Method for preparing NiB alloy through eddy current thermoelectric coupling
The in-situ addition of B is achieved in the nickel melt by eddy current thermoelectric coupling method, and the homogeneous nickel-boron alloy is generated, and the boric acid is recovered through sulfuric acid leaching treatment, which solves the problems of long production cycle, complex process and high cost in the existing NiB alloy preparation process, and achieves efficient and clean NiB alloy preparation.
Patent Information
- Application Number
- CN202510356795.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2025-06-27
AI Technical Summary
The existing NiB alloy preparation process has problems such as long production cycle, complex process and high production costs, making it difficult to prepare NiB alloys with a quality that is comparable to or even better than commercial alloy performance.
The eddy current thermoelectric coupling method is used to mix Mg powder and B2O3 and then process it by ball milling and pressing to form a mixed material. Then, the in-situ addition of B is achieved in the nickel melt by eddy current stirring, forming a homogeneous nickel-boron alloy and MgO-B2O3-based reduction melting slag, and the separation of slag gold is promoted through thermoelectric coupling, and boric acid is recovered through sulfuric acid leaching treatment to achieve clean preparation of the alloy.
It reduces production costs, simplifies the process flow, solves the microsegregation problem, achieves the improvement of high-temperature stability, corrosion resistance and magnetic properties of NiB alloys, and realizes a clean and sustainable production method through the recycling of boric acid.
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of nickel alloy preparation, and particularly relates to a method for preparing NiB alloy by eddy current thermoelectric coupling. Background Art
[0002] Nickel boride (NiB) alloy, as one of the important functional materials, has excellent properties and is widely used in various fields. Usually, the proportion of nickel content is relatively high, and the boron content is relatively low. It has characteristics such as high-temperature stability, corrosion resistance, and strong ferromagnetism. High-temperature stability means that the nickel boride alloy has good stability and heat resistance at high temperatures, is suitable for high-temperature working environments, and is widely used as an intermediate alloy in the aerospace field (such as engine parts, combustion chambers, etc.); corrosion resistance indicates that the nickel boride alloy can work stably for a long time in a harsh chemical environment (such as used in the manufacture of anti-corrosion equipment in chemical equipment manufacturing); magnetism shows that the nickel boride alloy can be used to manufacture magnetic materials (such as preparing electronic components, thermocouples, magnetic cores, etc.). The hardness and strength of the nickel boride alloy can also be adjusted by heat treatment or alloying to meet different engineering applications. Therefore, nickel boride alloy is widely used in the fields of electronics, aerospace, chemical industry, etc., providing important support for modern industry. Studying nickel boride alloy has certain value for studying the volume and density changes during the alloy solidification process.
[0003] At present, the preparation processes of NiB alloy include the melting method. By using high-temperature technologies such as arc heating or induction heating, high-purity nickel and boron powders (generally with a mass ratio of 2:1) are placed under high-purity argon protection for melting, and then the molten material is poured into a mold for casting. The casting temperature is generally controlled below 1200°C to avoid sintering. In addition, other elements such as copper and iron can be added according to specific needs; the boronizing method, which utilizes the permeability of nickel and other metals, injects boron elements into them at high temperatures to prepare high-purity nickel boride alloy. This method requires strict control of parameters such as temperature, time, and boron content to ensure the composition and performance of the alloy; the electroless plating method, especially electroless nickel-boron plating. Although the reducing agent such as dimethylamine borane used is relatively expensive and the plating bath stability is low, due to its many characteristics such as wear resistance, hardness, low friction, and solderability, its application in industries such as electronics, automobiles, and medical devices has become more and more extensive in recent years. The above processes have problems such as long production cycles, complex production processes, and high production costs. Therefore, how to reduce the production cost of the existing production technology, prepare a NiB alloy with quality equivalent to or even better than that of commercial alloys to obtain good economic benefits is the research direction of NiB alloy. Summary of the Invention
[0004] In the present invention, pure nickel metal is quickly melted in an induction furnace to obtain a nickel melt. An eddy current is formed in the nickel melt through the synergistic action of electromagnetic and mechanical stirring. B2O3 (boric acid) and magnesium powder are mixed and introduced into the interior of the nickel melt to carry out an in-situ reaction to generate elemental B and MgO. Under the action of the eddy current, elemental B is uniformly dispersed in the nickel melt. In addition, by adding an excessive amount of B2O3 and the generated MgO to form slag to generate 3MgO·B2O3, the melting point of the MgO-based slag is reduced, and the effect of slag-metal separation is improved. The effective separation of slag and metal is promoted through the action of thermoelectric coupling. After the reaction is completed, the smelting slag is treated with sulfuric acid to decompose the boron-magnesium ore, and the boric acid product is separated therefrom, and after dehydration, it is recycled to realize the clean preparation of the nickel-boron alloy.
[0005] A method for preparing NiB alloy by eddy current thermoelectric coupling includes the following steps: First, Mg powder and B2O3 are mixed and then ball-milled and compacted to obtain a mixed material; then the mixed material is uniformly added to the nickel melt in an eddy current manner. The mixed material undergoes a magnesiothermic self-propagating reduction reaction under the high-temperature environment of the melt and the action of eddy current stirring to realize the in-situ addition of B in the Ni melt, and a high-temperature melt composed of a homogeneous nickel-boron alloy and reduced smelting slag is obtained; the high-temperature melt is melted by electromagnetic induction heating to form a 3MgO·B2O3 smelting slag on the upper layer and a NiB alloy melt on the lower layer; the NiB alloy melt is solidified to obtain a NiB alloy ingot; the 3MgO·B2O3 smelting slag is acid-leached with sulfuric acid to obtain a mixed solution of H3BO3 and MgSO4. The mixed solution of H3BO3 and MgSO4 is subjected to low-temperature crystallization, filtration, and drying to obtain H3BO4, and the filtered mother liquor is recrystallized. Finally, boric acid (anhydrous boric anhydride) is recycled.
[0006] Furthermore, the ratio of Mg powder to B2O3 is based on the required nickel-boron alloy and the raw materials are proportioned according to chemical equation (1), making B2O3 in excess, and the excess range is 1.5 to 2.5 times.
[0007] 3Mg + 2B2O3 = 3MgO·B2O3 + 2B (1).
[0008] Furthermore, for the ball-milling and compaction, Mg powder and B2O3 are weighed separately and loaded into a mixing tank, ball-milled on a high-energy ball mill for 40 min to 60 min. After ball-milling, the particle sizes of Mg powder and B2O3 are 25 μm to 45 μm, and then compacted under the condition of a pressure of 10 Mpa to 20 Mpa.
[0009] Furthermore, the nickel melt is prepared by melting the nickel block required for the reaction into a molten state through induction heating, and then generating eddy currents in the melt through the synergistic effect of electromagnetic and mechanical stirring; the induction heating temperature is 1500°C to 1600°C, and the heating time is 30min to 50min; the stirring speed is 100rpm to 200rpm, and a straight-blade open-type turbine propeller or electromagnetic stirring is used.
[0010] Furthermore, the melting temperature of the high-temperature melt by electromagnetic induction heating is 1500° C. to 1600° C., the melting time is 30 min to 50 min, and the electromagnetic induction parameter is 2000 Hz to 4500 Hz.
[0011] Furthermore, the solidification of the NiB alloy melt is carried out in a water-cooled crystallizer at a solidification rate of 10°C / s to 20°C / s.
[0012] Furthermore, the 3MgO·B2O3 smelting slag is leached with sulfuric acid for 80 min to 120 min, at a temperature of 80° C. to 100° C., with a sulfuric acid concentration of 20% to 25%, and the leaching rate of B2O3 can reach more than 98%.
[0013] Compared with the prior art, the present invention is beneficial in that:
[0014] Compared with vacuum smelting, the method of the present invention adopts cheap B2O3 as raw material, has low production cost, and does not require too high a vacuum degree for preparation in a non-vacuum environment; compared with the traditional metallurgical method, the process adopts the synergistic effect of reduction and mechanical / electromagnetic stirring to make the B element obtained by magnesium thermal reduction uniformly dispersed in the high-temperature Ni matrix, and its maximum temperature can reach above 1800°C, effectively solving the problem of micro-segregation; the magnesium borate slag system generated by the present invention can obtain boric acid for recycling through secondary treatment, thereby realizing the clean and sustainable production of NiB alloy. DETAILED DESCRIPTION
[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0016] Example 1
[0017] A method for preparing NiB30 alloy by eddy current thermoelectric coupling, comprising the following steps: placing the required B2O3 material for the reaction in an oven and drying it at 150 °C for 24 h, then mixing 5787 g of Mg powder and 6907 g of B2O3 powder and putting them into a mixing tank, where the mixing ratio of B2O3 powder to Mg powder is 1:0.84 by weight (the addition amount of B2O3 is 2.5 times the chemical reaction stoichiometric formula), mixing on a ball mill for 60 min, and compacting to obtain a mixed material; putting 1 kg of Ni block into an induction furnace, heating it to 1500 °C to completely melt the Ni block into a molten state, then adding the mixed material into the nickel block melt in an eddy current manner, starting the mechanical stirring system and electromagnetic cooperative stirring through a straight-blade open-type turbine paddle, and setting the stirring speed to 200 rpm; the mixed material undergoes a magnesiothermic self-propagating reduction reaction under the high-temperature environment of the melt and the action of eddy current stirring, realizing the in-situ addition of B in the Ni melt, and obtaining a high-temperature melt composed of a homogeneous nickel boride alloy and a MgO-B2O3-based reduction smelting slag; heating and melting the high-temperature melt by electromagnetic induction to form a 3MgO·B2O3 smelting slag on the upper layer and a NiB alloy melt on the lower layer, and the electromagnetic induction parameters are: 4000 Hz, a smelting temperature of 1600 °C, and a smelting time of 50 min, ensuring that the slag also presents a molten state, improving the separation effect of the slag and the metal, forming a reduction slag on the upper layer and a NiB alloy melt on the lower layer; after refining and slag removal, solidifying at 20 °C / s under the action of a water-cooled crystallizer to obtain a nickel boride alloy ingot. The 3MgO·B2O3 smelting slag is acid-leached with sulfuric acid to obtain a mixed solution of H3BO3 and MgSO4, the mixed solution of H3BO3 and MgSO4 is subjected to low-temperature crystallization, filtration, and drying to obtain H3BO4, and the filtered mother liquor is recrystallized, and finally boric acid (anhydrous boric anhydride) is recycled.
[0018] The B content in the nickel boride alloy is 29.1% - 32.3%, the B2O3 content in the slag is 42.8%, the MgO content is 56.5%, the acid-leaching time of the slag is 120 min, the reaction temperature is 100 °C, the sulfuric acid concentration is 25%, and the leaching rate of B2O3 can reach 98.2%.
[0019] Example 2
[0020] A method for preparing NiB25 alloy by eddy current thermoelectric coupling includes the following steps: Place the required B2O3 material for the reaction in an oven and bake it at 150 °C for 24 h. Then, mix 3369 g of Mg powder and 4289 g of B2O3 powder and put them into a mixing tank. The mixing ratio of B2O3 powder to Mg powder is 1:0.79 by weight (the addition amount of B2O3 is 2.0 times the stoichiometric formula of the chemical reaction). Mix them on a ball mill for 55 min and compact to obtain a mixed material. Put 1 kg of Ni block into an induction furnace, heat it up to 1500 °C until the Ni block completely melts into a melt state. Then, add the mixed material into the nickel block melt in an eddy current manner, start the mechanical stirring system and electromagnetic cooperative stirring through a straight-blade open-type turbine paddle, and set the stirring speed to 180 rpm. The mixed material undergoes a magnesiothermic self-propagating reduction reaction under the high-temperature environment of the melt and the action of eddy current stirring, realizing the in-situ addition of B in the Ni melt, and obtaining a high-temperature melt composed of a homogeneous nickel boride alloy and a MgO-B2O3-based reduction smelting slag. Heat the high-temperature melt by electromagnetic induction melting to form a 3MgO·B2O3 smelting slag on the upper layer and a NiB alloy melt on the lower layer. The electromagnetic induction parameters are: 3500 Hz, melting temperature 1580 °C, and melting time 45 min, ensuring that the slag also presents a melt state, improving the separation effect of slag and metal, forming a reduction slag on the upper layer and a NiB alloy melt on the lower layer. After refining and slag removal, solidify at 18 °C / s under the action of a water-cooled crystallizer to obtain a nickel boride alloy ingot. The 3MgO·B2O3 smelting slag is acid-leached with sulfuric acid to obtain a mixed solution of H3BO3 and MgSO4. The mixed solution of H3BO3 and MgSO4 is subjected to low-temperature crystallization, filtration, and drying to obtain H3BO4, and the filtered mother liquor is recrystallized. Finally, boric acid (anhydrous boric anhydride) is recycled.
[0021] The B content in the nickel boride alloy is 25.5% - 28.3%, the B2O3 content in the slag is 45.8%, the MgO content is 53.6%, the acid-leaching time of the slag is 100 min, the reaction temperature is 95 °C, the sulfuric acid concentration is 20%, and the leaching rate of B2O3 can reach 98.1%.
[0022] Example 3
[0023] A method for preparing NiB₂₀ alloy by eddy current thermoelectric coupling, comprising the following steps: placing the required B₂O₃ material for the reaction in an oven and drying it at 150 °C for 24 h, then mixing 2192 g of Mg powder and 2898 g of B₂O₃ powder and putting them into a mixing tank, where the mixing ratio of B₂O₃ powder to Mg powder is 1:0.76 by weight (the addition amount of B₂O₃ is 1.8 times the stoichiometric formula of the chemical reaction), mixing on a ball mill for 45 min, and compacting to obtain a mixed material; putting 1 kg of Ni block into an induction furnace, heating it to 1500 °C to completely melt the Ni block into a melt state, then adding the mixed material into the nickel block melt in an eddy current manner, starting the mechanical stirring system and electromagnetic co-stirring through a straight-blade open-type turbine paddle, and setting the stirring speed to 170 rpm; the mixed material undergoes a magnesium thermal self-propagating reduction reaction under the high-temperature environment of the melt and the action of eddy current stirring to achieve in-situ addition of B in the Ni melt, obtaining a high-temperature melt composed of a homogeneous nickel boride alloy and a MgO-B₂O₃ system reduction smelting slag; heating and melting the high-temperature melt by electromagnetic induction to form a 3MgO·B₂O₃ smelting slag on the upper layer and a NiB alloy melt on the lower layer, and the electromagnetic induction parameters are: 3500 Hz, melting temperature 1550 °C, melting time 40 min, ensuring that the slag also presents a melt state, improving the separation effect of slag and metal, forming a reduction slag on the upper layer and a NiB alloy melt on the lower layer; after refining and slag removal, solidifying at 15 °C / s under the action of a water-cooled crystallizer to obtain a nickel boride alloy ingot. The 3MgO·B₂O₃ smelting slag is acid-leached with sulfuric acid to obtain a mixed solution of H₃BO₃ and MgSO₄, and the mixed solution of H₃BO₃ and MgSO₄ is subjected to low-temperature crystallization, filtration, and drying to obtain H₃BO₄, and the filtered mother liquor is recrystallized, and finally boric acid (anhydrous boric anhydride) is recycled.
[0024] The B content in the nickel boride alloy is 19.8% - 21.2%, the B₂O₃ content in the slag is 47.6%, the MgO content is 51.9%, the acid-leaching time of the slag is 95 min, the reaction temperature is 90 °C, the sulfuric acid concentration is 20%, and the leaching rate of B₂O₃ can reach 98.4%.
[0025] Example 4
[0026] A method for preparing NiB15 alloy by eddy current thermoelectric coupling, comprising the following steps: placing the required B2O3 material for the reaction in an oven and drying it at 150 °C for 24 h, then mixing 1484 g of Mg powder and 2061 g of B2O3 powder and putting them into a mixing tank, where the mixing ratio of B2O3 powder to Mg powder is 1:0.72 by weight (the addition amount of B2O3 is 1.6 times the chemical reaction stoichiometric formula), mixing on a ball mill for 45 min, and compacting to obtain a mixed material; putting 1 kg of Ni block into an induction furnace, heating it to 1500 °C to make the Ni block completely melt into a melt state, then adding the mixed material to the nickel block melt in an eddy current manner, starting the mechanical stirring system and electromagnetic cooperative stirring through a straight blade open type turbine paddle, and setting the stirring speed to 160 rpm; the mixed material undergoes a magnesium thermal self-propagating reduction reaction under the high-temperature environment of the melt and the action of eddy current stirring, realizing the in-situ addition of B in the Ni melt, and obtaining a high-temperature melt composed of a homogeneous nickel boride alloy and a MgO-B2O3 based reduction smelting slag; heating and melting the high-temperature melt through electromagnetic induction to form a 3MgO·B2O3 smelting slag on the upper layer and a NiB alloy melt on the lower layer, and the electromagnetic induction parameters are: 3000 Hz, a smelting temperature of 1550 °C, and a smelting time of 35 min, ensuring that the slag also presents a melt state, improving the separation effect of the slag and the metal, forming a reduction slag on the upper layer and a NiB alloy melt on the lower layer; after refining and slag removal, solidifying at 13 °C / s under the action of a water-cooled crystallizer to obtain a nickel boride alloy ingot. The 3MgO·B2O3 smelting slag is acid-leached with sulfuric acid to obtain a mixed solution of H3BO3 and MgSO4, the mixed solution of H3BO3 and MgSO4 is subjected to low-temperature crystallization, filtration, and drying to obtain H3BO4, and the filtered mother liquor is recrystallized, and finally boric acid (anhydrous boric anhydride) is recycled.
[0027] The B content in the nickel boride alloy is 14.4% - 16.5%, the B2O3 content in the slag is 48.7%, the MgO content is 50.6%, the acid-leaching time of the slag is 90 min, the reaction temperature is 90 °C, the sulfuric acid concentration is 20%, and the leaching rate of B2O3 can reach 98.2%.
[0028] Example 5
[0029] A method for preparing NiB10 alloy by eddy current thermoelectric coupling, comprising the following steps: placing the required B2O3 material for the reaction in an oven and drying it at 150 °C for 24 h, then mixing 749 g of Mg powder and 1072 g of B2O3 powder and putting them into a mixing tank, where the mixing ratio of B2O3 powder to Mg powder is 1:0.70 by weight (the addition amount of B2O3 is 1.5 times the chemical reaction stoichiometric formula), mixing on a ball mill for 40 min, and compacting to obtain a mixed material; putting 1 kg of Ni block into an induction furnace, heating it to 1500 °C to make the Ni block completely melt into a molten state, then adding the mixed material into the nickel block melt in an eddy current manner, starting the mechanical stirring system and electromagnetic co-stirring through a straight-blade open-type turbine paddle, and setting the stirring speed to 150 rpm; the mixed material undergoes a magnesium thermal self-propagating reduction reaction under the high-temperature environment of the melt and the action of eddy current stirring, realizing the in-situ addition of B in the Ni melt, and obtaining a high-temperature melt composed of a homogeneous nickel boride alloy and a MgO-B2O3-based reduction smelting slag; heating and melting the high-temperature melt by electromagnetic induction to form a 3MgO·B2O3 smelting slag on the upper layer and a NiB alloy melt on the lower layer, and the electromagnetic induction parameters are: 2000 Hz, a smelting temperature of 1500 °C, and a smelting time of 30 min, ensuring that the slag also presents a molten state, improving the separation effect of the slag and the metal, forming a reduction slag on the upper layer and a NiB alloy melt on the lower layer; after refining and slag removal, solidifying at 10 °C / s under the action of a water-cooled crystallizer to obtain a nickel boride alloy ingot. The 3MgO·B2O3 smelting slag is acid-leached with sulfuric acid to obtain a mixed solution of H3BO3 and MgSO4, the mixed solution of H3BO3 and MgSO4 is subjected to low-temperature crystallization, filtration, and drying to obtain H3BO4, and the filtered mother liquor is recrystallized, and finally boric acid (anhydrous boric anhydride) is recycled.
[0030] The B content in the nickel boride alloy is 10.6% - 11.7%, the B2O3 content in the slag is 52.8%, the MgO content is 46.6%, the acid-leaching time of the slag is 80 min, the reaction temperature is 80 °C, the sulfuric acid concentration is 20%, and the leaching rate of B2O3 can reach 98.1%.
Claims
1. A method for preparing NiB alloy by eddy current thermoelectric coupling, characterized in that: The method comprises the following steps: firstly mixing Mg powder and B2O3, and then ball milling and pressing a blank to obtain a mixed material; then uniformly adding the mixed material into a nickel melt in an eddy current manner, so that the mixed material undergoes a magnesium thermal self-propagating reduction reaction under the high temperature environment of the melt and the stirring action of the eddy current, thereby realizing the in-situ addition of B into the Ni melt, and obtaining a high-temperature melt consisting of a homogeneous nickel-boron alloy and a reducing smelting slag; smelting the high-temperature melt by electromagnetic induction heating to form a 3MgO·B2O3 smelting slag on its upper layer and a NiB alloy melt on its lower layer; solidifying the NiB alloy melt to obtain a NiB alloy ingot; acid leaching the 3MgO·B2O3 smelting slag with sulfuric acid to obtain a mixed solution of H3BO3 and MgSO4, subjecting the mixed solution of H3BO3 and MgSO4 to low-temperature crystallization, filtration and drying to obtain H3BO4, and recrystallizing the filtered mother liquor, and finally recycling the boric acid.
2. The method for preparing NiB alloy by eddy current thermoelectric coupling according to claim 1, characterized in that: The ratio of Mg powder and B2O3 is determined by the raw material ratio according to the required nickel-boron alloy according to the chemical equation (1), so that B2O3 is excessive, and the excess range is 1.5 to 2.5 times; 3Mg+2B2O3=3MgO·B2O3+2B(1).
3. The method for preparing NiB alloy by eddy current thermoelectric coupling according to claim 1, characterized in that: The ball milled compact is prepared by weighing Mg powder and B2O3 respectively and loading them into a mixing tank, and ball milling them on a high energy ball mill for 40 to 60 minutes. After ball milling, the particle sizes of the Mg powder and B2O3 are 25 μm to 45 μm, and then compacting them under a pressure of 10 MPa to 20 MPa.
4. The method for preparing NiB alloy by eddy current thermoelectric coupling according to claim 1, characterized in that: The nickel melt is prepared by melting the nickel block required for the reaction into a molten state through induction heating, and then generating eddy currents in the melt through the synergistic effect of electromagnetic and mechanical stirring; the induction heating temperature is 1500° C. to 1600° C., and the heating time is 30 min to 50 min; the stirring speed is 100 rpm to 200 rpm, and a straight-blade open-type turbine impeller or electromagnetic stirring is used.
5. The method for preparing NiB alloy by eddy current thermoelectric coupling according to claim 1, characterized in that: The high-temperature melt is heated by electromagnetic induction at a melting temperature of 1500° C. to 1600° C., a melting time of 30 min to 50 min, and an electromagnetic induction parameter of 2000 Hz to 4500 Hz.
6. The method for preparing NiB alloy by eddy current thermoelectric coupling according to claim 1, characterized in that: The NiB alloy melt is solidified in a water-cooled crystallizer at a solidification rate of 10°C / s to 20°C / s.
7. The method for preparing NiB alloy by eddy current thermoelectric coupling according to claim 1, characterized in that: The 3MgO·B2O3 smelting slag is leached with sulfuric acid for 80 minutes to 120 minutes, at a temperature of 80°C to 100°C, with a sulfuric acid concentration of 20% to 25%, and the leaching rate of B2O3 can reach more than 98%.