A process for preparing high-density tungsten alloy block fragments

Abstract

The present invention discloses a process for preparing high-density tungsten alloy bulk fragments, belonging to the technical field of bulk fragment preparation. The process for preparing high-density tungsten alloy bulk fragments comprises the following steps: step (1): tungsten, molybdenum and iridium are placed in a stainless steel ball mill, ball milled and mixed, rotary evaporated, vacuum dried, ground, crushed and sieved to obtain a pre-treated powder; step (2): a composite iron nanoarray is placed in a stearic acid surfactant, dispersed evenly, and then mixed with the pre-treated powder to obtain a composite powder; step (3): the composite powder is placed in a graphite mold, the mold filled with the composite powder is pre-pressed and placed in a sintering furnace, the furnace door is closed, and sintering is performed. After sintering is completed, the current and pressure are cut off, and the product is cooled, ground and polished to obtain high-density tungsten alloy bulk fragments. By adding the composite iron nanoarray and the stearic acid surfactant, the density, hardness and corrosion resistance of the tungsten alloy bulk fragments can be effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of preparing tungsten alloy block fragments, and in particular relates to a process for preparing high-density tungsten alloy block fragments. Background Art

[0002] Tungsten alloys, due to their high density, high hardness, excellent ductility, and corrosion resistance, are widely used in the military, aerospace, and nuclear industries. In particular, in the military, high-density tungsten alloy block fragments are a crucial component of weapon systems such as armor-piercing and anti-tank rounds, and their performance is directly related to the weapon's strike effectiveness and combat effectiveness. Therefore, research into the preparation process for high-density tungsten alloy block fragments is crucial for improving the performance and combat capabilities of weapon systems.

[0003] Secondly, with the advancement of technology and the changing nature of warfare, the performance requirements for high-density tungsten alloy block fragments are becoming increasingly demanding. They require not only higher density and hardness, but also improved impact resistance, corrosion resistance, and high-temperature resistance. Therefore, continuous innovation and optimization in the manufacturing process are necessary to meet the increasingly demanding operating environments.

[0004] A Chinese patent with authorization publication number CN 106694897 B discloses a method for preparing a tungsten-based high-density alloy bulk material, comprising the following steps: uniformly mixing tungsten powder, nickel powder, and iron powder required for the high-density tungsten alloy using a high-speed mixer, with the powder particle size ranging from 3 μm to 10 μm; feeding the mixed powder into a plasma powder making device using a powder feeder, vaporizing it in an ultra-high temperature plasma arc, and rapidly cooling it to form a composite nanopowder with a particle size ranging from 10 nm to 100 nm; placing an appropriate amount of the nanocomposite powder into a graphite mold, vacuum degassing it in an electric sintering device for 20-40 minutes, then filling it with argon gas for protection, maintaining the upper and lower punching pressures at 30 MPa to 100 MPa, applying electric heating, and heating the mold to 1100-1250°C at a heating rate of 30-40°C / min, maintaining the temperature for 1-3 minutes, and finally cooling it to room temperature at a cooling rate greater than 50°C per minute, thereby obtaining the desired bulk material. This method is simple, reasonable, and easy to operate. The resulting bulk material has high density and strong plasticity, and has great application value. However, the density, hardness, and corrosion resistance of the tungsten alloy bulk material prepared by this method still need to be improved. Summary of the Invention

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

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

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

[0008] Step (1): tungsten, molybdenum and iridium are placed in a stainless steel ball mill, and ball milled and mixed. After the mixing is completed, the mixture is rotary evaporated, vacuum dried, ground, crushed and sieved to obtain a pretreated powder;

[0009] Step (2): placing the composite iron nanoarray in a stearic acid surfactant, dispersing it evenly, and then mixing it with the pretreated powder to obtain a composite powder;

[0010] 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 and sintering is performed. After sintering, the current and pressure are cut off, and the mold is cooled, ground, and polished to obtain high-density tungsten alloy block fragments.

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

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

[0013] Q1: The nickel foam is sequentially immersed in dilute hydrochloric acid, ethanol, and ultrapure water, and ultrasonically treated. At the same time, cobalt nitrate hexahydrate, ammonium fluoride, and urea are added to the ultrapure water. After complete dissolution, the mixture is transferred to a polytetrafluoroethylene-lined autoclave. The ultrasonically treated nickel foam is added to the autoclave for primary treatment. After cooling, the nickel foam is washed with ultrapure water and ethanol, and vacuum dried to obtain a precursor.

[0014] Q2: Using the precursor as the working electrode, saturated silver / silver chloride and platinum sheet as the reference electrode and counter electrode respectively, and ferric nitrate aqueous solution as the electrodeposition solution, after the operation is completed, the precursor is vacuum dried to obtain ferric hydroxide @ precursor;

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

[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 a raw material, phosphotungstic acid is used as a catalyst, and hydrogen peroxide is used as an oxidant. A methyl stearate compound is prepared by a one-pot method, which is then added with ethylene oxide to obtain a methyl stearate ethoxy compound. The obtained methyl stearate ethoxy compound is hydrolyzed to prepare a stearic acid surfactant.

[0023] Preferably, in 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 30vt%, the heating temperature is 40-45°C, and the constant temperature reaction time is 20-40 min.

[0024] Preferably, in S2, the amount ratio of the methyl stearate compound, the catalyst and the 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, and when the ethylene oxide is added, the temperature of the container is 170-180°C, and the reaction is stopped when the temperature drops below 80°C and the pressure drops below 0.1 MPa.

[0025] Preferably, in S3, the usage ratio of methyl stearate ethoxylate, 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 step (2), the usage 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 step (3), after closing the furnace door, the vacuum in the furnace is evacuated to below 10 Pa, and 30 kPa of 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 50-200 ° C / min. The sintering temperature is 1100-1250 ° C, the holding time is 0-20 minutes, and the pressure is 20-200 MPa.

[0028] In summary, due to the adoption of the above technical solution, 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] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is a process flow chart for preparing high-density tungsten alloy block fragments of the present invention. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within 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 Qianan Chemical Raw Materials Co., Ltd., CAS No.: 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 Xinzhiyuan 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] Ferric 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 number: 12067-99-1;

[0046] EDTA-2Na was purchased from Henan Tianchou Chemical Products Co., Ltd., CAS number: 6381-92-6;

[0047] Hydrogen peroxide was purchased from Yangzhou Linghang Chemical Co., Ltd., CAS number: 7722-84-1;

[0048] Ethyl acetate was purchased from Shandong Huayu Chemical Technology Co., Ltd., CAS number: 141-78-6;

[0049] Phosphoric acid was purchased from Jinan Shuangying Chemical Co., Ltd., CAS number: 7664-38-2;

[0050] Ethylene oxide was purchased from Shanghai Shunshi Plastics Co., Ltd., CAS number: 75-21-8;

[0051] Sodium hydroxide was purchased from Wuhan Jixin Yibang Biotechnology Co., Ltd., CAS number: 1310-73-2;

[0052] Sodium chloride was purchased from Chengdu Kelong Chemical Co., Ltd., CAS number: 7647-14-5;

[0053] Anhydrous sodium sulfate was purchased from Nantong Runfeng Petrochemical Co., Ltd., CAS number: 7757-82-6;

[0054] Tungsten was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., CAS number: 7440-33-7;

[0055] Molybdenum was purchased from Beijing Solebow Technology Co., Ltd., CAS number: 7439-98-7;

[0056] Iridium was purchased from Hebei Zhentian Food Additive Co., Ltd., CAS number: 7439-88-5.

[0057] Example 1

[0058] This embodiment discloses a method for preparing a composite iron nanoparticle array, comprising the following steps:

[0059] Q1: The nickel foam was soaked in dilute hydrochloric acid, ethanol and ultrapure water in sequence and ultrasonically treated for 25 minutes. At the same time, 0.590g of cobalt nitrate hexahydrate, 0.227g of ammonium fluoride and 0.75g of urea were added to 38mL of ultrapure water. After complete dissolution, the mixture was transferred to a polytetrafluoroethylene-lined autoclave. The ultrasonically treated nickel foam was added to the autoclave and treated at 120°C for 8h. After cooling, the nickel foam was washed with ultrapure water and ethanol and dried in vacuo at 90°C for 8h to obtain a precursor.

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

[0061] Q3: Place the iron hydroxide @ precursor and sodium hypophosphite in two porcelain boats respectively, with the sodium hypophosphite placed upstream. Heat the boat under argon conditions at a rate of 2°C / min to 300°C, maintain the temperature for 2 hours, and cool it to obtain a composite iron nanoarray.

[0062] This embodiment discloses a method for preparing a stearic acid surfactant, comprising the following steps:

[0063] S1: 5.5 g of methyl linoleate, 0.33 g of phosphotungstic acid, and 1 g of EDTA-2Na were added to a container, mixed evenly at room temperature, and then 6 mL of a 30% by volume hydrogen peroxide solution was added dropwise under mechanical stirring. After the addition was complete, the container was heated and kept at 45°C for 30 min. After the reaction was complete, the reaction product was extracted with ethyl acetate, allowed to stand for stratification, the water layer was removed, and the oil layer was subjected to reduced pressure distillation and recrystallization to obtain a methyl stearate compound;

[0064] S2: 95g of methyl stearate compound was added to a container, 5g 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, 120mL 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 ethoxylate;

[0065] S3: Add 100g of methyl stearate ethoxylate into a single-necked flask, and add a mixed solution of 35g of sodium hydroxide and 85mL 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.

[0066] See Figure 1 As shown, this embodiment discloses a process for preparing high-density tungsten alloy block fragments, comprising the following steps:

[0067] Step (1): 92.5 g of tungsten, 6 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.

[0068] Step (2): 3 g of the composite iron nanoarray was placed in 7.5 mL of stearic acid surfactant, and after being evenly dispersed, it was mixed with 104 g of pretreated powder to obtain a composite powder;

[0069] 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.

[0070] Example 2

[0071] This embodiment discloses a method for preparing a composite iron nanoparticle array, comprising the following steps:

[0072] Q1: The nickel foam was soaked in dilute hydrochloric acid, ethanol and ultrapure water in sequence and ultrasonically treated for 25 minutes. At the same time, 0.585g of cobalt nitrate hexahydrate, 0.222g of ammonium fluoride and 0.72g of urea were added to 35mL of ultrapure water. After complete dissolution, the mixture was transferred to a polytetrafluoroethylene-lined autoclave. The ultrasonically treated nickel foam was added to the autoclave and treated at 120°C for 8h. After cooling, the nickel foam was washed with ultrapure water and ethanol and dried in vacuo at 90°C for 8h to obtain a precursor.

[0073] Q2: Using the precursor as the working electrode, saturated silver / silver chloride and platinum sheet as the reference electrode and counter electrode, respectively, and a 16 mg / mL ferric nitrate aqueous solution as the electrodeposition solution, the electrodeposition was run at -1.0 V for 300 s. After the run, the precursor was vacuum dried at 70°C for 10 h to obtain ferric hydroxide @ precursor;

[0074] Q3: Place the iron hydroxide @ precursor and sodium hypophosphite in two porcelain boats respectively, with the sodium hypophosphite placed upstream. Heat the boat under argon conditions at a rate of 2°C / min to 300°C, maintain the temperature for 2 hours, and cool it to obtain a composite iron nanoarray.

[0075] This embodiment discloses a method for preparing a stearic acid surfactant, comprising the following steps:

[0076] S1: 4 g of methyl linoleate, 0.24 g of phosphotungstic acid, and 0.8 g of EDTA-2Na were added to a container, mixed evenly at room temperature, and then 5 mL of a 30% by volume hydrogen peroxide solution was added dropwise under mechanical stirring. After the addition was complete, the container was heated and kept at 45°C for 30 min. After the reaction was complete, the reaction product was extracted with ethyl acetate, allowed to stand for stratification, the water layer was removed, and the oil layer was subjected to reduced pressure distillation and recrystallization to obtain a methyl stearate compound;

[0077] S2: 80 g of methyl stearate compound was added to a container, 4 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, 110 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;

[0078] S3: Add 95g of methyl stearate ethoxylate into a single-necked flask, and add a mixed solution of 30g of sodium hydroxide and 80mL 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.

[0079] See Figure 1 As shown, this embodiment discloses a process for preparing high-density tungsten alloy block fragments, comprising the following steps:

[0080] Step (1): 90 g of tungsten, 8 g of molybdenum and 2 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.

[0081] Step (2): 2 g of the composite iron nanoarray was placed in 5 mL of stearic acid surfactant, and after being evenly dispersed, it was mixed with 100 g of the pretreated powder to obtain a composite powder;

[0082] 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.

[0083] Example 3

[0084] This embodiment discloses a method for preparing a composite iron nanoparticle array, comprising the following steps:

[0085] Q1: The nickel foam was soaked in dilute hydrochloric acid, ethanol and ultrapure water in sequence and ultrasonically treated for 25 minutes. At the same time, 0.593g of cobalt nitrate hexahydrate, 0.232g of ammonium fluoride and 0.78g of urea were added to 40mL of ultrapure water. After complete dissolution, the mixture was transferred to a polytetrafluoroethylene-lined autoclave. The ultrasonically treated nickel foam was added to the autoclave and treated at 120°C for 8h. After cooling, the nickel foam was washed with ultrapure water and ethanol and dried in vacuo at 90°C for 8h to obtain a precursor.

[0086] Q2: Using the precursor as the working electrode, saturated silver / silver chloride and platinum sheet as the reference electrode and counter electrode, respectively, and a 16 mg / mL ferric nitrate aqueous solution as the electrodeposition solution, the electrodeposition was run at -1.0 V for 300 s. After the run, the precursor was vacuum dried at 70°C for 10 h to obtain ferric hydroxide @ precursor;

[0087] Q3: Place the iron hydroxide @ precursor and sodium hypophosphite in two porcelain boats respectively, with the sodium hypophosphite placed upstream. Heat the boat under argon conditions at a rate of 2°C / min to 300°C, maintain the temperature for 2 hours, and cool it to obtain a composite iron nanoarray.

[0088] This embodiment discloses a method for preparing a stearic acid surfactant, comprising the following steps:

[0089] S1: 7 g of methyl linoleate, 0.42 g of phosphotungstic acid, and 1.2 g of EDTA-2Na were added to a container, mixed evenly at room temperature, and then 7 mL of a 30% by volume hydrogen peroxide solution was added dropwise under mechanical stirring. After the addition was complete, the container was heated and kept at 45°C for 30 min. After the reaction was complete, the reaction product was extracted with ethyl acetate, allowed to stand for stratification, the water layer was removed, and the oil layer was subjected to reduced pressure distillation and recrystallization to obtain a methyl stearate compound;

[0090] S2: 110 g of methyl stearate compound was added to a container, 6 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, 130 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;

[0091] S3: 105 g of methyl stearate ethoxylate was added to a single-necked flask, and a mixed solution of 40 g of sodium hydroxide and 90 mL of ethanol was added at the same time. After reacting for 3 h, the pH was adjusted to 2, followed by condensation and reflux for 2 h. After cooling to room temperature, the ethanol was removed, and the product was dissolved with ethyl acetate and extracted with sodium chloride solution. The obtained ethyl acetate phase was dehydrated with anhydrous sodium sulfate, and the ethyl acetate was removed to obtain a stearic acid surfactant.

[0092] See Figure 1 As shown, this embodiment discloses a process for preparing high-density tungsten alloy block fragments, comprising the following steps:

[0093] Step (1): 95 g of tungsten, 4.5 g of molybdenum and 0.5 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.

[0094] Step (2): 4 g of the composite iron nanoarray was placed in 10 mL of stearic acid surfactant, and after being evenly dispersed, it was mixed with 108 g of pretreated powder to obtain a composite powder;

[0095] 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.

[0096] Example 4

[0097] This embodiment discloses a method for preparing a composite iron nanoparticle array, comprising the following steps:

[0098] Q1: The nickel foam was soaked in dilute hydrochloric acid, ethanol and ultrapure water in sequence and ultrasonically treated for 25 minutes. At the same time, 0.587g of cobalt nitrate hexahydrate, 0.224g of ammonium fluoride and 0.74g of urea were added to 37mL of ultrapure water. After complete dissolution, the mixture was transferred to a polytetrafluoroethylene-lined autoclave. The ultrasonically treated nickel foam was added to the autoclave and treated at 120°C for 8h. After cooling, the nickel foam was washed with ultrapure water and ethanol and dried in vacuo at 90°C for 8h to obtain a precursor.

[0099] Q2: Using the precursor as the working electrode, saturated silver / silver chloride and platinum sheet as the reference electrode and counter electrode, respectively, and a 16 mg / mL ferric nitrate aqueous solution as the electrodeposition solution, the electrodeposition was run at -1.0 V for 300 s. After the run, the precursor was vacuum dried at 70°C for 10 h to obtain ferric hydroxide @ precursor;

[0100] Q3: Place the iron hydroxide @ precursor and sodium hypophosphite in two porcelain boats respectively, with the sodium hypophosphite placed upstream. Heat the boat under argon conditions at a rate of 2°C / min to 300°C, maintain the temperature for 2 hours, and cool it to obtain a composite iron nanoarray.

[0101] This embodiment discloses a method for preparing a stearic acid surfactant, comprising the following steps:

[0102] S1: 6 g of methyl linoleate, 0.28 g of phosphotungstic acid, and 0.9 g of EDTA-2Na were added to a container, mixed evenly at room temperature, and then 5.5 mL of a 30% by volume hydrogen peroxide solution was added dropwise under mechanical stirring. After the addition was complete, the container was heated and kept at 45°C for 30 min. After the reaction was complete, the reaction product was extracted with ethyl acetate, and the mixture was allowed to stand for stratification. The water layer was separated, and the oil layer was subjected to reduced pressure distillation and recrystallization to obtain a methyl stearate compound;

[0103] S2: 100 g of methyl stearate compound was added to a container, 4.5 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, 105 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;

[0104] S3: Add 98g of methyl stearate ethoxylate into a single-necked flask, and add a mixed solution of 38g of sodium hydroxide and 82mL 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.

[0105] See Figure 1 As shown, this embodiment discloses a process for preparing high-density tungsten alloy block fragments, comprising the following steps:

[0106] Step (1): 93 g of tungsten, 6 g of molybdenum and 1 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.

[0107] Step (2): 2.5 g of the composite iron nanoarray was placed in 8 mL of stearic acid surfactant, and after being evenly dispersed, it was mixed with 102 g of the pretreated powder to obtain a composite powder;

[0108] 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.

[0109] Example 5

[0110] This embodiment discloses a method for preparing a composite iron nanoparticle array, comprising the following steps:

[0111] Q1: The nickel foam was sequentially immersed in dilute hydrochloric acid, ethanol and ultrapure water, and ultrasonically treated for 25 minutes. At the same time, 0.595g of cobalt nitrate hexahydrate, 0.230g of ammonium fluoride and 0.76g of urea were added to 39mL of ultrapure water. After complete dissolution, the mixture was transferred to a polytetrafluoroethylene-lined autoclave. The ultrasonically treated nickel foam was added to the autoclave and treated at 120°C for 8h. After cooling, the nickel foam was washed with ultrapure water and ethanol, and vacuum dried at 90°C for 8h to obtain a precursor.

[0112] Q2: Using the precursor as the working electrode, saturated silver / silver chloride and platinum sheet as the reference electrode and counter electrode, respectively, and a 16 mg / mL ferric nitrate aqueous solution as the electrodeposition solution, the electrodeposition was run at -1.0 V for 300 s. After the run, the precursor was vacuum dried at 70°C for 10 h to obtain ferric hydroxide @ precursor;

[0113] Q3: Place the iron hydroxide @ precursor and sodium hypophosphite in two porcelain boats respectively, with the sodium hypophosphite placed upstream. Heat the boat under argon conditions at a rate of 2°C / min to 300°C, maintain the temperature for 2 hours, and cool it to obtain a composite iron nanoarray.

[0114] This embodiment discloses a method for preparing a stearic acid surfactant, comprising the following steps:

[0115] S1: 5 g of methyl linoleate, 0.38 g of phosphotungstic acid, and 1.1 g of EDTA-2Na were added to a container, mixed evenly at room temperature, and then 6.5 mL of a 30% by volume hydrogen peroxide solution was added dropwise under mechanical stirring. After the addition was complete, the container was heated and kept at 45°C for 30 min. After the reaction was complete, the reaction product was extracted with ethyl acetate, allowed to stand for stratification, the water layer was removed, and the oil layer was subjected to reduced pressure distillation and recrystallization to obtain a methyl stearate compound;

[0116] S2: 85g of methyl stearate compound was added to a container, 5.5g 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 800rpm. After stirring, 125mL 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 0.1MPa to stop the reaction, and the material was discharged to obtain methyl stearate ethoxylate;

[0117] S3: 103 g of methyl stearate ethoxylate was added to a single-necked flask, and a mixed solution of 32 g of sodium hydroxide and 87 mL of ethanol was added at the same time. After reacting for 3 h, the pH was adjusted to 2, followed by condensation and reflux for 2 h. After cooling to room temperature, the ethanol was removed, and the product was dissolved in ethyl acetate and extracted with sodium chloride solution. The obtained ethyl acetate phase was dehydrated with anhydrous sodium sulfate, and the ethyl acetate was removed to obtain a stearic acid surfactant.

[0118] See Figure 1 As shown, this embodiment discloses a process for preparing high-density tungsten alloy block fragments, comprising the following steps:

[0119] Step (1): 94 g of tungsten, 4 g of molybdenum and 2 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.

[0120] Step (2): 3.5 g of the composite iron nanoarray was placed in 9 mL of stearic acid surfactant, and after being evenly dispersed, it was mixed with 106 g of pretreated powder to obtain a composite powder;

[0121] 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.

[0122] Example 6

[0123] This embodiment discloses a method for preparing a composite iron nanoparticle array, comprising the following steps:

[0124] Q1: The nickel foam was soaked in dilute hydrochloric acid, ethanol and ultrapure water in sequence and ultrasonically treated for 25 minutes. At the same time, 0.591g of cobalt nitrate hexahydrate, 0.229g of ammonium fluoride and 0.73g of urea were added to 37.5mL of ultrapure water. After complete dissolution, the mixture was transferred to a polytetrafluoroethylene-lined autoclave. The ultrasonically treated nickel foam was added to the autoclave and treated at 120°C for 8h. After cooling, the nickel foam was washed with ultrapure water and ethanol and dried in vacuo at 90°C for 8h to obtain a precursor.

[0125] Q2: Using the precursor as the working electrode, saturated silver / silver chloride and platinum sheet as the reference electrode and counter electrode, respectively, and a 16 mg / mL ferric nitrate aqueous solution as the electrodeposition solution, the electrodeposition was run at -1.0 V for 300 s. After the run, the precursor was vacuum dried at 70°C for 10 h to obtain ferric hydroxide @ precursor;

[0126] Q3: Place the iron hydroxide @ precursor and sodium hypophosphite in two porcelain boats respectively, with the sodium hypophosphite placed upstream. Heat the boat under argon conditions at a rate of 2°C / min to 300°C, maintain the temperature for 2 hours, and cool it to obtain a composite iron nanoarray.

[0127] This embodiment discloses a method for preparing a stearic acid surfactant, comprising the following steps:

[0128] S1: 6.5 g of methyl linoleate, 0.35 g of phosphotungstic acid, and 0.95 g of EDTA-2Na were added to a container, mixed evenly at room temperature, and then 6.5 mL of a 30% by volume hydrogen peroxide solution was added dropwise under mechanical stirring. After the addition was complete, the container was heated and kept at 45° C. for 30 min. After the reaction was complete, the reaction product was extracted with ethyl acetate, allowed to stand for stratification, the water layer was removed, and the oil layer was subjected to reduced pressure distillation and recrystallization 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 Compared with Example 1, in the preparation process of the composite iron nanoarray in Comparative Example 2, no ferric nitrate aqueous solution was added, and other conditions remained unchanged.

[0139] Comparative Example 3

[0140] Comparative Example 3 Compared with Example 1, in the preparation process of the composite iron nanoarray in Comparative Example 3, no sodium hypophosphite was added, and other conditions remained unchanged.

[0141] Comparative Example 4

[0142] Comparative Example 4 Compared with Example 1, in the preparation process of the stearic acid surfactant in Comparative Example 4, methyl linoleate was not added, and other conditions remained unchanged.

[0143] Comparative Example 5

[0144] Comparative Example 5 Compared with Example 1, in the preparation process of the stearic acid surfactant in Comparative Example 5, no hydrogen peroxide solution was added, and other conditions remained unchanged.

[0145] Comparative Example 6

[0146] Comparative Example 6 Compared with Example 1, in the preparation process of the stearic acid surfactant in Comparative Example 6, ethylene oxide was not added, and other conditions remained unchanged.

[0147] Comparative Example 7

[0148] Comparative Example 7 Compared with Example 1, in the preparation process of high-density tungsten alloy block fragments in Comparative Example 7, no composite iron nanoarrays were added, and other conditions remained unchanged.

[0149] Comparative Example 8

[0150] Comparative Example 8 Compared with Example 1, in the preparation process of high-density tungsten alloy block fragments in Comparative Example 8, no stearic acid surfactant was added, and other conditions remained unchanged.

[0151] The performance of the tungsten alloy block fragments prepared in Examples 1-6 and Comparative Examples 1-8 was tested. The density of the samples was tested according to the 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 Density, hardness and corrosion resistance test results of tungsten alloy block fragments prepared in Examples and Comparative Examples

[0153]

[0154] It can be seen from the test results in Table 1 that the tungsten alloy block fragments prepared in Examples 1-6 of the present invention have high density, hardness and excellent corrosion resistance. Comparison between Comparative Example 1 and Examples 1-6 shows that the addition of cobalt nitrate hexahydrate can effectively improve the density, hardness and corrosion resistance of the tungsten alloy block fragments; Comparison between Comparative Example 2 and Examples 1-6 shows that the addition of ferric nitrate aqueous solution can effectively improve the density, hardness and corrosion resistance of the tungsten alloy block fragments; Comparison between Comparative Example 3 and Examples 1-6 shows that the addition of sodium hypophosphite can effectively improve the density, hardness and corrosion resistance of the tungsten alloy block fragments; Comparison between Comparative Example 4 and Examples 1-6 shows that the addition of methyl linoleate can effectively improve the density, hardness and corrosion resistance of the tungsten alloy block fragments; Comparison between Comparative Example 5 and Examples 1-6 shows that the addition of hydrogen peroxide solution can effectively improve the density, hardness and corrosion resistance of tungsten alloy block fragments; comparison between Comparative Example 6 and Examples 1-6 shows that the addition of ethylene oxide can effectively improve the density, hardness and corrosion resistance of tungsten alloy block fragments; comparison between Comparative Example 7 and Examples 1-6 shows that the addition of composite iron nanoarrays can effectively improve the density, hardness and corrosion resistance of tungsten alloy block fragments; comparison between Comparative Example 8 and Examples 1-6 shows that the addition of stearic acid surfactant can effectively improve the density, hardness and corrosion resistance of tungsten alloy block fragments.

[0155] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0156] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A process for preparing high-density tungsten alloy block fragments, characterized in that: The following steps are involved: Step (1): tungsten, molybdenum and iridium are placed in a stainless steel ball mill and ball milled. After the mixing is completed, the mixture is rotary evaporated, vacuum dried, ground, crushed and sieved to obtain a pretreated powder; Step (2): placing the composite iron nanoarray in a stearic acid surfactant, dispersing it evenly, and then mixing it with the pretreated powder to obtain a composite powder; Step (3): loading the composite powder into a graphite mold, pre-pressing the mold filled with the composite powder and placing it in a sintering furnace, closing the furnace door, sintering, and after sintering, cutting off the current and pressure, cooling, grinding, and polishing to obtain high-density tungsten alloy block fragments; The method for preparing the composite iron nanoarray in step (2) comprises the following steps: Q1: The nickel foam is sequentially immersed in dilute hydrochloric acid, ethanol, and ultrapure water, and ultrasonically treated. At the same time, cobalt nitrate hexahydrate, ammonium fluoride, and urea are added to the ultrapure water. After complete dissolution, the mixture is transferred to a polytetrafluoroethylene-lined autoclave. The ultrasonically treated nickel foam is added to the autoclave for primary treatment. After cooling, the nickel foam is washed with ultrapure water and ethanol, and vacuum dried to obtain a precursor. Q2: Using the precursor as the working electrode, saturated silver / silver chloride and platinum sheet as the reference electrode and counter electrode respectively, and ferric nitrate aqueous solution as the electrodeposition solution, after the operation is completed, the precursor is vacuum dried to obtain ferric hydroxide @ precursor; Q3: Place the iron hydroxide @ precursor and sodium hypophosphite in two porcelain boats respectively, with the sodium hypophosphite placed upstream. Heat the temperature under argon conditions, maintain the temperature at one level, and cool to obtain a composite iron nanoarray.

2. A process for preparing high-density tungsten alloy block fragments according to claim 1, characterized in that: 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 mixing process, the grinding ball material is tungsten carbide, the ball milling medium is ethanol, the mixing time is 10-30 hours, the rotary evaporation temperature is 85-92°C, the rotary evaporation time is 2-4 hours, and the vacuum drying temperature is 60-70°C and the time is 12-18 hours.

3. A process for preparing high-density tungsten alloy block fragments according to claim 1, characterized in that: In Q1, the ultrasonic treatment time is 20-30 minutes, 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 treatment time is 6-8 hours, and the vacuum drying temperature is 70-90°C, and the time is 8-10 hours; 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 seconds, the vacuum drying temperature is 60-70°C, and the time is 10-12 hours; 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 hours.

4. A process for preparing high-density tungsten alloy block fragments according to claim 1, characterized in that: The preparation method of the stearic acid surfactant in step (2) comprises the following steps: 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; S2: adding a methyl stearate compound to a container, adding a catalyst, mixing thoroughly, evacuating the mixture, placing the mixture 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; 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.

5. A process for preparing high-density tungsten alloy block fragments according to claim 4, characterized in that: In 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.

6. A process for preparing high-density tungsten alloy block fragments according to claim 4, characterized in that: In S2, the amount ratio of the methyl stearate compound, the catalyst, and the ethylene oxide is (80-110) g: (4-6) g: (110-130) mL, the heating temperature is 90-95°C, and the stirring speed is 600-800 rpm. When the ethylene oxide is added, the temperature of the container is 170-180°C. The reaction is stopped when the temperature drops below 80°C and the pressure drops below 0.1 MPa.

7. A process for preparing high-density tungsten alloy block fragments according to claim 4, characterized in that: In the S3, the usage ratio of methyl stearate ethoxylate, 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.

8. A process for preparing high-density tungsten alloy block fragments according to claim 1, characterized in that: In the step (2), the usage ratio of the composite iron nanoarray, the stearic acid surfactant and the pretreated powder is (2-4) g: (5-10) mL: (100-108) g.

9. A process for preparing high-density tungsten alloy block fragments according to claim 1, characterized in that: In the step (3), after closing the furnace door, the vacuum in the furnace is evacuated to below 10 Pa, and 30 kPa of 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 50-200 ° C / min. The sintering temperature is 1100-1250 ° C, the holding time is 0-20 minutes, and the pressure is 20-200 MPa.

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