Preparation process of molybdenum-rhenium alloy

Abstract

The invention belongs to the technical field of powder metallurgy, and particularly relates to a preparation process of molybdenum-rhenium alloy. An existing molybdenum-rhenium alloy preparation process mainly comprises a dry method and a wet method, in the dry method, metal molybdenum powder and metal rhenium powder are mixed and ball-milled in a ball mill to form molybdenum-rhenium mixed powder, and the molybdenum-rhenium mixed powder is subjected to hydrogen reduction, isostatic pressing and sintering to form the molybdenum-rhenium alloy; the wet method comprises the following steps: dissolving ammonium metamolybdate and ammonium perrhenate in water to form a mixed solution; and the mixed solution is subjected to evaporation dehydration, hydrogen reduction, isostatic pressing and sintering to form the molybdenum-rhenium alloy. The preparation method has the problem of non-uniform distribution of metal rhenium in the molybdenum-rhenium alloy. The invention discloses a preparation process of a molybdenum-rhenium alloy, which comprises the following steps: mixing and ball-milling an ammonium perrhenate aqueous solution and molybdenum powder in a ball mill to form high-uniformity mixed powder; and the high-uniformity mixed powder is subjected to hydrogen reduction, isostatic pressing and sintering to form the molybdenum-rhenium alloy, and the preparation method has the characteristic that metal rhenium in the molybdenum-rhenium alloy is evenly distributed.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy technology, specifically relating to a preparation process of molybdenum-rhenium alloy. Background Technology

[0002] Molybdenum-rhenium alloys are solid solution strengthened alloys formed by adding a certain proportion of rhenium to a molybdenum matrix. They possess the following advantages: 1. Extremely high strength and melting point; 2. Excellent ductility and toughness; 3. Excellent recrystallization temperature; 4. Good electrical and thermal conductivity; 5. Low vapor pressure and good resistance to arc erosion. Existing preparation processes for molybdenum-rhenium alloys mainly include dry and wet methods. The dry method involves mixing and ball-milling molybdenum powder and rhenium powder to form a mixed molybdenum-rhenium powder, which is then reduced with hydrogen, isostatically pressed, and sintered to form the molybdenum-rhenium alloy. The wet method involves dissolving ammonium metamolybdate and ammonium perperurate in water to form a mixed solution, which is then evaporated to remove water, reduced with hydrogen, isostatically pressed, and sintered to form the molybdenum-rhenium alloy. The above preparation methods suffer from the problem of uneven distribution of rhenium in the molybdenum-rhenium alloy.

[0003] In 2019, CN111020330A disclosed a method for preparing molybdenum-rhenium alloy profiles, including: a molybdenum-rhenium alloy powder preparation step: mixing molybdenum powder and ammonium perlite in a required proportion, followed by reduction treatment to obtain molybdenum-rhenium alloy powder; a pressing and molding step: loading the molybdenum-rhenium alloy powder into a pressing mold for pressing and molding to obtain a pressed blank; a sintering step: sintering the pressed blank to obtain a sintered blank; and a hot isostatic pressing step: subjecting the sintered blank to hot isostatic pressing to obtain a fully dense molybdenum-rhenium alloy profile. This preparation method directly mixes metallic molybdenum powder and the inorganic salt ammonium perlite, which have vastly different physicochemical properties, resulting in uneven mixing.

[0004] CN114029496A, published in 2021, discloses a novel method for preparing ultrafine molybdenum-rhenium alloy powder. The main steps of this method are: liquid-phase mixing and preparation of raw materials → calcination and decomposition → carbothermic reduction → deep hydrogen reduction. Claim 2 specifies that the molybdenum source is ammonium molybdate and the rhenium source is ammonium rheniumate. Before calcination and decomposition, this process requires removing moisture from the mixed solution of ammonium molybdate and ammonium rheniumate through evaporation and crystallization, with continuous mechanical stirring during this process. This inevitably leads to uneven precipitation and crystallization of ammonium molybdate and ammonium rheniumate, affecting the uniformity of the mixed crystallization and ultimately the uniformity of the molybdenum-rhenium alloy powder.

[0005] In summary, existing molybdenum-rhenium alloy preparation processes generally suffer from uneven distribution of metallic rhenium in the alloy. Summary of the Invention

[0006] To address the aforementioned technical problems, the purpose of this invention is to provide a preparation process for a molybdenum-rhenium alloy with a more uniform rhenium distribution. The process involves: mixing and ball-milling ammonium perrhenate aqueous solution and molybdenum powder in a ball mill to form a highly uniform mixed powder; then subjecting the highly uniform mixed powder to hydrogen reduction, isostatic pressing, and sintering to form a molybdenum-rhenium alloy. Specifically, this preparation process is carried out according to the following steps:

[0007] An aqueous solution of ammonium perrhenate and molybdenum powder were added to a ball mill and mixed and ball-milled.

[0008] During the ball milling process, water is removed from the ball mill at a preset rate. During this process, the solid content of the system gradually increases until all the water in the system is removed, forming a highly uniform mixed powder.

[0009] Highly homogeneous mixed powder is reduced with hydrogen in a tube furnace to form molybdenum-rhenium alloy powder;

[0010] Molybdenum-rhenium alloy powder is isostatically pressed in a static press to form a molybdenum-rhenium alloy green billet;

[0011] The molybdenum-rhenium alloy green blank is sintered to form the molybdenum-rhenium alloy.

[0012] Unlike existing technologies, this invention uses a highly uniform mixed powder of ammonium perrhenate and metallic molybdenum powder for hydrogen reduction to form a molybdenum-rhenium alloy powder. During the hydrogen reduction process of ammonium perrhenate and metallic molybdenum powder, ammonium perrhenate decomposes into rhenium oxide upon heating and is simultaneously reduced to metallic rhenium by hydrogen. Controlling the hydrogen reduction temperature and flow rate allows for precise control of the uniformity of metallic rhenium within the molybdenum-rhenium alloy powder. The key challenge of this invention lies in preparing a highly uniform mixed powder of ammonium perrhenate and metallic molybdenum powder. To address this challenge, the inventors creatively employ a ball milling process, uniformly removing water from the mill at a predetermined rate during this process. The solid content of the system gradually increases until all water is removed, resulting in a highly uniform mixed powder. This method of simultaneous crystallization and ball milling produces a highly uniform mixed powder of ammonium perrhenate and metallic molybdenum powder.

[0013] The above describes the basic technical solution of the present invention. As a supplement and improvement to the basic technical solution, in a preferred embodiment, the content of the ammonium perrhenate aqueous solution is 15-25 wt%. The lower the content of the ammonium perrhenate aqueous solution, the more uniform the ball milling process, but more water needs to be removed, resulting in low efficiency in the ball milling process. Controlling the content of the ammonium perrhenate aqueous solution at 15-25 wt% achieves the best overall effect.

[0014] In a preferred embodiment, the particle size D of the highly uniform mixed powder is... 50 ≤10μm. Molybdenum powder and ammonium perrhenate were mixed and crystallized by ball milling to a particle size D.50 ≤10μm, thus achieving a molybdenum-rhenium alloy with highly uniform rhenium distribution. When the particle size D of the highly uniform mixed powder is... 50 For particles larger than 10μm, the particle size needs to be reduced by extending the ball milling time.

[0015] In a preferred embodiment, the diameter of the grinding balls in the ball mill is 2–10 mm. This is to ball mill ammonium perrhenate and molybdenum powder into D... 50 For highly uniform mixed powders with a particle size ≤10μm, grinding balls of 2–10mm are required. To minimize contamination of the powder by the ball mill material, the ball mill cavity and grinding balls should be made of high-strength materials such as tungsten carbide. To improve the grinding effect, grinding balls of different diameters can be combined, with smaller diameter balls filling the gaps between larger diameter balls to enhance the grinding efficiency. A ball-to-powder ratio of 5–10:1 will achieve satisfactory results.

[0016] In a preferred embodiment, the temperature of the mixing and ball milling process is 60–80°C, and the pressure is -0.02–-0.085 MPaG. Since this invention requires removing water from the ammonium perrhenate solution during ball milling, the temperature of the mixing and ball milling process needs to be controlled at 60–80°C, and the pressure at -0.02–-0.085 MPaG. Specifically, based on the rate of change in the mixed crystal particle size during ball milling, a pressure of -0.02–-0.085 MPaG is used to remove water from the system. If the mixed crystal particle size decreases slowly during ball milling, a lower negative pressure or a lower vacuum degree is needed to slow down the rate of water removal. If the mixed crystal particle size decreases quickly during ball milling, a higher negative pressure or a higher vacuum degree can be used to accelerate the rate of water removal from the system. The basic purpose is to match the rate of water removal with the rate of particle size decrease. Compared to the ball milling process of directly mixing ammonium perrhenate and molybdenum powder, the ball milling process of the present invention involves a large amount of water expanding and vaporizing inside the system, which avoids the aggregation of ammonium perrhenate and molybdenum powder and improves the uniformity of mixed crystallization.

[0017] In a preferred embodiment, the mixing and ball milling process takes > 3.0 hours. This is achieved by controlling the particle size D of the highly uniform mixed powder. 50 Under the premise of ≤10μm, the longer the ball milling time, the more uniform the distribution of metallic rhenium in the final molybdenum-rhenium alloy. The ball milling time should be adapted to the rate of moisture removal from the system. The optimal state is that after uniform moisture removal, the particle size D of the highly uniform mixed powder is achieved. 50 ≤10μm, continue ball milling for 30 minutes.

[0018] In a preferred embodiment, the temperature of the hydrogen reduction process is 600–800°C. This temperature requires hydrogen to reduce ammonium perrhenate to metallic rhenium, and also to reduce other rhenium oxides or molybdenum oxides to metallic rhenium or metallic molybdenum. The cooling process after hydrogen reduction must be carried out under the protection of hydrogen or an inert gas to prevent the reduced, high-temperature metallic rhenium and metallic molybdenum from being re-oxidized by oxygen in the air.

[0019] In a preferred embodiment, the isostatic pressing process is carried out at a pressure of 200–300 MPa for 30–180 seconds. The molybdenum-rhenium alloy powder prepared by this invention is used to obtain a green compact through isostatic pressing. The prepared molybdenum-rhenium alloy powder is loaded into a rubber sleeve, and the pressure is controlled at 200–300 MPa in a static press for 30–180 seconds to obtain a green compact with optimal mechanical properties.

[0020] In a preferred embodiment, the temperature of the sintering process is controlled to be between 1800 and 2200°C. The green billet is sintered at 1800–2200°C to fully alloy and form a molybdenum-rhenium alloy.

[0021] This invention discloses a preparation process for a molybdenum-rhenium alloy with a more uniform distribution of rhenium. In a ball mill, an ammonium perrhenate aqueous solution and molybdenum powder are mixed and ball-milled, while moisture is removed from the system to promote the formation of a highly uniform mixed powder. The highly uniform mixed powder is then subjected to hydrogen reduction, isostatic pressing, and sintering to form the molybdenum-rhenium alloy. The molybdenum-rhenium alloy prepared by the process described in this patent exhibits the characteristics of uniform rhenium distribution and excellent mechanical properties. Detailed Implementation

[0022] The present invention will be specifically described below through embodiments, but the present invention is not limited to these embodiments.

[0023] Example 1

[0024] (1) Material preparation:

[0025] Weigh out 30.000g of molybdenum powder (content: 99.992%, particle size D). 50 =26.452μm), for backup.

[0026] Weigh out 39.200g of ammonium perrhenate (content: 99.995%) and 150g of deionized water (75℃) into a 500ml beaker. Stir with a glass rod to dissolve. Once dissolved, set aside.

[0027] (2) Mixing ball milling:

[0028] Molybdenum powder and ammonium perrhenate aqueous solution were added to a planetary high-efficiency ball mill. Approximately 50g of 3mm diameter tungsten carbide grinding beads and approximately 450g of 8mm diameter tungsten carbide grinding beads were added. A water ring vacuum pump was connected to the ball mill exhaust port, and the vacuum pump was turned on to control the internal pressure of the ball mill to -0.07MPaG. The ball mill was started, and the speed was set to 350 rpm. 75℃ hot water was introduced into the ball mill jacket to maintain the internal temperature at 75℃, and ball milling was continued for 6 hours. Approximately 140g of water was distilled off at this point. The material in the ball mill was sieved to separate the grinding beads, obtaining a highly homogeneous mixed powder. The particle size D of the highly homogeneous mixed powder was measured. 50 =6.542μm. The ammonium perrhenate content of the highly homogeneous mixed powder was found to be 54.651%.

[0029] (3) Hydrogen reduction:

[0030] The highly homogeneous mixed powder was transferred into a vacuum tube furnace. High-purity nitrogen gas was introduced into the furnace at a flow rate of 0.2 L / min for 10 minutes. After purging, hydrogen gas was introduced into the furnace at a flow rate of 0.5 L / min, and the furnace temperature was set to 750°C for hydrogen reduction for 5.0 hours. After hydrogen reduction, the flow rate was set to 0.05 L / min, and the furnace was allowed to cool naturally. Approximately 57 g of molybdenum-rhenium alloy powder was obtained after natural cooling to room temperature. The molybdenum-rhenium alloy powder was evenly spread in a 4 cm x 4 cm groove with a depth of 3 mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 # The ICP-OES analysis showed that the contents were 47.476%, 47.641%, 47.537%, 47.627%, and 47.498% respectively, with an average content of 47.556%. The standard deviation was 0.075%, and the relative standard deviation was 0.157%.

[0031] (4) Cold isostatic pressing:

[0032] Molybdenum-rhenium alloy powder was loaded into a rubber sleeve and statically pressed in a static press. The static pressure was controlled at 250 MPa, and the holding time was 150 seconds. After static pressing, a green molybdenum-rhenium alloy billet was obtained.

[0033] (4) Roasting:

[0034] The molybdenum-rhenium alloy green billet was sintered in a vacuum tube furnace at a controlled temperature of 2000℃ under a hydrogen atmosphere to obtain the molybdenum-rhenium alloy. The rhenium content in the molybdenum-rhenium alloy was found to be 47.527%, with an absolute deviation of -0.029% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of -0.061% from the average content of the molybdenum-rhenium alloy powder.

[0035] Example 2

[0036] Example 2 is based on Example 1, but with a reduced content of ammonium perrhenate aqueous solution. Specifically, 39.200g of ammonium perrhenate (content: 99.995%) and 222g of deionized water (75℃) are weighed into a 500ml beaker and dissolved by stirring with a glass rod. Once dissolved, it is ready for use.

[0037] After ball milling for 10 hours, a highly homogeneous mixed powder was obtained. The particle size D of the highly homogeneous mixed powder was then measured. 50 =5.724μm.

[0038] After reduction with hydrogen, approximately 57g of molybdenum-rhenium alloy powder was obtained. The powder was evenly spread in a 4cm x 4cm groove with a depth of 3mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 # The ICP-OES analysis showed that the contents were 47.484%, 47.562%, 47.491%, 47.612%, and 47.517% respectively, with an average content of 47.533%. The standard deviation was 0.054%, and the relative standard deviation was 0.113%.

[0039] After sintering, a molybdenum-rhenium alloy was obtained. The rhenium content in the molybdenum-rhenium alloy was found to be 47.509%, with an absolute deviation of -0.024% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of -0.051% from the average content of the molybdenum-rhenium alloy powder.

[0040] Example 3

[0041] Example 3 increases the content of ammonium perrhenate solution based on Example 1. Specifically, weigh 39.200g of ammonium perrhenate (content: 99.995%) and 118g of deionized water (75℃) into a 500ml beaker, stir with a glass rod to dissolve, and set aside.

[0042] After ball milling for 4 hours, a highly homogeneous mixed powder was obtained. The particle size D of the highly homogeneous mixed powder was then measured. 50 =6.426μm.

[0043] After reduction with hydrogen, approximately 57g of molybdenum-rhenium alloy powder was obtained. The powder was evenly spread in a 4cm x 4cm groove with a depth of 3mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 #The ICP-OES analysis showed that the contents were 47.584%, 47.415%, 47.354%, 47.662%, and 47.612% respectively, with an average content of 47.525%. The standard deviation was 0.133%, and the relative standard deviation was 0.281%.

[0044] After sintering, a molybdenum-rhenium alloy was obtained. The rhenium content in the molybdenum-rhenium alloy was found to be 47.562%, with an absolute deviation of 0.037% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of 0.077% from the average content of the molybdenum-rhenium alloy powder.

[0045] Example 4

[0046] Example 4 reduces the ball milling temperature based on Example 1. Specifically, the ball milling temperature is controlled at 60°C.

[0047] After ball milling for 9 hours, a highly homogeneous mixed powder was obtained. The particle size D of the highly homogeneous mixed powder was then measured. 50 =6.517μm.

[0048] After reduction with hydrogen, approximately 57g of molybdenum-rhenium alloy powder was obtained. The powder was evenly spread in a 4cm x 4cm groove with a depth of 3mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 # The ICP-OES analysis showed that the concentrations were 47.464%, 47.476%, 47.609%, 47.601%, and 47.566% respectively, with an average concentration of 47.543%. The standard deviation was 0.069%, and the relative standard deviation was 0.145%.

[0049] After sintering, a molybdenum-rhenium alloy was obtained. The rhenium content in the molybdenum-rhenium alloy was found to be 47.564%, with an absolute deviation of 0.021% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of 0.044% from the average content of the molybdenum-rhenium alloy powder.

[0050] Example 5

[0051] Example 5 increases the ball milling temperature based on Example 1. Specifically, the ball milling temperature is controlled at 80°C.

[0052] After ball milling for 4.5 hours, a highly homogeneous mixed powder was obtained. The particle size D of the highly homogeneous mixed powder was then measured. 50 =6.493μm.

[0053] After reduction with hydrogen, approximately 57g of molybdenum-rhenium alloy powder was obtained. The powder was evenly spread in a 4cm x 4cm groove with a depth of 3mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 # The ICP-OES analysis showed that the contents were 47.723%, 47.472%, 47.617%, 47.391%, and 47.513% respectively, with an average content of 47.543%. The standard deviation was 0.129%, and the relative standard deviation was 0.272%.

[0054] After sintering, a molybdenum-rhenium alloy was obtained. The rhenium content in the molybdenum-rhenium alloy was found to be 47.511%, with an absolute deviation of -0.032% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of -0.068% from the average content of the molybdenum-rhenium alloy powder.

[0055] Example 6

[0056] Example 6 reduces the ball mill vacuum degree based on Example 1. Specifically, the ball mill vacuum degree is controlled to be -0.02 MPaG.

[0057] After ball milling for 8 hours, a highly homogeneous mixed powder was obtained. The particle size D of the highly homogeneous mixed powder was then measured. 50 =6.375μm.

[0058] After reduction with hydrogen, approximately 57g of molybdenum-rhenium alloy powder was obtained. The powder was evenly spread in a 4cm x 4cm groove with a depth of 3mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 # The ICP-OES analysis showed that the contents were 47.492%, 47.560%, 47.501%, 47.611%, and 47.563% respectively, with an average content of 47.545%. The standard deviation was 0.049%, and the relative standard deviation was 0.103%.

[0059] After sintering, a molybdenum-rhenium alloy was obtained. The rhenium content in the molybdenum-rhenium alloy was found to be 47.568%, with an absolute deviation of 0.023% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of 0.048% from the average content of the molybdenum-rhenium alloy powder.

[0060] Example 7

[0061] Example 7 improves the ball mill vacuum degree based on Example 1. Specifically, the ball mill vacuum degree is controlled to be -0.085 MPaG.

[0062] After ball milling for 3.5 hours, a highly homogeneous mixed powder was obtained. The particle size D of the highly homogeneous mixed powder was then measured. 50 =6.664μm.

[0063] After reduction with hydrogen, approximately 57g of molybdenum-rhenium alloy powder was obtained. The powder was evenly spread in a 4cm x 4cm groove with a depth of 3mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 # The ICP-OES analysis showed that the contents were 47.624%, 47.643%, 47.471%, 47.348%, and 47.432% respectively, with an average content of 47.504%. The standard deviation was 0.127%, and the relative standard deviation was 0.267%.

[0064] After sintering, a molybdenum-rhenium alloy was obtained. The rhenium content in the molybdenum-rhenium alloy was found to be 47.543%, with an absolute deviation of 0.039% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of 0.083% from the average content of the molybdenum-rhenium alloy powder.

[0065] Example 8

[0066] Example 8 extends the ball milling time based on Example 1 to reduce the particle size of the highly uniform mixed powder.

[0067] After ball milling for 11 hours, a highly homogeneous mixed powder was obtained. The particle size D of the highly homogeneous mixed powder was then measured. 50 =3.752μm.

[0068] After reduction with hydrogen, approximately 57g of molybdenum-rhenium alloy powder was obtained. The powder was evenly spread in a 4cm x 4cm groove with a depth of 3mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 # The ICP-OES analysis showed that the contents were 47.612%, 47.624%, 47.537%, 47.630%, and 47.517% respectively, with an average content of 47.584%. The standard deviation was 0.053%, and the relative standard deviation was 0.111%.

[0069] After sintering, a molybdenum-rhenium alloy was obtained. The rhenium content in the molybdenum-rhenium alloy was found to be 47.582%, with an absolute deviation of -0.002% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of -0.004% from the average content of the molybdenum-rhenium alloy powder.

[0070] Example 9

[0071] Example 9 shortens the ball milling time and increases the particle size of the highly uniform mixed powder based on Example 1.

[0072] After ball milling for 3.25 hours, a highly homogeneous mixed powder was obtained. The particle size D of the highly homogeneous mixed powder was then measured. 50 =9.976μm.

[0073] After reduction with hydrogen, approximately 57g of molybdenum-rhenium alloy powder was obtained. The powder was evenly spread in a 4cm x 4cm groove with a depth of 3mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 # The ICP-OES analysis showed that the contents were 47.772%, 47.428%, 47.435%, 47.654%, and 47.534% respectively, with an average content of 47.565%. The standard deviation was 0.148%, and the relative standard deviation was 0.311%.

[0074] After sintering, a molybdenum-rhenium alloy was obtained. The rhenium content in the molybdenum-rhenium alloy was found to be 47.529%, with an absolute deviation of -0.036% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of -0.075% from the average content of the molybdenum-rhenium alloy powder.

[0075] Comparative Example 1

[0076] Comparative Example 1 shortens the ball milling time and increases the particle size of the highly uniform mixed powder based on Example 1.

[0077] After ball milling for 2 hours, a highly homogeneous mixed powder was obtained. The particle size D of the highly homogeneous mixed powder was then measured. 50 =16.472μm.

[0078] After reduction with hydrogen, approximately 57g of molybdenum-rhenium alloy powder was obtained. The powder was evenly spread in a 4cm x 4cm groove with a depth of 3mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 #The ICP-OES analysis showed that the contents were 47.813%, 47.735%, 47.424%, 47.358%, and 47.283% respectively, with an average content of 47.523%. The standard deviation was 0.236%, and the relative standard deviation was 0.498%.

[0079] After sintering, a molybdenum-rhenium alloy was obtained. The rhenium content in the molybdenum-rhenium alloy was found to be 47.579%, with an absolute deviation of 0.056% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of 0.119% from the average content of the molybdenum-rhenium alloy powder.

[0080] Comparative Example 2

[0081] Comparative Example 2 was based on Example 1, where molybdenum powder and ammonium perrhenate were directly mixed and ball-milled in a ball mill.

[0082] After ball milling for 6 hours, a highly homogeneous mixed powder was obtained. The particle size D of the highly homogeneous mixed powder was then measured. 50 =6.713μm.

[0083] After reduction with hydrogen, approximately 57g of molybdenum-rhenium alloy powder was obtained. The powder was evenly spread in a 4cm x 4cm groove with a depth of 3mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 # The ICP-OES analysis showed that the content of the compounds was 47.875%, 47.246%, 47.791%, 47.428%, and 47.543% respectively, with an average content of 47.577%. The standard deviation was 0.259%, and the relative standard deviation was 0.544%.

[0084] After sintering, a molybdenum-rhenium alloy was obtained. The rhenium content in the molybdenum-rhenium alloy was found to be 47.516%, with an absolute deviation of -0.061% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of -0.127% from the average content of the molybdenum-rhenium alloy powder.

[0085] Comparative Example 3

[0086] Comparative Example 3, based on Example 1, directly mixed and ball-milled molybdenum powder and rhenium powder in a ball mill. Specifically: Weigh out 30.000g of molybdenum powder (content: 99.992%, particle size D). 50 =26.452μm); Weigh out 27.302g of rhenium powder (content: 99.993%, particle size D). 50 =31.246μm), molybdenum powder and rhenium powder were fed into a ball mill for mixing and ball milling.

[0087] After ball milling for 6 hours, a mixed powder was obtained. The particle size D of the mixed powder was measured. 50 =6.243μm.

[0088] After reduction with hydrogen, approximately 57g of molybdenum-rhenium alloy powder was obtained. The powder was evenly spread in a 4cm x 4cm groove with a depth of 3mm. Samples were taken from the upper left, upper right, center, lower left, and lower right, and numbered sequentially as 1. # 2 # 3 # 4 # 5 # The ICP-OES analysis showed that the contents were 48.141%, 47.367%, 47.841%, 47.641%, and 47.158% respectively, with an average content of 47.630%. The standard deviation was 0.387%, and the relative standard deviation was 0.812%.

[0089] After sintering, a molybdenum-rhenium alloy was obtained. The rhenium content in the molybdenum-rhenium alloy was found to be 47.527%, with an absolute deviation of -0.103% from the average content of the molybdenum-rhenium alloy powder and a relative deviation of -0.215% from the average content of the molybdenum-rhenium alloy powder.

[0090] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. 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 process for preparing molybdenum-rhenium alloy, wherein an aqueous solution of ammonium perrhenate and molybdenum powder are mixed and ball-milled in a ball mill to form a highly homogeneous mixed powder; and the highly homogeneous mixed powder is reduced by hydrogen, isostatic pressed, and sintered to form a molybdenum-rhenium alloy, characterized in that, The preparation process is carried out according to the following procedures: An ammonium perrhenate aqueous solution and molybdenum powder are added into a ball mill for mixing and ball milling; During the mixing and ball milling, water is removed from the ball mill at a preset rate, and the solid content of the system gradually increases until all the water in the system is removed, forming a high-uniformity mixed powder; The high-uniformity mixed powder is reduced by hydrogen in a tube furnace, forming a molybdenum-rhenium alloy powder; The molybdenum-rhenium alloy powder is isostatically pressed in a static press, forming a molybdenum-rhenium alloy green body; The molybdenum-rhenium alloy green body is sintered, forming a molybdenum-rhenium alloy.

2. The preparation process of claim 1, wherein, The ammonium perrhenate aqueous solution has a content of 15-25wt%.

3. The preparation process of claim 1, wherein, The particle size D of the high-uniformity mixed powder is 50 ≦ 10 μm.

4. The preparation process of claim 1, wherein, The diameter of the ball milling beads filled in the ball mill is 2-10mm.

5. The preparation process of claim 1, wherein, The temperature of the mixing and ball milling process is 60-80℃, and the pressure is -0.02--0.085MPaG.

6. The preparation process of claim 1, wherein, The time of the mixing and ball milling process is >3.0 hours.

7. The preparation process of claim 1, wherein, The temperature of the hydrogen reduction process is 600-800℃.

8. The preparation process of claim 1, wherein, The pressure of the isostatic pressing process is 200-300MPa, and the time is 30-180 seconds.

9. The preparation process of claim 1, wherein, The temperature of the sintering process is 1800-2200℃.