Nano samarium oxide dispersion strengthened NiCoCrAlY alloy powder and preparation method thereof

Abstract

The invention discloses nano samarium oxide dispersion strengthened NiCoCrAlY alloy powder and a preparation method thereof, and relates to the technical field of alloy powder preparation. The method specifically comprises the following steps that a NiCoCrAlY alloy bar is smelted, then heat preservation is conducted, and a liquid alloy melt is obtained; the liquid alloy melt is subjected to high-pressure inert gas atomization powder preparation, nano samarium oxide flow perpendicular to the liquid flow direction of the alloy melt is synchronously introduced in the powder preparation process, high-temperature alloy liquid drops formed during atomization are impacted and wrapped, and target powder is obtained; performing hot isostatic pressing on the target powder to obtain a target alloy bar; a target alloy bar is repeatedly subjected to multiple smelting, high-pressure inert gas atomization powder manufacturing and hot isostatic pressing treatment, an alloy bar is obtained, then the alloy bar is subjected to high-pressure inert gas atomization powder manufacturing, and the nanometer samarium oxide dispersion strengthening type NiCoCrAlY alloy powder is obtained. By adopting the preparation method disclosed by the invention, the nano samarium oxide dispersion strengthened NiCoCrAlY alloy powder with excellent morphology, nano samarium oxide dispersity and purity can be obtained.

Description

Technical Field

[0001] This invention relates to a nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder and its preparation method, belonging to the field of alloy powder preparation technology. Background Technology

[0002] ODS alloys (oxide dispersion reinforced alloys) have significantly improved high-temperature stability and radiation resistance due to the dispersed nano-oxide particles inside them. They have become ideal materials for nuclear reactor cladding, key aerospace components and high-temperature protective coatings, showing broad prospects in high-temperature applications in nuclear energy and aerospace.

[0003] Atomization is a method of obtaining metal powder by directly breaking up molten metal. It features high production efficiency and low production cost, and is one of the most commonly used methods for preparing metal powder for spraying. Atomization powder preparation is mainly divided into three methods: high-pressure inert gas atomization (GA), plasma rotating electrode atomization (PREP), and ultrasonic atomization. However, these methods have not yet been used to prepare ODS-type spray powder.

[0004] As an important high-temperature protective coating material, NiCoCrAlY alloy can form a dense α-Al2O3 film on its surface in high-temperature oxidizing environments, thus endowing it with excellent resistance to high-temperature oxidation and hot corrosion. To meet the increasingly demanding requirements for material performance in related technical fields, it is necessary to further improve the comprehensive performance of NiCoCrAlY alloy. By combining nano-samarium oxide (Sm2O3) with this alloy, oxide dispersion strengthened (ODS) type NiCoCrAlY alloy can be prepared, thereby significantly improving its service performance in extreme high-temperature environments. However, there are significant differences between NiCoCrAlY alloy and nano-samarium oxide in terms of particle size, density, and many other properties, making it difficult to prepare ODS type NiCoCrAlY alloy with uniformly dispersed nano-samarium oxide through gas atomization powdering.

[0005] Therefore, it is necessary to provide a nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder and its preparation method to improve the controllability of process parameters, enhance the stability of ODS-type NiCoCrAlY alloy powder during preparation, alleviate the problems of nano-samarium oxide agglomeration, uneven distribution, and poor sphericity during preparation, improve the quality of ODS-type NiCoCrAlY alloy powder, achieve structural expansion of ODS-type NiCoCrAlY alloy powder, and reduce preparation costs, thereby achieving the goal of preparing high-quality ODS-type NiCoCrAlY alloy powder in a simple and efficient manner. Summary of the Invention

[0006] To address the problem of achieving internal dispersion of nano-ceramic phases in alloy powders, this invention provides a nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder and its preparation method. This method not only ensures the uniform distribution of nano-ceramic phases and high sphericity of the alloy powder, but also effectively avoids the problems of poor powder sphericity, low coating density, easy oxidation during ball milling, and nanoparticle agglomeration and segregation caused by traditional methods.

[0007] One objective of this invention is to provide a method for preparing nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder, specifically including the following steps: (1) Melt NiCoCrAlY alloy rods and then keep them warm to obtain liquid alloy melt. The liquid alloy melt is then atomized with high pressure inert gas to make powder. During the powder making process, nano samarium oxide flow perpendicular to the flow direction of the alloy melt is introduced simultaneously to impact and encapsulate the high-temperature alloy droplets formed in the atomization to obtain the target powder.

[0008] (2) The target powder is wrapped in a sleeve and then hot isostatically pressed to obtain the target alloy rod.

[0009] (3) Repeat the steps (1) melting, high pressure inert gas atomization powdering and step (2) hot isostatic pressing to obtain alloy rods. Then, the alloy rods are melted again, high pressure inert gas atomization powdering is performed again, and then sieved to obtain nano samarium oxide dispersion-reinforced NiCoCrAlY alloy powder.

[0010] Preferably, the melting conditions in step (1) are: melting NiCoCrAlY alloy rods at a melting temperature of 1450~1550℃ in an inert atmosphere (such as argon); and the heat preservation conditions after melting are: standing for 3~5 minutes.

[0011] More preferably, the melting method in step (1) is vacuum induction melting (VIM); the vacuum degree of the melting is 1×10⁻⁶. -3 MPa.

[0012] Preferably, the conditions for high-pressure inert gas atomization powder preparation in step (1) are as follows: inert gas (such as argon with a purity of 5N) is used as the atomization medium, the inert gas pressure is 1~10MPa, and the inert gas is preheated to 500~800℃ before impacting the alloy melt droplets.

[0013] Preferably, in step (1), the atomizing medium for the nano-samarium oxide flow is argon gas with a flow rate of 0.5~2m³. 3 / kg, argon pressure is 1~10MPa; the amount of nano-samarium oxide added to the nano-samarium oxide stream is introduced according to the mass ratio of nano-samarium oxide to NiCoCrAlY alloy rod (0.5~5):100, impacting and encapsulating the high-temperature alloy droplets formed in atomization.

[0014] Preferably, the sheath in step (2) is made of stainless steel or low-carbon steel.

[0015] Preferably, the conditions for hot isostatic pressing in step (2) are: hot isostatic pressing temperature 900~1300℃, pressure 90~150MPa, and hot isostatic pressing time 3~6h.

[0016] Preferably, when the target alloy rod is repeatedly subjected to the melting of step (1), high-pressure inert gas atomization powdering and the hot isostatic pressing treatment of step (2) in step (3), no nano samarium oxide flow is introduced; the target alloy rod is repeatedly subjected to step (1) and step (2) once or more.

[0017] Preferably, the conditions for remelting in step (3) are as follows: the alloy rod is melted at a melting temperature of 1450~1550℃ under an inert atmosphere, and then kept at a constant temperature for 3~5 minutes; the conditions for re-high pressure inert gas atomization powdering are as follows: an inert gas (such as argon with a purity of 5N) is used as the atomization medium, the inert gas pressure is 1~10MPa, and the inert gas is preheated to 500~800℃ before impacting the alloy melt droplets; the size of the nano-samarium oxide dispersion-strengthened NiCoCrAlY alloy powder obtained by sieving is 15~45µm.

[0018] More preferably, in step (3), the alloy rod is remelted using vacuum induction melting (VIM); the vacuum degree of the remelted alloy rod is 1×10⁻⁶. -3 MPa.

[0019] Another objective of this invention is to provide a nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder obtained by the preparation method of this invention.

[0020] Mechanism of the invention: This invention produces nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder (i.e., ODS-type NiCoCrAlY alloy powder) through multiple high-pressure inert gas atomization powdering combined with hot isostatic pressing (HIP), ensuring uniform bonding of the raw material powder and effective powder forming. The synergistic effect of multiple high-pressure inert gas atomization powdering and HIP allows the nano-oxide components to partially dissolve in NiCoCrAlY, forming a substitution solid solution. The powder forming process employs non-mechanical alloying (MA). Therefore, the alloy powder undergoes minimal oxidation during preparation, resulting in a finished powder with good morphology, suitable for thermal spraying.

[0021] The beneficial effects of this invention are: (1) The present invention prepares ODS type NiCoCrAlY alloy powder by using multiple high-pressure inert gas atomization powdering combined with hot isostatic pressing. Compared with ordinary metallurgical powder mixing, the finished powder has a more uniform distribution of nano-ceramic phase. At the same time, crucible-free powdering can be used in the smelting process, avoiding the introduction of various impurities at high temperature.

[0022] (2) The present invention obtains the final ODS type NiCoCrAlY alloy powder by high pressure inert gas atomization powder preparation. Compared with the flake-shaped and flat powder obtained by high energy ball mill mechanical alloying powder preparation, the ODS type NiCoCrAlY alloy powder obtained by this method has better sphericity and can be directly used for thermal spraying without any post-processing. At the same time, since there is no mechanical energy, it can also better avoid the alloy powder from failing due to oxidation during the preparation process.

[0023] (3) This invention prepares ODS type NiCoCrAlY alloy powder by combining multiple high-pressure inert gas atomization powder preparation with hot isostatic pressing process, which effectively enhances the controllability of the preparation process, thereby improving the quality controllability of ODS type NiCoCrAlY alloy powder, and at the same time effectively improves the product yield, making it suitable for industrial promotion and application. Attached Figure Description

[0024] Figure 1 This is a scanning electron microscope image of the target powder surface obtained in step (1) of Embodiment 1 of the present invention.

[0025] Figure 2 This is a surface scan elemental distribution diagram of a single particle in the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared in Example 1 of the present invention.

[0026] Figure 3 This is a scanning electron microscope image of the surface of the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared in Example 1 of the present invention.

[0027] Figure 4 Cross-sectional view and surface scan elemental distribution map of the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared in Example 1 of this invention.

[0028] Figure 5 This is an image showing the overall morphology of the nano-samarium oxide-reinforced NiCoCrAlY alloy powder prepared in Comparative Example 1 of this invention.

[0029] Figure 6 This is a magnified image of the microstructure of a single particle of the samarium oxide-reinforced NiCoCrAlY alloy powder prepared in Comparative Example 1 of this invention.

[0030] Figure 7 This is an image showing the overall morphology of the nano-samarium oxide-reinforced NiCoCrAlY alloy powder prepared in Comparative Example 2 of this invention.

[0031] Figure 8 This is a magnified image of the microstructure of a single particle of the samarium oxide-reinforced NiCoCrAlY alloy powder prepared in Comparative Example 2 of this invention. Detailed Implementation

[0032] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. In the embodiments and comparative examples of this invention, unless otherwise specified, all chemical reagents used in the experiments were commercially available analytical grade. The NiCoCrAlY alloys (including rods and powders) used in the embodiments and comparative examples of this invention are all high-temperature alloy materials known in the art, and their composition includes Ni, Co, Cr, Al, and Y. Using the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared in the embodiments of this invention as raw material, and K438 nickel-based high-temperature alloy as the substrate, the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder is sprayed onto the substrate surface to form a coating 100-300 μm thick, serving as the metal bonding layer for the high-temperature thermal barrier coating.

[0033] Example 1 A method for preparing nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder specifically includes the following steps: (1) NiCoCrAlY alloy rods were subjected to argon protection under a vacuum of 1×10⁻⁶. -3 Under MPa conditions, vacuum induction melting was performed at a melting temperature of 1500℃. After homogenization, the melt was held at this temperature for 4 minutes to obtain a liquid alloy melt. Argon gas (purity grade 5N) was preheated to 600℃, and the liquid alloy melt was atomized into powder using high-pressure inert gas at a pressure of 8MPa. During the powdering process, a nano-samarium oxide stream perpendicular to the flow direction of the alloy melt was simultaneously introduced (the atomizing medium was argon gas, and the flow rate was 0.5m³). 3 / kg, pressure 1MPa), impacting and enveloping the high-temperature alloy droplets formed in the atomization, causing them to cool and solidify (cooling rate 8×10 6 The target powder is obtained by uniformly distributing nano-samarium oxide on the alloy surface at ℃ / s, wherein the nano-samarium oxide is introduced at a mass ratio of 0.5:100 between nano-samarium oxide and NiCoCrAlY alloy rod.

[0034] (2) The target powder is wrapped in a stainless steel sleeve and then subjected to hot isostatic pressing at 1000℃ and 100MPa for 4 hours to obtain the target alloy rod.

[0035] (3) Repeat step (1) melting, high-pressure inert gas atomization powdering and step (2) hot isostatic pressing to prepare alloy rods. In this case, the repeated steps (1) and (2) do not introduce nano samarium oxide flow. Finally, the alloy rods are heated in a vacuum of 1×10 -3 Under MPa conditions, vacuum induction melting was carried out at a melting temperature of 1500℃. After uniform melting, the alloy melt was held at the temperature for 4 minutes to obtain the alloy melt. Then, argon gas (purity grade 5N) was preheated to 600℃, and the alloy melt was atomized into powder under high pressure of 8MPa. After sieving, 15~45µm nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder was obtained.

[0036] The target powder obtained in step (1) of this embodiment was subjected to scanning electron microscopy to observe the powder morphology. The results are as follows: Figure 1 As shown; via Figure 1 It can be seen that after one high-pressure inert gas atomization powdering process, the samarium oxide nanoparticles are uniformly distributed on the surface of the NiCoCrAlY powder. However, the samarium oxide nanoparticles are irregularly shaped and do not penetrate into the interior of the NiCoCrAlY powder. The dispersed phase distribution in the coating prepared using this powder is uneven. A second high-pressure inert gas atomization powdering process is required to allow the samarium oxide nanoparticles to penetrate into the interior of the NiCoCrAlY powder.

[0037] Surface scan elemental distribution tests were performed on the cross-section of a single particle of the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared in this embodiment. The results are as follows: Figure 2 As shown; via Figure 2 The cross-sectional diagram of the alloy powder shows that samarium has entered the interior of the finished alloy powder and is relatively dispersed within it, forming ODS-type NiCoCrAlY alloy powder.

[0038] Scanning electron microscopy was performed on the samarium oxide nanoparticle-reinforced NiCoCrAlY alloy powder prepared in the examples, and the results are as follows: Figure 3 As shown; via Figure 3 It can be concluded that the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared in this embodiment has excellent sphericity, and the powder particle size distribution after sieving is 15~45µm, which meets the requirements of NiCoCrAlY powder for thermal spraying.

[0039] The cross-section of the coating prepared in this embodiment was tested by scanning electron microscopy, and the results are as follows: Figure 4 As shown; via Figure 4 It can be seen that the nano-samarium oxide coated on the alloy powder forms a dotted dispersion in the coating through supersonic flame spraying, and the coating basically has the microstructure characteristics of an ODS type coating.

[0040] The surface scan elemental distribution experiment was performed on the coating prepared in this embodiment, and the results are as follows: Figure 4 As shown; via Figure 4 As can be seen from the distribution of samarium, the white dotted areas in the coating are identified as samarium oxide ceramic phase, proving that the ODS type alloy coating was successfully prepared by this method.

[0041] Example 2 A method for preparing nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder specifically includes the following steps: (1) NiCoCrAlY alloy rods were subjected to argon protection under a vacuum of 1×10⁻⁶. -3 Under MPa conditions, vacuum induction melting was performed at a melting temperature of 1550℃. After homogenization, the melt was held at this temperature for 3 minutes to obtain a liquid alloy melt. Argon gas (purity grade 5N) was preheated to 800℃, and the liquid alloy melt was atomized into powder using high-pressure inert gas at a pressure of 1 MPa. During the powdering process, a nano-samarium oxide stream perpendicular to the flow direction of the alloy melt was simultaneously introduced (the atomizing medium was argon gas, and the flow rate was 1 m³ / s). 3 / kg, pressure 10MPa), impacting and enveloping the high-temperature alloy droplets formed in the atomization, causing them to cool and solidify (cooling rate 5×10 6 (℃ / s), nano-samarium oxide is uniformly distributed on the alloy surface to obtain the target powder, wherein the nano-samarium oxide is introduced in a mass ratio of nano-samarium oxide to NiCoCrAlY alloy rod of 5:100.

[0042] (2) The target powder is wrapped in a stainless steel sleeve and then subjected to hot isostatic pressing at 1300℃ and 90MPa for 3 hours to obtain the target alloy rod.

[0043] (3) Repeat the second step (1) melting, high-pressure inert gas atomization powdering and step (2) hot isostatic pressing to prepare alloy rods. In the repeated steps (1) and (2), no nano samarium oxide flow is introduced. Finally, the alloy rods are heated in a vacuum of 1×10 -3 Under MPa conditions, vacuum induction melting was carried out at a melting temperature of 1550℃. After uniform melting, the alloy melt was held at the temperature for 3 minutes to obtain the alloy melt. Then, argon gas (purity grade 5N) was preheated to 800℃, and the alloy melt was atomized into powder under high pressure at 1MPa. After sieving, 15~45µm nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder was obtained.

[0044] The target powder obtained in step (1) of this embodiment was subjected to scanning electron microscopy to observe the powder morphology. The test results showed that after one high-pressure inert gas atomization powder preparation, the nano samarium oxide was uniformly distributed on the surface of the NiCoCrAlY powder. However, the nano samarium oxide was irregularly shaped and the nano samarium oxide particles did not enter the interior of the NiCoCrAlY powder. The dispersed phase distribution in the coating prepared using this powder was uneven. It is necessary to perform multiple high-pressure inert gas atomization powder preparations to allow the nano samarium oxide to enter the interior of the NiCoCrAlY powder.

[0045] The cross-section of a single particle of the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared in this embodiment was subjected to surface scan elemental distribution test. The test results showed that samarium had entered the interior of the finished alloy powder and was relatively dispersed within it, forming ODS-type NiCoCrAlY alloy powder.

[0046] Scanning electron microscopy (SEM) was performed on the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared in this embodiment. The results showed that the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared by multiple high-pressure inert gas atomization powdering processes has excellent sphericity. After sieving, the powder particle size distribution is 15~45µm, which meets the requirements for NiCoCrAlY powder for thermal spraying.

[0047] Scanning electron microscopy was performed on the cross-section of the coating prepared in this embodiment. The results showed that the nano-samarium oxide coated on the alloy powder was dispersed in the coating in a dotted pattern by supersonic flame spraying, and the coating basically had the microstructure characteristics of an ODS type coating.

[0048] The coating prepared in the example was subjected to surface scan elemental distribution test. The test results showed that the distribution of samarium element determined that the white dotted areas in the coating were samarium oxide ceramic phase, proving that the ODS type alloy coating was successfully prepared by this method.

[0049] Example 3 A method for preparing nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder specifically includes the following steps: (1) NiCoCrAlY alloy rods were subjected to argon protection under a vacuum of 1×10⁻⁶. -3 Under MPa conditions, vacuum induction melting was performed at a melting temperature of 1450℃. After homogenization, the melt was held at this temperature for 5 minutes to obtain a liquid alloy melt. Argon gas (purity grade 5N) was preheated to 500℃, and the liquid alloy melt was atomized into powder using high-pressure inert gas at a pressure of 10MPa (high-pressure inert gas atomization temperature of 1500℃). During the powdering process, nano-samarium oxide flow perpendicular to the flow direction of the alloy melt was simultaneously introduced (the atomizing medium was argon gas, and the flow rate was 2m³). 3 / kg, pressure 8MPa), impacting and enveloping the high-temperature alloy droplets formed in the atomization, causing them to cool and solidify (cooling rate 1×10⁻⁶). 7 (℃ / s), nano-samarium oxide is uniformly distributed on the alloy surface to obtain the target powder, wherein the nano-samarium oxide is introduced at a mass ratio of 1:100 between nano-samarium oxide and NiCoCrAlY alloy rod.

[0050] (2) The target powder is wrapped in a low carbon steel sheath and then subjected to hot isostatic pressing at 900℃ and 150MPa for 6 hours to obtain the target alloy rod.

[0051] (3) Repeat steps (1) melting, high-pressure inert gas atomization powdering and step (2) hot isostatic pressing to prepare alloy rods three times. In the repeated steps (1) and (2), no nano samarium oxide flow is introduced. Finally, the alloy rods are heated in a vacuum of 1×10 -3 Under MPa conditions, vacuum induction melting was carried out at a melting temperature of 1450℃. After uniform melting, the alloy melt was held at the temperature for 5 minutes to obtain the alloy melt. Then, argon gas (purity grade 5N) was preheated to 500℃, and the alloy melt was atomized into powder under high pressure at 10MPa. After sieving, 15~45µm nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder was obtained.

[0052] The target powder obtained in step (1) of this embodiment was subjected to scanning electron microscopy to observe the powder morphology. The test results showed that after one high-pressure inert gas atomization powder preparation, the nano samarium oxide was uniformly distributed on the surface of the NiCoCrAlY powder. However, the nano samarium oxide was irregularly shaped and the nano samarium oxide particles did not enter the interior of the NiCoCrAlY powder. The dispersed phase distribution in the coating prepared using this powder was uneven. It is necessary to perform multiple high-pressure inert gas atomization powder preparations to allow the nano samarium oxide to enter the interior of the NiCoCrAlY powder.

[0053] The cross-section of a single particle of the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared in this embodiment was subjected to surface scan elemental distribution test. The test results showed that samarium had entered the interior of the finished alloy powder and was relatively dispersed within it, forming ODS-type NiCoCrAlY alloy powder.

[0054] Scanning electron microscopy (SEM) was performed on the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared in this embodiment. The results showed that the nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared by multiple high-pressure inert gas atomization powdering processes has excellent sphericity. After sieving, the powder particle size distribution is 15~45µm, which meets the requirements for NiCoCrAlY powder for thermal spraying.

[0055] Scanning electron microscopy was performed on the cross-section of the coating prepared in this embodiment. The results showed that the nano-samarium oxide coated on the alloy powder was dispersed in the coating in a dotted pattern by supersonic flame spraying, and the coating basically had the microstructure characteristics of an ODS type coating.

[0056] The coating prepared in the example was subjected to surface scan elemental distribution test. The test results showed that the distribution of samarium element determined that the white dotted areas in the coating were samarium oxide ceramic phase, proving that the ODS type alloy coating was successfully prepared by this method.

[0057] In summary, this invention prepares nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder (ODS-type NiCoCrAlY alloy powder) by combining multiple high-pressure inert gas atomization powder preparation with multiple hot isostatic pressing. This method effectively improves the sphericity and uniformity of the finished sprayed powder while enhancing the controllability of the preparation process, thereby obtaining ODS-type NiCoCrAlY alloy powder with superior quality and strong applicability.

[0058] Comparative Example 1 A method for preparing nano-samarium oxide-reinforced NiCoCrAlY alloy powder specifically includes the following steps: NiCoCrAlY alloy powder with a particle size of 15-45 μm and samarium oxide nanoparticles with a particle size of 100 nm were weighed in a mass ratio of 100:1 to form a solid powder. Then, the solid powder and corundum grinding balls were placed in a ball milling jar under the condition of a ball-to-particle ratio of 10:1, and anhydrous ethanol was added to the ball milling jar, wherein the amount of anhydrous ethanol added was 10% of the mass of the solid powder. The ball milling was carried out at room temperature at a speed of 200 rpm in an intermittent mode of "ball milling for 30 min, stopping and cooling for 15 min", with a total effective ball milling time of 10 h, and then the nano-samarium oxide-reinforced NiCoCrAlY alloy powder was obtained.

[0059] Scanning electron microscopy (SEM) was performed on the samarium oxide-reinforced NiCoCrAlY alloy powder prepared in this comparative example. The overall morphology of the powder is shown in the figure below. Figure 5 As shown in the magnified image of the microstructure of a single powder particle, see below. Figure 6 As shown, by Figure 5 and Figure 6The particle size of the powder obtained in this comparative example is comparable to that of the initial commercial raw material powder (15~45μm), but its sphericity is poor and it is mostly flake-shaped powder. In thermal spraying, it is easy to cause the powder feeding pipe to be blocked or the flow rate to be unstable, which is not suitable for the preparation of coating materials. This is because mechanical ball milling can only physically adhere the nano samarium oxide to the surface of the alloy powder. This bonding method is fragile and causes the powder sphericity to be destroyed into flakes, which seriously damages the powder flowability and spraying stability.

[0060] Comparative Example 2 A method for preparing nano-samarium oxide-reinforced NiCoCrAlY alloy powder specifically includes the following steps: (1) Grind commercial NiCoCrAlY alloy powder to 800nm~5μm using a sand mill.

[0061] (2) Add 100 nm nano samarium oxide (with the amount of nano samarium oxide added to the nano NiCoCrAlY alloy powder (800 nm ~ 5 μm) to form a solid material. Then add deionized water to the solid material until the mass percentage of the solid material is 60% to obtain a solid-liquid mixture. Subsequently, add dispersant PVA (the amount of PVA added is 0.5% of the mass percentage of the solid-liquid mixture) to prevent particle agglomeration. Then add 0.5% of cellulose of the solid-liquid mixture to form a suspension slurry.

[0062] (3) Under the conditions of continuous stirring at 300 rpm, inlet temperature of 250℃, outlet temperature of 100℃, tower pressure of 0 MPa, and atomizer frequency of 50 Hz (25000 rpm), spray drying was carried out using argon gas at 80℃ as the atomizing medium to prepare nano-samarium oxide reinforced NiCoCrAlY alloy powder.

[0063] Scanning electron microscopy was performed on the nano-samarium oxide-reinforced NiCoCrAlY alloy powder prepared in this comparative example. The overall morphology of the powder is shown in the figure below. Figure 7 As shown in the magnified image of the microstructure of a single powder particle, see below. Figure 8 As shown, by Figure 7 and Figure 8 The powder obtained in this comparative example is mainly spherical / near-spherical, without obvious edges, flakes or irregular broken morphology; the geometry of most particles is close to "spherical"; the particle size is 10~50μm, which meets the requirements of thermal spraying powder, but the samarium oxide distribution shows agglomeration and is not dispersed enough. At the same time, the powder bonding is not dense enough and it is easily dispersed during thermal spraying, so it is not suitable for preparing coating materials.

[0064] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder and its preparation method, characterized in that, Specifically, the following steps are included: (1) Melt NiCoCrAlY alloy rods and then keep them warm to obtain liquid alloy melt. The liquid alloy melt is then atomized into powder by high pressure inert gas. During the powder making process, nano samarium oxide flow perpendicular to the flow direction of the alloy melt is introduced simultaneously to impact and encapsulate the high temperature alloy droplets formed in the atomization to obtain the target powder. (2) The target powder is wrapped in a sleeve and then hot isostatically pressed to obtain the target alloy rod; (3) Repeat the steps (1) melting, high pressure inert gas atomization powdering and step (2) hot isostatic pressing to obtain alloy rods. Then, the alloy rods are melted again, high pressure inert gas atomization powdering is performed again, and then sieved to obtain nano samarium oxide dispersion-reinforced NiCoCrAlY alloy powder.

2. The method for preparing nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder according to claim 1, characterized in that, The melting conditions in step (1) are: melting NiCoCrAlY alloy rods at a melting temperature of 1450~1550℃ under an inert atmosphere; the heat preservation conditions after melting are: standing for 3~5 minutes.

3. The method for preparing nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder according to claim 1, characterized in that, The conditions for high-pressure inert gas atomization powder production in step (1) are as follows: inert gas is used as the atomization medium, the inert gas pressure is 1~10MPa, and the inert gas is preheated to 500~800℃ before impacting the alloy melt droplets.

4. The method for preparing nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder according to claim 1, characterized in that, In step (1), the atomizing medium for the nano-samarium oxide flow is argon gas, and the argon gas flow rate is 0.5~2m³. 3 / kg, argon pressure is 1~10MPa; the amount of nano-samarium oxide added to the nano-samarium oxide stream is introduced according to the mass ratio of nano-samarium oxide to NiCoCrAlY alloy rod (0.5~5):100, impacting and encapsulating the high-temperature alloy droplets formed in atomization.

5. The method for preparing nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder according to claim 1, characterized in that, The sheath in step (2) is made of stainless steel or low-carbon steel.

6. The method for preparing nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder according to claim 1, characterized in that, The conditions for hot isostatic pressing in step (2) are: hot isostatic pressing temperature 900~1300℃, pressure 90~150MPa, and hot isostatic pressing time 3~6h.

7. The method for preparing nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder according to claim 1, characterized in that, In step (3), when the target alloy rod is repeatedly subjected to step (1) melting, high-pressure inert gas atomization powdering and step (2) hot isostatic pressing, no nano samarium oxide flow is introduced; the target alloy rod is repeatedly subjected to step (1) and step (2) once or more.

8. The method for preparing nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder according to claim 1, characterized in that, The conditions for remelting in step (3) are as follows: the alloy rod is melted at a melting temperature of 1450~1550℃ under an inert atmosphere, and then kept at a constant temperature for 3~5 minutes; the conditions for re-high pressure inert gas atomization powdering are as follows: inert gas is used as the atomization medium, the inert gas pressure is 1~10MPa, and the inert gas is preheated to 500~800℃ before impacting the alloy melt droplets; the size of the nano samarium oxide dispersion-strengthened NiCoCrAlY alloy powder obtained by sieving is 15~45µm.

9. The nano-samarium oxide dispersion-reinforced NiCoCrAlY alloy powder prepared by the method according to any one of claims 1 to 8.

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