the electron gun is started to melt the ingot head to form a molten pool, and then the iron-cobalt electrode is scanned to melt and pull the ingot. After cooling, a first-melted ingot is obtained. Step S4, Second Vacuum Electron Beam Melting and Pulling: After swapping the head and tail of the first-melting ingot, it is reloaded into the furnace, and the vacuum melting and pulling steps are repeated. After cooling, a second-melting ingot is obtained. Step S5, Quality Inspection: Remove the ingot head and riser from the secondary smelting ingot, take samples to test the chemical composition, and if they pass the test, they are finished products; The resulting alloy, by mass percentage, consists of 55%–65% Fe, 35%–45% Co, and the balance impurities; wherein the impurities are B≤0.005ppm, O≤115ppm, N≤27ppm, C≤39ppm, S≤0.31ppm, Cu≤5ppm, Mg≤0.005ppm, Ti≤0.01ppm, Cr≤0.04ppm, Si≤0.11ppm, Mo≤0.35ppm, and V≤0.72ppm.

2. The method for preparing the iron-cobalt alloy used as a metal catalyst according to claim 1, characterized in that, The alloy contains 58%–62% Fe and 38%–42% Co by mass percentage.

3. The method for preparing an iron-cobalt alloy used as a metal catalyst according to claim 1, characterized in that, In step S1, the purity of the pure iron is better than 99.99%, and the specifications are Φ20~100mm×200~1700mm; the purity of the pure cobalt is better than 99.996%, and the specifications are 200~1700mm long×50~200mm wide×3~10mm thick; the specifications of the iron-cobalt electrode are 200~1700mm long×50~300mm wide×50~280mm thick.

4. The method for preparing an iron-cobalt alloy used as a metal catalyst according to claim 1, characterized in that, In step S2, the specifications of the pure iron ingot head are Φ49~298mm×25~30cm; when loading the furnace, the ingot head is raised into the copper crystallizer with a diameter of Φ50~300mm, and is 2~3mm lower than the top of the crystallizer.

5. The method for preparing an iron-cobalt alloy used as a metal catalyst according to claim 1, characterized in that, In step S3, the smelting vacuum degree meets the following requirement: the vacuum degree inside the furnace is better than 5×10⁻⁶. -2 Pa, the vacuum level of the electron gun chamber is better than ; The electron gun filament is preheated for 10 minutes, the initial emission current is set to 1.8–3A, and then increased to 3.5–4A; the electron beam scanning speed is 0.62–0.65 mm / s, the ingot pulling speed is 0.52–0.56 mm / s; the melting power is 55–220 kW, the cooling water flow rate is 55 L / min, the water temperature is ≤40℃, the molten pool holding time is 6–8 s, and the cooling time is 3–8 hours.

6. The method for preparing an iron-cobalt alloy used as a metal catalyst according to claim 1, characterized in that, In step S4, after sawing off 25-30cm of the original ingot head of the primary smelting ingot, it is replaced and loaded into the furnace; the electron gun emission current is initially set to 2-3A, and then increased to 4-4.5A; the electron beam scanning speed is 0.6-0.7mm / s, the ingot pulling speed is 0.5-0.6mm / s; and the cooling time is 3-8 hours.

7. The method for preparing an iron-cobalt alloy used as a metal catalyst according to claim 1, characterized in that, In steps S3 and S4, the electrode rotation speed is 5 r / min during melting, and the distance between the molten pool and the top of the copper crystallizer is controlled at 2-3 cm; the electron beam scanning pattern is circular and magnified to a distance of 1-2 cm from the inner wall of the crystallizer.

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