Ceramic powder for plasma spraying and preparation method thereof

Abstract

The invention relates to ceramic powder for plasma spraying and a preparation method thereof, and the preparation method comprises the following steps: sequentially carrying out calcination treatment, ultrasonic dispersion treatment, screening treatment and drying treatment on powder after spray granulation to obtain the ceramic powder for plasma spraying. By means of the process, secondary agglomeration of the ceramic powder for plasma spraying can be reduced, the flowability of the powder is improved, and the repose angle of the powder is reduced.

Description

Technical Field

[0001] This invention relates to the field of ceramic powder preparation technology, and in particular to a ceramic powder for plasma spraying and its preparation method. Background Technology

[0002] Plasma spraying technology uses a compressed electric arc as a heat source. A continuous working gas (argon, nitrogen, or hydrogen, etc.) passes through the compressed arc and is ionized, becoming a high-temperature, high-speed plasma jet. The coating material is heated to a molten or semi-molten state by the plasma jet and is then sprayed at high speed onto a roughened, clean substrate surface. After quenching and solidification, a coating layer is formed. Plasma spraying can also be used to prepare ceramic coatings on metal substrates, combining the excellent mechanical properties of metals with the high-temperature resistance, wear resistance, and corrosion resistance of ceramics. This allows the material to meet the mechanical and environmental performance requirements during operation, resulting in a material that meets operational needs. It can be used in aerospace, machinery manufacturing, chemical, petroleum, and metallurgical industries. The flowability of spherical powder with a certain particle size is crucial for plasma spraying during high-speed spraying. Powder with good flowability ensures continuous and stable powder delivery; ensures uniform carrier gas transport; improves coating uniformity and quality; and increases powder deposition efficiency and material utilization.

[0003] CN119977548A discloses the preparation and application of a YAG transparent ceramic suspension for plasma spraying. The preparation method includes the following steps: ① Preparing commercially available high-purity 99.99% micron-sized Y2O3 powder into a slurry with a volume solid content of 14.0 vol.%~16.0 vol.%, adding a polyacrylic acid anionic dispersant, and then ball milling; ② Centrifuging the slurry obtained in step ① to remove the suspension, adding deionized water, and stirring with a high-speed mixer; ③ Centrifuging the slurry obtained in step ② twice, drying the wet material after removing the suspension, sieving, and calcining; ④ Mixing the Y2O3 powder obtained in step ③ with commercially available high-purity 99.99% Al2O3 powder in a stoichiometric ratio of Y3Al5O 12Weigh the slurry, using anhydrous ethanol as solvent and polyethyleneimine as dispersant, adjust the slurry's solid content to 35wt.%~40wt.%, ball mill for 15h~30h, then add 3wt.%~6wt.% PVB (total mass of Y2O3 and Al2O3 powders), and continue ball milling for 12h~15h; ⑤ Spray granulation of the slurry obtained in step ④ is performed at a spray atomization speed of 8000r / min and a hot air temperature of 85℃~90℃ to obtain Y2O3-Al2O3 spherical powder; sieve to obtain high-flowability powder; ⑥ Calcine the powder obtained in step ⑤, dry grind the powder, and sieve; then classify it using an ultrasonic vibrating sieve, taking powder with a mesh size of 325 or larger for subsequent plasma spraying; ⑦ Prepare a suspension of the powder obtained in step ⑥ with a volume solid content of 10vol.%~13vol.%, add ammonium polyacrylate dispersant to obtain the final product. The powder is prone to secondary agglomeration after sintering.

[0004] In summary, there is a need to develop a method for preparing ceramic powder for plasma spraying to reduce secondary agglomeration of the powder, improve its flowability, and reduce its angle of repose. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides a ceramic powder for plasma spraying and its preparation method. The powder is subjected to calcination, ultrasonic dispersion, sieving and drying treatments in sequence after spray granulation to reduce secondary agglomeration of the powder, improve the flowability of the powder and reduce the angle of repose of the powder.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing ceramic powder for plasma spraying, the method comprising: subjecting the powder after spray granulation to calcination, ultrasonic dispersion, sieving and drying in sequence to obtain the ceramic powder for plasma spraying.

[0008] This invention involves calcining the spray-granulated powder to induce sintering of the internal substances through solid-phase diffusion, reducing porosity and increasing the powder's density and strength. This makes the resulting ceramic powder for plasma spraying less prone to breakage during the spraying process. The powder is then subjected to ultrasonic dispersion, effectively breaking and dispersing particle agglomerates through shear force, impact force, and vortex flow effects, ensuring uniform dispersion in the liquid. This reduces secondary agglomeration, improves powder flowability, and lowers the angle of repose. The powder is then sieved and dried to obtain the plasma spraying ceramic powder. The plasma spraying ceramic powder prepared by this invention exhibits good stability, high coating quality, and high deposition efficiency during plasma spraying.

[0009] In this invention, the angle of repose, also known as the angle of rest, is the smallest angle between the inclined plane and the horizontal surface when the object placed on it is in a critical state of sliding down the inclined plane (that is, as the angle of inclination increases, the object on the inclined plane will slide down more easily; the angle of the critical state when the object reaches the state of starting to slide down is called the angle of repose).

[0010] As a preferred technical solution of the present invention, the purity of the ceramic material in the powder after spray granulation is 96-99%, for example, it can be 96%, 97%, 98% or 99%, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0011] Preferably, the ceramic material comprises carbides.

[0012] Preferably, the carbide comprises B4C and / or WC-Co.

[0013] Preferably, the particle size of the powder after spray granulation is 20~150μm, for example, it can be 20μm, 30μm, 50μm, 80μm, 120μm or 150μm, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0014] In this invention, carbides with a particle size of 20~150μm after spray granulation are sequentially subjected to calcination, ultrasonic dispersion, sieving, and drying to obtain ceramic powder for plasma spraying. This reduces secondary agglomeration of the powder, improves its flowability, and lowers its angle of repose. This is because larger particles only require lower energy to break up secondary agglomeration. If ultrasonic dispersion is replaced with wet polishing, the large particles will break into irregular small particles, which will reduce the flowability of the powder.

[0015] As a preferred technical solution of the present invention, the calcination temperature is 1200~2200℃, for example, it can be 1200℃, 1400℃, 1600℃, 1800℃, 2000℃ or 2200℃, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0016] Preferably, the calcination treatment includes vacuum calcination treatment and / or pressureless calcination treatment.

[0017] Preferably, the calcination treatment is carried out under a protective atmosphere.

[0018] Preferably, the protective atmosphere includes argon.

[0019] Preferably, the calcination time is 1 to 8 hours, for example, 1 hour, 2 hours, 4 hours, 6 hours or 8 hours, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0020] Preferably, the dispersion medium for the ultrasonic dispersion treatment includes water.

[0021] Preferably, the power of the ultrasonic dispersion treatment is 300~1000W, for example, it can be 300W, 400W, 500W, 600W, 700W, 800W, 900W or 1000W, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0022] This invention limits the ultrasonic dispersion power to 300-1000W to effectively break down and disperse particle agglomerates through the shear force, impact force, and vortex flow effects of ultrasonic dispersion, ensuring uniform dispersion in the liquid. This reduces secondary agglomeration of the powder, improves powder flowability, and lowers the angle of repose. If the ultrasonic dispersion power is less than 300W, the powder cannot be effectively broken down, resulting in poor particle uniformity. Furthermore, the core of the powder may not reach its melting point during plasma spraying, leading to decreased deposition efficiency. If the ultrasonic dispersion power is greater than 1000W, the powder will be excessively broken down, resulting in excessively small particle sizes. In this case, the powder has a very large specific surface area, and the van der Waals forces and electrostatic forces between powder particles far exceed their gravity, leading to severe agglomeration and clumping, and extremely poor flowability.

[0023] Preferably, the ultrasonic dispersion treatment time is 2 to 8 hours, for example, it can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours or 8 hours, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0024] This invention limits the ultrasonic dispersion treatment time to 2-8 hours. This utilizes the shear force, impact force, and vortex flow effects of ultrasonic dispersion to effectively break down and disperse particle agglomerates, ensuring uniform dispersion in the liquid. This reduces secondary agglomeration of the powder, improves powder flowability, and lowers the angle of repose. If the ultrasonic dispersion treatment time is less than 2 hours, the powder cannot be effectively broken down, resulting in poor particle uniformity. Furthermore, the core of the powder may not reach its melting point during plasma spraying, leading to decreased deposition efficiency. If the ultrasonic dispersion treatment time is greater than 8 hours, the powder will be excessively broken down, resulting in excessively small particle sizes. In this case, the powder has a very large specific surface area, and the van der Waals forces and electrostatic forces between powder particles far exceed their gravity, leading to severe agglomeration and clumping, and extremely poor flowability.

[0025] Preferably, the particle size of the powder after ultrasonic dispersion is 20~100μm, for example, it can be 20μm, 40μm, 50μm, 60μm, 80μm or 100μm, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0026] As a preferred technical solution of the present invention, the screening process includes: screening using a 100-200 mesh sieve, for example, it can be 100 mesh, 150 mesh or 200 mesh, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0027] Preferably, the drying temperature is 40~80℃, for example, it can be 40℃, 50℃, 60℃, 70℃, 75℃ or 80℃, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0028] It should be noted that the drying process in this invention is carried out in a vacuum drying oven.

[0029] Preferably, the drying time is 2 to 8 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours or 8 hours, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0030] As a preferred embodiment of the present invention, the preparation of the powder after spray granulation includes the following steps:

[0031] (1) The ceramic material, binder, dispersant, defoamer and solvent are mixed to obtain a slurry;

[0032] (2) Spray granulation is performed on the slurry to obtain the spray granulated powder.

[0033] This invention first prepares a slurry by mixing ceramic materials with binders, dispersants, defoamers, and solvents. This is because ceramic materials have extremely poor flowability, causing bridging and blockage in the powder feeder, preventing them from being stably and uniformly fed into the plasma jet by the carrier gas. The binder's role is to enable the granulated powder to withstand the mechanical impact during transportation and feeding, preventing the powder particles from breaking before reaching the plasma jet. The dispersant ensures that the ceramic materials, binders, and other components are uniformly distributed in the solvent, preventing sedimentation. This ensures that each atomized droplet in the spray granulation process contains a micro-mixture of all components. After drying, each spray-granulated powder particle has a highly consistent chemical composition. The defoamer's role is to eliminate air bubbles generated during mixing and conveying the slurry, preventing hollow spheres in the granulated powder, thereby ensuring the powder's density and thermal conductivity. The slurry is then spray-granulated to prepare spherical powder with excellent flowability and controllable particle size, facilitating subsequent processing.

[0034] As a preferred embodiment of the present invention, the ceramic material includes carbides.

[0035] Preferably, the carbide comprises B4C and / or WC-Co.

[0036] Preferably, the adhesive comprises any one or a combination of at least two of polyvinyl alcohol (PVA), polyvinyl butyral (PVB), or sodium carboxymethyl cellulose (CMC), wherein typical but non-limiting combinations include: a combination of polyvinyl alcohol and polyvinyl butyral, a combination of polyvinyl alcohol and sodium carboxymethyl cellulose, a combination of polyvinyl butyral and sodium carboxymethyl cellulose, and a combination of polyvinyl alcohol, polyvinyl butyral, and sodium carboxymethyl cellulose.

[0037] Preferably, the dispersant comprises an amino alcohol and / or an ammonium polycarboxylate salt.

[0038] Preferably, the defoamer comprises polyether and / or silicone.

[0039] Preferably, the solvent includes water and / or an organic solvent.

[0040] As a preferred technical solution of the present invention, the mass ratio of ceramic material, binder, dispersant, defoamer and solvent in the mixing process is (20~50):(0.5~2):(0.3~1):(0.01~0.05):1, for example, it can be 20:0.5:0.3:0.01:1, 20:2:1:0.05:1, 40:1:0.5:0.03:1, 40:0.5:0.3:0.01:1 or 50:2:1:0.05:1, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0041] Preferably, the mixing is carried out in a ball mill.

[0042] Preferably, the rotational speed of the ball mill is 200~500 r / min, for example, it can be 200 r / min, 300 r / min, 400 r / min or 500 r / min, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0043] Preferably, the ball milling time is 60 to 180 minutes, for example, 60 minutes, 90 minutes, 120 minutes, 150 minutes or 180 minutes, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0044] As a preferred technical solution of the present invention, the temperature of the spray granulation is 70~250℃, for example, it can be 70℃, 100℃, 180℃, 220℃ or 250℃, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0045] Preferably, the rotation speed of the spray granulation is 15,000 to 25,000 r / min, for example, it can be 15,000 r / min, 17,000 r / min, 20,000 r / min, 23,000 r / min or 25,000 r / min, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0046] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0047] (1) The ceramic material, binder, dispersant, defoamer and solvent are mixed in a mass ratio of (20~50):(0.5~2):(0.3~1):(0.01~0.05):1 to obtain a slurry;

[0048] (2) The slurry is sprayed at a temperature of 70~250℃ and a rotation speed of 15000~25000r / min to obtain spray-granulated powder;

[0049] (3) The powder after spray granulation is subjected to calcination treatment at a temperature of 1200~2200℃ for 1~8h, ultrasonic dispersion treatment at a power of 300~1000W for 2~8h, sieving treatment, and drying treatment at a temperature of 40~80℃ for 2~8h to obtain the ceramic powder for plasma spraying.

[0050] In a second aspect, the present invention provides a ceramic powder for plasma spraying, wherein the ceramic powder for plasma spraying is prepared by the preparation method described in the first aspect.

[0051] The ceramic powder for plasma spraying provided by this invention has good flowability and a small angle of repose.

[0052] Compared with the prior art, the present invention has at least the following beneficial effects:

[0053] This invention reduces secondary agglomeration of powder, improves powder flowability, and lowers the angle of repose of powder by sequentially subjecting the powder after spray granulation to calcination, ultrasonic dispersion, sieving, and drying. The angle of repose of the powder is controlled to be below 35°. Attached Figure Description

[0054] Figure 1This is a SEM image of the ceramic powder for plasma spraying provided in Embodiment 1 of the present invention.

[0055] Figure 2 This is a SEM image of the ceramic powder for plasma spraying provided in Embodiment 5 of the present invention.

[0056] Figure 3 This is a SEM image of the ceramic powder for plasma spraying provided in Comparative Example 1 of the present invention. Detailed Implementation

[0057] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0058] Example 1

[0059] This embodiment provides a method for preparing ceramic powder for plasma spraying, the method comprising the following steps:

[0060] (1) B4C, polyvinyl alcohol (brand name: AQ4104), amino alcohol (PRODUKT KV 5088, Sima Chemical), polyether (HF-910, Hengbin) and water were ball-milled at a speed of 300 r / min for 120 min in a mass ratio of 40:1:0.5:0.03:1 to obtain a slurry;

[0061] (2) The slurry is spray-granulated at a temperature of 250°C and a rotation speed of 20,000 r / min to obtain spray-granulated powder with a particle size of 40~150 μm; wherein the purity of B4C in the spray-granulated powder is 98%;

[0062] (3) Under argon atmosphere, 180g of spray-granulated powder was subjected to vacuum pressureless calcination at a temperature of 2100℃ for 4h to obtain calcined powder.

[0063] (4) The calcined powder is added to a 22.5L ultrasonic dispersion device and 10L of water is added. The ultrasonic dispersion is carried out at a power of 500W for 4 hours to obtain ultrasonically dispersed powder with a particle size of 20~80μm.

[0064] (5) The powder after ultrasonic dispersion was sieved using a 150-mesh sieve to remove large particles. The sieved powder was then dried in a vacuum drying oven at 70°C for 6 hours to obtain the ceramic powder for plasma spraying. The SEM image of the ceramic powder for plasma spraying is shown below. Figure 1 As shown.

[0065] Example 2

[0066] This embodiment provides a method for preparing ceramic powder for plasma spraying, the method comprising the following steps:

[0067] (1) WC-Co, polyvinyl butyral (Maclean P697959), polycarboxylate ammonium salt (CE64, Sima Chemical), organosilicon (HF900, Hengbin) and isopropanol (Aowei Chemical) were ball-milled at a speed of 200 r / min for 180 min in a mass ratio of 50:0.5:0.3:0.01:1 to obtain a slurry;

[0068] (2) The slurry is spray-granulated at a temperature of 70°C and a rotation speed of 25000 r / min to obtain spray-granulated powder with a particle size of 40~60 μm; wherein the purity of WC-Co in the spray-granulated powder is 98%;

[0069] (3) Under argon atmosphere, 150g of spray-granulated powder was subjected to vacuum calcination at 1200℃ for 8h to obtain calcined powder.

[0070] (4) The calcined powder is added to a 22.5L ultrasonic dispersion device and 10L of water is added. The ultrasonic dispersion is performed at a power of 1000W for 2 hours to obtain ultrasonically dispersed powder with a particle size of 40~60μm.

[0071] (5) Use a 200-mesh sieve to sieve the powder after ultrasonic dispersion to remove large particles, and dry the sieved powder in a vacuum drying oven at a temperature of 100°C for 8 hours to obtain the ceramic powder for plasma spraying.

[0072] Example 3

[0073] This embodiment provides a method for preparing ceramic powder for plasma spraying, the method comprising the following steps:

[0074] (1) B4C, sodium carboxymethyl cellulose (Maclean), ammonium polycarboxylate (MQ-5088, Meiqilin), polyether (K1012, Sima Chemical) and water were ball-milled at a speed of 500 r / min for 60 min in a mass ratio of 20:2:1:0.05:1 to obtain a slurry;

[0075] (2) The slurry is spray-granulated at a temperature of 250°C and a rotation speed of 15000 r / min to obtain spray-granulated powder with a particle size of 80~100 μm; wherein the purity of B4C in the spray-granulated powder is 97%;

[0076] (3) Under argon atmosphere, 200g of spray-granulated powder was subjected to pressureless calcination at 2200℃ for 1h to obtain calcined powder;

[0077] (4) The calcined powder is added to a 22.5L ultrasonic dispersion device and 10L of water is added. The ultrasonic dispersion is carried out at a power of 300W for 8 hours to obtain ultrasonically dispersed powder with a particle size of 80~100μm.

[0078] (5) Use a 100-mesh sieve to sieve the powder after ultrasonic dispersion to remove large particles, and dry the sieved powder in a vacuum drying oven at a temperature of 80°C for 4 hours to obtain the ceramic powder for plasma spraying.

[0079] Example 4

[0080] This embodiment provides a method for preparing ceramic powder for plasma spraying. The only difference from Embodiment 1 is that the power of ultrasonic dispersion treatment in step (4) is adjusted from 500W to 200W. All other aspects are the same as in Embodiment 1.

[0081] Example 5

[0082] This embodiment provides a method for preparing ceramic powder for plasma spraying. The only difference from Embodiment 1 is that the power of ultrasonic dispersion in step (4) is adjusted from 500W to 1500W. All other aspects are the same as in Embodiment 1, and the SEM image of the ceramic powder for plasma spraying is shown below. Figure 2 As shown.

[0083] Example 6

[0084] This embodiment provides a method for preparing ceramic powder for plasma spraying. The only difference from Embodiment 1 is that the ultrasonic dispersion treatment time in step (4) is adjusted from 4 hours to 1 hour. All other aspects are the same as in Embodiment 1.

[0085] Example 7

[0086] This embodiment provides a method for preparing ceramic powder for plasma spraying. The only difference from Embodiment 1 is that the ultrasonic dispersion treatment time in step (4) is adjusted from 4h to 10h, while the rest is the same as in Embodiment 1.

[0087] Comparative Example 1

[0088] This comparative example provides a method for preparing ceramic powder for plasma spraying. The only difference from Example 1 is that step (4) and the drying process in step (5) are not included in the preparation method. Specifically, the calcined powder is directly sieved to obtain the ceramic powder for plasma spraying. Otherwise, the method is identical to Example 1, and the SEM image of the ceramic powder for plasma spraying is shown below. Figure 3 As shown.

[0089] Since the powder in this comparative example is dry powder after calcination and has not undergone ultrasonic dispersion, there is no need to perform the drying process in step (5).

[0090] Comparative Example 2

[0091] This comparative example provides a method for preparing ceramic powder for plasma spraying. The only difference between this method and Example 1 is that step (4) is not included in the preparation method, i.e., the powder after calcination is directly sieved. All other aspects are the same as in Example 1.

[0092] The angle of repose of the ceramic powders for plasma spraying obtained in Examples 1-7 and Comparative Examples 1-2 was measured using an angle of repose tester. The particle breakage of the ceramic powders for plasma spraying was observed using a scanning electron microscope. At the same time, the purity of the ceramic material in the ceramic powders for plasma spraying was measured using an inductively coupled plasma emission spectrometer. The test results are shown in Table 1.

[0093] Table 1

[0094]

[0095] The test results show that:

[0096] (1) As can be seen from Examples 1 to 3, the present invention reduces secondary agglomeration of powder, improves powder flowability, and reduces the angle of repose of powder by ultrasonic dispersion of calcined powder, and controls the angle of repose of ceramic powder for plasma spraying to below 35°.

[0097] (2) As can be seen from Examples 1 and 4-5, the ultrasonic dispersion power in Example 1 is 500W, the angle of repose of the resulting ceramic powder for plasma spraying is 32°, and the powder particles are not broken; while in Example 4 the ultrasonic dispersion power is 200W, the angle of repose of the resulting ceramic powder for plasma spraying is 43°, and the powder particles are not broken; in Example 5 the ultrasonic dispersion power is 1500W, the angle of repose of the resulting ceramic powder for plasma spraying is 42°, and the powder particles are broken. This shows that the power of ultrasonic dispersion in this invention affects the flowability of the ceramic powder for plasma spraying. Too low a power will not achieve the dispersion effect, and too high a power will cause the powder particles to break, and will not achieve the effect of improving the flowability of the powder.

[0098] (3) As can be seen from Examples 1 and 6-7, the ultrasonic dispersion treatment time in Example 1 is 4 hours, and the angle of repose of the resulting ceramic powder for plasma spraying is 32°, and the powder particles are not broken; while the ultrasonic dispersion treatment time in Example 6 is 1 hour, and the angle of repose of the resulting ceramic powder for plasma spraying is 40°, and the powder particles are not broken; while the ultrasonic dispersion treatment time in Example 7 is 10 hours, and the angle of repose of the resulting ceramic powder for plasma spraying is 41°, and the powder particles are broken. This shows that the ultrasonic dispersion treatment time in the present invention affects the flowability of the ceramic powder for plasma spraying. If the time is too short, the dispersion effect cannot be achieved, and if the time is too long, the powder particles will break, and the effect of improving the flowability of the powder cannot be achieved.

[0099] (4) As can be seen from Example 1 and Comparative Examples 1-2, the present invention can reduce the secondary agglomeration of powder, improve the flowability of powder, and reduce the angle of repose of powder by ultrasonic dispersion treatment of calcined powder.

[0100] In summary, this invention reduces secondary agglomeration of powder, improves powder flowability, and lowers the angle of repose of powder by sequentially subjecting the powder after spray granulation to calcination, ultrasonic dispersion, sieving, and drying. Furthermore, it controls the angle of repose of the ceramic powder for plasma spraying to below 35°.

[0101] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing ceramic powder for plasma spraying, characterized in that, The preparation method includes: sequentially subjecting the spray-granulated powder to calcination, ultrasonic dispersion, sieving, and drying to obtain the ceramic powder for plasma spraying.

2. The preparation method according to claim 1, characterized in that, The purity of the ceramic material in the powder after spray granulation is 96-99%. Preferably, the ceramic material comprises carbides; Preferably, the carbide comprises B4C and / or WC-Co; Preferably, the particle size of the powder after spray granulation is 20~150μm.

3. The preparation method according to claim 1 or 2, characterized in that, The calcination temperature is 1200~2200℃; Preferably, the calcination treatment includes vacuum calcination treatment and / or pressureless calcination treatment; Preferably, the calcination treatment is carried out under a protective atmosphere; Preferably, the protective atmosphere includes argon; Preferably, the calcination treatment time is 1-8 hours; Preferably, the dispersion medium for the ultrasonic dispersion treatment includes water; Preferably, the power of the ultrasonic dispersion treatment is 300~1000W; Preferably, the ultrasonic dispersion treatment time is 2-8 hours; Preferably, the particle size of the powder after ultrasonic dispersion treatment is 20~100μm.

4. The preparation method according to any one of claims 1-3, characterized in that, The screening process includes: screening using a 100-200 mesh sieve; Preferably, the drying temperature is 40~80℃; Preferably, the drying process takes 2 to 8 hours.

5. The preparation method according to any one of claims 1-4, characterized in that, The preparation of the powder after spray granulation includes the following steps: (1) The ceramic material, binder, dispersant, defoamer and solvent are mixed to obtain a slurry; (2) Spray granulation is performed on the slurry to obtain the spray granulated powder.

6. The preparation method according to claim 5, characterized in that, The ceramic material includes carbides; Preferably, the carbide comprises B4C and / or WC-Co; Preferably, the adhesive comprises any one or a combination of at least two of polyvinyl alcohol, polyvinyl butyral, or sodium carboxymethyl cellulose; Preferably, the dispersant comprises an amino alcohol and / or an ammonium polycarboxylate salt; Preferably, the defoamer comprises polyether and / or silicone; Preferably, the solvent includes water and / or an organic solvent.

7. The preparation method according to claim 5 or 6, characterized in that, The mass ratio of ceramic material, binder, dispersant, defoamer, and solvent in the mixing process is (20~50):(0.5~2):(0.3~1):(0.01~0.05):1; Preferably, the mixing is carried out in a ball mill; Preferably, the rotational speed of the ball mill is 200~500 r / min; Preferably, the ball milling time is 60-180 minutes.

8. The preparation method according to any one of claims 5-7, characterized in that, The spray granulation temperature is 70~250℃; Preferably, the rotation speed of the spray granulation is 15000~25000 r / min.

9. The preparation method according to any one of claims 1-8, characterized in that, The preparation method includes the following steps: (1) The ceramic material, binder, dispersant, defoamer and solvent are mixed in a mass ratio of (20~50):(0.5~2):(0.3~1):(0.01~0.05):1 to obtain a slurry; (2) The slurry is sprayed at a temperature of 70~250℃ and a rotation speed of 15000~25000r / min to obtain spray-granulated powder; (3) The powder after spray granulation is subjected to calcination treatment at a temperature of 1200~2200℃ for 1~8h, ultrasonic dispersion treatment at a power of 300~1000W for 2~8h, sieving treatment, and drying treatment at a temperature of 40~80℃ for 2~8h to obtain the ceramic powder for plasma spraying.

10. A ceramic powder for plasma spraying, characterized in that, The ceramic powder for plasma spraying is prepared using the preparation method described in any one of claims 1-9.

Images