Grain refinement and ignition performance collaborative optimization preparation method of rare earth sparking alloy

Abstract

The invention relates to a grain refinement and ignition performance collaborative optimization preparation method of a rare earth sparking alloy, and belongs to the technical field of rare earth sparking alloy manufacturing, the preparation raw materials of a blank comprise 35-45% of lanthanum, 15-30% of cerium, 5-15% of tin, 5-10% of zinc, 5-10% of praseodymium, 1-5% of neodymium and 15-25% of iron. By adopting the synergistic effect of the nanoscale active metal additive and the blank, the rare earth sparking alloy can generate continuous sparks under slight friction or impact, and the ignition performance of the traditional rare earth sparking alloy is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of rare earth ignition alloy manufacturing, and particularly relates to a grain refinement and ignition performance synergistic optimization preparation method of a rare earth ignition alloy. BACKGROUND

[0002] Ignition alloy, also known as fire alloy or flint alloy, is an alloy that can self-ignite after contacting with air, mainly including rare earth alloy, zirconium alloy, and metal powder of iron, cobalt, nickel, vanadium, titanium, manganese, etc. Such metal powder is collectively referred to as ignition metal, which is divided into non-rare earth type and rare earth type.

[0003] The grain of the traditional rare earth ignition alloy is relatively rough, and internal inclusions, pores or uneven grain size are easily formed, resulting in a large fluctuation range of hardness and tensile strength, and some products are easily broken under repeated impact or friction, which can easily produce "broken slag" and cannot continuously ignite. SUMMARY

[0004] The purpose of the present application is to provide a grain refinement and ignition performance synergistic optimization preparation method of a rare earth ignition alloy to solve the above problems.

[0005] The above purpose is achieved by the following technical solutions:

[0006] The present application provides a grain refinement and ignition performance synergistic optimization preparation method of a rare earth ignition alloy, and the preparation method of the rare earth ignition alloy comprises the following steps:

[0007] (1) Liquid state melting treatment: the blank is placed in a high-temperature heat treatment furnace, first heated to 850-1050 DEG C and kept for 5-6 h to obtain a metal liquid;

[0008] (2) Grain refinement: the melted metal liquid is poured into an intermediate ladle preheated to 900 DEG C, the leakage nozzle at the bottom of the intermediate ladle controls the metal liquid to flow out in a stable and continuous liquid flow at a speed of 1-5 m / s; below the leakage nozzle, a pre-set atomizing nozzle sprays atomizing medium at a speed of 300-600 m / s to interact with the metal liquid to shear the metal liquid into atomized droplets; the atomized droplets are injected into a condensation tower to fly, settle, cool and solidify to obtain solid powder particles;

[0009] (3) Adding active metal for synergistic optimization: the active metal additive and the solid powder particles are simultaneously added to a stirrer for stirring at 25 r / min for 5-10 min, and then ultrasonic vibration at a frequency of 20-40 kHz is applied for 10-15 min to obtain a preform;

[0010] (4) Spark plasma sintering: the preform is placed in a sintering cavity for spark plasma sintering in a nitrogen environment, and the rare earth ignition alloy is obtained after cooling.

[0011] As a further optimization scheme of the present application, the preparation raw material of the blank includes 35-45% of lanthanum, 15-30% of cerium, 5-15% of tin, 5-10% of zinc, 5-10% of praseodymium, 1-5% of neodymium and 15-25% of iron in percentage.

[0012] As a further optimization scheme of the present application, the preparation process of the blank is as follows: the component raw materials are weighed according to the mass percentage, and are put into a smelting furnace together, and then high-temperature smelting is carried out in an oxygen-isolated state; after the component raw materials are melted, electromagnetic stirring is used to mix them uniformly, and then the furnace is discharged, and the ingot is obtained by cooling and casting in an oxygen-isolated state.

[0013] As a further optimization scheme of the present application, the atomizing medium in step (2) is nitrogen.

[0014] As a further optimization scheme of the present application, the preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder and aluminum powder are mixed to obtain the active metal additive; the preparation process of the iron powder is as follows: sponge iron is obtained by reducing steel iron phosphorus with hydrogen, and then the iron powder is obtained by crushing and screening; the preparation process of the titanium powder is as follows: sponge titanium is obtained by reducing titanium chloride with magnesium by using the Kroll method, and then the titanium powder is obtained by crushing and screening; the particle size of the magnesium powder, the iron powder, the titanium powder and the aluminum powder is 10-15 nm.

[0015] As a further optimization scheme of the present application, the mass ratio of the magnesium powder, the iron powder, the titanium powder and the aluminum powder is 1:0.5:0.3:0.8.

[0016] As a further optimization scheme of the present application, the mass ratio of the active metal additive to the solid powder particles is 0.2:1.

[0017] As a further optimization scheme of the present application, in step (1), the temperature is raised at a rate of 7 ℃ / min; in step (4), the spark plasma sintering is carried out at a pressure of 50 MPa-60 MPa, the temperature is raised to 600 ℃-700 ℃ at a rate of 200 ℃ / min, and the temperature is maintained for 3 min-6 min; in the step (4), the temperature is lowered at a rate of 8 ℃ / min.

[0018] The beneficial effects of the present application are that the present application uses nanoscale active metal additives to synergize with the blank, so that the rare earth ignition alloy can produce continuous sparks under slight friction or impact, increase the ignition performance of the traditional rare earth ignition alloy, and the atomized medium interacts with the metal liquid to shear the metal liquid into atomized droplets, and after the atomized droplets solidify in the condensation tower, fine spherical powders are formed, and after the fine spherical powders are subjected to spark plasma sintering, the crystal grains will not grow larger in a very short time, and a high-density grain-refined rare earth ignition alloy can be obtained, which has uniform internal particle size, small hardness and tensile strength fluctuation range, and is not easy to break under repeated impact or friction, and can continuously ignite. DETAILED DESCRIPTION

[0019] It is necessary to point out here that the following detailed description is only used to further illustrate the present application, and cannot be understood as limiting the protection scope of the present application, and the skilled in the art can make some non-essential improvements and adjustments to the present application according to the above application content.

[0020] The method used in the present application is a conventional method known to those skilled in the art unless otherwise specified, and the reagents and other materials used are commercially available products unless otherwise specified.

[0021] Example 1

[0022] The preparation process of the blank is as follows: the raw materials of each component are weighed according to the mass percentage, 35% lanthanum, 15% cerium, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 25% iron are put into a smelting furnace, and then high-temperature smelting is carried out in an oxygen-isolated state; after the raw materials of each component are melted, electromagnetic stirring is used to mix them uniformly, and then the furnace is discharged; the ingot is obtained by cooling and casting in an oxygen-isolated state.

[0023] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; wherein the preparation process of the iron powder is as follows: sponge iron is obtained by reducing steel phosphorus with hydrogen, and then the iron powder is obtained by crushing and sieving; the preparation process of the titanium powder is as follows: sponge titanium is obtained by reducing titanium chloride with magnesium by the Crowl method, and then the titanium powder is obtained by crushing and sieving; the particle size of the magnesium powder, iron powder, titanium powder and aluminum powder is 10-15 nm.

[0024] Melted liquid treatment: the blank is placed in a high-temperature heat treatment furnace, heated to 850℃ at a rate of 7℃ / min, and kept for 5h to obtain a metal liquid.

[0025] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 2 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 300 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0026] Synergistic optimization with the addition of active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 5 min. Then, ultrasonic vibration at a frequency of 20 kHz was applied for 10 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0027] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 600°C at a pressure of 50 MPa at a rate of 200°C / min, held for 3 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0028] Example 2

[0029] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 40% lanthanum, 20% cerium, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 15% iron into a melting furnace. Then, melt at high temperature in an oxygen-isolated state. After the raw materials are melted, mix them evenly with electromagnetic stirring, remove them from the furnace, and cool and cast them into ingots in an oxygen-isolated state to obtain the billet.

[0030] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder, and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder, and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; wherein, the preparation process of the iron powder is: using hydrogen to reduce rolled steel phosphorus to obtain sponge iron, and then crushing and sieving to obtain iron powder; the preparation process of the titanium powder is: using the Klauer process to reduce titanium chloride with magnesium to obtain sponge titanium, and then crushing and sieving to obtain titanium powder; the particle size of the magnesium powder, iron powder, titanium powder, and aluminum powder is 10-15 nm;

[0031] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 900℃ at a rate of 7℃ / min and held for 5.5h to obtain molten metal;

[0032] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 3 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 450 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0033] Synergistic optimization with added active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 7 min. Then, ultrasonic vibration at a frequency of 30 kHz was applied for 12 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0034] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 650°C at a pressure of 55 MPa at a rate of 200°C / min, held for 4 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0035] Example 3

[0036] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 40% lanthanum, 17% cerium, 5% tin, 5% zinc, 9% praseodymium, 4% neodymium and 20% iron into a melting furnace. Then, melt at high temperature in an oxygen-isolated state. After the raw materials are melted, mix them evenly with electromagnetic stirring, remove them from the furnace, and cool and cast them into ingots in an oxygen-isolated state to obtain the billet.

[0037] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder, and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder, and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; wherein, the preparation process of the iron powder is: using hydrogen to reduce rolled steel phosphorus to obtain sponge iron, and then crushing and sieving to obtain iron powder; the preparation process of the titanium powder is: using the Klauer process to reduce titanium chloride with magnesium to obtain sponge titanium, and then crushing and sieving to obtain titanium powder; the particle size of the magnesium powder, iron powder, titanium powder, and aluminum powder is 10-15 nm;

[0038] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 1050℃ at a rate of 7℃ / min and held for 6 hours to obtain molten metal;

[0039] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 5 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 600 m / s to interact with the molten metal, shearing the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0040] Synergistic optimization with added active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 10 min. Then, ultrasonic vibration at a frequency of 40 kHz was applied for 15 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0041] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 700°C at a pressure of 60 MPa at a rate of 200°C / min, held for 6 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0042] Comparative Example 1

[0043] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 50% cerium, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 25% iron into a melting furnace. Then, melt at high temperature in an oxygen-isolated state. After the raw materials are melted, mix them evenly with electromagnetic stirring, remove them from the furnace, and cool and cast them into ingots in an oxygen-isolated state to obtain the billet.

[0044] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder, and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder, and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; wherein, the preparation process of the iron powder is: using hydrogen to reduce rolled steel phosphorus to obtain sponge iron, and then crushing and sieving to obtain iron powder; the preparation process of the titanium powder is: using the Klauer process to reduce titanium chloride with magnesium to obtain sponge titanium, and then crushing and sieving to obtain titanium powder; the particle size of the magnesium powder, iron powder, titanium powder, and aluminum powder is 10-15 nm;

[0045] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850°C at a rate of 7°C / min and held for 5 hours to obtain molten metal;

[0046] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 2 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 300 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0047] Synergistic optimization with the addition of active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 5 min. Then, ultrasonic vibration at a frequency of 20 kHz was applied for 10 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0048] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 600°C at a pressure of 50 MPa at a rate of 200°C / min, held for 3 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0049] Comparative Example 2

[0050] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 50% lanthanum, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 25% iron into a melting furnace. Then, melt at high temperature in an oxygen-isolated state. After the raw materials are melted, mix them evenly with electromagnetic stirring, remove them from the furnace, and cool and cast them into ingots in an oxygen-isolated state to obtain the billet.

[0051] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder, and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder, and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; wherein, the preparation process of the iron powder is: using hydrogen to reduce rolled steel phosphorus to obtain sponge iron, and then crushing and sieving to obtain iron powder; the preparation process of the titanium powder is: using the Klauer process to reduce titanium chloride with magnesium to obtain sponge titanium, and then crushing and sieving to obtain titanium powder; the particle size of the magnesium powder, iron powder, titanium powder, and aluminum powder is 10-15 nm;

[0052] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850°C at a rate of 7°C / min and held for 5 hours to obtain molten metal;

[0053] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 2 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 300 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0054] Synergistic optimization with the addition of active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 5 min. Then, ultrasonic vibration at a frequency of 20 kHz was applied for 10 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0055] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 600°C at a pressure of 50 MPa at a rate of 200°C / min, held for 3 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0056] Comparative Example 3

[0057] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 35% lanthanum, 15% cerium, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 25% iron into a melting furnace. Then, under the condition of oxygen isolation, high-temperature melting is carried out. After each component raw material melts, it is mixed evenly by electromagnetic stirring, removed from the furnace, and cooled and cast into ingots under the condition of oxygen isolation to obtain the billet.

[0058] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850°C at a rate of 7°C / min and held for 5 hours to obtain molten metal;

[0059] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 2 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 300 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0060] Spark plasma sintering: Solid powder particles are placed in a nitrogen atmosphere and heated to 600°C at a pressure of 50 MPa at a rate of 200°C / min, held at that temperature for 3 min, and then cooled at a rate of 8°C / min to obtain rare earth ignition alloy.

[0061] Comparative Example 4

[0062] The billet preparation process is as follows: Weigh each component raw material according to the mass percentage, and put 35% lanthanum, 15% cerium, 7% tin, 8% zinc, 6% praseodymium, 4% neodymium and 25% iron into a melting furnace. Then, under the condition of oxygen isolation, high-temperature melting is carried out. After each component raw material melts, it is mixed evenly by electromagnetic stirring, removed from the furnace, and cooled and cast into ingots under the condition of oxygen isolation to obtain the billet.

[0063] The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder and aluminum powder are mixed (the mass ratio of magnesium powder, iron powder, titanium powder and aluminum powder is 1:0.5:0.3:0.8) to obtain the active metal additive; the particle size of the magnesium powder, iron powder, titanium powder and aluminum powder is 10-15nm.

[0064] Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850°C at a rate of 7°C / min and held for 5 hours to obtain molten metal;

[0065] Grain refinement: The molten metal is poured into a preheated tundish at 900°C. A nozzle at the bottom of the tundish controls the molten metal to flow out at a stable and continuous speed of 2 m / s. Below the nozzle, a pre-set atomizing nozzle sprays nitrogen gas at 300 m / s, which interacts with the molten metal and shears the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles.

[0066] Synergistic optimization with the addition of active metals: Active metal additives and solid powder particles were added to a stirrer and stirred at 25 r / min for 5 min. Then, ultrasonic vibration at a frequency of 20 kHz was applied for 10 min to obtain a preform (the mass ratio of active metal additives to solid powder particles was 0.2:1).

[0067] Spark plasma sintering: The preform is placed in a nitrogen atmosphere and heated to 600°C at a pressure of 50 MPa at a rate of 200°C / min, held for 3 min, and then cooled at a rate of 8°C / min to obtain a rare earth ignition alloy.

[0068] Performance testing

[0069] ①The Vickers hardness of the rare earth ignition alloys prepared by the methods of Examples 1-3 and Comparative Examples 1-4 was tested according to the test methods in GB / T 4340.1-2009 "Metallic Materials - Vickers Hardness Test".

[0070] ② The density of the rare earth ignition alloys prepared by the methods in Examples 1-3 and Comparative Examples 1-4 was tested according to the test methods in GB / T 1423-1996 "Test Methods for Density of Precious Metals and Their Alloys";

[0071] ③ The rare earth ignition alloys prepared by the methods in Examples 1-3 and Comparative Examples 1-4 were subjected to thermal fatigue testing according to the test methods in GB / T 13303-2021 "Determination of Oxidation Resistance of Steel". The samples were kept at 300℃ for 2 hours, and the presence of an oxide layer was observed. At the same time, their coefficient of thermal expansion was measured. The test results are shown in Table 1.

[0072] Table 1

[0073] As can be seen from Table 1, by comparing the test data obtained from Examples 1-3 of the experimental group, it can be seen that Example 1 has better overall performance. By comparing Example 1, which has the best performance among the examples, with Comparative Examples 1-4, it can be seen that Example 1 is also better than any of the Comparative Examples 1-4.

[0074] Comparing Example 1 with Comparative Example 1, it can be found that Comparative Example 1 did not use lanthanum but increased the amount of cerium added. The lack of lanthanum resulted in a relative decrease in Vickers hardness and density compared to Example 1, and a decrease in thermal fatigue resistance. Comparing Example 1 with Comparative Example 2, it can be found that Comparative Example 2 did not use cerium but increased the amount of lanthanum added. This resulted in similar test values ​​between Comparative Example 2 and Comparative Example 1, indicating that lanthanum and cerium have a synergistic effect. A suitable component ratio can improve the performance of rare earth ignition alloys.

[0075] Comparing Example 1 with Comparative Example 3, it can be found that Comparative Example 3 did not add active metals and solid powder particles for synergistic optimization. The test results confirm that the rare earth ignition alloy with added active metals has superior performance.

[0076] Comparing Example 1 with Comparative Example 4, it can be found that Comparative Example 4 added ordinary iron powder and titanium powder, and the test results are slightly different from those of Example 1.

[0077] ④ The tensile strength and elongation of the rare earth ignition alloys prepared by the methods in Example 1 and Comparative Examples 1-4 were tested according to the test methods in GB / T 228.1-2010 "Metallic materials, tensile testing - Part 1: Test method at room temperature". The test results are shown in Table 2.

[0078] Table 2

[0079] As can be seen from Table 2, Example 1 has better physical properties than Comparative Examples 1-4, with better tensile strength and elongation.

[0080] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for synergistically optimizing the grain refinement and ignition performance of rare earth ignition alloys, characterized in that, The preparation method of rare earth ignition alloys includes the following steps: (1) Molten liquid treatment: The billet is placed in a high-temperature heat treatment furnace and heated to 850-1050℃ and held for 5-6 hours to obtain molten metal; (2) Grain refinement: The molten metal is poured into a tundish preheated to 900°C. The molten metal flows out at a speed of 1-5 m / s in a stable and continuous flow form through the nozzle at the bottom of the tundish. Below the nozzle, a pre-set atomizing nozzle sprays atomizing medium at 300-600 m / s to interact with the molten metal and shear the molten metal into atomized droplets. The atomized droplets are injected into a condensation tower, where they fly, settle, cool, and solidify to obtain solid powder particles. (3) Adding active metals for synergistic optimization: Add the active metal additives and solid powder particles to the stirrer at 25r / min for 5-10min, then apply ultrasonic vibration at a frequency of 20-40kHz for 10-15min to obtain the preform. (4) Spark plasma sintering: The preform is placed in the sintering chamber and spark plasma sintering is carried out in a nitrogen atmosphere. After cooling, rare earth ignition alloy is obtained.

2. The method for preparing rare earth ignition alloys with synergistic optimization of grain refinement and ignition performance according to claim 1, characterized in that, The raw materials for preparing the billet, by percentage, include 35-45% lanthanum, 15-30% cerium, 5-15% tin, 5-10% zinc, 5-10% praseodymium, 1-5% neodymium, and 15-25% iron.

3. The method for synergistically optimizing grain refinement and ignition performance of rare earth ignition alloys according to claim 2, characterized in that, The billet preparation process is as follows: weigh each component raw material according to the mass percentage, put them into the melting furnace together, and then melt them at high temperature in an oxygen-isolated state; after each component raw material melts, mix them evenly with electromagnetic stirring, remove them from the furnace, and cool and cast them into ingots in an oxygen-isolated state to obtain the billet.

4. The method for preparing rare earth ignition alloys with synergistic optimization of grain refinement and ignition performance according to claim 1, characterized in that, In step (2), the atomizing medium is nitrogen.

5. The method for synergistically optimizing grain refinement and ignition performance of rare earth ignition alloys according to claim 1, characterized in that, The preparation process of the active metal additive is as follows: magnesium powder, iron powder, titanium powder and aluminum powder are mixed to obtain the active metal additive; wherein, the preparation process of the iron powder is as follows: hydrogen is used to reduce iron-coated steel phosphorus to obtain sponge iron, which is then crushed and sieved to obtain iron powder; the preparation process of the titanium powder is as follows: magnesium is used to reduce titanium chloride to obtain sponge titanium, which is then crushed and sieved to obtain titanium powder; the particle size of the magnesium powder, iron powder, titanium powder and aluminum powder is 10-15 nm.

6. The method for synergistically optimizing grain refinement and ignition performance of rare earth ignition alloys according to claim 5, characterized in that, The mass ratio of magnesium powder, iron powder, titanium powder and aluminum powder is 1:0.5:0.3:0.

8.

7. The method for preparing rare earth ignition alloys with synergistic optimization of grain refinement and ignition performance according to claim 6, characterized in that, The mass ratio of the active metal additive to the solid powder particles is 0.2:

1.

8. The method for preparing rare earth ignition alloys with synergistic optimization of grain refinement and ignition performance according to claim 1, characterized in that, In step (1), the temperature is increased at a rate of 7℃ / min; in step (4), the discharge plasma sintering is carried out at a pressure of 50MPa-60MPa, the temperature is increased to 600℃-700℃ at a rate of 200℃ / min, and held for 3min-6min; in step (4), the temperature is decreased at a rate of 8℃ / min.

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