High-strength arsenic-based alloy and preparation method thereof

Abstract

The invention discloses a high-strength arsenic-based alloy and a preparation method thereof, and relates to the technical field of arsenic-based alloys. The preparation method comprises the following steps: activating the arsenic slag purified powder; carrying out hydrogen plasma treatment on the reduced iron powder; carrying out ball milling on the activated arsenic powder and active iron powder in a liquid nitrogen environment to form arsenic / iron core-shell structure powder; titanium powder and aluminum powder are added into the arsenic / iron core-shell structure powder for heat treatment to remove impurities; carrying out chemical indium plating and plasma spraying treatment on the powder with the impurities removed to obtain powder with the surface containing WC-Co, putting the powder with the surface containing WC-Co into a CVD furnace, introducing acetylene and argon, and carrying out heat treatment to obtain powder with the surface growing with a graphene / carbon nanotube hybrid layer; and finally, vacuum hot pressed sintering is conducted, and the high-strength arsenic-based alloy is obtained. The arsenic-based alloy prepared through the method has good mechanical strength.

Description

Technical Field

[0001] This invention relates to the field of arsenic-based alloy technology, specifically to a high-strength arsenic-based alloy and its preparation method. Background Technology

[0002] Arsenic is a metalloid element with unique physicochemical properties, and both its elemental form and compounds have significant applications in various fields. In materials science, arsenic is often used as a key component in alloy preparation, forming intermetallic compounds or solid solutions with metallic elements to impart special electrical, magnetic, or mechanical properties to materials. For example, alloys formed by arsenic with metals such as iron, copper, and nickel show potential applications in superconducting materials and wear-resistant materials. Meanwhile, arsenic is a common byproduct of non-ferrous smelting and chemical production; its resource utilization can not only reduce environmental pollution but also turn waste into treasure, possessing significant environmental and economic value. Arsenic-based alloys are alloy materials formed by combining arsenic as the main component or key functional component with metallic elements such as iron, copper, and nickel. Due to the unique effects of arsenic, these alloys have potential applications in superconducting materials, wear-resistant coatings, and functional structural components. For example, arsenic-iron alloys have attracted much attention in superconducting research, while arsenic-copper alloys have shown potential in the field of wear-resistant materials. The development of their preparation technology is of great significance for promoting the high-value utilization of arsenic resources.

[0003] However, the mechanical properties of current arsenic-based alloys still have significant shortcomings, especially in terms of strength, which needs further improvement. Existing preparation processes mostly rely on traditional melting and reduction sintering methods, which are prone to problems such as unstable control of arsenic content, residual impurities, and coarse microstructure. As a result, the key mechanical properties of the alloys, such as compressive strength and tensile strength, cannot meet the requirements of high-end applications, which greatly limits their promotion and application in high-load and high-reliability fields. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength arsenic-based alloy and its preparation method, thereby solving the technical problem of poor strength in arsenic-based alloys mentioned in the background art. The arsenic-based alloy of this invention possesses excellent mechanical strength.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a high-strength arsenic-based alloy includes the following steps: S1. The purified arsenic slag powder is mixed with nano-cerium powder and heated under H2 / Ar atmosphere. After cooling, activated arsenic powder with CeAsO4 coating on the surface is obtained. S2. Reduced iron powder is treated with hydrogen plasma to obtain surface-reconstructed active iron powder; S3. Activated arsenic powder and activated iron powder are ball-milled in liquid nitrogen to form arsenic / iron core-shell structured powder. S4. Add titanium powder to arsenic / iron core-shell structure powder, perform vacuum heat treatment to obtain sulfur impurity conversion powder, then add aluminum powder and dry mix, place in an argon atmosphere for heat treatment to obtain oxygen impurity conversion powder. S5. The sulfur and oxygen impurity conversion powder is chemically plated with indium to form an indium coating layer on the powder surface, thus obtaining indium-coated powder. S6. WC-Co powder is plasma sprayed onto the surface of indium-coated powder to form a composite layer, thereby obtaining powder containing WC-Co on the surface; S7. Place the powder containing WC-Co on the surface into a CVD furnace, introduce acetylene and argon gas, and perform heat treatment to obtain powder with a graphene / carbon nanotube hybrid layer grown on the surface. S8. High-strength arsenic-based alloy is obtained by vacuum hot pressing and sintering of powder with graphene / carbon nanotube hybrid layer grown on its surface.

[0006] In the technical solution of this invention, firstly, nano-cerium powder reacts with oxygen adsorbed on the surface of arsenic powder in a hydrogen-argon atmosphere to generate a dense layer of high-melting-point CeAsO4. This layer inhibits arsenic volatilization and reduces interfacial energy through grain boundary purification. At the same time, hydrogen plasma is used to remove the oxide layer of iron powder and expose nano-sized active iron atoms. Combined with the cold welding effect of liquid nitrogen ball milling, an As@Fe core-shell structure is constructed to eliminate stress concentration caused by differences in raw material particle size and optimize element diffusion paths, thereby initially improving the mechanical properties of arsenic-based alloys.

[0007] Secondly, sulfur and oxygen impurities, which are originally detrimental to alloy performance, are transformed into chemical substances that strengthen the alloy. Adding titanium powder to the alloy system allows it to fully react with sulfur impurities, generating TiS2 nanosheets with a hexagonal layered structure. These TiS2 nanosheets are uniformly distributed within the alloy, firmly pinning dislocations through a bypass mechanism, hindering dislocation movement, and effectively segmenting grains, thus refining grain size and significantly improving the alloy's strength and toughness. Meanwhile, aluminum powder reacts with oxygen impurities to generate metastable γ-Al2O3 nanoparticles. γ-Al2O3 nanoparticles possess excellent high-temperature stability, forming a robust barrier within the alloy, hindering dislocation migration, and suppressing abnormal grain growth. This successfully transforms oxygen impurities into a strengthening carrier for the alloy, significantly improving the mechanical properties of arsenic-based alloys.

[0008] Finally, an initial coating of the alloy is achieved using ultrathin indium. The molten ultrathin indium layer fills the pores within the alloy, significantly reducing porosity and increasing density. Furthermore, the indium layer absorbs stress through plastic deformation, eliminating interfacial microcracks and enhancing mechanical strength. A WC-Co layer is then constructed on top of the indium layer. The hard WC phase provides a robust framework, directly bearing the applied load and endowing the alloy with strong load-bearing capacity, while the Co binder phase fully utilizes its bonding effect, enhancing the interfacial bonding between layers and ensuring the stability of the entire structure. Then, in the CVD process, cobalt nanoparticles in the WC-Co hard layer catalyze the acetylene cracking. Carbon atoms undergo dehydrogenation and recombination on the cobalt surface, while tungsten carbide lattice defects trap carbon atoms, triggering sp... 2 Hybrid nucleation occurs when carbon saturation is low, carbon atoms extend and grow into a few-layer graphene substrate on the flat WC crystal plane, while at the protrusions of cobalt particles, due to higher carbon saturation, they curl into carbon nanotubes. The two types of structures are covalently bonded to the root of the carbon nanotubes through the defect sites of the graphene five-membered rings, ultimately forming a three-dimensional continuous graphene / carbon nanotube network. When the alloy is under stress, this network can dissipate a large amount of energy through crack bridging and deflection mechanisms, further improving the toughness and strength of the alloy.

[0009] This invention achieves matrix densification, defect functionalization, and interface optimization through the synergistic effect of raw material processing, impurity utilization, and structural construction, thereby significantly improving the mechanical strength of arsenic-based alloys.

[0010] Preferably, in step S1, the amount of nano-cerium powder added is 1 to 3 wt% of the mass of the arsenic slag purified powder.

[0011] Preferably, in step S1, the heating temperature is 400-420°C and the heating time is 1-2 hours.

[0012] Preferably, in step S3, the mass ratio of activated arsenic powder to activated iron powder is 1:0.5 to 1.0.

[0013] Preferably, in step S4, the amount of titanium powder added is 0.8 to 1.5 wt% of the arsenic / iron core-shell structure powder.

[0014] Preferably, in step S4, the amount of aluminum powder added is 1.0 to 1.8 wt% of the sulfur impurity conversion powder. Preferably, in step S5, the thickness of the indium layer in the indium-coated powder is 10–36 nm.

[0015] In the technical solution of this invention, as described above, the indium layer absorbs stress through plastic deformation, eliminates interfacial microcracks, and improves mechanical strength. The research team discovered through experiments that the thickness of the indium layer must be at least 10 nm to achieve a significant improvement in the mechanical strength of the arsenic-based alloy. Therefore, this invention controls the thickness of the indium layer to ≥10 nm. However, another problem encountered by the research team is the poor thermal stability of some of the prepared arsenic-based alloy materials, leading to cracks on the surface of the arsenic-based alloy. In-depth research revealed that this is significantly influenced by the thickness of the indium layer in the arsenic-based alloy. When the indium layer thickness exceeds a critical value (36 nm), the difference in thermal expansion coefficients between it and the arsenic matrix leads to the initiation of microcracks at grain boundaries. Repeated melting and solidification of the thick indium layer under thermal cycling further expands the cracks. Figure 1 and Figure 2 The images show polished arsenic-based alloys after thermal cycling treatment, with indium layer thicknesses of 36 nm and 45 nm, respectively. It can be observed that the polished area of ​​the arsenic-based alloy with a 36 nm indium layer thickness is smooth and flat, while the polished area of ​​the 45 nm indium layer thickness shows more cracks, demonstrating that the indium layer thickness has a significant impact on the thermal stability of the arsenic-based alloy material. Therefore, this invention controls the indium layer thickness to be less than 36 nm.

[0016] Preferably, in step S6, the particle size of the WC-Co powder is 20–50 μm.

[0017] Preferably, in step S7, the heat treatment temperature is 950–980°C and the heat treatment time is 30–50 min.

[0018] A high-strength arsenic-based alloy is prepared by the method described above.

[0019] Compared with the prior art, the beneficial effects of the present invention are: 1. Through the synergistic effect of raw material processing, impurity utilization and structural construction, the matrix densification, defect functionalization and interface optimization are achieved simultaneously, thereby significantly improving the mechanical strength of arsenic-based alloys.

[0020] 2. Strictly control the thickness of the indium layer within a certain range. This not only absorbs stress and improves strength through plastic deformation, but also avoids grain boundary microcracks caused by differences in thermal expansion coefficients, thereby improving thermal stability. Attached Figure Description

[0021] Figure 1 This is a polished image of the arsenic-based alloy prepared in Example 4 of the present invention after undergoing thermal cycling treatment.

[0022] Figure 2 The image shows a polished arsenic-based alloy prepared for Comparative Example 5 after undergoing thermal cycling treatment. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] A method for preparing a high-strength arsenic-based alloy includes the following steps: Step 1: Weigh 500g of purified arsenic slag powder (As content ≥98wt%), then add 13g of nano-cerium powder and mix in a three-dimensional mixer for 30 minutes until homogeneous. Transfer the mixed powder to a tube furnace, introduce a H2 / Ar (volume ratio 1:9) mixed gas (total flow rate 500mL / min), set the heating temperature to 410℃, and the heating time to 1.5h. After heating, turn off the gas source and allow the powder to cool to room temperature with the furnace to obtain activated arsenic powder with a CeAsO4 coating on the surface.

[0026] Step 2: Weigh 300g of reduced iron powder (Fe≥99.5wt%) and place it in a plasma hydrogen reduction furnace. Introduce high-purity hydrogen into the furnace, controlling the hydrogen flow rate at 10L / min. Turn on a 5kW radio frequency plasma to treat the iron powder for 60 minutes. After treatment, turn off the plasma and gas source, allow it to cool naturally, and then remove it to obtain surface-reconstructed active iron powder (oxygen content <200ppm).

[0027] Step 3: Weigh 300g of activated arsenic powder and 250g of activated iron powder, mix them evenly, and then place them into a stainless steel ball mill jar cooled with liquid nitrogen. Add 5mm diameter cemented carbide grinding balls to the ball mill jar, controlling the ball-to-powder ratio to 10:1, and ball mill at 200r / min for 2 hours in a liquid nitrogen environment (-196℃). After ball milling, remove the powder to obtain arsenic / iron core-shell structure powder.

[0028] Step 4: Add 1.3 wt% of titanium powder (99.9% purity, particle size ≤45 μm) to the arsenic / iron core-shell structure powder, mix, and transfer to a vacuum furnace. Heat to 700°C at 10°C / min under vacuum, hold for 2 hours, and cool to obtain sulfur impurity conversion powder. Then add 1.6 wt% of aluminum powder (99.5% purity, particle size 1-3 μm) to the sulfur impurity conversion powder, dry mix in an argon glove box for 30 minutes, and then place in an argon atmosphere furnace. Heat to 660°C at 10°C / min, hold for 1 hour, and cool to obtain oxygen impurity conversion powder.

[0029] Step 5: Take 100g of oxygen impurity conversion powder and place it in a chemical plating bath. Prepare the plating solution: indium sulfate (In2(SO4)3•9H2O) 30g / L, sodium citrate 80g / L, thiourea 0.5g / L, and adjust the pH to 3.5 with sulfuric acid. Place the plating bath in a 45℃ water bath and turn on mechanical stirring (speed 300r / min) to deposit an indium coating layer with a thickness of 30nm on the powder surface. After plating is completed, remove the powder, clean and dry it to obtain indium-coated powder.

[0030] Step 6: Load the indium-coated powder into the powder feeder of the plasma spraying equipment, using WC-15Co powder with a particle size of 35μm as the spraying material. Set the plasma spraying parameters: plasma power 40kW, argon flow rate 40L / min, hydrogen flow rate 10L / min, powder feed rate 20g / min, and spraying distance 100mm. Start the equipment to spray the indium-coated powder, forming a 1.5±0.2μm WC-Co composite layer on the powder surface, resulting in powder with WC-Co content on the surface.

[0031] Step 7: Place the powder containing WC-Co on its surface into a CVD furnace. After closing the furnace door, introduce acetylene and argon gas, controlling the acetylene flow rate at 50 mL / min and the argon flow rate at 200 mL / min. Set the heating rate to 20℃ / min, heat to 960℃, and hold for 40 minutes. After the holding period, stop the acetylene supply, continue the argon supply until the furnace temperature cools to room temperature, and remove the powder to obtain powder with a graphene / carbon nanotube hybrid layer grown on its surface.

[0032] Step 8: Load the powder with the graphene / carbon nanotube hybrid layer grown on its surface into a graphite mold and place it in a vacuum hot press furnace. First, evacuate the furnace to ≤10°C. -3 The pressure is increased to 800℃ at a rate of 10℃ / min, while an axial pressure of 30MPa is applied simultaneously. After reaching the set temperature, the temperature and pressure are maintained for 1 hour. Then, the heating device is turned off, and the pressure is maintained until the furnace temperature cools to room temperature. The furnace body is opened, the mold is removed, and a high-strength arsenic-based alloy is obtained after demolding.

[0033] Example 2

[0034] A method for preparing a high-strength arsenic-based alloy includes the following steps: Step 1: Weigh 500g of purified arsenic slag powder (As content ≥98wt%), then add 8g of nano-cerium powder and mix in a three-dimensional mixer for 30 minutes until homogeneous. Transfer the mixed powder to a tube furnace, introduce a H2 / Ar (volume ratio 1:9) mixed gas (total flow rate 500mL / min), set the heating temperature to 410℃, and the heating time to 1.5h. After heating, turn off the gas source and allow the powder to cool to room temperature with the furnace to obtain activated arsenic powder with a CeAsO4 coating on the surface.

[0035] Step 2: Weigh 300g of reduced iron powder (Fe≥99.5wt%) and place it in a plasma hydrogen reduction furnace. Introduce high-purity hydrogen into the furnace, controlling the hydrogen flow rate at 10L / min. Turn on a 5kW radio frequency plasma to treat the iron powder for 60 minutes. After treatment, turn off the plasma and gas source, allow it to cool naturally, and then remove it to obtain surface-reconstructed active iron powder (oxygen content <200ppm).

[0036] Step 3: Weigh 300g of activated arsenic powder and 180g of activated iron powder, mix them evenly, and place them into a stainless steel ball mill jar cooled with liquid nitrogen. Add 5mm diameter cemented carbide grinding balls to the ball mill jar, controlling the ball-to-powder ratio to 10:1, and ball mill at 200r / min for 2 hours in a liquid nitrogen environment (-196℃). After ball milling, remove the powder to obtain arsenic / iron core-shell structure powder.

[0037] Step 4: Add 0.9 wt% of titanium powder (99.9% purity, particle size ≤45 μm) to the arsenic / iron core-shell structure powder, mix, and transfer to a vacuum furnace. Heat to 700℃ at 10℃ / min under vacuum, hold for 2 hours, and cool to obtain sulfur impurity conversion powder. Then add 1.2 wt% of aluminum powder (99.5% purity, particle size 1-3 μm) to the sulfur impurity conversion powder, dry mix in an argon glove box for 30 minutes, and then place in an argon atmosphere furnace. Heat to 660℃ at 10℃ / min, hold for 1 hour, and cool to obtain oxygen impurity conversion powder.

[0038] Step 5: Take 100g of oxygen impurity conversion powder and place it in a chemical plating bath. Prepare the plating solution: indium sulfate (In2(SO4)3•9H2O) 30g / L, sodium citrate 80g / L, thiourea 0.5g / L, and adjust the pH to 3.5 with sulfuric acid. Place the plating bath in a 45℃ water bath and turn on mechanical stirring (speed 300r / min) to deposit an indium coating layer with a thickness of 20nm on the powder surface. After plating is completed, remove the powder, clean and dry it to obtain indium-coated powder.

[0039] Step 6: Load the indium-coated powder into the powder feeder of the plasma spraying equipment, using WC-15Co powder with a particle size of 30μm as the spraying material. Set the plasma spraying parameters: plasma power 40kW, argon flow rate 40L / min, hydrogen flow rate 10L / min, powder feed rate 20g / min, and spraying distance 100mm. Start the equipment to spray the indium-coated powder, forming a 1.5±0.2μm WC-Co composite layer on the powder surface, resulting in powder with WC-Co content on the surface.

[0040] Step 7: Place the powder containing WC-Co on its surface into a CVD furnace. After closing the furnace door, introduce acetylene and argon gas, controlling the acetylene flow rate at 50 mL / min and the argon flow rate at 200 mL / min. Set the heating rate to 20℃ / min, heat to 960℃, and hold for 40 minutes. After the holding period, stop the acetylene supply, continue the argon supply until the furnace temperature cools to room temperature, and remove the powder to obtain powder with a graphene / carbon nanotube hybrid layer grown on its surface.

[0041] Step 8: Load the powder with the graphene / carbon nanotube hybrid layer grown on its surface into a graphite mold and place it in a vacuum hot press furnace. First, evacuate the furnace to ≤10°C. -3 The pressure is increased to 800℃ at a rate of 10℃ / min, while an axial pressure of 30MPa is applied simultaneously. After reaching the set temperature, the temperature and pressure are maintained for 1 hour. Then, the heating device is turned off, and the pressure is maintained until the furnace temperature cools to room temperature. The furnace body is opened, the mold is removed, and a high-strength arsenic-based alloy is obtained after demolding.

[0042] Example 3

[0043] A method for preparing a high-strength arsenic-based alloy includes the following steps: Step 1: Weigh 500g of purified arsenic slag powder (As content ≥98wt%), then add 10g of nano-cerium powder and mix in a three-dimensional mixer for 30 minutes until homogeneous. Transfer the mixed powder to a tube furnace, introduce a H2 / Ar (volume ratio 1:9) mixed gas (total flow rate 500mL / min), set the heating temperature to 410℃, and the heating time to 1.5h. After heating, turn off the gas source and allow the powder to cool to room temperature with the furnace to obtain activated arsenic powder with a CeAsO4 coating on the surface.

[0044] Step 2: Weigh 300g of reduced iron powder (Fe≥99.5wt%) and place it in a plasma hydrogen reduction furnace. Introduce high-purity hydrogen into the furnace, controlling the hydrogen flow rate at 10L / min. Turn on a 5kW radio frequency plasma to treat the iron powder for 60 minutes. After treatment, turn off the plasma and gas source, allow it to cool naturally, and then remove it to obtain surface-reconstructed active iron powder (oxygen content <200ppm).

[0045] Step 3: Weigh 300g of activated arsenic powder and 200g of activated iron powder, mix them evenly, and then place them into a stainless steel ball mill jar cooled with liquid nitrogen. Add 5mm diameter cemented carbide grinding balls to the ball mill jar, controlling the ball-to-powder ratio to 10:1, and ball mill at 200r / min for 2 hours in a liquid nitrogen environment (-196℃). After ball milling, remove the powder to obtain arsenic / iron core-shell structure powder.

[0046] Step 4: Add 1.0 wt% of titanium powder (99.9% purity, particle size ≤45 μm) to the arsenic / iron core-shell structure powder, mix, and transfer to a vacuum furnace. Heat to 700℃ at 10℃ / min under vacuum, hold for 2 hours, and cool to obtain sulfur impurity conversion powder. Then add 1.4 wt% of aluminum powder (99.5% purity, particle size 1-3 μm) to the sulfur impurity conversion powder, dry mix in an argon glove box for 30 minutes, and then place in an argon atmosphere furnace. Heat to 660℃ at 10℃ / min, hold for 1 hour, and cool to obtain oxygen impurity conversion powder.

[0047] Step 5: Take 100g of oxygen impurity conversion powder and place it in a chemical plating bath. Prepare the plating solution: indium sulfate (In2(SO4)3•9H2O) 30g / L, sodium citrate 80g / L, thiourea 0.5g / L, and adjust the pH to 3.5 with sulfuric acid. Place the plating bath in a 45℃ water bath and turn on mechanical stirring (speed 300r / min) to deposit an indium coating layer with a thickness of 25nm on the powder surface. After plating is completed, remove the powder, clean and dry it to obtain indium-coated powder.

[0048] Step 6: Load the indium-coated powder into the powder feeder of the plasma spraying equipment, using WC-15Co powder with a particle size of 30μm as the spraying material. Set the plasma spraying parameters: plasma power 40kW, argon flow rate 40L / min, hydrogen flow rate 10L / min, powder feed rate 20g / min, and spraying distance 100mm. Start the equipment to spray the indium-coated powder, forming a 1.5±0.2μm WC-Co composite layer on the powder surface, resulting in powder with WC-Co content on the surface.

[0049] Step 7: Place the powder containing WC-Co on its surface into a CVD furnace. After closing the furnace door, introduce acetylene and argon gas, controlling the acetylene flow rate at 50 mL / min and the argon flow rate at 200 mL / min. Set the heating rate to 20℃ / min, heat to 960℃, and hold for 40 minutes. After the holding period, stop the acetylene supply, continue the argon supply until the furnace temperature cools to room temperature, and remove the powder to obtain powder with a graphene / carbon nanotube hybrid layer grown on its surface.

[0050] Step 8: Load the powder with the graphene / carbon nanotube hybrid layer grown on its surface into a graphite mold and place it in a vacuum hot press furnace. First, evacuate the furnace to ≤10°C. -3 The pressure is increased to 800℃ at a rate of 10℃ / min, while an axial pressure of 30MPa is applied simultaneously. After reaching the set temperature, the temperature and pressure are maintained for 1 hour. Then, the heating device is turned off, and the pressure is maintained until the furnace temperature cools to room temperature. The furnace body is opened, the mold is removed, and a high-strength arsenic-based alloy is obtained after demolding.

[0051] Example 4

[0052] A method for preparing a high-strength arsenic-based alloy includes the following steps: Step 1: Weigh 500g of purified arsenic slag powder (As content ≥98wt%), then add 15g of nano-cerium powder and mix in a three-dimensional mixer for 30 minutes until homogeneous. Transfer the mixed powder to a tube furnace, introduce a H2 / Ar (volume ratio 1:9) mixed gas (total flow rate 500mL / min), set the heating temperature to 420℃, and the heating time to 2h. After heating, turn off the gas source and allow the powder to cool to room temperature with the furnace to obtain activated arsenic powder with a CeAsO4 coating on the surface.

[0053] Step 2: Weigh 300g of reduced iron powder (Fe≥99.5wt%) and place it in a plasma hydrogen reduction furnace. Introduce high-purity hydrogen into the furnace, controlling the hydrogen flow rate at 10L / min. Turn on a 5kW radio frequency plasma to treat the iron powder for 60 minutes. After treatment, turn off the plasma and gas source, allow it to cool naturally, and then remove it to obtain surface-reconstructed active iron powder (oxygen content <200ppm).

[0054] Step 3: Weigh 300g of activated arsenic powder and 300g of activated iron powder, mix them evenly, and then place them into a stainless steel ball mill jar cooled with liquid nitrogen. Add 5mm diameter cemented carbide grinding balls to the ball mill jar, controlling the ball-to-powder ratio to 10:1, and ball mill at 200r / min for 2 hours in a liquid nitrogen environment (-196℃). After ball milling, remove the powder to obtain arsenic / iron core-shell structure powder.

[0055] Step 4: Add 1.5 wt% of titanium powder (99.9% purity, particle size ≤45 μm) to the arsenic / iron core-shell structure powder, mix, and transfer to a vacuum furnace. Heat to 700℃ at 10℃ / min under vacuum, hold for 2 hours, and cool to obtain sulfur impurity conversion powder. Then add 1.8 wt% of aluminum powder (99.5% purity, particle size 1-3 μm) to the sulfur impurity conversion powder, dry mix in an argon glove box for 30 minutes, and then place in an argon atmosphere furnace. Heat to 660℃ at 10℃ / min, hold for 1 hour, and cool to obtain oxygen impurity conversion powder.

[0056] Step 5: Take 100g of oxygen impurity conversion powder and place it in a chemical plating bath. Prepare the plating solution: indium sulfate (In2(SO4)3•9H2O) 30g / L, sodium citrate 80g / L, thiourea 0.5g / L, and adjust the pH to 3.5 with sulfuric acid. Place the plating bath in a 45℃ water bath and turn on mechanical stirring (speed 300r / min) to deposit an indium coating layer with a thickness of 36nm on the powder surface. After plating is completed, remove the powder, clean and dry it to obtain indium-coated powder.

[0057] Step 6: Load the indium-coated powder into the powder feeder of the plasma spraying equipment, using WC-15Co powder with a particle size of 50μm as the spraying material. Set the plasma spraying parameters: plasma power 40kW, argon flow rate 40L / min, hydrogen flow rate 10L / min, powder feed rate 20g / min, and spraying distance 100mm. Start the equipment to spray the indium-coated powder, forming a 1.5±0.2μm WC-Co composite layer on the powder surface, resulting in powder with WC-Co content on the surface.

[0058] Step 7: Place the powder containing WC-Co on its surface into a CVD furnace. After closing the furnace door, introduce acetylene and argon gas, controlling the acetylene flow rate at 50 mL / min and the argon flow rate at 200 mL / min. Set the heating rate to 20℃ / min, heat to 980℃, and hold for 50 minutes. After the holding period, stop the acetylene supply, continue the argon supply until the furnace temperature cools to room temperature, and remove the powder to obtain powder with a graphene / carbon nanotube hybrid layer grown on its surface.

[0059] Step 8: Load the powder with the graphene / carbon nanotube hybrid layer grown on its surface into a graphite mold and place it in a vacuum hot press furnace. First, evacuate the furnace to ≤10°C. -3 The pressure is increased to 800℃ at a rate of 10℃ / min, while an axial pressure of 30MPa is applied simultaneously. After reaching the set temperature, the temperature and pressure are maintained for 1 hour. Then, the heating device is turned off, and the pressure is maintained until the furnace temperature cools to room temperature. The furnace body is opened, the mold is removed, and a high-strength arsenic-based alloy is obtained after demolding.

[0060] Example 5

[0061] A method for preparing a high-strength arsenic-based alloy includes the following steps: Step 1: Weigh 500g of purified arsenic slag powder (As content ≥98wt%), then add 5g of nano-cerium powder and mix in a three-dimensional mixer for 30 minutes until homogeneous. Transfer the mixed powder to a tube furnace, introduce a H2 / Ar (volume ratio 1:9) mixed gas (total flow rate 500mL / min), set the heating temperature to 400℃, and the heating time to 1h. After heating, turn off the gas source and allow the powder to cool to room temperature with the furnace to obtain activated arsenic powder with a CeAsO4 coating on the surface.

[0062] Step 2: Weigh 300g of reduced iron powder (Fe≥99.5wt%) and place it in a plasma hydrogen reduction furnace. Introduce high-purity hydrogen into the furnace, controlling the hydrogen flow rate at 10L / min. Turn on a 5kW radio frequency plasma to treat the iron powder for 60 minutes. After treatment, turn off the plasma and gas source, allow it to cool naturally, and then remove it to obtain surface-reconstructed active iron powder (oxygen content <200ppm).

[0063] Step 3: Weigh 300g of activated arsenic powder and 150g of activated iron powder, mix them evenly, and then place them into a stainless steel ball mill jar cooled with liquid nitrogen. Add 5mm diameter cemented carbide grinding balls to the ball mill jar, controlling the ball-to-powder ratio to 10:1, and ball mill at 200r / min for 2 hours in a liquid nitrogen environment (-196℃). After ball milling, remove the powder to obtain arsenic / iron core-shell structure powder.

[0064] Step 4: Add 0.8 wt% of titanium powder (99.9% purity, particle size ≤45 μm) to the arsenic / iron core-shell structure powder, mix, and transfer to a vacuum furnace. Heat to 700℃ at 10℃ / min under vacuum, hold for 2 hours, and cool to obtain sulfur impurity conversion powder. Then add 1.0 wt% of aluminum powder (99.5% purity, particle size 1-3 μm) to the sulfur impurity conversion powder, dry mix in an argon glove box for 30 minutes, and then place in an argon atmosphere furnace. Heat to 660℃ at 10℃ / min, hold for 1 hour, and cool to obtain oxygen impurity conversion powder.

[0065] Step 5: Take 100g of oxygen impurity conversion powder and place it in a chemical plating bath. Prepare the plating solution: indium sulfate (In2(SO4)3•9H2O) 30g / L, sodium citrate 80g / L, thiourea 0.5g / L, and adjust the pH to 3.5 with sulfuric acid. Place the plating bath in a 45℃ water bath and turn on mechanical stirring (speed 300r / min) to deposit an indium coating layer with a thickness of 10nm on the powder surface. After plating is completed, remove the powder, clean and dry it to obtain indium-coated powder.

[0066] Step 6: Load the indium-coated powder into the powder feeder of the plasma spraying equipment, using WC-15Co powder with a particle size of 20μm as the spraying material. Set the plasma spraying parameters: plasma power 40kW, argon flow rate 40L / min, hydrogen flow rate 10L / min, powder feed rate 20g / min, and spraying distance 100mm. Start the equipment to spray the indium-coated powder, forming a 1.5±0.2μm WC-Co composite layer on the powder surface, resulting in powder with WC-Co content on the surface.

[0067] Step 7: Place the powder containing WC-Co on its surface into a CVD furnace. After closing the furnace door, introduce acetylene and argon gas, controlling the acetylene flow rate at 50 mL / min and the argon flow rate at 200 mL / min. Set the heating rate to 20℃ / min, heat to 950℃, and hold for 30 minutes. After the holding period, stop the acetylene supply and continue the argon supply until the furnace temperature cools to room temperature. Remove the powder to obtain powder with a graphene / carbon nanotube hybrid layer grown on its surface.

[0068] Step 8: Load the powder with the graphene / carbon nanotube hybrid layer grown on its surface into a graphite mold and place it in a vacuum hot press furnace. First, evacuate the furnace to ≤10°C.-3 The pressure is increased to 800℃ at a rate of 10℃ / min, while an axial pressure of 30MPa is applied simultaneously. After reaching the set temperature, the temperature and pressure are maintained for 1 hour. Then, the heating device is turned off, and the pressure is maintained until the furnace temperature cools to room temperature. The furnace body is opened, the mold is removed, and a high-strength arsenic-based alloy is obtained after demolding.

[0069] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that steps 1 and 2 are omitted in the preparation process of the arsenic-based alloy, that is, the arsenic powder is not subjected to activation treatment and the iron powder is not subjected to activation treatment.

[0070] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that step 4 is omitted in the preparation of the arsenic-based alloy, that is, titanium powder and aluminum powder are not added to the arsenic / iron core-shell structure powder for heat treatment.

[0071] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that step 5 is omitted in the preparation process of the arsenic-based alloy, that is, the oxygen impurity conversion powder is not coated with an indium layer.

[0072] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that steps 6 and 7 are omitted in the preparation of the arsenic-based alloy, that is, no graphene / carbon nanotube hybrid layer is grown on the powder surface.

[0073] Comparative Example 5: The difference between Comparative Example 5 and Example 4 is that in step 5 of the arsenic-based alloy preparation process, an indium coating layer with a thickness of 45 nm is deposited on the powder surface.

[0074] Performance testing: 1. Compressive Strength Test: A universal testing machine was used to test the compressive strength of metallic materials at high temperatures according to GB / T 14453-1993, "Test Method for High-Temperature Compressive Strength of Metallic Materials". The prepared high-strength arsenic-based alloy was machined into cylindrical specimens with a diameter of 10 mm and a height of 15 mm. Axial pressure was applied to the specimens at a loading rate of 2 mm / min at room temperature until failure occurred. The maximum load value was recorded. The compressive strength was calculated using the formula "Compressive Strength = Maximum Load / Specimen Cross-sectional Area". Each sample was tested three times, and the average value was taken as the final result. The test results are shown in Table 1.

[0075] 2. Elongation at break test: According to GB / T 228.1-2010 "Metallic materials, tensile testing—Part 1: Tests at room temperature," the alloy was machined into circular tensile specimens with a gauge length of 25 mm and a gauge diameter of 5 mm. Tensile tests were performed at room temperature using a universal testing machine at a loading rate of 5 mm / min until the specimen broke. The gauge length after fracture was measured, and the elongation at break was calculated using the formula: "Elongation at break = (Gazelle length after fracture - Original gauge length) / Original gauge length × 100%". Each sample was tested three times, and the average value was taken. The test results are shown in Table 1.

[0076] 3. High-Temperature Stability Test: The alloy sample was placed in a high-temperature box furnace and held at 800℃ for 100 hours. After cooling to room temperature with the furnace, its compressive strength after high-temperature treatment was determined according to the compressive strength test method described above. High-temperature stability is expressed as "high-temperature strength retention rate = (compressive strength after high-temperature treatment / initial compressive strength at room temperature) × 100%". Each sample was tested three times, and the average value was taken as the test result. The test results are shown in Table 1.

[0077] 4. Thermal Cycling Performance Test: The alloy was placed in a thermal cycling test chamber. The thermal cycling parameters were set as follows: low temperature -40℃ for 30 minutes, high temperature 120℃ for 30 minutes, completing one cycle; a total of 100 cycles were performed. After the cycle was completed, the sample was removed, and the polished surface was observed for cracks. The test results are shown in Table 1.

[0078] Table 1:

[0079] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-strength arsenic-based alloy, characterized in that, Includes the following steps: S1. The purified arsenic slag powder is mixed with nano-cerium powder and heated under H2 / Ar atmosphere. After cooling, activated arsenic powder with CeAsO4 coating on the surface is obtained. S2. Reduced iron powder is treated with hydrogen plasma to obtain surface-reconstructed active iron powder; S3. Activated arsenic powder and activated iron powder are ball-milled in liquid nitrogen to form arsenic / iron core-shell structured powder. S4. Add titanium powder to arsenic / iron core-shell structure powder, perform vacuum heat treatment to obtain sulfur impurity conversion powder, then add aluminum powder and dry mix, place in an argon atmosphere for heat treatment to obtain oxygen impurity conversion powder. S5. The sulfur and oxygen impurity conversion powder is chemically plated with indium to form an indium coating layer on the powder surface, thus obtaining indium-coated powder. S6. WC-Co powder is plasma sprayed onto the surface of indium-coated powder to form a composite layer, thereby obtaining powder containing WC-Co on the surface; S7. Place the powder containing WC-Co on the surface into a CVD furnace, introduce acetylene and argon gas, and perform heat treatment to obtain powder with a graphene / carbon nanotube hybrid layer grown on the surface. S8. High-strength arsenic-based alloy is obtained by vacuum hot pressing and sintering of powder with graphene / carbon nanotube hybrid layer grown on its surface.

2. The method for preparing a high-strength arsenic-based alloy according to claim 1, characterized in that, In step S1, the amount of nano-cerium powder added is 1 to 3 wt% of the mass of the arsenic slag purification powder.

3. The method for preparing a high-strength arsenic-based alloy according to claim 1, characterized in that, In step S1, the heating temperature is 400-420℃ and the heating time is 1-2 hours.

4. The method for preparing a high-strength arsenic-based alloy according to claim 1, characterized in that, In step S3, the mass ratio of activated arsenic powder to activated iron powder is 1:0.5 to 1.

0.

5. The method for preparing a high-strength arsenic-based alloy according to claim 1, characterized in that, In step S4, the amount of titanium powder added is 0.8 to 1.5 wt% of the arsenic / iron core-shell structure powder.

6. The method for preparing a high-strength arsenic-based alloy according to claim 1, characterized in that, In step S4, the amount of aluminum powder added is 1.0 to 1.8 wt% of the sulfur impurity conversion powder.

7. The method for preparing a high-strength arsenic-based alloy according to claim 1, characterized in that, In step S5, the thickness of the indium layer in the indium-coated powder is 10–36 nm.

8. The method for preparing a high-strength arsenic-based alloy according to claim 1, characterized in that, In step S6, the particle size of the WC-Co powder is 20–50 μm.

9. The method for preparing a high-strength arsenic-based alloy according to claim 1, characterized in that, In step S7, the heat treatment temperature is 950–980°C and the heat treatment time is 30–50 min.

10. A high-strength arsenic-based alloy, characterized in that, Prepared by the method described in any one of claims 1-9 above.

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