Preparation method for in-situ synthesis of ODS multi-principal element alloy powder

Abstract

The invention relates to a preparation method for in-situ synthesis of ODS multi-principal element alloy powder. According to the method, nano-oxides are introduced through in-situ oxidation in the thermal spraying process and selective oxidation of Al or Cr in alloy powder, and uniform distribution of the nano-oxides in the alloy powder is achieved through high-speed impact and splashing of the powder on the liquid level in the spraying process; and after spraying is completed, the alloy powder is rapidly cooled in the cooling liquid, and the spherical shape is still kept. The ODS alloy powder prepared through the method has the advantages that oxide particles are distributed in the powder in a dispersed mode, the powder preparing efficiency is high, and meanwhile structure control over the ODS alloy powder can be achieved by adjusting the composition proportion of the raw material powder and the spraying technology.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy powder feedstock preparation, and particularly to a method for preparing spherical powders with uniformly dispersed nano-oxide particles generated by in-situ reaction inside multi-principal element alloy powders containing Al or Cr through a thermal spraying-flame quenching technique. The powders can be widely used in the manufacture of components for extreme environments such as high temperature resistance, radiation resistance, and corrosion resistance. Background Art

[0002] High-temperature components used in fields such as aerospace, nuclear energy, petrochemical power generation, etc. face complex and severe service environments, and their performance and service life are significantly reduced after long-term service. Oxide dispersion strengthened (ODS) alloys can withstand extremely high radiation and high-temperature environments and maintain good mechanical properties and oxidation resistance. Currently, ODS alloys have been used in the manufacture of components for extreme environments such as nuclear reactor cladding materials and combustion chambers and turbine blades in aeroengines. However, the problems of the preparation quality and efficiency of ODS alloy powder feedstock are major obstacles restricting their large-scale application. The mechanical alloying process based on long-cycle high-energy ball milling is the currently relatively common method for preparing ODS alloy powders. However, the ODS alloy powders prepared by this method exhibit problems such as uneven distribution of oxides, easy agglomeration of powders, poor sphericity, easy introduction of impurities, and production efficiency problems such as complex process flows. In the publicly disclosed technologies such as "A Nano-Oxide Dispersed Strengthened High-Entropy Alloy Bonding Layer and Its Preparation Method and Application (ZL202210349595.6)", "ODS / GH4169 Composite Material and Its Preparation Method and Molding (ZL202311754820.5)", "A Corrosion-Resistant Oxide Dispersion Strengthened Steel and Its Preparation Method (202311380991.6)", etc., there are problems such as oxides being unable to enter the interior of alloy powders and long process times.

[0003] The literature "Research on New Preparation Technology and Microstructure of Oxide Dispersion Strengthened Ferritic Alloys" and "Preparation and Characterization of Al 2 O 3 Dispersion Strengthened Copper-Tin Alloy Powders" reported a new powder preparation method that uses pre-oxidation to introduce oxygen elements into alloy powders instead of the mechanical alloying process. The patent "A Nano-Oxide Dispersed MCrA1Y Anti-Oxidation Coating and Its Preparation Method (202111177182.6)" disclosed a method for preparing ODS alloy powders by means of a pre-oxidation process. The alloy powders are laid flat in a high-temperature furnace and kept at a temperature of 600 - 1000 °C for 5 hours to form NiCoCrA1YTa multi-component alloy powders with uniformly dispersed nano-oxides. However, the upper limit of the heating temperature of the high-temperature furnace (≤1000 °C) and the process time (>5 hours) severely limit the production quality and efficiency of ODS alloy powders. Summary of the Invention

[0004] In view of the problems of poor powder quality and insufficient production efficiency in the current ODS alloy powder preparation technology, the present invention provides a method for in-situ preparation of ODS alloy powder by thermal spraying-flame quenching method. This method breaks new ground in the formation method of nano-oxides. By using in-situ oxidation during thermal spraying and selective oxidation of Al or Cr in the alloy powder to introduce nano-oxides, and through the high-speed impact and splashing of the powder at the liquid surface during spraying, the uniform distribution of nano-oxides inside the alloy powder is achieved. After spraying, the alloy powder is rapidly cooled in the coolant and still maintains a spherical shape. The ODS alloy powder obtained by this method contains 2-5 vol.% of in-situ oxides, with a particle size of 100-500 nm, and at the same time does not affect the sphericity and fluidity of the alloy powder. The ODS alloy powder prepared by the present invention has the advantages of dispersed distribution of oxide particles inside the powder and high powder preparation efficiency. At the same time, through the adjustment of the composition ratio of the raw material powder and the spraying process, the microstructure control of the ODS alloy powder can be realized.

[0005] A preparation method for in-situ synthesis of ODS multi-principal element alloy powder includes the following steps:

[0006] Step 1: Select and match a multi-principal element alloy powder containing Al or Cr. After drying, the original powder is obtained;

[0007] Among them, in the multi-principal element alloy, the elements involved include basic elements and balance elements. The basic element is one or two of Al and Cr, and the percentage of the element in the multi-principal element alloy is: Al 5-30 at.%, Cr 10-30 at.%; the balance elements are one or more of Ni, Fe, and Co, and the sum of the ratios of the balance elements in the multi-principal element alloy is greater than 40 at.%; the particle size range is 50-150 μm;

[0008] Step 2: Use the original powder in Step 1 as the thermal spraying feedstock, and thermally spray it into the coolant for flame quenching;

[0009] Among them, the thermal spraying power is 25-40 kW, and the gun distance is 100-450 mm; the powder feeding gas in thermal spraying is compressed air, or a mixture of compressed air and argon; in the powder feeding gas, the volume ratio of argon is 0-70 vol.%;

[0010] Step 3: Collect the powder sprayed into the coolant in Step 2. After filtration, ultrasonic cleaning, drying, and sieving, spherical ODS alloy powder is obtained.

[0011] The multi-principal element alloy is one or more of AlCoCrFeNi, CoCrFeNi, CoCrNi, NiCoCrAl, NiCrAl, FeCrAl, and NiCr.

[0012] The original powder further includes a modifying element X, and the addition amount of the modifying element is 0 to 2.0 wt.% of the mass of the original powder; X is one or more of Si, Ti, Mo, V, and rare earth elements; the rare earth elements are Y, Ce, or La.

[0013] The thermal spraying is ion spraying or flame spraying; the coolant includes a water-based cooling medium or an oil-based cooling medium; the water-based cooling medium is deionized water or brine, and the oil-based cooling medium is mineral oil or kerosene.

[0014] The ODS multi-principal element alloy powder obtained by the method can be used as a raw material for high-temperature components or antioxidant coatings under the working conditions of room temperature to 1100 °C.

[0015] The substantial features of the present invention are:

[0016] In the existing technology, ODS alloy powder is prepared by long-term mechanical alloying of alloy powder mixed with nano-oxides, which has problems such as uneven distribution of oxides (only existing on the powder surface), easy agglomeration of nano-powders, long ball milling cycle, and poor sphericity.

[0017] In view of the above problems, the present invention particularly provides a method for in-situ preparing ODS alloy spherical powder by thermal spraying-flame quenching technology. The present invention creatively applies thermal spraying technology to the field of powder manufacturing, uses an alloy powder with an Al and Cr content of 5-30 at.% as the initial feedstock, utilizes the ultra-high temperature flame flow (<15000 °C) and its ultra-fast heating rate (millisecond level) of plasma spraying / flame spraying to greatly increase the pre-oxidation temperature and heating rate, and rapidly generate oxides through in-situ selective oxidation reaction; uses a liquid medium as the spraying substrate and collects the powder after in-situ oxidation. The nano-oxides in the ODS alloy powder prepared by this method have better dispersion and controllability, the process is more concise, and the efficiency is also higher.

[0018] In specific operations, the powder matrix is a multi-component alloy containing Al or Cr (content < 30 at.%), and the powder contains nano-aluminum oxide or chromium oxide particles with a dispersed distribution inside. The particle size range of the oxide is 100 - 500 nm, and the volume fraction is 2 - 5 vol.%, which reduces the high-temperature oxidation rate and high-temperature softening rate of the powder by 60% and 90% respectively. The original powder is sprayed onto a liquid medium using thermal spraying technology. Nano-particles are synthesized by the selective oxidation of Al and Cr elements in an ultra-high temperature flame flow, and the dispersed distribution of nano-oxides inside the powder is achieved by the high-speed impact of the powder on the liquid surface. The dispersion of nano-oxides in the ODS alloy powder prepared is better, and the powder maintains a high sphericity and fluidity. The key step is to use a multi-component alloy powder containing Al or Cr as the original feedstock and apply thermal spraying technology to spray the original feedstock into a liquid medium. To achieve the selective oxidation and efficient collection of the powder, the following key parameters need to be met: the original spraying feedstock is a multi-principal element alloy powder with 5 - 30 at.% of Al and Cr, and the spraying matrix is a liquid medium (such as distilled water), which is different from the single principal element or coated mixed powder in the current thermal spraying feedstock and the metal spraying matrix.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) The present invention provides a spherical ODS alloy powder feedstock and a preparation method. During the preparation process, the oxidation temperature is increased by 1400%, and the required time is reduced by 2900%. The powder maintains good sphericity and fluidity (particle size 15 - 53 μm, flow rate 18.7 s / 50 g). The present invention overcomes the problem that oxides cannot be distributed inside the powder in the traditional powder preparation process, and the number density of nano-oxides inside the powder reaches 2.35×10 10 particles·m -3 ⁻³, and the volume fraction is 5 vol.%. This powder is suitable for fields such as additive manufacturing and thermal spraying.

[0021] (2) The present invention uses a multi-principal element alloy powder containing Al or Cr as the raw material, and generates nano-oxides by in-situ oxidation during thermal spraying and the high affinity of Al and Cr with oxygen. The dispersed distribution of nano-oxides inside the powder is achieved by the high-speed impact and splash of the powder on the liquid surface. There is no report on the research of preparing ODS alloy powder by this method. Compared with the current technology of preparing ODS alloy powder by mechanical alloying, the present invention has the advantages of more uniform and dispersed distribution of oxides inside the powder matrix, high powder sphericity, and high powder preparation efficiency.

[0022] (3) The ODS alloy powder prepared by the present invention consists of an alloy matrix and nano-oxides with a dispersed distribution inside. The composition of the nano-oxides is controllable (aluminum oxide or chromium oxide), the particle size is 100 - 500 nm, and the volume fraction is 2 - 5 vol.%.

[0023] (4) As in Example 1 of the present invention, AlCoCrFeNi alloy powder was used as the raw material, and dispersed nano-aluminum oxide with a particle size of 100 - 200 nm and a volume fraction of 3.2 vol.% was in-situ formed inside it by thermal spraying - flame quenching.

[0024] (5) As in Example 2 of the present invention, Al 0.2 CoCrFeNi alloy powder was used as the raw material, and dispersed nano-chromium oxide with a particle size of 150 - 500 nm and a volume fraction of 3.9 vol.% was in-situ formed inside it by thermal spraying - flame quenching.

[0025] (6) As in Example 3 of the present invention, CoCrFeNi alloy powder was used as the raw material, and dispersed nano-chromium oxide with a particle size of 150 - 500 nm and a volume fraction of 4.1 vol.% was in-situ formed inside it by thermal spraying - flame quenching.

[0026] (7) As in Example 4 of the present invention, NiCrAlY alloy powder was used as the raw material, and dispersed nano-chromium oxide with a particle size of 150 - 500 nm and a volume fraction of 3.5 vol.% was in-situ formed inside it by thermal spraying - flame quenching.

[0027] (8) As in Comparative Example 1 of the present invention, AlCoCrFeNi alloy powder and nano-aluminum oxide powder were used as the raw materials. After mechanical alloying for 12 hours, the oxides only existed on the surface of the powder, and it was impossible to achieve the dispersed distribution of oxides inside the powder. Description of the Drawings

[0028] Figure 1 shows the comparison of the surface morphologies of the powders prepared in Example 1 and Comparative Example 1: Among them, Figure 1 (a) is the morphology photo of the ODS alloy powder prepared by the thermal spraying - flame quenching method (Example 1), Figure 1 (b) is the morphology photo of the powder prepared by the mechanical alloying method (Comparative Example 1);

[0029] Figure 2 shows the comparison of the cross-sectional morphologies of the powders prepared in Example 1 and Comparative Example 1: Among them, Figure 2 (a), Figure 2 (b) are the morphology photos of the ODS alloy powder prepared by the thermal spraying - flame quenching method (Example 1); Figure 2 (c), Figure 2 (d) are the morphology photos of the powder prepared by the mechanical alloying method (Comparative Example 1);

[0030] Figure 3 shows the comparison of the element distribution results inside the powders prepared in Example 1 and Comparative Example 1: Among them, Figure 3(a) Element distribution results of ODS alloy powder prepared by thermal spraying flame quenching method (Example 1); Figure 3 (b) Element distribution results of powder prepared by mechanical alloying process (Comparative Example 1);

[0031] Figure 4 are the TEM and EDS results of the internal nano-oxides in the ODS alloy powder of Example 1: Among them, Figure 4 (a), Figure 4 (b) are the FIB sampling areas and morphologies of the powder; Figure 4 (c), Figure 4 (d) are the HRTEM and SAED images of a single nano-oxide; Figure 4 (e) is the element distribution image of the nano-oxide.

[0032] Figure 5 is the comparison chart of the high-temperature oxidation rate detection of the powders prepared in Example 1 and Comparative Example 1;

[0033] Figure 6 is the comparison chart of the high-temperature softening rate detection of the powders prepared in Example 1 and Comparative Example 1. Detailed implementation manners

[0034] To further understand the present invention, the present invention will be further described below in conjunction with examples, comparative examples and their attached drawings. It should be noted that the following examples are used to introduce the characteristics and advantages of the present invention, and no restrictive requirements are imposed on the present invention.

[0035] Example 1:

[0036] In this example, AlCoCrFeNi alloy powder is used as the raw material, and nano-aluminum oxide particles are synthesized by selective oxidation of Al during thermal spraying to realize the in-situ preparation of nano-aluminum oxide-reinforced AlCoCrFeNi alloy powder. The operation steps are as follows:

[0037] Step 1: Select an equimolar ratio AlCoCrFeNi alloy powder suitable for thermal spraying, with a composition of 20 at.% Al - 20 at.% Co - 20 at.% Cr - 20 at.% Fe - 20 at.% Ni, screen the particle size to 50 - 150 μm, and dry it in an 80°C oven for 4 h for standby;

[0038] Step 2: Use the original powder in Step 1 as the plasma spraying-flame quenching feed, and spray the original powder into distilled water using a self-made device. The process parameters used are: power 32 kW, gun distance 200 mm, compressed air as the powder feeding gas (the same in the following examples), and the flow rate is 3 - 10 L / min;

[0039] Step 3: Collect the powder sprayed into the coolant in Step 2. After filtration, ultrasonic cleaning, drying, and sieving, spherical ODS alloy powder with a particle size of 50 - 150 μm is obtained.

[0040] The powder prepared above was observed using a scanning electron microscope (SEM, JSM7100F, JEOL). The same applies to the following examples. The surface morphology of the powder prepared in Example 1 is shown in Figure 1 (a), presenting a regular spherical shape; the cross-sectional morphology of the powder is shown in Figure 2 (a)(b), with oxide particles dispersedly distributed inside. The average particle size of the particles is 132 nm, and the volume fraction is 3.2 vol.%.

[0041] The cross-sectional elemental distribution analysis of the powder prepared above was performed using a field emission electron probe microscope (EPMA, JXA-8530F, JEOL). The same applies to the following examples. The results are shown in Figure 3 (a). The powder of Example 1 is composed of an AlCoCrFeNi matrix and nano-alumina particles;

[0042] The structure and composition analysis of the nano-oxides inside the powder prepared in Example 1 were performed using a transmission electron microscope (TEM, G2 F30, Tecnai). The results are shown in Figure 4 . The composition of the spherical nano-oxide particles is alumina, which is formed by the selective oxidation of Al in the raw materials during the plasma spraying flame quenching process. When the molten powder is sprayed into the liquid medium, the nano-alumina particles enter the powder interior by the violent impact and splash of the powder;

[0043] An electronic analytical balance was used to record the mass change of the powders prepared in Example 1 and Comparative Example 1 within 100 hours of exposure in a high-temperature atmospheric environment and calculate the weight gain rate. The results are shown in Figure 5 . The oxidation rate of the ODS alloy powder prepared in Example 1 is maintained at <1.25 mg / cm 2 at 900 °C, showing a 90% decrease compared to Comparative Example 1. The ODS alloy powder prepared by the present invention has obvious antioxidant performance advantages compared to the current technology;

[0044] A microhardness tester (HMV-2T, Shimadzu) was used to detect the hardness change of the powders prepared in Example 1 and Comparative Example 1 within 100 hours of exposure in a high-temperature atmospheric environment and calculate the softening rate. The load for the hardness test was 100 g (HV0.1), the loading time was 15 s, and the average value was taken after multiple measurements (>10 times). The results are shown in Figure 6。The Vickers hardness of the ODS alloy powder prepared in Example 1 remained above 330 HV at 900 °C, and the softening rate within 100 hours was less than 5%. The ODS alloy powder prepared in the present invention has obvious advantages in anti-softening performance compared with the current technology. The powder raw materials prepared in the present invention can meet the relevant requirements of high-temperature components or high-temperature resistant coatings in terms of high-temperature oxidation performance, anti-softening performance, and sphericity, etc.

[0045] Example 2:

[0046] In this example, an Al 0.2 CoCrFeNi alloy powder was used as the raw material, with a composition of 5 at.% Al - 23.75 at.% Co - 23.75 at.% Cr - 23.75 at.% Fe - 23.75 at.% Ni. Nano-chromium oxide particles were introduced by the selective oxidation of Cr during the thermal spraying process to achieve the in-situ preparation of nano-chromium oxide-reinforced Al 0.2 CoCrFeNi alloy powder. The operating steps are as follows:

[0047] Step 1: Select an Al 0.2 CoCrFeNi alloy powder suitable for thermal spraying, screen the particle size to 50 - 150 μm, and dry it in an 80 °C oven for 4 h for later use;

[0048] Step 2: Use the original powder in Step 1 as the feed for thermal spraying - flame quenching, and spray the original powder into distilled water using a self-made device. The process parameters used are: power 30 kW, and the other parameters are the same as those in Example 1;

[0049] Step 3: Collect the powder sprayed into the coolant in Step 2, and obtain spherical ODS alloy powder with a particle size of 50 - 150 μm after filtration, ultrasonic cleaning, drying, and sieving.

[0050] In Example 2, an alloy with low Al and high Cr content was used as the raw material, and the obtained powder was in a regular spherical shape, and the surface morphology was similar to Figure 1 (a); Disperse chromium oxide particles were formed inside the powder, with a particle size range of 150 - 500 nm, an average particle size of 360 nm, and a volume fraction of 3.7 vol.%. The cross-sectional morphology was similar to Figure 2 (a)(b); The inside of the powder was composed of a CoCrFeNi matrix and dispersed nano-chromium oxide particles, and the element distribution results were similar to Figure 3 (a).

[0051] Example 3:

[0052] In this embodiment, CoCrFeNi alloy powder with a composition of 25 at.% Co - 25 at.% Cr - 25 at.% Fe - 25 at.% Ni is used as the raw material. Nano-chromium oxide particles are introduced by the selective oxidation of Cr during the thermal spraying process to achieve the in-situ preparation of nano-chromium oxide-reinforced CoCrFeNi alloy powder. The operation steps are as follows:

[0053] Step 1: Select CoCrFeNi alloy powder suitable for thermal spraying, screen the particle size to 50 - 150 μm, and dry it in an 80°C oven for 4 h for standby.

[0054] Step 2: Use the original powder in Step 1 as the plasma spraying-flame quenching feedstock, and spray the original powder into distilled water using a self-made device. The process parameters used are: power 28 kW, and the other parameters are the same as those in Example 1.

[0055] Step 3: Collect the powder sprayed into the coolant in Step 2, and obtain spherical ODS alloy powder with a particle size of 50 - 150 μm after filtration, ultrasonic cleaning, drying, and sieving.

[0056] The powder prepared in Example 3 is in a regular spherical shape, and its surface morphology is similar to Figure 1 (a); Disperse chromium oxide particles are formed inside the powder. The particle size range of the particles is 150 - 500 nm, the average particle size is 409 nm, and the volume fraction is 4.2 vol.%. The cross-sectional morphology is similar to Figure 2 (a)(b); The in-situ reaction product in Example 3 is nano-chromium oxide particles; The elemental distribution result inside the powder is similar to Figure 3 (a), and it is composed of a CoCrFeNi alloy matrix and chromium oxide nanoparticles.

[0057] Example 4:

[0058] In this embodiment, based on NiCrAlY powder raw material with a composition of Ni balance - 22 at.% Cr - 10 at.% Al - 0.5 at.% Y, nano-chromium oxide particles are introduced by the selective oxidation of Cr during the thermal spraying-flame quenching process to achieve the in-situ preparation of ODS powder feedstock. The operation steps are as follows:

[0059] Step 1: Select NiCrAlY alloy powder suitable for thermal spraying, screen the particle size to 50 - 150 μm, and dry it in an 80°C oven for 4 h for standby.

[0060] Step 2: Use the original powder in Step 1 as the plasma spraying-flame quenching feedstock, and spray the original powder into distilled water using a self-made device. The process parameters used are: power 30 kW, and the other parameters are the same as those in Example 2.

[0061] Step 3: Collect the powder sprayed into the coolant in Step 2. After filtration, ultrasonic cleaning, drying, and sieving, spherical ODS alloy powder with a particle size of 50 - 150 μm is obtained.

[0062] The powder prepared in Example 4 is in the shape of regular spheres, and its surface morphology is similar to that of Figure 1 (a); Dispersively distributed chromium oxide particles are formed inside the powder. The particle size range of the particles is 200 - 500 nm, the average particle size is 449 nm, and the volume fraction is 3.5 vol.%. The cross-sectional morphology is similar to that of Figure 2 (a)(b); The inside of the powder is composed of a NiCrAl alloy matrix and nano chromium oxide particles, and the elemental distribution results are similar to those of Figure 3 (a).

[0063] Comparative Example 1:

[0064] To illustrate the microstructural characteristics and process advantages of the ODS alloy powder prepared by the present invention, this comparative example is specifically set as a reference. This comparative example uses AlCoCrFeNi alloy powder and nano-aluminum oxide as raw materials, with a composition of 20 at.% Al - 20 at.% Co - 20 at.% Cr - 20 at.% Fe - 20 at.% Ni. ODS alloy powder is prepared by mechanical alloying. The preparation method of Comparative Example 1 is different from those of Examples 1, 2, 3, and 4 in that the introduction method of the oxide is external addition rather than in-situ generation. The operation steps are as follows:

[0065] Step 1: Select α-aluminum oxide powder with a particle size of 50 nm and AlCoCrFeNi alloy powder, sieve the particle size to 50 - 150 μm, and dry it in an 80°C oven for 4 h for standby.

[0066] Step 2: Use a planetary ball mill to mechanically alloy the raw material powders of AlCoCrFeNi and nano-aluminum oxide. The parameters are as follows: 5 wt.% aluminum oxide, a ball-to-material ratio of 20:1, a rotation speed of 400 r / min, and a time of 12 h.

[0067] Step 3: Collect the powder after ball milling in Step 2, and obtain alloy powder with a particle size of 50 - 150 μm after sieving.

[0068] The surface morphology and cross-sectional morphology of the powder prepared in Comparative Example 1 are shown in Figure 1 (b) and Figure 2 (c)(d). The oxide only exists on the surface of the powder and cannot be evenly distributed inside the powder; the elemental distribution results inside the powder are shown in Figure 3 (b), and no oxide is observed inside the powder.

[0069] The detection results of the comparative examples show that the oxides in the powders prepared by the current technology (mechanical alloying) usually only exist on the powder surface. This is because the physicochemical environment (factors such as temperature, pressure, atmosphere, etc.) of mechanical alloying causes a lack of sufficient oxygen diffusion inside the powder, thus restricting the formation and dispersion of oxides inside the powder.

[0070] The comparison between Examples 1-4 and Comparative Example 1 shows that the present invention can efficiently achieve the dispersion distribution of nano-oxides inside the alloy powder.

[0071] The thermal spraying-flame quenching technology provided by the present invention has the characteristics of simple process, high powder-making efficiency, low cost, etc. This technology uses alloy powders containing Al or Cr as raw materials, realizes the in-situ formation of oxides through the selective oxidation reaction of the powders during the thermal spraying process, and makes the distribution of oxides more uniform inside the powders through the high-speed impact and splash of the powders on the liquid surface. The microstructure of the ODS alloy powder can be regulated by adjusting the composition ratio of the raw materials and the spraying process. The ODS alloy powder prepared by the present invention has uniformly distributed nano-oxides inside, with a content of 2-5 vol.%, a particle size of 100-500 nm, and the powder has good sphericity and fluidity.

[0072] As described above, the embodiments and their accompanying drawings have introduced the present invention in detail. It should be noted that the above-described embodiments are used to introduce the characteristics and advantages of the present invention, and no restrictive requirements are imposed on the present invention. However, it should be emphasized that all similar modifications, supplements, substitutions, etc. made within the principle scope of the present invention should be included within the protection scope of the present invention.

[0073] Matters not covered by the present invention are well-known technologies.

Claims

1. A method for preparing in-situ synthesized ODS multi-principal alloy powder, characterized in that: The method comprises the following steps: Step 1: Select a multi-principal alloy powder containing Al or Cr, and obtain the original powder after drying; Among them, the elements involved in the multi-principal alloy include basic elements and residual elements, the basic elements are one or two of Al and Cr, and the percentage of the elements in the multi-principal alloy is: Al 5-30at.%, Cr 10-30at.%; the residual elements are one or more elements of Ni, Fe, and Co, and the sum of the residual elements in the multi-principal alloy is greater than 40at.%, and the particle size range is 50-150μm; Step 2: using the original powder in step 1 as a thermal spray feed, thermally spraying it into a coolant for flame quenching; The thermal spraying power is 25-40kW, and the gun distance is 100-450mm. The powder feeding gas in the thermal spraying is compressed air, or a mixture of compressed air and argon. The volume ratio of argon in the powder feeding gas is 0-70vol.%; The coolant is a water-based cooling medium or an oil-based cooling medium; Step 3: Collect the powder sprayed into the coolant in step 2, and obtain spherical ODS alloy powder after filtering, ultrasonic cleaning, drying and sieving.

2. The method for preparing in-situ synthesized ODS multi-principal component alloy powder according to claim 1, characterized in that: The multi-principal alloy is one or more of AlCoCrFeNi, CoCrFeNi, CoCrNi, NiCoCrAl, NiCrAl, FeCrAl, and NiCr.

3. The method for preparing in-situ synthesized ODS multi-principal component alloy powder according to claim 1, characterized in that: The original powder also includes a modifying element X, and the amount of the modifying element added is 0-2.0wt.% of the original powder mass; X is one or more of Si, Ti, Mo, V and rare earth elements; and the rare earth element is Y, Ce or La.

4. The method for preparing in-situ synthesized ODS multi-principal component alloy powder according to claim 1, characterized in that: The thermal spraying is ion spraying or flame spraying; the water-based cooling medium is deionized water or salt water, and the oil-based cooling medium is mineral oil or kerosene.

5. Application of the ODS multi-principal alloy powder obtained by the method according to claim 1, characterized in that: Used as raw material for high temperature components or anti-oxidation coatings under working conditions from room temperature to 1100℃.

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