Cobalt-based alloy powder and preparation method thereof

Abstract

The invention provides cobalt-based alloy powder and a preparation method thereof. The cobalt-based alloy powder comprises, by weight, 20%-30% of chromium, 3%-8% of molybdenum, 3%-8% of tungsten, 0-2% of aluminum, 0-2% of titanium, 0-0.5% of boron, 0.1%-0.4% of carbon, 0.05%-0.2% of nitrogen and the balance cobalt. According to the cobalt-based alloy powder and the preparation method thereof, the prepared cobalt-based alloy powder is high in hardness and wear resistance and good in plasticity and toughness, a more compact and stable oxidation film can be formed on the surface of cobalt-based alloy, and the oxidation film can prevent oxygen from further contact with an alloy matrix, reduce the oxidation rate and improve the oxidation resistance of the alloy; according to the preparation method, the high-performance cobalt-based alloy powder meeting the requirements of different application scenes can be stably prepared, and the cobalt-based alloy powder shows excellent characteristics in the aspects of mechanical performance, high-temperature performance, corrosion resistance and the like and has wide market application prospects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alloy materials, and in particular to a cobalt-based alloy powder and a preparation method thereof. BACKGROUND

[0002] With the rapid development of modern industries such as aerospace, automobile manufacturing, medical devices, etc., the demand for high-performance alloy materials is increasingly urgent. Cobalt-based alloys have a wide application prospect in the manufacture of many key components due to their excellent high-temperature strength, corrosion resistance, wear resistance, and good biocompatibility.

[0003] Traditional cobalt-based alloy materials have insufficient alloy strength, and some existing cobalt-based alloy powder preparation methods cannot meet the requirements of high-precision and high-performance product forming in subsequent advanced manufacturing processes such as 3D printing forming, etc., resulting in high scrap rate and high production cost.

[0004] Therefore, it is necessary to provide a cobalt-based alloy powder and a preparation method thereof to solve the above technical problems. SUMMARY

[0005] The present application provides a cobalt-based alloy powder and a preparation method thereof, which solves the problems in the background art.

[0006] To solve the above technical problems, the cobalt-based alloy powder provided by the present application comprises the following weight groups:

[0007] Chromium: 20-30%, Molybdenum: 3-8%, Tungsten: 3-8%, Aluminum: 0-2%, Titanium: 0-2%, Boron: 0-0.5%, Carbon: 0.1-0.4%, Nitrogen: 0.05-0.2%, and the balance is cobalt.

[0008] Preferably, the particle size distribution range of the cobalt-based alloy powder is 15-53 μm, and the loose bulk density is between 4.0-5.0 g / cm 3

[0009] Preferably, the cobalt-based alloy powder comprises the following weight groups: Chromium: 22-28%, Molybdenum: 4-6%, Tungsten: 4-6%, Aluminum: 0.5-1.5%, Titanium: 0.5-1.5%, Boron: 0.1-0.3%, Carbon: 0.2-0.3%, Nitrogen: 0.1-0.15%, and the balance is cobalt.

[0010] Preferably, it further comprises rare earth elements: 1-3%, and the rare earth elements include light rare earth elements or heavy rare earth elements, wherein the light rare earth elements include one or a combination of lanthanum, cerium, praseodymium, neodymium, and promethium.

[0011] ​Preferably, the heavy rare earth elements include one or a combination of yttrium, erbium, and dysprosium.

[0012] A method for preparing a cobalt-based alloy powder, for preparing the cobalt-based alloy powder, comprising the following steps:

[0013] S1, raw material pretreatment: selecting high-purity metal raw materials according to weight ratio, the purity is not less than 99.5%, using chemical cleaning method, removing the oxide layer and impurities on the surface of the metal raw materials with appropriate acid solution, after cleaning, repeatedly washing with deionized water until the washing liquid is neutral, then drying by vacuum drying or low-temperature nitrogen blowing, ensuring that the raw materials are dry and clean;

[0014] S2, vacuum melting: after the pretreated metal raw materials are accurately weighed according to the designed proportion, they are put into a vacuum induction melting furnace; first, 40-60% of the total amount of cobalt is added as a base material, heated to 1400-1500°C, after the base material is completely melted, chromium, molybdenum, and tungsten are added in turn, and stirred and melted at 1500-1600°C for 30-60 minutes to ensure that each element is fully dissolved and fused; then, trace elements such as aluminum, titanium, boron, and carbon are added, and the melting is continued for 20-40 minutes; finally, the remaining cobalt is added, heated to 1650-1750°C, and kept for 10-20 minutes to make the molten liquid reach a highly uniform state;

[0015] S3, high-pressure gas atomization: after melting is completed, high-pressure inert gas is used for atomization, the molten liquid is injected into the atomization chamber through the bottom nozzle or the side nozzle, and high-pressure inert gas is sprayed from the top or the side at a pressure of 3-6 MPa, the pressure inside the atomization chamber is maintained at 0.3-0.7 MPa, the molten liquid is rapidly broken into small droplets under the impact of high-speed gas flow, the droplets are rapidly cooled and solidified by contacting with the circulating cooling gas in the atomization chamber during falling, and the initial powder is formed;

[0016] S4, screening and post-treatment: the initial powder is classified and selected by using a vibrating screening device, and the powder with a particle size in the range of 15-53 μm is selected, the screened powder is put into a vacuum heat treatment furnace for low-temperature annealing treatment to eliminate the internal stress of the powder, improve the crystal structure of the powder, and improve its comprehensive performance.

[0017] Preferably, the acid solution in S1 is a mixed solution of hydrochloric acid and sulfuric acid.

[0018] Preferably, the vacuum degree during the whole melting process in S2 is maintained at 5×10 -6 P.

[0019] Preferably, nitrogen or argon is used as the atomizing gas in S3.

[0020] Preferably, the annealing temperature in S4 is 300-400°C, and the time is 2-4 hours.

[0021] Compared with the related art, the cobalt-based alloy powder and the preparation method thereof provided by the application have the following beneficial effects:

[0022] The cobalt-based alloy powder and the preparation method thereof provided by the application have the following beneficial effects: BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A preferred embodiment structure diagram of the cobalt-based alloy powder and the preparation method thereof provided by the application is shown in the figure.

[0024] Figure 2 A specific step flow chart of vacuum melting of the cobalt-based alloy powder and the preparation method thereof provided by the application is shown in the figure. DETAILED DESCRIPTION

[0025] The application will be further described below in combination with the drawings and embodiments.

[0026] Please refer to Figure 1 , 2 , wherein, Figure 1 A preferred embodiment structure diagram of the cobalt-based alloy powder and the preparation method thereof provided by the application is shown in the figure. Figure 2 A specific step flow chart of vacuum melting of the cobalt-based alloy powder and the preparation method thereof provided by the application is shown in the figure.

[0027] Embodiment 1, the cobalt-based alloy powder comprises the following weight components:

[0028] Chromium: 20%, Molybdenum: 3%, Tungsten: 3%, Aluminum: 1%, Titanium: 1%, Boron: 0.2%, Carbon: 0.1%, Nitrogen: 0.05%, and the balance is cobalt, the particle size distribution range of the cobalt-based alloy powder is 15-53 μm, and the loose bulk density is between 4.0-5.0 g / cm 3 .

[0029] It also comprises rare earth elements: 1%, the rare earth elements comprise light rare earth elements or heavy rare earth elements, wherein the light rare earth elements comprise one or more combinations of lanthanum, cerium, praseodymium, neodymium, promethium, and the heavy rare earth elements comprise one or more combinations of yttrium, erbium, dysprosium.

[0030] A method for preparing a cobalt-based alloy powder, for preparing the cobalt-based alloy powder, comprising the following steps:

[0031] S1, raw material pretreatment: selecting high-purity raw metal materials of each component according to weight ratio, the purity is not less than 99.5%, using chemical cleaning method, removing the oxide layer and impurities on the surface of the metal raw material with appropriate acid solution, the acid solution is a mixed solution of hydrochloric acid and sulfuric acid, after cleaning, repeatedly washing with deionized water until the washing liquid is neutral, then drying by vacuum drying or low-temperature nitrogen blowing, to ensure that the raw material is dry and clean;

[0032] S2, vacuum melting: after the pretreated metal raw materials are accurately weighed according to the designed proportion, they are put into a vacuum induction melting furnace; first, 40-60% of the total amount of cobalt is added as a base material, heated to 1400-1500℃, after the base material is completely melted, chromium, molybdenum and tungsten are added in turn, and stirred and melted at 1500-1600℃ for 30 minutes to ensure that each element is fully dissolved and fused; then, trace elements such as aluminum, titanium, boron and carbon are added, and the melting is continued for 20 minutes; finally, the remaining cobalt is added, heated to 1650-1750℃, and kept for 10 minutes to make the molten liquid reach a highly uniform state, and the vacuum degree is maintained at 5×10 -6 P;

[0033] S3, high-pressure gas atomization: after melting is completed, high-pressure inert gas is used for atomization, the molten liquid is injected into the atomization chamber through the bottom nozzle or the side nozzle, and high-pressure inert gas is sprayed from the top or the side at a pressure of 3-6MPa, preferably nitrogen or argon, the pressure in the atomization chamber is maintained at 0.3-0.7MPa, the molten liquid is rapidly broken into small droplets under the impact of high-speed gas flow, the droplets are rapidly cooled and solidified by contacting with the circulating cooling gas in the atomization chamber during falling, and the initial powder is formed;

[0034] S4, screening and post-treatment: the initial powder is classified and selected by using a vibrating screening device, and the powder with a particle size in the range of 15-53μm is selected, the screened powder is put into a vacuum heat treatment furnace for low-temperature annealing treatment, the annealing temperature is 300-400℃, and the time is 2 hours, to eliminate the internal stress of the powder, improve the crystal structure of the powder, and improve the comprehensive performance.

[0035] Example 2, the cobalt-based alloy powder comprises the following weight components:

[0036] chromium: 25%, molybdenum: 5%, tungsten: 5%, aluminum: 1%, titanium: 1%, boron: 0.3%, carbon: 0.2%, nitrogen: 0.1%, and the balance is cobalt, the particle size distribution range of the cobalt-based alloy powder is 15-53μm, and the loose bulk density is between 4.0-5.0g / cm 3 .

[0037] Also included are rare earth elements: 2%, the rare earth elements including light rare earth elements or heavy rare earth elements, wherein the light rare earth elements include one or more combinations of lanthanum, cerium, praseodymium, neodymium, promethium, and the heavy rare earth elements include one or more combinations of yttrium, erbium, dysprosium.

[0038] A method for preparing a cobalt-based alloy powder, for preparing the cobalt-based alloy powder, comprising the following steps:

[0039] S1, raw material pretreatment: select high-purity metal raw materials of each component by weight ratio, the purity is not less than 99.5%, adopt chemical cleaning method, remove the oxide layer and impurities on the surface of metal raw materials by using appropriate acid solution, the acid solution is a mixed solution of hydrochloric acid and sulfuric acid, after cleaning, repeatedly rinse with deionized water until the rinse liquid is neutral, then dry by vacuum drying or low-temperature nitrogen blowing, ensure that the raw materials are dry and clean;

[0040] S2, vacuum melting: after the pretreated metal raw materials are accurately weighed according to the designed proportion, they are put into a vacuum induction melting furnace; first, add 40-60% of the total amount of cobalt as a base material, heat to 1400-1500℃, after the base material is completely melted, add chromium, molybdenum and tungsten in turn, stir and melt at 1500-1600℃ for 40 minutes to ensure that each element is fully dissolved and fused; then, add trace elements such as aluminum, titanium, boron and carbon, continue to melt for 25 minutes; finally, add the remaining cobalt, heat to 1650-1750℃, and keep for 13 minutes to make the molten liquid reach a highly uniform state, and the vacuum degree is maintained at 5*10 -6 P;

[0041] S3, high-pressure gas atomization: after melting is completed, high-pressure inert gas is used for atomization, the molten liquid is injected into the atomization chamber through the bottom nozzle or the side nozzle, and high-pressure inert gas is sprayed from the top or the side at a pressure of 3-6MPa, preferably nitrogen or argon, the pressure in the atomization chamber is maintained at 0.3-0.7MPa, the molten liquid is rapidly broken into small droplets under the impact of high-speed gas flow, the droplets are rapidly cooled and solidified by contacting with the circulating cooling gas in the atomization chamber during falling, and the initial powder is formed;

[0042] S4, screening and post-treatment: use a vibrating screening device to grade and select the initial powder, select the powder with a particle size in the range of 15-53μm, and put the screened powder into a vacuum heat treatment furnace for low-temperature annealing treatment, the annealing temperature is 300-400℃, and the time is 2.5 hours, to eliminate the internal stress of the powder, improve the crystal structure of the powder, and improve its comprehensive performance.

[0043] Example 3, the cobalt-based alloy powder includes the following weight components:

[0044] Chromium: 28%, Molybdenum: 6%, Tungsten: 7%, Aluminum: 1.5%, Titanium: 2%, Boron: 0.4%, Carbon: 0.3%, Nitrogen: 1.5%, the balance being Cobalt, the particle size distribution of the Cobalt-based alloy powder ranges from 15 to 53 microns, the loose bulk density ranges from 4.0 to 5.0 g / cm 3 .

[0045] Also includes rare earth elements: 2.5%, the rare earth elements include light rare earth elements or heavy rare earth elements, wherein the light rare earth elements include one or more combinations of lanthanum, cerium, praseodymium, neodymium, promethium, and the heavy rare earth elements include one or more combinations of yttrium, erbium, dysprosium.

[0046] A preparation method of a Cobalt-based alloy powder, for preparing the Cobalt-based alloy powder, comprising the following steps:

[0047] S1, raw material pretreatment: selecting high-purity metal raw materials of each component according to weight ratio, the purity is not less than 99.5%, using chemical cleaning method, removing the oxide layer and impurities on the surface of the metal raw materials with appropriate acid solution, the acid solution is a mixed solution of hydrochloric acid and sulfuric acid, after cleaning, repeatedly washing with deionized water until the washing liquid is neutral, then drying by vacuum drying or low-temperature nitrogen blowing, ensuring that the raw materials are dry and clean;

[0048] S2, vacuum melting: after the pretreated metal raw materials are accurately weighed according to the designed proportion, they are put into a vacuum induction melting furnace; first, 40-60% of the total amount of cobalt is added as a base material, heated to 1400-1500℃, after the base material is completely melted, chromium, molybdenum and tungsten are added in turn, and stirred and melted at 1500-1600℃ for 50 minutes to ensure that each element is fully dissolved and fused; then, aluminum, titanium, boron, carbon and other trace elements are added, and the melting is continued for 30 minutes; finally, the remaining cobalt is added, heated to 1650-1750℃, and kept for 20 minutes to make the molten liquid reach a highly uniform state, and the vacuum degree is maintained at 5*10 -6 P;

[0049] S3, high-pressure gas atomization: after melting is completed, high-pressure inert gas is used for atomization, the molten liquid is injected into the atomization chamber through the bottom nozzle or the side nozzle, and high-pressure inert gas is sprayed from the top or the side at a pressure of 3-6 MPa, preferably nitrogen or argon, the pressure in the atomization chamber is maintained at 0.3-0.7 MPa, the molten liquid is rapidly broken into small droplets under the impact of high-speed gas flow, the droplets are rapidly cooled and solidified by contacting with the circulating cooling gas in the atomization chamber during falling, and the initial powder is formed;

[0050] S4, screening and post-processing: using a vibrating screening device to grade the initial powder, selecting the powder with a particle size in the range of 15-53 μm, and placing the screened powder into a vacuum heat treatment furnace for low-temperature annealing treatment, with an annealing temperature of 300-400 °C and a time of 3 hours, to eliminate the internal stress of the powder, improve the crystal structure of the powder, and improve the comprehensive performance thereof.

[0051] Example 4, the cobalt-based alloy powder includes the following weight components:

[0052] chromium: 25%, molybdenum: 8%, tungsten: 7%, aluminum: 1%, titanium: 2%, boron: 0.5%, carbon: 0.4%, nitrogen: 0.2%, and the balance being cobalt, the particle size distribution range of the cobalt-based alloy powder being 15-53 μm, and the loose bulk density being 4.0-5.0 g / cm 3 .

[0053] Further including rare earth elements: 3%, the rare earth elements including light rare earth elements or heavy rare earth elements, wherein the light rare earth elements include one or more combinations of lanthanum, cerium, praseodymium, neodymium, and promethium, and the heavy rare earth elements include one or more combinations of yttrium, erbium, and dysprosium.

[0054] A preparation method of a cobalt-based alloy powder, for preparing the cobalt-based alloy powder, including the following steps:

[0055] S1, raw material pretreatment: selecting high-purity metal raw materials of each component according to the weight ratio, with a purity of not less than 99.5%, using chemical cleaning method to remove the oxide layer and impurities on the surface of the metal raw materials by using appropriate acid solution, the acid solution being a mixed solution of hydrochloric acid and sulfuric acid, after cleaning, repeatedly washing with deionized water until the washing liquid is neutral, and then drying by vacuum drying or low-temperature nitrogen blowing, to ensure that the raw materials are dry and clean;

[0056] S2, vacuum melting: after the pretreated metal raw materials are accurately weighed according to the designed proportion, they are placed into a vacuum induction melting furnace; first, 40-60% of the total amount of cobalt is added as a base material, heated to 1400-1500 °C, after the base material is completely melted, chromium, molybdenum, and tungsten are added in turn, and stirred and melted at 1500-1600 °C for 60 minutes to ensure that each element is fully dissolved and fused; then, aluminum, titanium, boron, carbon, and other trace elements are added, and the melting is continued for 40 minutes; finally, the remaining cobalt is added, heated to 1650-1750 °C, and kept for 20 minutes to make the molten liquid reach a highly uniform state, and the vacuum degree is maintained at 5 x 10 -6 P during the whole melting process.

[0057] S3, high-pressure gas atomization: after smelting is completed, high-pressure inert gas is used for atomization, the molten liquid is injected into an atomization chamber through a bottom drain or a side nozzle, and high-pressure inert gas, preferably nitrogen or argon, is sprayed from the top or the side in multiple directions at a pressure of 3-6 MPa, the internal pressure of the atomization chamber is maintained at 0.3-0.7 MPa, the molten liquid is rapidly broken into small droplets under the impact of high-speed gas flow, the droplets are rapidly cooled and solidified by contacting the circulating cooling gas in the atomization chamber during falling, and initial powder is formed;

[0058] S4, screening and post-processing: the initial powder is classified and screened by using a vibrating screening device, the powder with a particle size in the range of 15-53 mu m is selected, and the screened powder is placed in a vacuum heat treatment furnace for low-temperature annealing treatment, the annealing temperature is 300-400 DEG C, and the time is 4 hours, so as to eliminate the stress in the powder, improve the crystal structure of the powder, and improve the comprehensive performance.

[0059] Compared with the related art, the cobalt-based alloy powder and the preparation method thereof have the following beneficial effects:

[0060] The cobalt-based alloy powder prepared by the method has high hardness and wear resistance, good plasticity and toughness, and a more dense and stable oxide film can be formed on the surface of the cobalt-based alloy, which can prevent further contact between oxygen and the alloy matrix, reduce the oxidation rate, and improve the oxidation resistance of the alloy. The preparation method can stably prepare high-performance cobalt-based alloy powder meeting the requirements of different application scenarios, and the prepared alloy powder has excellent characteristics in terms of mechanical properties, high-temperature performance and corrosion resistance, and has a broad market application prospect.

[0061] The above only describes the embodiments of the present application, and does not limit the patent scope of the present application, any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. A cobalt-based alloy powder, characterized in that: The following weight groups are included: Chromium: 20-30%, molybdenum: 3-8%, tungsten: 3-8%, aluminum: 0-2%, titanium: 0-2%, boron: 0-0.5%, carbon: 0.1-0.4%, nitrogen: 0.05-0.2%, and the balance is cobalt.

2. The cobalt-based alloy powder according to claim 1, characterized in that The particle size distribution range of the cobalt-based alloy powder is 15-53 μm, and the apparent density is 4.0-5.0 g / cm 3 between.

3. The cobalt-based alloy powder according to claim 1, characterized in that It comprises the following weight groups: chromium: 22-28%, molybdenum: 4-6%, tungsten: 4-6%, aluminum: 0.5-1.5%, titanium: 0.5-1.5%, boron: 0.1-0.3%, carbon: 0.2-0.3%, nitrogen: 0.1-0.15%, and the balance is cobalt.

4. The cobalt-based alloy powder according to claim 1, characterized in that It also includes rare earth elements: 1-3%, wherein the rare earth elements include light rare earth elements or heavy rare earth elements, wherein the light rare earth elements include: one or more combinations of lanthanum, cerium, praseodymium, neodymium, and promethium.

5. The cobalt-based alloy powder according to claim 4, characterized in that The heavy rare earth elements include: one or a combination of yttrium, erbium, and dysprosium.

6. A method for preparing a cobalt-based alloy powder, for preparing the cobalt-based alloy powder according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Raw material pretreatment: Select high-purity metal raw materials of each component by weight, with a purity of not less than 99.5%. Use chemical cleaning method to remove the oxide layer and impurities on the surface of the metal raw materials with appropriate acid solution. After cleaning, rinse repeatedly with deionized water until the rinse solution is neutral. Then, vacuum dry or blow dry with low-temperature nitrogen to ensure that the raw materials are dry and clean; S2. Vacuum Melting: The pretreated metal raw materials are accurately weighed according to the designed ratio and placed in a vacuum induction melting furnace. First, cobalt, which accounts for 40-60% of the total cobalt content, is added as a base material and the temperature is raised to 1400-1500°C. After the base material is completely melted, chromium, molybdenum, and tungsten are added in sequence and stirred and melted at 1500-1600°C for 30-60 minutes to ensure that all elements are fully dissolved and fused. Subsequently, trace elements such as aluminum, titanium, boron, and carbon are added and the melting continues for 20-40 minutes. Finally, the remaining cobalt is added and the temperature is raised to 1650-1750°C and maintained for 10-20 minutes to allow the melt to reach a highly uniform state. S3. High-pressure gas atomization: After smelting is completed, high-pressure inert gas is used for atomization. The melt is injected into the atomization chamber through the bottom nozzle or side nozzle. At the same time, high-pressure inert gas is sprayed from multiple directions at a pressure of 3-6 MPa from the top or side. The pressure inside the atomization chamber is maintained at 0.3-0.7 MPa. The melt is rapidly broken into tiny droplets under the impact of high-speed airflow. During the falling process, the droplets are rapidly cooled and solidified by contact with the circulating cooling gas in the atomization chamber to form initial powder; S4. Screening and post-processing: Use vibration screening equipment to grade and screen the initial powder, and select powder with a particle size within the range of 15-53μm. The screened powder is placed in a vacuum heat treatment furnace for low-temperature annealing to eliminate internal stress in the powder, improve the crystal structure of the powder, and enhance its overall performance.

7. The cobalt-based alloy powder and the preparation method thereof according to claim 6, characterized in that: The acid solution in S1 is a mixed solution of hydrochloric acid and sulfuric acid.

8. The cobalt-based alloy powder and the preparation method thereof according to claim 1, characterized in that: The vacuum degree in S2 during the whole smelting process was maintained at 5×10 -6 P.

9. The cobalt-based alloy powder and the preparation method thereof according to claim 1, characterized in that: In the S3, nitrogen or argon is used as the atomizing gas.

10. The cobalt-based alloy powder and the preparation method thereof according to claim 1, characterized in that: The annealing temperature in S4 is 300-400° C. and the annealing time is 2-4 hours.

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