Re-W nano-alloy and preparation method and application thereof

Abstract

The invention provides a Re-W nano-alloy and a preparation method and application thereof, and belongs to the technical field of alloy materials. The preparation method comprises the following steps: reacting sodium tungstate with nitric acid, calcining and ball-milling, and modifying with tannic acid to obtain modified tungsten oxide nano powder; tungsten powder reacts with hydrogen peroxide, then acetic acid is added to prepare acetylated peroxotungstic acid powder, the acetylated peroxotungstic acid powder, perrhenic acid and oxalic acid are mixed and dissolved in an organic solvent, a water phase containing modified tungsten oxide nanometer powder and an emulsifier is dropwise added into the mixture, and the Re-W nanometer alloy is prepared through emulsification, heating reaction, centrifugation, washing, drying, calcination and hydrogen reduction. The preparation method of the prepared Re-W nano-alloy is simple and mild in condition, and the prepared Re-W nano-alloy can obviously improve the hardness, toughness, strength, wear resistance, high temperature resistance, pressure resistance and the like of a base material, can be used for preparing wear-resistant, high-temperature-resistant and high-pressure-resistant alloy materials and has wide application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and in particular to a Re-W nano alloy and a preparation method and application thereof. Background Art

[0002] Metal nanoalloys are relatively stable aggregates of a few to several thousand metal atoms bound together by physical or chemical forces. Their size is comparable to the Fermi wavelength of electrons, typically less than 3 nanometers. Due to their unique structure, metal nanoalloys often exhibit molecular-like properties, resulting in excellent physical and chemical properties such as optics, electricity, magnetism, catalysis, and chirality.

[0003] Generally, there are four main methods for synthesizing metal nanoalloys: the first is the reduction-growth method, in which the speed of the reaction depends on the reducing power of the reducing agent. Commonly used reducing agents include strong reducing agents such as sodium borohydride, mild reducing agents such as sodium cyanoborohydride, and CO. The second is the seed-growth method, which uses smaller metal nanoalloys as seeds to gradually grow larger metal nanoalloys. The third is the alloying method, which uses a certain amount of foreign motifs to gradually replace the motifs on the surface of the original nanoalloy to achieve metal exchange, thereby obtaining a heterometallic alloy nanoalloy. The fourth is the ligand exchange method, which generates a nanoalloy protected by another ligand or multiple ligands by exchanging peripheral protective ligands. However, the synthesis process of most metal nanoalloys is complex, requires strict control of thermodynamic and kinetic processes, and has low yields. In addition, the use of reducing agents can cause pollution, which is not in line with the principles of green chemistry. Therefore, the development of new ligands and synthesis methods for the efficient synthesis of nanoalloys is urgently needed.

[0004] Currently, the ligands used to synthesize metal nanoalloys mainly include three categories: thiol ligands, alkynyl ligands and phosphine ligands. However, the yield of synthesizing nanoalloys with these ligands is uneven and the methods are complicated.

[0005] Re-W nanoalloy, also known as tungsten-rhenium (W-Re) alloy, has a series of excellent physical and chemical properties, which makes it widely used in aerospace, aviation, navigation, military and defense fields. However, there is currently no simple, convenient and gentle method to prepare Re-W nanoalloy. Summary of the Invention

[0006] The purpose of the present invention is to provide a Re-W nanoalloy and its preparation method and application. The preparation method is simple and the conditions are mild. The prepared Re-W nanoalloy can significantly improve the hardness, toughness, strength, wear resistance, high temperature resistance, and pressure resistance of the base material. It can be used to prepare wear-resistant, high temperature-resistant, and high pressure-resistant alloy materials and has broad application prospects.

[0007] The technical solution of the present invention is achieved as follows: the present invention provides a method for preparing a Re-W nano alloy, comprising reacting sodium tungstate with nitric acid, calcining and ball milling, and modifying with tannic acid to obtain modified tungsten oxide nano powder; reacting tungsten powder with hydrogen peroxide, and then adding acetic acid to obtain acetylated peroxytungstic acid powder, which is mixed with perrhenic acid and oxalic acid and dissolved in an organic solvent; dripping an aqueous phase containing the modified tungsten oxide nano powder and an emulsifier into the mixture, emulsifying, heating for reaction, centrifuging, washing, drying, calcining, and hydrogen reduction to obtain a Re-W nano alloy.

[0008] As a further improvement of the present invention, the following steps are included: S1. Preparation of tungsten oxide nanopowder: Sodium tungstate and concentrated nitric acid are dissolved in water, stirred and reacted, filtered, washed, dried, calcined, and ball-milled to obtain tungsten oxide nanopowder; S2. Modified tungsten oxide nanopowder: Tungsten oxide nanopowder is added to water, tannic acid and a catalyst are added, heated and stirred to react, centrifuged, washed, and dried to obtain modified tungsten oxide nanopowder; S3. Preparation of tungsten oxide / rhenium oxide@tungsten oxide nanopowder: Mix hydrogen peroxide with water, cool and add tungsten powder, stir and react, centrifuge, collect the centrifuge liquid, add acetic acid, heat and reflux to react, dry, wash, and dry to obtain acetylated peroxytungstic acid powder, dissolve the acetylated peroxytungstic acid powder, perrhenic acid, and oxalic acid in an organic solvent to obtain an oil phase; add modified tungsten oxide nanopowder and an emulsifier into water, ultrasonically disperse them uniformly to obtain an aqueous phase; add the aqueous phase dropwise into the oil phase, emulsify, heat and stir to react, centrifuge, wash, dry, and calcine to obtain tungsten oxide / rhenium oxide@tungsten oxide nanopowder; S4. Reduction: Reduce the tungsten oxide / rhenium oxide@tungsten oxide nanopowder with hydrogen to obtain a Re-W nanoalloy.

[0009] As a further improvement of the present invention, the mass ratio of sodium tungstate, concentrated nitric acid and water in step S1 is 10-12:15-20:150-200, the stirring reaction is 30-40 minutes, the calcination temperature is 450-550°C, the time is 1-3 hours, and the ball milling time is 1-3 hours.

[0010] As a further improvement of the present invention, the mass ratio of the tungsten oxide nanopowder, tannic acid and catalyst in step S2 is 10:3-4:0.5-1, the catalyst is a Tris-HCl solution with a pH of 8.5-9.5, and the temperature of the heating and stirring reaction is 45-55° C. for 2-4 hours.

[0011] As a further improvement of the present invention, the concentration of the hydrogen peroxide in step S3 is 25-30wt%, the ratio of the hydrogen peroxide, water, tungsten powder, and acetic acid is 7-10:70-100:8-12:12-15, the cooling temperature is 0-2°C, the stirring reaction is 20-24h, the heating reflux reaction time is 10-12h, the acetylated peroxytungstic acid powder, perrhenic acid, oxalic acid, modified tungsten oxide nanopowder, and emulsifier are 8-10:4-5:2-3:3-5:1-2, the heating and stirring reaction temperature is 50-60°C, the time is 1-3h, and the calcination temperature is 500-600°C, and the time is 2-4h.

[0012] As a further improvement of the present invention, the method of hydrogen reduction in step S4 is as follows: reduction at 200-300°C for 1-3 hours, heating to 350-450°C for reduction for 1-3 hours, heating to 1000-1100°C, and reduction for 2-4 hours, and the hydrogen ventilation rate is 0.9-1.1 L / min.

[0013] As a further improvement of the present invention, the organic solvent is selected from at least one of ethyl acetate, petroleum ether, chloroform, butyl acetate, and propyl acetate; and the emulsifier is selected from at least one of Tween-20, Tween-40, Tween-60, Tween-80, and Tween-85.

[0014] As a further improvement of the present invention, the following steps are specifically included: S1. Preparation of tungsten oxide nanopowder: Dissolve 10-12 parts by weight of sodium tungstate and 15-20 parts by weight of concentrated nitric acid in 150-200 parts by weight of water, stir and react for 30-40 minutes, filter, wash, dry, calcine at 450-550°C for 1-3 hours, and ball mill for 1-3 hours to produce tungsten oxide nanopowder; S2. Modified tungsten oxide nanopowder: Add 10 parts by weight of tungsten oxide nanopowder to water, add 3-4 parts by weight of tannic acid and 0.5-1 part by weight of a catalyst, heat to 45-55°C, stir and react for 2-4 hours, centrifuge, wash, and dry to produce modified tungsten oxide nanopowder; the catalyst is a Tris-HCl solution with a pH of 8.5-9.5; S3. Preparation of tungsten oxide / rhenium oxide@tungsten oxide nanopowder: Mix 7-10 parts by weight of hydrogen peroxide with 70-100 parts by weight of water, cool to 0-2°C, add 8-12 parts by weight of tungsten powder, stir and react for 20-24 hours, centrifuge, collect the centrifuge liquid, add 12-15 parts by weight of acetic acid, heat and reflux for 10-12 hours, dry, wash, and dry to obtain acetylated peroxytungstic acid powder, then mix 8-10 parts by weight of acetylated peroxytungstic acid powder and 4-5 parts by weight of tungsten powder. Perrhenic acid and 2-3 parts by weight of oxalic acid are dissolved in 200 parts by weight of an organic solvent to obtain an oil phase. 3-5 parts by weight of modified tungsten oxide nanopowder and 1-2 parts by weight of an emulsifier are added to 100 parts by weight of water and uniformly dispersed by ultrasonication to obtain an aqueous phase. The aqueous phase is dropwise added to the oil phase, emulsified, heated to 50-60°C, stirred for reaction for 1-3 hours, centrifuged, washed, dried, and calcined at 500-600°C for 2-4 hours to obtain tungsten oxide / rhenium oxide@tungsten oxide nanopowder. S4. Reduction: The tungsten oxide / rhenium oxide@tungsten oxide nanopowder is reduced with hydrogen at 200-300°C for 1-3 hours, then heated to 350-450°C for 1-3 hours, and then heated to 1000-1100°C for 2-4 hours. The hydrogen flow rate is 0.9-1.1 L / min to obtain a Re-W nanoalloy.

[0015] The present invention further protects a Re-W nano alloy prepared by the above preparation method.

[0016] The present invention further protects the use of the above-mentioned Re-W nano alloy in preparing wear-resistant, high-temperature-resistant and high-pressure-resistant alloy materials.

[0017] The present invention has the following beneficial effects: the alloy is a mixture of two or more metal elements, and at the nanoscale, due to the synergistic effect, the alloyed bimetallic clusters have more and richer properties. Re-W nano alloys can achieve high-density W alloy components and can withstand high-temperature and high-pressure application scenarios. At the same time, the participation of Re can improve the strength and plasticity of the material and increase the recrystallization temperature, which is beneficial to improving the mechanical properties and stability of the material in a high-temperature environment and improving the material's resistance to thermal shock damage. Re is solid-dissolved in W, which can cause W lattice distortion, hinder dislocation movement, and achieve solid solution strengthening, so the hardness of the part is also very high. The grain size of the Re-W nano alloy is significantly refined, which helps to improve the strength and toughness of the material. Due to its high hardness and good toughness, the Re-W nano alloy exhibits excellent wear resistance.

[0018] Tungsten powder is used as raw material to react with hydrogen peroxide (H2O2) to generate peroxytungstic acid, which is then acetylated and dried to obtain acetylated peroxytungstic acid, which can then be further subjected to a sol-gel reaction.

[0019] The present invention first prepares tungsten oxide powder by precipitation, ball milling it to obtain a nanoscale material, and then surface-modifying it with tannic acid to produce modified tungsten oxide nanopowder. This nanopowder serves as a core and is ultrasonically uniformly distributed in water. Because the surface contains multiple carboxyl and hydroxyl groups found in tannic acid, it facilitates the in-situ deposition and reaction of acetylated peroxytungstic acid, perrhenic acid, and oxalic acid through hydrogen bonding, thereby forming a core-shell structure. After hydrogen reduction, a Re-W nanoalloy is produced. By adopting a reasonable Re-W ratio and forming a core-shell Re-W nanoalloy, the resistance to dislocation motion is increased, while segregation at grain boundaries enhances grain boundary bonding, thereby achieving grain boundary strengthening and significantly improving the hardness, wear resistance, and mechanical properties of the matrix material.

[0020] The Re-W nano alloy prepared by the present invention has a simple preparation method and mild conditions. The prepared Re-W nano alloy can significantly improve the hardness, toughness, strength, wear resistance, high temperature resistance, pressure resistance, etc. of the base material, can be used to prepare wear-resistant, high temperature resistant, and high pressure resistant alloy materials, and has broad application prospects. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0022] Tungsten powder, purity >99.99%, particle size 1-5μm.

[0023] Example 1

[0024] This embodiment provides a method for preparing a Re-W nanoalloy, comprising the following steps: S1. Preparation of tungsten oxide nanopowder: dissolving 10 g of sodium tungstate and 15 g of concentrated nitric acid in 150 mL of water, stirring and reacting for 30 min, filtering, washing, drying, calcining at 450° C. for 1 h, and ball milling for 1 h to obtain tungsten oxide nanopowder; S2. Modified tungsten oxide nanopowder: adding 10 g of tungsten oxide nanopowder to 200 mL of water, adding 3 g of tannic acid and 0.5 g of a catalyst, heating to 45° C., stirring and reacting for 2 h, centrifuging, washing, and drying to obtain modified tungsten oxide nanopowder; the catalyst is a Tris-HCl solution with a pH of 8.5; S3. Preparation of tungsten oxide / rhenium oxide@tungsten oxide nanopowder: dissolving 7 g of tungsten oxide and tungsten oxide nanopowder in 150 mL of water, stirring and reacting for 30 min, filtering, washing, drying, calcining at 450° C. for 1 h, and ball milling for 1 h to obtain tungsten oxide nanopowder; Mix 25wt% hydrogen peroxide with 70mL of water, cool to 0°C, add 8g of tungsten powder, stir and react for 20h, centrifuge, collect the centrifuge liquid, add 12g of acetic acid, heat under reflux for 10h, dry, wash, and dry to obtain acetylated peroxytungstic acid powder. Dissolve 8g of acetylated peroxytungstic acid powder, 4g of perrhenic acid, and 2g of oxalic acid in 200g of ethyl acetate to obtain an oil phase. Add 3g of modified tungsten oxide nanopowder and 1g of Tween-60 to 100mL of water and ultrasonically disperse at 1000W for 15min to obtain an aqueous phase. Add the aqueous phase dropwise to the oil phase, emulsify at 8000r / min for 15min, heat to 50°C, stir and react for 1h, centrifuge, wash, dry, and calcine at 500°C for 2h to obtain tungsten oxide / rhenium oxide@tungsten oxide nanopowder. S4. Reduction: Tungsten oxide / rhenium oxide@tungsten oxide nanopowder was reduced with hydrogen at 200°C for 1 hour, then heated to 350°C for 1 hour, and then heated to 1000°C for 2 hours. The hydrogen flow rate was 0.9 L / min to obtain Re-W nano alloy.

[0025] Example 2

[0026] This embodiment provides a method for preparing a Re-W nanoalloy, comprising the following steps: S1. Preparation of tungsten oxide nanopowder: dissolving 12 g of sodium tungstate and 20 g of concentrated nitric acid in 200 mL of water, stirring and reacting for 40 min, filtering, washing, drying, calcining at 550° C. for 3 h, and ball milling for 3 h to obtain tungsten oxide nanopowder; S2. Modified tungsten oxide nanopowder: adding 10 g of tungsten oxide nanopowder to 200 mL of water, adding 4 g of tannic acid and 1 g of a catalyst, heating to 55° C., stirring and reacting for 4 h, centrifuging, washing, and drying to obtain modified tungsten oxide nanopowder; the catalyst is a Tris-HCl solution with a pH of 9.5; S3. Preparation of tungsten oxide / rhenium oxide@tungsten oxide nanopowder: dissolving 10 g of sodium tungstate and 20 g of concentrated nitric acid in 200 mL of water, stirring and reacting for 4 h, centrifuging, washing, and drying to obtain modified tungsten oxide nanopowder; the catalyst is a Tris-HCl solution with a pH of 9.5; Mix 30 wt% hydrogen peroxide with 100 mL of water, cool to 2°C, add 12 g of tungsten powder, stir and react for 24 h, centrifuge, collect the centrifuge, add 15 g of acetic acid, heat under reflux for 12 h, dry, wash, and dry to obtain acetylated peroxytungstic acid powder. Dissolve 10 g of acetylated peroxytungstic acid powder, 5 g of perrhenic acid, and 3 g of oxalic acid in 200 g of butyl acetate to obtain an oil phase. Add 5 g of modified tungsten oxide nanopowder and 2 g of Tween-80 to 100 mL of water and ultrasonically disperse at 1000 W for 15 min to obtain an aqueous phase. Add the aqueous phase dropwise to the oil phase, emulsify at 8000 rpm for 15 min, heat to 60°C, stir and react for 3 h, centrifuge, wash, dry, and calcine at 600°C for 4 h to obtain tungsten oxide / rhenium oxide@tungsten oxide nanopowder. S4. Reduction: Tungsten oxide / rhenium oxide@tungsten oxide nanopowder was reduced with hydrogen at 300°C for 3 hours, then heated to 450°C for 3 hours, and then heated to 1100°C for 4 hours. The hydrogen flow rate was 1.1 L / min to obtain Re-W nano alloy.

[0027] Example 3

[0028] This embodiment provides a method for preparing a Re-W nanoalloy, comprising the following steps: S1. Preparation of tungsten oxide nanopowder: dissolving 11 g of sodium tungstate and 17 g of concentrated nitric acid in 170 mL of water, stirring and reacting for 35 min, filtering, washing, drying, calcining at 500° C. for 2 h, and ball milling for 2 h to obtain tungsten oxide nanopowder; S2. Modified tungsten oxide nanopowder: adding 10 g of tungsten oxide nanopowder to 200 mL of water, adding 3.5 g of tannic acid and 0.7 g of a catalyst, heating to 50° C., stirring and reacting for 3 h, centrifuging, washing, and drying to obtain modified tungsten oxide nanopowder; the catalyst is a Tris-HCl solution with a pH of 9; S3. Preparation of tungsten oxide / rhenium oxide@tungsten oxide nanopowder: dissolving 8 g of tungsten oxide and rhenium oxide in 170 mL of water, stirring and reacting for 3 h, centrifuging, washing, and drying to obtain modified tungsten oxide nanopowder; the catalyst is a Tris-HCl solution with a pH of 9; 27 wt% hydrogen peroxide was mixed with 80 mL of water, cooled to 1°C, and 10 g of tungsten powder was added. The mixture was stirred for 22 h, centrifuged, and the centrifuge liquid was collected. 13 g of acetic acid was added and the mixture was heated under reflux for 11 h. The mixture was dried, washed, and dried to obtain acetylated peroxytungstic acid powder. 9 g of acetylated peroxytungstic acid powder, 4.5 g of perrhenic acid, and 2.5 g of oxalic acid were dissolved in 200 g of propyl acetate to obtain an oil phase. 4 g of modified tungsten oxide nanopowder and 1.5 g of Tween-85 were added to 100 mL of water and ultrasonically dispersed at 1000 W for 15 min to obtain an aqueous phase. The aqueous phase was added dropwise to the oil phase and emulsified at 8000 rpm for 15 min. The mixture was heated to 55°C, stirred for 2 h, centrifuged, washed, dried, and calcined at 550°C for 3 h to obtain tungsten oxide / rhenium oxide@tungsten oxide nanopowder. S4. Reduction: Tungsten oxide / rhenium oxide@tungsten oxide nanopowder was reduced with hydrogen at 250°C for 2 hours, then heated to 400°C for 2 hours, and then heated to 1050°C for 3 hours. The hydrogen flow rate was 1 L / min to obtain Re-W nano alloy.

[0029] Comparative Example 1 Compared with embodiment 3, the difference is that step S2 is not performed.

[0030] The details are as follows: S1. Preparation of tungsten oxide nanopowder: Dissolve 11 g of sodium tungstate and 17 g of concentrated nitric acid in 170 mL of water, stir and react for 35 minutes, filter, wash, dry, calcine at 500°C for 2 hours, and ball mill for 2 hours to obtain tungsten oxide nanopowder. Preparation of tungsten oxide / rhenium oxide@tungsten oxide nanopowder: 8 g of 27 wt% hydrogen peroxide was mixed with 80 mL of water, cooled to 1°C, 10 g of tungsten powder was added, stirred and reacted for 22 h, centrifuged, the centrifuge liquid was collected, 13 g of acetic acid was added, the mixture was heated under reflux for 11 h, dried, washed, and dried to obtain acetylated peroxytungstic acid powder. 9 g of acetylated peroxytungstic acid powder, 4.5 g of perrhenic acid, and 2.5 g of oxalic acid were dissolved in 200 g of propyl acetate to obtain an oil phase. 4 g of tungsten oxide nanopowder and 1.5 g of Tween-85 were added to 100 mL of water and ultrasonically dispersed at 1000 W for 15 min to obtain an aqueous phase. The aqueous phase was dropwise added to the oil phase, emulsified at 8000 rpm for 15 min, heated to 55°C, stirred and reacted for 2 h, centrifuged, washed, dried, and calcined at 550°C for 3 h to obtain tungsten oxide / rhenium oxide@tungsten oxide nanopowder. S3. Reduction: The tungsten oxide / rhenium oxide@tungsten oxide nanopowders were reduced with hydrogen at 250°C for 2 hours, then heated to 400°C for 2 hours, and then heated to 1050°C for 3 hours. The hydrogen flow rate was 1 L / min to produce a Re-W nanoalloy.

[0031] Comparative Example 2 Compared with Example 3, the difference is that no acetylated peroxytungstic acid powder is added in step S3.

[0032] The details are as follows: S1. Preparation of tungsten oxide nanopowder: Dissolve 11 g of sodium tungstate and 17 g of concentrated nitric acid in 170 mL of water, stir and react for 35 minutes, filter, wash, dry, calcine at 500°C for 2 hours, and ball mill for 2 hours to obtain tungsten oxide nanopowder. S2. Modified tungsten oxide nanopowder: Add 10g of tungsten oxide nanopowder to 200mL of water, add 3.5g of tannic acid and 0.7g of catalyst, heat to 50°C, stir and react for 3h, centrifuge, wash, and dry to obtain modified tungsten oxide nanopowder. The catalyst is a Tris-HCl solution with a pH of 9; S3. Preparation of rhenium oxide@tungsten oxide nanopowder: 4.5 g of perrhenic acid and 2.5 g of oxalic acid were dissolved in 200 g of propyl acetate to obtain an oil phase. 4 g of modified tungsten oxide nanopowder and 1.5 g of Tween-85 were added to 100 mL of water and ultrasonically dispersed at 1000 W for 15 minutes to obtain an aqueous phase. The aqueous phase was added dropwise to the oil phase and emulsified at 8000 rpm for 15 minutes. The mixture was heated to 55°C and stirred for 2 hours. The mixture was centrifuged, washed, dried, and calcined at 550°C for 3 hours to obtain rhenium oxide@tungsten oxide nanopowder. S4. Reduction: Re-W nanopowders were reduced with hydrogen at 250°C for 2 hours, then heated to 400°C for 2 hours, and then heated to 1050°C for 3 hours. The hydrogen flow rate was 1 L / min to produce a Re-W nanoalloy.

[0033] Comparative Example 3 Compared with Example 3, the difference is that steps S1 and S2 are not performed.

[0034] The details are as follows: Preparation of tungsten oxide / rhenium oxide nanopowder: 8 g of 27 wt% hydrogen peroxide was mixed with 80 mL of water, cooled to 1°C, 10 g of tungsten powder was added, stirred and reacted for 22 h, centrifuged, the centrifuge liquid was collected, 13 g of acetic acid was added, the mixture was heated under reflux for 11 h, dried, washed, and dried to obtain acetylated peroxytungstic acid powder. 9 g of acetylated peroxytungstic acid powder, 4.5 g of perrhenic acid, and 2.5 g of oxalic acid were dissolved in 200 g of propyl acetate to obtain an oil phase. 1.5 g of Tween-85 was added to 500 mL of water and ultrasonically dispersed at 1000 W for 15 min to obtain an aqueous phase. The oil phase was dropwise added to the aqueous phase, emulsified at 8000 rpm for 15 min, heated to 55°C, stirred and reacted for 2 h, centrifuged, washed, dried, and calcined at 550°C for 3 h to obtain tungsten oxide / rhenium oxide nanopowder. S4. Reduction: The tungsten oxide / rhenium oxide nanopowders were reduced with hydrogen at 250°C for 2 hours, then heated to 400°C for 2 hours, and then heated to 1050°C for 3 hours. The hydrogen flow rate was 1 L / min to produce a Re-W nanoalloy.

[0035] Test Example 1 The Re-W nanoalloys prepared in Examples 1-3 of the present invention and Comparative Examples 1-3 were added to a tungsten-based alloy to prepare a modified alloy, wherein the tungsten content was 95wt%, cobalt was 0.4wt%, iron was 1.5wt%, the Re-W nanoalloy was 2wt%, and nickel was the balance. The preparation method was as follows: the raw materials were weighed in proportion, ball-milled to an average particle size of 1-2μm, and then pre-formed at a pressure of 100MPa to obtain a compact with a size of Φ170mm×4mm. The compact was heated to above 600°C to remove the forming agent, and then heated to above 700°C for pre-sintering to obtain a rough blank. The rough blank was heated to 1500°C under hydrogen protection and sintered for 2h. The rough blank was then subjected to high-temperature shaping at 700°C and a shaping pressure of 500N. The rough blank was naturally cooled in air to obtain the modified alloy, and the performance indicators were tested.

[0036] The results are shown in Table 1.

[0037] Among them, the test method of volume wear rate is as follows: Friction and wear performance tests were conducted using a high-speed reciprocating friction and wear testing machine at 1000 r / min. The ambient temperature was 23±2°C, the humidity was 50±5%, the test time was 30 minutes, and the friction load was 60N. The wear rate was characterized by volume, calculated as follows: Volume wear rate = V / (F×L) Volume wear rate, unit: mm 3 / Nm; V represents the wear volume, unit is mm 3 ; F represents the friction load, unit is N; L represents the total sliding length, unit is m.

[0038] Table 1

[0039] As can be seen from the above table, the modified alloys prepared by adding the Re-W nano-alloys prepared in Examples 1-3 of the present invention to the tungsten-based alloy have good mechanical properties, wear resistance and hardness.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a Re-W nano alloy, characterized in that: Sodium tungstate is reacted with nitric acid, calcined and ball-milled, and modified with tannic acid to obtain modified tungsten oxide nanopowder; tungsten powder is reacted with hydrogen peroxide, and then acetic acid is added to obtain acetylated peroxytungstic acid powder, which is mixed with perrhenic acid and oxalic acid and dissolved in an organic solvent. An aqueous phase containing modified tungsten oxide nanopowder and an emulsifier is added dropwise thereto, followed by emulsification, heating reaction, centrifugation, washing, drying, calcination, and hydrogen reduction to obtain Re-W nano alloy.

2. The preparation method according to claim 1, wherein The following steps are involved: S1. Preparation of tungsten oxide nanopowder: Dissolve sodium tungstate and concentrated nitric acid in water, stir, filter, wash, dry, calcine, and ball-mill to produce tungsten oxide nanopowder. S2. Modified tungsten oxide nanopowder: Add tungsten oxide nanopowder to water, tannic acid and a catalyst, heat and stir to react, centrifuge, wash, and dry to produce modified tungsten oxide nanopowder. S3. Preparation of tungsten oxide / rhenium oxide@tungsten oxide nanopowder: Mix hydrogen peroxide with water, cool, add tungsten powder, stir to react, centrifuge, collect the centrifuge liquid, add acetic acid, heat under reflux to react, dry, wash, and dry to produce acetylated peroxytungstic acid powder. Dissolve the acetylated peroxytungstic acid powder, perrhenic acid, and oxalic acid in an organic solvent to produce an oil phase. Add the modified tungsten oxide nanopowder and an emulsifier to water and ultrasonically disperse uniformly to produce an aqueous phase. Add the aqueous phase dropwise to the oil phase, emulsify, heat and stir to react, centrifuge, wash, dry, and calcine to produce tungsten oxide / rhenium oxide@tungsten oxide nanopowder. S4. Reduction: Reduce the tungsten oxide / rhenium oxide@tungsten oxide nanopowder with hydrogen to produce a Re-W nanoalloy.

3. The preparation method according to claim 2, characterized in that In step S1, the mass ratio of sodium tungstate, concentrated nitric acid, and water is 10-12:15-20:150-200, the stirring reaction is carried out for 30-40 minutes, the calcination temperature is 450-550° C., the time is 1-3 hours, and the ball milling time is 1-3 hours.

4. The preparation method according to claim 2, characterized in that In step S2, the mass ratio of the tungsten oxide nanopowder, tannic acid, and catalyst is 10:3-4:0.5-1, the catalyst is a Tris-HCl solution with a pH of 8.5-9.5, the temperature of the heating and stirring reaction is 45-55° C., and the time is 2-4 hours.

5. The preparation method according to claim 2, characterized in that The concentration of the hydrogen peroxide in step S3 is 25-30wt%, the ratio of the hydrogen peroxide, water, tungsten powder, and acetic acid is 7-10:70-100:8-12:12-15, the cooling temperature is 0-2°C, the stirring reaction is 20-24h, the heating reflux reaction time is 10-12h, the acetylated peroxytungstic acid powder, perrhenic acid, oxalic acid, modified tungsten oxide nanopowder, and emulsifier are 8-10:4-5:2-3:3-5:1-2, the heating and stirring reaction temperature is 50-60°C, the time is 1-3h, and the calcination temperature is 500-600°C, and the time is 2-4h.

6. The preparation method according to claim 2, characterized in that The method of hydrogen reduction in step S4 is as follows: reduction at 200-300°C for 1-3h, heating to 350-450°C for reduction for 1-3h, heating to 1000-1100°C, and reduction for 2-4h, and the hydrogen ventilation rate is 0.9-1.1L / min.

7. The preparation method according to claim 2, characterized in that The organic solvent is selected from at least one of ethyl acetate, petroleum ether, chloroform, butyl acetate, and propyl acetate; the emulsifier is selected from at least one of Tween-20, Tween-40, Tween-60, Tween-80, and Tween-85.

8. The preparation method according to claim 2, wherein The specific steps include: S1. Preparation of tungsten oxide nanopowder: Dissolve 10-12 parts by weight of sodium tungstate and 15-20 parts by weight of concentrated nitric acid in 150-200 parts by weight of water, stir and react for 30-40 minutes, filter, wash, dry, calcine at 450-550°C for 1-3 hours, and ball mill for 1-3 hours to produce tungsten oxide nanopowder. S2. Modified tungsten oxide nanopowder: Add 10 parts by weight of tungsten oxide nanopowder to water, add 3-4 parts by weight of tannic acid and 0.5-1 part by weight of a catalyst, heat to 45-55°C, stir and react for 2-4 hours, centrifuge, wash, and dry to produce modified tungsten oxide nanopowder. The catalyst is a Tris-HCl solution with a pH of 8.5-9.

5. S3. Preparation of tungsten oxide / rhenium oxide@tungsten oxide nanopowder: Mix 7-10 parts by weight of hydrogen peroxide with 70-100 parts by weight of water, cool to 0-2°C, add 8-12 parts by weight of tungsten powder, stir and react for 20-24 hours, centrifuge, collect the centrifuge liquid, add 12-15 parts by weight of acetic acid, heat and reflux for 10-12 hours, dry, wash, dry, and obtain acetylated peroxytungstic acid powder. Mix 8-10 parts by weight of acetylated peroxytungstic acid powder and 4-5 parts by weight of acetylated peroxytungstic acid powder.

1. 2-3 parts by weight of perrhenic acid and 200 parts by weight of oxalic acid are dissolved in 200 parts by weight of an organic solvent to obtain an oil phase; 3-5 parts by weight of modified tungsten oxide nanopowder and 1-2 parts by weight of an emulsifier are added to 100 parts by weight of water and uniformly dispersed by ultrasonication to obtain an aqueous phase; the aqueous phase is added dropwise to the oil phase, emulsified, heated to 50-60°C, stirred for reaction for 1-3 hours, centrifuged, washed, dried, and calcined at 500-600°C for 2-4 hours to obtain tungsten oxide / rhenium oxide@tungsten oxide nanopowder; S4. Reduction: Hydrogen reduction of tungsten oxide / rhenium oxide@tungsten oxide nanopowders was performed at 200-300°C for 1-3 hours, then at 350-450°C for 1-3 hours, and finally at 1000-1100°C for 2-4 hours. The hydrogen flow rate was 0.9-1.1 L / min to produce a Re-W nanoalloy.

9. A Re-W nano alloy prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the Re-W nano alloy according to claim 9 in preparing wear-resistant, high-temperature-resistant and high-pressure-resistant alloy materials.

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