Preparation process of high-density tungsten alloy blocky fragments

Abstract

The invention discloses a high-density tungsten alloy blocky fragment preparation process, and belongs to the technical field of blocky fragment preparation. The preparation process of the high-density tungsten alloy blocky fragments comprises the following steps that (1) tungsten, molybdenum and iridium are put into a stainless steel ball-milling tank, ball-milling mixing, rotary evaporation, vacuum drying, grinding, crushing and sieving are carried out, and pretreated powder is obtained; (2) putting a composite iron nano array into a stearic acid surfactant, uniformly dispersing, and mixing with the pretreated powder to obtain composite powder; and (3) the composite powder is loaded into a graphite mold, the mold loaded with the composite powder is pre-pressed and then placed into a sintering furnace, a furnace door is closed, sintering is conducted, after sintering is finished, current and pressure are cut off, cooling, grinding and polishing are conducted, and the high-density tungsten alloy blocky fragments are obtained. By adding the composite iron nano array and the stearic acid surfactant, the density, hardness and corrosion resistance of the tungsten alloy blocky fragments can be effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of tungsten alloy bulk fragments, and particularly relates to a preparation process for high-density tungsten alloy bulk fragments. Background Art

[0002] Tungsten alloys, due to their characteristics such as high density, high hardness, good ductility, and corrosion resistance, have a wide range of applications in the military, aerospace, nuclear industry and other fields. Especially in the military field, as an important part of weapon systems such as armor-piercing projectiles and armor-piercing fragmentation projectiles, the performance of high-density tungsten alloy bulk fragments is directly related to the striking effect and combat effectiveness of weapons. Therefore, studying the preparation process of high-density tungsten alloy bulk fragments is of great significance for improving the performance and combat capabilities of weapon systems.

[0003] Secondly, with the progress of technology and the change of the form of war, the performance requirements for high-density tungsten alloy bulk fragments are also getting higher and higher. It is not only required to have higher density and hardness, but also better impact resistance, corrosion resistance, and high-temperature resistance, etc. Therefore, it is necessary to continuously innovate and optimize the preparation process to meet the increasingly stringent usage environment.

[0004] Chinese Patent with the authorized announcement number CN 106694897 B discloses a method for preparing tungsten-based high-density alloy bulk materials. The steps are as follows: using a high-speed mixer to uniformly mix tungsten powder, nickel powder, and iron powder required for high-density tungsten alloy, and the powder particle size is 3μm - 10μm; feeding the mixed powder into a plasma powder preparation device with a powder feeder, vaporizing it in an ultra-high-temperature plasma arc, and rapidly cooling to form composite nano-powder, and the particle size of the nano-composite powder is 10nm - 100nm; putting an appropriate amount of nano-composite powder into a graphite mold, in an electric sintering device, performing vacuum degassing for 20 - 40min, then filling with argon for protection, keeping the upper and lower punching pressures at 30MPa - 100MPa, heating by electricity, heating at a heating rate of 30 - 40°C / min to 1100 - 1250°C, continuing to keep warm for 1 - 3min, and finally cooling to room temperature at a cooling rate of more than 50°C per minute to obtain the required bulk material. This method is simple, reasonable, and easy to operate. The prepared bulk material has a high density and strong plasticity, and has great application value. However, there is still room for improvement in the density, hardness, and corrosion resistance of the tungsten alloy bulk material prepared by this method. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation process for high-density tungsten alloy bulk fragments, aiming to solve the technical problems of poor density, hardness, and corrosion resistance of tungsten alloy bulk fragments in the prior art.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] The present invention provides a preparation process for high-density tungsten alloy bulk fragments, comprising the following steps:

[0008] Step (1): Load tungsten, molybdenum and iridium into a stainless steel ball milling tank for ball milling and mixing. After mixing, perform rotary evaporation, vacuum drying, grinding, crushing, sieving to obtain pretreated powder;

[0009] Step (2): Place the composite iron nanoarray in a stearic acid surfactant. After dispersing evenly, mix it with the pretreated powder to obtain composite powder;

[0010] Step (3): Load the composite powder into a graphite mold. After pre-pressing the mold filled with the composite powder, place it in a sintering furnace, close the furnace door, sinter. After sintering, cut off the current and pressure, cool, grind and polish to obtain high-density tungsten alloy bulk fragments.

[0011] Preferably, in the step (1), the mass ratio of tungsten, molybdenum and iridium is (90 - 95):(4.5 - 8):(0.5 - 2). During the ball milling and mixing process, the material of the grinding balls is tungsten carbide, the ball milling medium is ethanol, the mixing time is 10 - 30 h, the rotary evaporation temperature is 85 - 92 °C, the rotary evaporation time is 2 - 4 h, the vacuum drying temperature is 60 - 70 °C, and the time is 12 - 18 h.

[0012] Preferably, the preparation method of the composite iron nanoarray in the step (2) comprises the following steps:

[0013] Q1: Soak nickel foam in dilute hydrochloric acid, ethanol and ultrapure water in sequence, perform ultrasonic treatment. Meanwhile, add cobalt nitrate hexahydrate, ammonium fluoride and urea to ultrapure water. After complete dissolution, transfer it to a high-pressure autoclave with a polytetrafluoroethylene inner liner. Add the ultrasonically treated nickel foam to the high-pressure autoclave for primary treatment. After cooling, wash the nickel foam with ultrapure water and ethanol, and obtain a precursor after vacuum drying;

[0014] Q2: Use the precursor as the working electrode, use saturated silver / silver chloride and a platinum sheet as the reference electrode and the counter electrode respectively, and use an iron nitrate aqueous solution as the electrodeposition solution. After the operation, vacuum dry the precursor to obtain iron hydroxide@precursor;

[0015] Q3: Place the iron hydroxide@precursor and sodium hypophosphite in two porcelain boats respectively, with sodium hypophosphite placed upstream. Heat up under argon conditions, maintain at the first level, and obtain a composite iron nanoarray after cooling.

[0016] In the above process, the nickel foam is first pretreated to remove oxides and impurities on the surface of the nickel foam, and cobalt is loaded on the surface of the nickel foam by a hydrothermal method to prepare a precursor; then, iron hydroxide is fixed on the surface of the precursor by an electrodeposition method for growth to obtain iron hydroxide@precursor; and the composite iron nanoarray is synthesized by one-step phosphating of the iron hydroxide@precursor in a tubular furnace.

[0017] Preferably, in Q1, the ultrasonic treatment time is 20-30 min, the usage ratio of cobalt nitrate hexahydrate, ammonium fluoride, urea and ultrapure water is (0.582-0.597) g: (0.222-0.232) g: (0.72-0.78) g: (35-40) mL, the primary treatment temperature is 120-140°C, the time is 6-8 h, and the vacuum drying temperature is 70-90°C, and the time is 8-10 h; in Q2, the concentration of the ferric nitrate aqueous solution is 16 mg / mL, the process is carried out at -1.0 V for 300 s, the vacuum drying temperature is 60-70°C, and the time is 10-12 h; in Q3, the temperature is increased to 300°C at 2°C / min during the heating process, and the primary holding time is 2-4 h.

[0018] Preferably, the preparation method of the stearic acid surfactant in step (2) comprises the following steps:

[0019] S1: adding methyl linoleate, phosphotungstic acid and EDTA-2Na to a container, mixing them uniformly at room temperature and adding hydrogen peroxide solution dropwise under mechanical stirring. After the addition is complete, heating the container and reacting at a constant temperature. After the reaction is complete, extracting the reaction product with ethyl acetate, allowing the layers to stand, removing the water layer, and subjecting the oil layer to vacuum distillation and recrystallization to obtain a methyl stearate compound;

[0020] S2: adding a methyl stearate compound to a container, adding phosphoric acid, mixing thoroughly, evacuating the mixture, placing it in a high-pressure reactor, heating and stirring, adding ethylene oxide, reacting, cooling, stopping the reaction, and discharging the mixture to obtain a methyl stearate ethoxy compound;

[0021] S3: Add methyl stearate ethoxylate to a single-necked flask, and simultaneously add a mixed solution of sodium hydroxide and ethanol. After the reaction, adjust the pH, then condense and reflux, cool to room temperature and remove the ethanol. Then, dissolve the product with ethyl acetate and extract with sodium chloride solution. After dehydrating the obtained ethyl acetate phase with anhydrous sodium sulfate, remove the ethyl acetate to obtain a stearic acid surfactant.

[0022] In the above process, methyl linoleate is used as the raw material, phosphotungstic acid is used as the catalyst, and hydrogen peroxide is used as the oxidant. The methyl stearate compound is prepared by a one-pot method, and then it is added with ethylene oxide to obtain the methyl stearate ethoxylate compound. The obtained methyl stearate ethoxylate compound is hydrolyzed to prepare the stearic acid surfactant.

[0023] Preferably, in the step S1, the dosage ratio of methyl linoleate, phosphotungstic acid, EDTA-2Na and hydrogen peroxide solution is (4 - 7) g : (0.24 - 0.42) g : (0.8 - 1.2) g : (5 - 7) mL. The volume fraction of the hydrogen peroxide solution is 30 vt%, the temperature rising temperature is 40 - 45 °C, and the constant temperature reaction time is 20 - 40 min.

[0024] Preferably, in the step S2, the dosage ratio of the methyl stearate compound, the catalyst and ethylene oxide is (80 - 110) g : (4 - 6) g : (110 - 130) mL. The heating temperature is 90 - 95 °C, the stirring speed is 600 - 800 rpm. When adding ethylene oxide, the temperature of the container is 170 - 180 °C, and the reaction stops when the temperature drops below 80 °C and the pressure drops below 0.1 MPa.

[0025] Preferably, in the step S3, the dosage ratio of the methyl stearate ethoxylate compound, sodium hydroxide and ethanol is (95 - 105) g : (30 - 40) g : (80 - 90) mL. The reaction time is 2 - 3 h, the pH is adjusted to 2 - 2.4, and the condensation reflux time is 1 - 2 h.

[0026] Preferably, in the step (2), the dosage ratio of the composite iron nanoarray, the stearic acid surfactant and the pretreated powder is (2 - 4) g : (5 - 10) mL : (100 - 108) g.

[0027] Preferably, in the step (3), after closing the furnace door, the vacuum in the furnace is pumped to below 10 Pa, and 30 kPa high-purity argon is introduced for sintering. During the sintering process, it is set that the temperature rises from room temperature to 700 °C within 3 min, and then the temperature is raised to the sintering temperature at a heating rate of 50 - 200 °C / min. The sintering temperature is 1100 - 1250 °C, the heat preservation time is 0 - 20 min, and the pressure is 20 - 200 MPa.

[0028] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are:

[0029] 1. The present invention first ball-mills tungsten, molybdenum, and iridium powders to obtain a pretreated powder. The addition of iridium can increase the density of the alloy powder. The prepared composite iron nanoarray is then placed in a stearic acid surfactant and mixed with the pretreated powder. This allows the composite iron nanoarray to be evenly dispersed in the pretreated powder, thereby improving the hardness and corrosion resistance of the tungsten alloy block fragments. During the sintering process, the stearic acid surfactant decomposes and volatilizes at high temperatures and has no effect on the final tungsten alloy block fragments. Therefore, the tungsten alloy block fragments obtained by this method have high density, high hardness, and excellent corrosion resistance.

[0030] 2. The present invention uses nickel foam as a substrate and loads cobalt, ferric hydroxide and sodium hypophosphite on its surface to obtain a composite iron nanoarray. Adding the composite iron nanoarray to a tungsten alloy mixed powder can improve the mechanical strength and wear resistance of the tungsten alloy block fragments. The small size effect of the nanoarray enables it to act as a grain refiner in the alloy, helping to reduce the number of grain boundaries and increase grain boundary strength, thereby enhancing the overall mechanical properties of the alloy; the nanoarray is uniformly distributed in the tungsten alloy, forming a dispersion strengthening effect, effectively hindering dislocation movement, and improving the yield strength and tensile strength of the alloy; the interface area between the nanoarray and the tungsten alloy matrix is greatly increased, enhancing the interfacial bonding force and improving the fracture toughness of the alloy. The resulting interface effect can also promote load transfer, allowing the alloy to effectively disperse stress when subjected to force; and the addition of the composite iron nanoarray can form a dense protective layer on the tungsten alloy surface, preventing direct contact between the corrosive medium and the alloy matrix, and reducing the corrosion rate; at the same time, the composite iron nanoarray can act as an electrode, reacting preferentially during the corrosion process, protecting the alloy matrix from corrosion.

[0031] 3. The present invention uses methyl linoleate, ethylene oxide, sodium hydroxide, and ethanol as raw materials to synthesize a stearic acid surfactant. After mixing this substance with the composite iron nanoarray, the composite iron nanoarray and tungsten alloy composite powder can be effectively dispersed, preventing agglomeration and oxidation between particles, and improving the dispersion uniformity of the composite iron nanoarray in the alloy, thereby fully utilizing the excellent properties of the nanoparticles and improving the hardness and strength of the tungsten alloy. In addition, during the preparation process of tungsten alloy block fragments, the stearic acid surfactant undergoes a thermal decomposition reaction at high temperature, and the ester bonds contained therein will break at high temperature to generate fatty acids and alcohol compounds with lower boiling points and volatility. These fatty acids and alcohol compounds are then removed during the high-temperature treatment process and will not affect the final tungsten alloy block fragments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0033] Figure 1 It is the process flow chart for the preparation of high-density tungsten alloy bulk fragments of the present invention. Specific embodiments

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0035] The chemical reagents used in the examples and comparative examples are all commercially available products, and the manufacturers and CAS numbers are as follows:

[0036] Nickel foam was purchased from Wuzhou Sanhe New Material Technology Co., Ltd.

[0037] Hydrochloric acid was purchased from Guangzhou Zhuohou Environmental Protection Technology Co., Ltd., CAS number: 7647-01-0;

[0038] Ethanol was purchased from Suzhou Qian'an Chemical Raw Material Co., Ltd., CAS number: 64-17-5;

[0039] Cobalt nitrate hexahydrate was purchased from Hubei Chengfeng Chemical Co., Ltd., CAS number: 10026-22-9;

[0040] Ammonium fluoride was purchased from Henan Xinyuanyuan Chemical Products Co., Ltd., CAS number: 12125-01-8;

[0041] Urea was purchased from Jinan Boyang Chemical Co., Ltd., CAS number: 57-13-6;

[0042] Iron nitrate was purchased from Jinan Jiayang Chemical Co., Ltd., CAS number: 10421-48-4;

[0043] Sodium hypophosphite was purchased from Wuhan Jixin Yibang Biotechnology Co., Ltd., CAS number: 10039-56-2;

[0044] Methyl linoleate was purchased from Wuhan Huaxiang Kejie Biotechnology Co., Ltd., CAS number: 112-63-0;

[0045] Phosphotungstic acid was purchased from Guangdong Fangxin Biotechnology Co., Ltd., CAS No.: 12067-99-1;

[0046] EDTA-2Na was purchased from Henan Tianchou Chemical Products Co., Ltd., CAS No.: 6381-92-6;

[0047] Hydrogen peroxide was purchased from Yangzhou Linghang Chemical Co., Ltd., CAS No.: 7722-84-1;

[0048] Ethyl acetate was purchased from Shandong Huayu Chemical Technology Co., Ltd., CAS No.: 141-78-6;

[0049] Phosphoric acid was purchased from Jinan Shuangying Chemical Co., Ltd., CAS No.: 7664-38-2;

[0050] Ethylene oxide was purchased from Shanghai Shunshi Plasticization Co., Ltd., CAS No.: 75-21-8;

[0051] Sodium hydroxide was purchased from Wuhan Jixin Yibang Biotechnology Co., Ltd., CAS No.: 1310-73-2;

[0052] Sodium chloride was purchased from Chengdu Kelong Chemical Co., Ltd., CAS No.: 7647-14-5;

[0053] Anhydrous sodium sulfate was purchased from Nantong Runfeng Petrochemical Co., Ltd., CAS No.: 7757-82-6;

[0054] Tungsten was purchased from Shanghai Macklin Biochemical Co., Ltd., CAS No.: 7440-33-7;

[0055] Molybdenum was purchased from Beijing Solarbio Science & Technology Co., Ltd., CAS No.: 7439-98-7;

[0056] Iridium was purchased from Hebei Zhentian Food Additive Co., Ltd., CAS No.: 7439-88-5.

[0057] Example 1

[0058] This example discloses a preparation method of a composite iron nanoarray, including the following steps:

[0059] Q1: Immerse nickel foam in dilute hydrochloric acid, ethanol and ultrapure water in sequence, and perform ultrasonic treatment for 25 min. At the same time, add 0.590 g of cobalt nitrate hexahydrate, 0.227 g of ammonium fluoride and 0.75 g of urea to 38 mL of ultrapure water. After complete dissolution, transfer it to a high-pressure autoclave with a polytetrafluoroethylene inner liner. Add the ultrasonically treated nickel foam to the high-pressure autoclave, perform primary treatment at 120 °C for 8 h. After cooling, wash the nickel foam with ultrapure water and ethanol, and vacuum dry it at 90 °C for 8 h to obtain a precursor;

[0060] Q2: Using the precursor as the working electrode, saturated silver / silver chloride and a platinum sheet as the reference electrode and the counter electrode respectively, an aqueous solution of iron nitrate with a concentration of 16 mg / mL as the electrodeposition solution, running at -1.0 V for 300 s. After the operation, the precursor is vacuum dried at 70 °C for 10 h to obtain iron hydroxide@precursor;

[0061] Q3: Place iron hydroxide@precursor and sodium hypophosphite in two porcelain boats respectively, with sodium hypophosphite placed upstream. Heat up under argon atmosphere, and during the heating process, heat up to 300 °C at a rate of 2 °C / min, hold at the first stage for 2 h, and after cooling, obtain the composite iron nanoarray.

[0062] This example discloses a preparation method of a stearic acid surfactant, which includes the following steps:

[0063] S1: Add 5.5 g of methyl linoleate, 0.33 g of phosphotungstic acid, and 1 g of EDTA-2Na into a container, mix evenly at room temperature, and under the condition of mechanical stirring, dropwise add 6 mL of hydrogen peroxide solution with a volume fraction of 30 vt%. After the dropping is completed, heat up the container and react at a constant temperature of 45 °C for 30 min. After the reaction, extract the reaction product with ethyl acetate, let it stand for layering, separate the aqueous layer, and subject the oil layer to vacuum distillation and recrystallization to obtain the methyl stearate compound;

[0064] S2: Add 95 g of the methyl stearate compound into a container, add 5 g of phosphoric acid, fully mix it, then evacuate it and put it into a high-pressure reactor. Heat and stir at 90 °C, with a stirring speed of 800 rpm. After stirring, add 120 mL of ethylene oxide at 180 °C, react, cool down, stop the reaction when the temperature drops below 80 °C and the pressure drops below 0.1 MPa, and discharge to obtain the methyl stearate ethoxylate compound;

[0065] S3: Add 100 g of the methyl stearate ethoxylate compound into a single-neck flask, and at the same time add a mixed solution of 35 g of sodium hydroxide and 85 mL of ethanol. After reacting for 3 h, adjust the pH to 2, then carry out reflux condensation for 2 h. After cooling to room temperature, remove ethanol, then dissolve the product with ethyl acetate, extract it with sodium chloride solution, and after removing water from the obtained ethyl acetate phase with anhydrous sodium sulfate, remove ethyl acetate to obtain the stearic acid surfactant.

[0066] Refer to Figure 1 As shown, this example discloses a preparation process of high-density tungsten alloy bulk fragments, which includes the following steps:

[0067] Step (1): Load 92.5 g of tungsten, 6 g of molybdenum, and 1.5 g of iridium into a stainless-steel ball-milling jar for ball-milling and mixing. During the ball-milling and mixing process, the grinding balls are made of tungsten carbide, the ball-milling medium is ethanol, the mixing time is 20 h. After mixing, perform rotary evaporation at 92 °C for 3 h, vacuum dry at 70 °C for 15 h, grind, crush, and sieve to obtain the pretreated powder;

[0068] Step (2): Place 3 g of the composite iron nanoarray in 7.5 mL of stearic acid surfactant. After dispersing evenly, mix it with 104 g of the pretreated powder to obtain the composite powder;

[0069] Step (3): Load the composite powder into a graphite mold. After pre-pressing the mold filled with the composite powder, place it in a sintering furnace, close the furnace door, evacuate the furnace to below 10 Pa, and introduce 30 kPa of high-purity argon for sintering. During the sintering process, set the temperature to rise from room temperature to 700 °C within 3 min, and then rise to the sintering temperature at a heating rate of 120 °C / min. The sintering temperature is 1250 °C, the holding time is 20 min, and the pressure is 150 MPa. After sintering, cut off the current and pressure, cool, grind, and polish to obtain a high-density tungsten alloy bulk fragment.

[0070] Example 2

[0071] This example discloses a preparation method of a composite iron nanoarray, including the following steps:

[0072] Q1: Soak the nickel foam in dilute hydrochloric acid, ethanol, and ultrapure water in sequence, and perform ultrasonic treatment for 25 min. Meanwhile, add 0.585 g of cobalt nitrate hexahydrate, 0.222 g of ammonium fluoride, and 0.72 g of urea to 35 mL of ultrapure water. After complete dissolution, transfer it to a high-pressure autoclave with a polytetrafluoroethylene inner liner. Add the ultrasonically treated nickel foam to the high-pressure autoclave, perform primary treatment at 120 °C for 8 h. After cooling, wash the nickel foam with ultrapure water and ethanol, and vacuum dry at 90 °C for 8 h to obtain the precursor;

[0073] Q2: Use the precursor as the working electrode, use saturated silver / silver chloride and platinum sheet as the reference electrode and counter electrode respectively, use an aqueous solution of iron nitrate with a concentration of 16 mg / mL as the electrodeposition solution, operate at -1.0 V for 300 s. After the operation, vacuum dry the precursor at 70 °C for 10 h to obtain iron hydroxide@precursor;

[0074] Q3: Place the iron hydroxide@precursor and sodium hypophosphite in two porcelain boats respectively, with sodium hypophosphite placed upstream. Heat under argon atmosphere, and heat up to 300 °C at a heating rate of 2 °C / min during the heating process, hold at the first stage for 2 h, and after cooling, obtain the composite iron nanoarray.

[0075] This embodiment discloses a preparation method of a stearic acid surfactant, which includes the following steps:

[0076] S1: Add 4 g of methyl linoleate, 0.24 g of phosphotungstic acid, and 0.8 g of EDTA-2Na into a container, mix evenly at room temperature, and under the condition of mechanical stirring, dropwise add 5 mL of hydrogen peroxide solution with a volume fraction of 30 vt%. After the dropwise addition is completed, heat up the container, keep the temperature constant at 45 °C for 30 min. After the reaction is completed, extract the reaction product with ethyl acetate, let it stand for stratification, separate the aqueous layer, and perform vacuum distillation and recrystallization on the oil layer to obtain a methyl stearate compound;

[0077] S2: Add 80 g of the methyl stearate compound into a container, add 4 g of phosphoric acid, fully mix it, then evacuate it and put it into a high-pressure reactor. Heat and stir at 90 °C, and the stirring speed is 800 rpm. After stirring, add 110 mL of ethylene oxide at 180 °C, react, cool down, stop the reaction when the temperature drops below 80 °C and the pressure drops below 0.1 MPa, and discharge the material to obtain a methyl stearate ethoxylate compound;

[0078] S3: Add 95 g of the methyl stearate ethoxylate compound into a single-neck flask, and at the same time add a mixed solution of 30 g of sodium hydroxide and 80 mL of ethanol. After reacting for 3 h, adjust the pH to 2, then carry out condensation reflux for 2 h. After cooling to room temperature, remove the ethanol, then dissolve the product with ethyl acetate, extract it with a sodium chloride solution, and after dehydrating the obtained ethyl acetate phase with anhydrous sodium sulfate, remove the ethyl acetate to obtain a stearic acid surfactant.

[0079] Refer to Figure 1 As shown in the figure, this embodiment discloses a preparation process of high-density tungsten alloy bulk fragments, which includes the following steps:

[0080] Step (1): Load 90 g of tungsten, 8 g of molybdenum, and 2 g of iridium into a stainless steel ball milling tank for ball milling and mixing. During the ball milling and mixing process, the grinding ball material is tungsten carbide, the ball milling medium is ethanol, the mixing time is 20 h. After the mixing is completed, carry out rotary evaporation at 92 °C for 3 h, vacuum dry at 70 °C for 15 h, grind, crush, and sieve to obtain a pretreated powder;

[0081] Step (2): Place 2 g of the composite iron nanorod array in 5 mL of the stearic acid surfactant. After dispersing evenly, mix it with 100 g of the pretreated powder to obtain a composite powder;

[0082] Step (3): Load the composite powder into a graphite mold. After pre-pressing the mold filled with the composite powder, place it in a sintering furnace, close the furnace door, evacuate the furnace to a vacuum below 10 Pa, and introduce 30 kPa of high-purity argon for sintering. During the sintering process, set the temperature to rise from room temperature to 700 °C within 3 minutes, and then rise to the sintering temperature at a heating rate of 120 °C / min. The sintering temperature is 1250 °C, the holding time is 20 minutes, and the pressure is 150 MPa. After sintering, cut off the current and pressure, cool, grind, and polish to obtain a high-density tungsten alloy bulk fragment.

[0083] Example 3

[0084] This example discloses a preparation method of a composite iron nanoarray, including the following steps:

[0085] Q1: Immerse nickel foam in dilute hydrochloric acid, ethanol, and ultrapure water in sequence, and perform ultrasonic treatment for 25 minutes. Meanwhile, add 0.593 g of cobalt nitrate hexahydrate, 0.232 g of ammonium fluoride, and 0.78 g of urea to 40 mL of ultrapure water. After complete dissolution, transfer it to a high-pressure autoclave with a polytetrafluoroethylene inner lining. Add the ultrasonically treated nickel foam to the high-pressure autoclave, perform primary treatment at 120 °C for 8 hours. After cooling, wash the nickel foam with ultrapure water and ethanol, and vacuum dry it at 90 °C for 8 hours to obtain a precursor.

[0086] Q2: Use the precursor as the working electrode, use saturated silver / silver chloride and a platinum sheet as the reference electrode and the counter electrode respectively, use an aqueous solution of iron nitrate with a concentration of 16 mg / mL as the electrodeposition solution, run at -1.0 V for 300 s. After the operation is completed, vacuum dry the precursor at 70 °C for 10 hours to obtain iron hydroxide@precursor.

[0087] Q3: Place the iron hydroxide@precursor and sodium hypophosphite in two porcelain boats respectively, with sodium hypophosphite placed upstream. Heat up under argon conditions, and raise the temperature to 300 °C at a rate of 2 °C / min during the heating process, hold at the first stage for 2 hours, and after cooling, obtain a composite iron nanoarray.

[0088] This example discloses a preparation method of a stearic acid surfactant, including the following steps:

[0089] S1: Add 7 g of methyl linoleate, 0.42 g of phosphotungstic acid, and 1.2 g of EDTA-2Na to a container, mix evenly at room temperature, and under the condition of mechanical stirring, dropwise add 7 mL of hydrogen peroxide solution with a volume fraction of 30 vt%. After the dropping is completed, raise the temperature of the container, keep the temperature constant at 45 °C for 30 minutes. After the reaction is completed, extract the reaction product with ethyl acetate, let it stand for layering, separate the aqueous layer, and perform vacuum distillation and recrystallization on the oil layer to obtain a methyl stearate compound.

[0090] S2: Add 110 g of methyl stearate compound into a container, add 6 g of phosphoric acid, mix well, then evacuate it and place it into a high-pressure reactor. Heat and stir at 90 °C with a stirring speed of 800 rpm. After stirring, add 130 mL of ethylene oxide at 180 °C, react, cool down. Stop the reaction when the temperature drops below 80 °C and the pressure drops below 0.1 MPa. Discharge to obtain methyl stearate ethoxylate compound.

[0091] S3: Add 105 g of methyl stearate ethoxylate compound into a single-neck flask, and simultaneously add a mixed solution of 40 g of sodium hydroxide and 90 mL of ethanol. After reacting for 3 h, adjust the pH to 2, then carry out condensation reflux for 2 h. After cooling to room temperature, remove ethanol, then dissolve the product with ethyl acetate, extract with sodium chloride solution. After dehydrating the obtained ethyl acetate phase with anhydrous sodium sulfate, remove ethyl acetate to obtain a stearic acid surfactant.

[0092] Refer to Figure 1 As shown, this embodiment discloses a preparation process of high-density tungsten alloy bulk fragments, including the following steps:

[0093] Step (1): Load 95 g of tungsten, 4.5 g of molybdenum and 0.5 g of iridium into a stainless steel ball milling tank for ball milling and mixing. During the ball milling and mixing process, the grinding ball material is tungsten carbide, the ball milling medium is ethanol, and the mixing time is 20 h. After mixing, carry out rotary evaporation at 92 °C for 3 h and vacuum drying at 70 °C for 15 h, then grind, crush and sieve to obtain a pretreated powder.

[0094] Step (2): Place 4 g of composite iron nanorods array into 10 mL of stearic acid surfactant, disperse evenly, and then mix it with 108 g of pretreated powder to obtain a composite powder.

[0095] Step (3): Load the composite powder into a graphite mold. After pre-pressing the mold filled with the composite powder, place it into a sintering furnace, close the furnace door, evacuate the furnace to below 10 Pa, and introduce 30 kPa of high-purity argon for sintering. During the sintering process, set the temperature to rise from room temperature to 700 °C within 3 min, then rise to the sintering temperature at a heating rate of 120 °C / min. The sintering temperature is 1250 °C, the holding time is 20 min, and the pressure is 150 MPa. After sintering, cut off the current and pressure, cool, grind and polish to obtain high-density tungsten alloy bulk fragments.

[0096] Example 4

[0097] This embodiment discloses a preparation method of a composite iron nanorods array, including the following steps:

[0098] Q1: Soak nickel foam successively in dilute hydrochloric acid, ethanol, and ultrapure water, and perform ultrasonic treatment for 25 min. Meanwhile, add 0.587 g of cobalt nitrate hexahydrate, 0.224 g of ammonium fluoride, and 0.74 g of urea to 37 mL of ultrapure water. After complete dissolution, transfer it to a high-pressure autoclave with a polytetrafluoroethylene inner liner. Add the ultrasonically treated nickel foam to the high-pressure autoclave, perform primary treatment at 120 °C for 8 h. After cooling, wash the nickel foam with ultrapure water and ethanol, and vacuum dry it at 90 °C for 8 h to obtain the precursor;

[0099] Q2: Use the precursor as the working electrode, use saturated silver / silver chloride and platinum sheet as the reference electrode and counter electrode respectively, use an aqueous solution of iron nitrate with a concentration of 16 mg / mL as the electrodeposition solution, run at -1.0 V for 300 s. After the operation, vacuum dry the precursor at 70 °C for 10 h to obtain iron hydroxide@precursor;

[0100] Q3: Place iron hydroxide@precursor and sodium hypophosphite in two porcelain boats respectively, with sodium hypophosphite placed upstream. Heat up under argon atmosphere, and heat up to 300 °C at a rate of 2 °C / min during the heating process. Keep at the first stage for 2 h, and after cooling, obtain the composite iron nanoarray.

[0101] This example discloses a preparation method of a stearic acid surfactant, including the following steps:

[0102] S1: Add 6 g of methyl linoleate, 0.28 g of phosphotungstic acid, and 0.9 g of EDTA-2Na to a container, mix evenly at room temperature, and under the condition of mechanical stirring, dropwise add 5.5 mL of hydrogen peroxide solution with a volume fraction of 30 vt%. After the addition is complete, heat up the container, keep the temperature constant at 45 °C for 30 min. After the reaction, extract the reaction product with ethyl acetate, let it stand for stratification, separate the aqueous layer, and perform vacuum distillation and recrystallization on the oil layer to obtain the methyl stearate compound;

[0103] S2: Add 100 g of the methyl stearate compound to a container, add 4.5 g of phosphoric acid, fully mix it, then evacuate it and put it into a high-pressure reaction kettle. Heat and stir at 90 °C, with a stirring speed of 800 rpm. After stirring, add 105 mL of ethylene oxide at 180 °C, react, cool down, stop the reaction when the temperature drops below 80 °C and the pressure drops below 0.1 MPa, and discharge the material to obtain the methyl stearate ethoxylate compound;

[0104] S3: Add 98 g of the methyl stearate ethoxylate compound to a single-neck flask, and at the same time add a mixed solution of 38 g of sodium hydroxide and 82 mL of ethanol. After reacting for 3 h, adjust the pH to 2, then perform condensation reflux for 2 h. After cooling to room temperature, remove ethanol, then dissolve the product with ethyl acetate, extract it with a sodium chloride solution, dehydrate the obtained ethyl acetate phase with anhydrous sodium sulfate, and then remove ethyl acetate to obtain the stearic acid surfactant.

[0105] Refer to Figure 1 As shown, this embodiment discloses a preparation process of high-density tungsten alloy bulk fragments, including the following steps:

[0106] Step (1): Load 93 g of tungsten, 6 g of molybdenum, and 1 g of iridium into a stainless steel ball milling tank for ball milling and mixing. During the ball milling and mixing process, the grinding ball material is tungsten carbide, the ball milling medium is ethanol, the mixing time is 20 h. After mixing, rotary evaporation is carried out at 92 °C for 3 h, vacuum drying is carried out at 70 °C for 15 h, followed by grinding, crushing, and sieving to obtain the pretreated powder;

[0107] Step (2): Place 2.5 g of composite iron nanowire arrays in 8 mL of stearic acid surfactant. After uniform dispersion, mix it with 102 g of pretreated powder to obtain the composite powder;

[0108] Step (3): Load the composite powder into a graphite mold. After pre-pressing the mold filled with the composite powder, place it in a sintering furnace, close the furnace door, evacuate the furnace to below 10 Pa, and introduce 30 kPa of high-purity argon for sintering. During the sintering process, it is set that the temperature rises from room temperature to 700 °C within 3 min, and then the temperature is raised to the sintering temperature at a heating rate of 120 °C / min. The sintering temperature is 1250 °C, the holding time is 20 min, and the pressure is 150 MPa. After sintering, cut off the current and pressure, cool, grind, and polish to obtain high-density tungsten alloy bulk fragments.

[0109] Example 5

[0110] This embodiment discloses a preparation method of composite iron nanowire arrays, including the following steps:

[0111] Q1: Immerse nickel foam in dilute hydrochloric acid, ethanol, and ultrapure water in sequence, and perform ultrasonic treatment for 25 min. At the same time, add 0.595 g of cobalt nitrate hexahydrate, 0.230 g of ammonium fluoride, and 0.76 g of urea to 39 mL of ultrapure water. After complete dissolution, transfer it to a high-pressure autoclave with a polytetrafluoroethylene inner lining. Add the ultrasonically treated nickel foam to the high-pressure autoclave, perform primary treatment at 120 °C for 8 h. After cooling, wash the nickel foam with ultrapure water and ethanol, and vacuum dry it at 90 °C for 8 h to obtain the precursor;

[0112] Q2: Use the precursor as the working electrode, use saturated silver / silver chloride and platinum sheet as the reference electrode and counter electrode respectively, use an aqueous solution of iron nitrate with a concentration of 16 mg / mL as the electrodeposition solution, run at -1.0 V for 300 s. After running, vacuum dry the precursor at 70 °C for 10 h to obtain iron hydroxide@precursor;

[0113] Q3: Place iron hydroxide @ precursor and sodium hypophosphite in two porcelain boats respectively, with sodium hypophosphite placed upstream. Heat under argon atmosphere, heating at a rate of 2 °C / min to 300 °C during the heating process, hold at the first stage for 2 h, and after cooling, obtain composite iron nanoarrays.

[0114] This example discloses a preparation method of a stearic acid surfactant, including the following steps:

[0115] S1: Add 5 g of methyl linoleate, 0.38 g of phosphotungstic acid, and 1.1 g of EDTA-2Na into a container, mix evenly at room temperature, and under the condition of mechanical stirring, dropwise add 6.5 mL of hydrogen peroxide solution with a volume fraction of 30 vt%. After the addition is completed, heat up the container, react at a constant temperature of 45 °C for 30 min. After the reaction ends, extract the reaction product with ethyl acetate, let it stand for layering, separate the aqueous layer, and conduct vacuum distillation and recrystallization on the oil layer to obtain a methyl stearate compound.

[0116] S2: Add 85 g of the methyl stearate compound into a container, add 5.5 g of phosphoric acid, fully mix them, then evacuate and put them into a high-pressure reactor, heat and stir at 90 °C, with a stirring speed of 800 rpm. After stirring, add 125 mL of ethylene oxide at 180 °C, react, cool down, stop the reaction when the temperature drops below 80 °C and the pressure drops below 0.1 MPa, and discharge to obtain a methyl stearate ethoxylate compound.

[0117] S3: Add 103 g of the methyl stearate ethoxylate compound into a single-neck flask, and at the same time add a mixed solution of 32 g of sodium hydroxide and 87 mL of ethanol. After reacting for 3 h, adjust the pH to 2, then carry out reflux condensation for 2 h. After cooling to room temperature, remove ethanol, then dissolve the product with ethyl acetate, extract with sodium chloride solution, dehydrate the obtained ethyl acetate phase with anhydrous sodium sulfate, and then remove ethyl acetate to obtain the stearic acid surfactant.

[0118] Refer to Figure 1 As shown, this example discloses a preparation process of high-density tungsten alloy bulk fragments, including the following steps:

[0119] Step (1): Load 94 g of tungsten, 4 g of molybdenum, and 2 g of iridium into a stainless steel ball milling tank for ball milling and mixing. During the ball milling and mixing process, the grinding ball material is tungsten carbide, the ball milling medium is ethanol, the mixing time is 20 h. After the mixing is completed, carry out rotary evaporation at 92 °C for 3 h, vacuum dry at 70 °C for 15 h, grind, crush, and sieve to obtain a pretreated powder.

[0120] Step (2): Place 3.5 g of the composite iron nanoarrays in 9 mL of the stearic acid surfactant, disperse evenly, and then mix it with 106 g of the pretreated powder to obtain a composite powder.

[0121] Step (3): Load the composite powder into a graphite mold. After pre-pressing the mold filled with the composite powder, place it in a sintering furnace, close the furnace door, evacuate the furnace to a vacuum below 10 Pa, and introduce 30 kPa of high-purity argon for sintering. During the sintering process, set the temperature to rise from room temperature to 700 °C within 3 minutes, and then rise to the sintering temperature at a heating rate of 120 °C / min. The sintering temperature is 1250 °C, the holding time is 20 minutes, and the pressure is 150 MPa. After sintering, cut off the current and pressure, cool, grind, and polish to obtain high-density tungsten alloy bulk fragments.

[0122] Example 6

[0123] This example discloses a preparation method of a composite iron nanorod array, including the following steps:

[0124] Q1: Immerse nickel foam in dilute hydrochloric acid, ethanol, and ultrapure water in sequence, and perform ultrasonic treatment for 25 minutes. Meanwhile, add 0.591 g of cobalt nitrate hexahydrate, 0.229 g of ammonium fluoride, and 0.73 g of urea to 37.5 mL of ultrapure water. After complete dissolution, transfer it to a high-pressure autoclave with a polytetrafluoroethylene inner liner. Add the ultrasonically treated nickel foam to the high-pressure autoclave, perform primary treatment at 120 °C for 8 hours. After cooling, wash the nickel foam with ultrapure water and ethanol, and vacuum dry it at 90 °C for 8 hours to obtain a precursor.

[0125] Q2: Use the precursor as the working electrode, use saturated silver / silver chloride and a platinum sheet as the reference electrode and the counter electrode respectively, use an aqueous solution of iron nitrate with a concentration of 16 mg / mL as the electrodeposition solution, run at -1.0 V for 300 s. After the operation, vacuum dry the precursor at 70 °C for 10 hours to obtain iron hydroxide@precursor.

[0126] Q3: Place the iron hydroxide@precursor and sodium hypophosphite in two porcelain boats respectively, with sodium hypophosphite placed upstream. Heat up under argon conditions, and heat up to 300 °C at a rate of 2 °C / min during the heating process, hold at the first stage for 2 hours, and after cooling, obtain the composite iron nanorod array.

[0127] This example discloses a preparation method of a stearic acid surfactant, including the following steps:

[0128] S1: Add 6.5 g of methyl linoleate, 0.35 g of phosphotungstic acid, and 0.95 g of EDTA-2Na to a container, mix evenly at room temperature, and under the condition of mechanical stirring, dropwise add 6.5 mL of hydrogen peroxide solution with a volume fraction of 30 vt%. After the dropping is completed, heat up the container and react at a constant temperature of 45 °C for 30 minutes. After the reaction, extract the reaction product with ethyl acetate, let it stand for layering, separate the aqueous layer, and perform vacuum distillation and recrystallization on the oil layer to obtain a methyl stearate compound.

[0129] S2: 90 g of methyl stearate compound was added to a container, 5.8 g of phosphoric acid was added, and after thorough mixing, the mixture was evacuated and placed in an autoclave, heated and stirred at 90 ° C, with a stirring speed of 800 rpm. After stirring, 115 mL of ethylene oxide was added at 180 ° C, reacted, cooled, and the temperature was reduced to below 80 ° C. The pressure was reduced to below 0.1 MPa to stop the reaction, and the material was discharged to obtain methyl stearate ethoxy compound;

[0130] S3: Add 101g of methyl stearate ethoxylate into a single-necked flask, and add a mixed solution of 34g of sodium hydroxide and 88mL of ethanol at the same time. After reacting for 3h, adjust the pH to 2, then condense and reflux for 2h. After cooling to room temperature, remove the ethanol, and then dissolve the product with ethyl acetate and extract with sodium chloride solution. After dehydrating the obtained ethyl acetate phase with anhydrous sodium sulfate, remove the ethyl acetate to obtain a stearic acid surfactant.

[0131] See Figure 1 As shown, this embodiment discloses a process for preparing high-density tungsten alloy block fragments, comprising the following steps:

[0132] Step (1): 91.5 g of tungsten, 7 g of molybdenum and 1.5 g of iridium were placed in a stainless steel ball mill and ball milled. During the ball milling process, the grinding balls were made of tungsten carbide and the ball milling medium was ethanol. The mixing time was 20 h. After the mixing was completed, the mixture was rotary evaporated at 92 ° C for 3 h and vacuum dried at 70 ° C for 15 h. The mixture was ground, crushed and sieved to obtain a pretreated powder.

[0133] Step (2): 2.7 g of the composite iron nanoarray was placed in 7 mL of stearic acid surfactant, and after being evenly dispersed, it was mixed with 103 g of pretreated powder to obtain a composite powder;

[0134] Step (3): The composite powder is loaded into a graphite mold, and the mold filled with the composite powder is pre-pressed and placed in a sintering furnace. The furnace door is closed, the vacuum in the furnace is evacuated to below 10Pa, and 30kPa high-purity argon is introduced for sintering. The sintering process is set within 3 minutes, the temperature is raised from room temperature to 700°C, and then raised to the sintering temperature at a heating rate of 120°C / min. The sintering temperature is 1250°C, the holding time is 20 minutes, and the pressure is 150MPa. After the sintering is completed, the current and pressure are cut off, and the product is cooled, ground, and polished to obtain high-density tungsten alloy block fragments.

[0135] Comparative Example 1

[0136] Comparative Example 1 Compared with Example 1, in the preparation process of the composite iron nanoarray in Comparative Example 1, cobalt nitrate hexahydrate was not added, and other conditions remained unchanged.

[0137] Comparative Example 2

[0138] Comparative Example 2 is compared with Example 1. In the preparation process of the composite iron nanoarray in Comparative Example 2, iron nitrate aqueous solution is not added, and other conditions remain unchanged.

[0139] Comparative Example 3

[0140] Comparative Example 3 is compared with Example 1. In the preparation process of the composite iron nanoarray in Comparative Example 3, sodium hypophosphite is not added, and other conditions remain unchanged.

[0141] Comparative Example 4

[0142] Comparative Example 4 is compared with Example 1. In the preparation process of the stearic acid surfactant in Comparative Example 4, methyl linoleate is not added, and other conditions remain unchanged.

[0143] Comparative Example 5

[0144] Comparative Example 5 is compared with Example 1. In the preparation process of the stearic acid surfactant in Comparative Example 5, hydrogen peroxide solution is not added, and other conditions remain unchanged.

[0145] Comparative Example 6

[0146] Comparative Example 6 is compared with Example 1. In the preparation process of the stearic acid surfactant in Comparative Example 6, ethylene oxide is not added, and other conditions remain unchanged.

[0147] Comparative Example 7

[0148] Comparative Example 7 is compared with Example 1. In the preparation process of the high-density tungsten alloy bulk fragment in Comparative Example 7, the composite iron nanoarray is not added, and other conditions remain unchanged.

[0149] Comparative Example 8

[0150] Comparative Example 8 is compared with Example 1. In the preparation process of the high-density tungsten alloy bulk fragment in Comparative Example 8, the stearic acid surfactant is not added, and other conditions remain unchanged.

[0151] The properties of the tungsten alloy bulk fragments prepared in Examples 1-6 and Comparative Examples 1-8 were tested. The density of the samples was tested according to Standard ASTM B311-09, the hardness of the samples was tested according to ASTM E18-2020, and the corrosion resistance of the samples was tested according to GB / T 10125-2021. The test results are shown in Table 1:

[0152] Table 1 Test results of density, hardness, and corrosion resistance of tungsten alloy bulk fragments prepared in examples and comparative examples

[0153]

[0154] As can be seen from the test results in Table 1, the tungsten alloy bulk fragments prepared in Examples 1-6 of the present invention have high density, hardness and excellent corrosion resistance. By comparing Comparative Example 1 with Examples 1-6, it can be seen that adding cobalt nitrate hexahydrate can effectively improve the density, hardness and corrosion resistance of the tungsten alloy bulk fragments; by comparing Comparative Example 2 with Examples 1-6, it can be seen that adding an aqueous solution of iron nitrate can effectively improve the density, hardness and corrosion resistance of the tungsten alloy bulk fragments; by comparing Comparative Example 3 with Examples 1-6, it can be seen that adding sodium hypophosphite can effectively improve the density, hardness and corrosion resistance of the tungsten alloy bulk fragments; by comparing Comparative Example 4 with Examples 1-6, it can be seen that adding methyl linoleate can effectively improve the density, hardness and corrosion resistance of the tungsten alloy bulk fragments; by comparing Comparative Example 5 with Examples 1-6, it can be seen that adding hydrogen peroxide solution can effectively improve the density, hardness and corrosion resistance of the tungsten alloy bulk fragments; by comparing Comparative Example 6 with Examples 1-6, it can be seen that adding ethylene oxide can effectively improve the density, hardness and corrosion resistance of the tungsten alloy bulk fragments; by comparing Comparative Example 7 with Examples 1-6, it can be seen that adding a composite iron nanoarray can effectively improve the density, hardness and corrosion resistance of the tungsten alloy bulk fragments; by comparing Comparative Example 8 with Examples 1-6, it can be seen that adding a stearic acid surfactant can effectively improve the density, hardness and corrosion resistance of the tungsten alloy bulk fragments.

[0155] As described above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

[0156] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to only the specific embodiments. Obviously, according to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principle and practical application of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A preparation process for high-density tungsten alloy bulk fragments, characterized in that, It includes the following steps: Step (1): Load tungsten, molybdenum and iridium into a stainless steel ball milling jar, carry out ball milling and mixing. After the mixing is completed, carry out rotary evaporation, vacuum drying, grinding, crushing and sieving to obtain a pretreated powder; Step (2): Place the composite iron nanoarray in a stearic acid surfactant. After dispersing evenly, mix it with the pretreated powder to obtain a composite powder; Step (3): Load the composite powder into a graphite mold. After pre-pressing the mold filled with the composite powder, place it in a sintering furnace, close the furnace door, sinter. After the sintering is completed, cut off the current and pressure, cool, grind and polish to obtain a high-density tungsten alloy bulk fragment.

2. The preparation process of a high-density tungsten alloy bulk fragment according to claim 1, characterized in that, In the said step (1), the mass ratio of tungsten, molybdenum and iridium is (90 - 95):(4.5 - 8):(0.5 - 2). During the ball milling and mixing process, the grinding ball material is tungsten carbide, the ball milling medium is ethanol, the mixing time is 10 - 30 h, the rotary evaporation temperature is 85 - 92 °C, the rotary evaporation time is 2 - 4 h, the vacuum drying temperature is 60 - 70 °C, and the time is 12 - 18 h.

3. The preparation process of a high-density tungsten alloy bulk fragment according to claim 1, characterized in that, The preparation method of the composite iron nanoarray in the said step (2) includes the following steps: Q1: Immerse nickel foam in dilute hydrochloric acid, ethanol and ultrapure water in sequence, carry out ultrasonic treatment. At the same time, add cobalt nitrate hexahydrate, ammonium fluoride and urea to ultrapure water. After completely dissolving, transfer it to a high-pressure autoclave with a polytetrafluoroethylene inner liner. Add the ultrasonically treated nickel foam to the high-pressure autoclave, carry out primary treatment. After cooling, wash the nickel foam with ultrapure water and ethanol, and vacuum dry to obtain a precursor; Q2: Use the precursor as the working electrode, use saturated silver / silver chloride and platinum sheet as the reference electrode and counter electrode respectively, and use an iron nitrate aqueous solution as the electrodeposition solution. After the operation is completed, vacuum dry the precursor to obtain iron hydroxide@precursor; Q3: Place the iron hydroxide@precursor and sodium hypophosphite in two porcelain boats respectively, with sodium hypophosphite placed upstream. Heat up under argon conditions, maintain at the first level, and after cooling, obtain the composite iron nanoarray.

4. The preparation process of a high-density tungsten alloy bulk fragment according to claim 3, characterized in that, In the said Q1, the ultrasonic treatment time is 20 - 30 min, and the dosage ratio of cobalt nitrate hexahydrate, ammonium fluoride, urea and ultrapure water is (0.582 - 0.597) g:(0.222 - 0.232) g:(0.72 - 0.78) g:(35 - 40) mL. The primary treatment temperature is 120 - 140 °C, the time is 6 - 8 h, the vacuum drying temperature is 70 - 90 °C, and the time is 8 - 10 h; in the said Q2, the concentration of the iron nitrate aqueous solution is 16 mg / mL, run at - 1.0 V for 300 s, the vacuum drying temperature is 60 - 70 °C, and the time is 10 - 12 h; in the said Q3, heat up at a rate of 2 °C / min to 300 °C during the heating process, and the primary holding time is 2 - 4 h.

5. The preparation process of a high-density tungsten alloy bulk fragment according to claim 1, characterized in that, The preparation method of the stearic acid surfactant in the said step (2) includes the following steps: S1: Add methyl linoleate, phosphotungstic acid and EDTA-2Na into a container, mix evenly at room temperature, and under the condition of mechanical stirring, dropwise add hydrogen peroxide solution. After the addition is completed, heat up the container, carry out a constant-temperature reaction. After the reaction ends, extract the reaction product with ethyl acetate, let it stand for stratification, separate the aqueous layer, and carry out vacuum distillation on the oil layer and recrystallization to obtain a methyl stearate compound; S2: Add the methyl stearate compound into a container, add a catalyst, fully mix it, then evacuate it and put it into a high-pressure reactor, heat and stir. After stirring, add ethylene oxide, react, cool down, stop the reaction, and discharge to obtain a methyl stearate ethoxylate compound; S3: Add the methyl stearate ethoxylate compound into a single-neck flask, and at the same time add a mixed solution of sodium hydroxide and ethanol. After the reaction, adjust the pH, then carry out condensation reflux. After cooling to room temperature, remove the ethanol, then dissolve the product with ethyl acetate, extract with sodium chloride solution. After dehydrating the obtained ethyl acetate phase with anhydrous sodium sulfate, remove the ethyl acetate to obtain a stearic acid surfactant.

6. The preparation process of a high-density tungsten alloy bulk fragment according to claim 5, characterized in that, In the above S1, the dosage ratio of methyl linoleate, phosphotungstic acid, EDTA-2Na and hydrogen peroxide solution is (4 - 7) g : (0.24 - 0.42) g : (0.8 - 1.2) g : (5 - 7) mL, the volume fraction of the hydrogen peroxide solution is 30 vt%, the heating temperature is 40 - 45 °C, and the constant-temperature reaction time is 20 - 40 min.

7. The preparation process of a high-density tungsten alloy bulk fragment according to claim 5, characterized in that, In the above S2, the dosage ratio of the methyl stearate compound, catalyst and ethylene oxide is (80 - 110) g : (4 - 6) g : (110 - 130) mL, the heating temperature is 90 - 95 °C, the stirring speed is 600 - 800 rpm. When adding ethylene oxide, the temperature of the container is 170 - 180 °C. When the temperature drops below 80 °C and the pressure drops below 0.1 MPa, stop the reaction.

8. A preparation process for high-density tungsten alloy bulk fragments according to claim 5, characterized in that, In the above S3, the dosage ratio of the methyl stearate ethoxylate compound, sodium hydroxide and ethanol is (95 - 105) g : (30 - 40) g : (80 - 90) mL, the reaction time is 2 - 3 h, adjust the pH = 2 - 2.4, and the condensation reflux time is 1 - 2 h.

9. The preparation process of a high-density tungsten alloy bulk fragment according to claim 1, characterized in that, In the above step (2), the dosage ratio of the composite iron nanoarray, stearic acid surfactant and pretreated powder is (2 - 4) g : (5 - 10) mL : (100 - 108) g.

10. A preparation process for high-density tungsten alloy bulk fragments according to claim 1, characterized in that, [[ID=|1]] In the above step (3), after closing the furnace door, evacuate the inside of the furnace to below 10 Pa, and introduce 30 kPa of high-purity argon for sintering. During the sintering process, it is set that within 3 min, the temperature rises from room temperature to 700 °C, and then it rises to the sintering temperature at a heating rate of 50 - 200 °C / min. The sintering temperature is 1100 - 1250 °C, the heat preservation time is 0 - 20 min, and the pressure is 20 - 200 MPa.

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