High-entropy ceramic slurry for photocuring forming and preparation method thereof

Abstract

The invention relates to the technical field of advanced ceramic material additive manufacturing, in particular to high-entropy ceramic slurry for photocuring forming and a preparation method of the high-entropy ceramic slurry, and the slurry is prepared from the following raw materials in parts by mass: 55-75 parts of high-entropy ceramic powder, 20-35 parts of reactive diluent, 10-20 parts of oligomer, 1-3 parts of photoinitiator, 2-4 parts of dispersing agent and 0.1-0.5 part of defoaming agent. The high-entropy ceramic powder with specific particle size distribution is adopted, and the synergistic combination of the water-based resin system and the dispersing agent is preferably selected, so that the technical problems of high viscosity and poor stability of the high-solid-content ceramic slurry in photocuring printing are effectively solved. The prepared slurry has the characteristics of high solid content, low viscosity, good storage stability, high curing rate and the like, is suitable for 3D printing processes such as surface projection photocuring and the like, and can be used for obtaining high-precision and high-density complex-structure high-entropy ceramic parts after printing, degreasing and sintering.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology for high-performance ceramic materials, and specifically relates to a high-entropy ceramic slurry with high solids content, low viscosity, and high stability suitable for 3D printing technologies such as surface projection photopolymerization (SLA / DLP) and its preparation method. Background Technology

[0002] High-entropy ceramics are a new type of ceramic material composed of four or more main metals or rare earth elements in equimolar or near-equimolar ratios. Their high-entropy effect, lattice distortion effect, and hysteresis diffusion effect endow them with significantly higher strength, toughness, excellent thermal stability, and corrosion resistance than traditional ceramics, making them promising for applications in thermal barrier coatings, nuclear waste solidification, and high-temperature structural components. However, the extremely high hardness and melting point of high-entropy ceramics make it difficult to process complex components using traditional subtractive manufacturing methods.

[0003] Photopolymerization 3D printing technology enables rapid, moldless molding of complex ceramic parts. The key to this technology lies in preparing a high-performance ceramic slurry, requiring a high solids content (typically >50 vol%) to ensure the density of the sintered body, while also possessing low viscosity (typically <3 Pa·s@30s). -1 To ensure good leveling and printing accuracy, high-entropy ceramic powders need to possess good stability to prevent particle sedimentation. Currently, due to their large density differences and high surface energy, high-entropy ceramic powders are prone to particle agglomeration, leading to a sharp increase in the viscosity of high-solids content slurries. This results in problems such as uneven layup and increased defects during the printing process. Existing technologies often struggle to balance high solids content and low viscosity, limiting the application of high-entropy ceramics in additive manufacturing. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-entropy ceramic slurry with high solid content, low viscosity, good stability, and suitable for photocuring molding, as well as its preparation method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A high-entropy ceramic slurry for photocuring comprises the following components by mass: 55-75 parts high-entropy ceramic powder, 20-35 parts reactive diluent, 10-20 parts oligomer, 1-3 parts photoinitiator, 2-4 parts dispersant, and 0.1-0.5 parts defoamer.

[0006] Preferably, the high-entropy ceramic powder is a single-phase solid solution composed of carbides, borides, or oxides of five or more rare earth or transition metal elements, with a D50 particle size of 0.3-1.0 μm and a D100 particle size ≤ 5 μm. More preferably, the high-entropy ceramic powder is a high-entropy rare earth zirconate with the composition (Gd,Y,Sm,La,Dy)₂Zr₂O₇.

[0007] Preferably, the reactive diluent is one or a combination of two of 1,6-hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate (TMPTA); the oligomer is waterborne polyurethane acrylate (PUA) with a functionality of 2-3.

[0008] Preferably, the dispersant is a polycarboxylate-type polymeric dispersant; the photoinitiator is phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (819); and the defoamer is an organosilicon defoamer.

[0009] This invention also provides a method for preparing the above-mentioned high-entropy ceramic slurry, comprising the following steps: S1: Mix all oligomers, reactive diluents, dispersants and defoamers, and stir with a high-speed shear mixer at 800-1200 rpm for 10-15 minutes to obtain a uniform resin matrix; S2: Add the high-entropy ceramic powder to the resin matrix in 2-4 batches. After each batch is added, first use a planetary mixer to mix at a low speed of 100-300 rpm for 10 minutes, and then use a high-speed shear machine to disperse at a speed of 1500-2000 rpm for 5 minutes. S3: The slurry obtained in step S2 is ball-milled for 2-4 hours, using zirconia grinding balls with a ball-to-material ratio of 2:1 to 4:1. S4: Add photoinitiator to the ball-milled slurry, and under light-proof and vacuum conditions, use a planetary centrifugal mixer to degas and mix for 3-8 minutes at a revolution speed of 1000-2000 rpm and a rotation speed of 500-1000 rpm. The vacuum degree is controlled at -0.08~-0.1 MPa to obtain the final slurry.

[0010] The beneficial effects of this invention are as follows: By selecting high-entropy ceramic powder with a specific particle size distribution (D50 of 0.3-1.0 μm, D100≤5 μm) and combining the synergistic effect of waterborne polyurethane acrylate oligomers and polycarboxylate dispersants, low viscosity (<2.8 Pa·s) with high solid content (up to 60 vol%) is achieved, with good slurry leveling properties, making it suitable for high-precision photopolymerization printing.

[0011] By combining stepwise mixing (low-speed premixing + high-speed shearing) with ball milling, the ceramic particles are fully dispersed and coated, effectively breaking down particle agglomerates and significantly improving the uniformity and stability of the slurry. No hard sedimentation was observed after 24 hours of standing.

[0012] The preparation method of this invention is simple, operates under mild conditions, and is easy to scale up for production. The resulting slurry cures quickly, exhibits high green strength, and the ceramic parts obtained after debinding and sintering have a complete structure, high dimensional accuracy, and a relative density of over 98%. Detailed Implementation

[0013] The present invention will be described in detail below through examples, but the invention is not limited thereto. Unless otherwise specified, all raw materials used are industrial grade.

[0014] Example 1 A high-entropy ceramic slurry for photocuring, comprising, by weight: High-entropy ceramic powder (Gd, Y, Sm, La, Dy)2Zr2O7 (D50=0.5μm, D100=4.5μm): 60 parts Reactive diluent HDDA: 25 parts Oligomer: Waterborne polyurethane acrylate (functionality = 2): 15 parts Photoinitiator 819: 1.5 parts Dispersant: Polycarboxylate dispersant: 3 parts Defoamer (organic silicone defoamer): 0.3 parts Preparation method: S1: Mix 15 parts of water-based PUA, 25 parts of HDDA, 3 parts of dispersant and 0.3 parts of defoamer, and stir at 1000 rpm for 12 minutes using a high-speed shear mixer to obtain the resin matrix.

[0015] S2: Add 60 parts of high-entropy ceramic powder to the resin matrix in three batches. After each batch is added, mix at low speed of 200 rpm for 10 minutes with a planetary mixer, and then disperse at 1800 rpm for 5 minutes with a high-speed shear mixer.

[0016] S3: Transfer the obtained slurry into a ball mill jar, use zirconia balls as the grinding medium (ball-to-material ratio 3:1), and ball mill for 3 hours.

[0017] S4: After ball milling, add 1.5 parts of photoinitiator 819, transfer to a planetary centrifugal mixer, and under vacuum of -0.09MPa and in the dark, degas and mix for 5 minutes at 1500rpm revolution and 800rpm rotation to obtain the slurry.

[0018] Performance testing:

[0019] Example 2: A high-entropy ceramic slurry for photocuring, comprising, by mass parts: High-entropy ceramic powder (Hf, Zr, Ti, Ta, Nb) C (D50=0.8μm, D100=4.0μm): 70 parts Reactive diluent TMPTA: 20 parts Oligomer: 10 parts of waterborne polyurethane acrylate (functionality = 3) Photoinitiator 819: 2 parts Dispersant: 3.5 parts polycarboxylate dispersant Defoamer: 0.4 parts silicone defoamer Preparation method: S1: Mixed resin matrix (1000 rpm / 15 min).

[0020] S2: Add ceramic powder in four batches, each batch is mixed at low speed (150 rpm / 10 min) and dispersed at high speed (2000 rpm / 5 min).

[0021] S3: Ball milling treatment (ball-to-material ratio 4:1, time 4 hours).

[0022] S4: Add photoinitiator, vacuum degassing and mixing (2000 rpm revolution, 1000 rpm rotation, vacuum degree -0.1 MPa, time 3 minutes).

[0023] Performance testing:

[0024] Example 3 A high-entropy ceramic slurry for photocuring, comprising, by weight: High-entropy ceramic powder (Al, Cr, Ti, V, Nb) B2 (D50=0.3μm, D100=3.0μm): 55 parts Reactive diluent HDDA / TMPTA (mass ratio 1:1): 28 parts Oligomer: Waterborne polyurethane acrylate (functionality = 2): 12 parts Photoinitiator 819: 1.2 parts Dispersant: Polycarboxylate dispersant: 2.5 parts Defoamer: Organosilicon defoamer: 0.2 parts Preparation method: S1: Mix 12 parts of water-based PUA, 28 parts of mixed reactive diluent, 2.5 parts of dispersant and 0.2 parts of defoamer, and stir at 800 rpm for 15 minutes using a high-speed shear mixer to obtain the resin matrix.

[0025] S2: Add 55 parts of high-entropy boride powder to the resin matrix in two batches. After each batch is added, mix at low speed of 300 rpm for 10 minutes using a planetary mixer, and then disperse at high speed of 1500 rpm for 5 minutes using a high-speed shear mixer.

[0026] S3: The obtained slurry is ball-milled with zirconia grinding balls at a ball-to-material ratio of 2:1 for 2 hours.

[0027] S4: Add 1.2 parts of photoinitiator 819 to the ball-milled slurry. Under light-proof conditions and a vacuum of -0.08 MPa, use a planetary centrifugal mixer at a revolution speed of 1000 rpm and a rotation speed of 500 rpm for 8 minutes to degas and mix, thus obtaining the final slurry.

[0028] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-entropy ceramic slurry for photocuring molding, characterized in that, It includes the following components by mass: 55-75 parts high-entropy ceramic powder, 20-35 parts reactive diluent, 10-20 parts oligomer, 1-3 parts photoinitiator, 2-4 parts dispersant, and 0.1-0.5 parts defoamer.

2. The high-entropy ceramic slurry for photocuring as described in claim 1, characterized in that: The high-entropy ceramic powder is a single-phase solid solution composed of carbides, borides or oxides of five or more rare earth or transition metal elements, with a D50 particle size of 0.3-1.0 μm and a D100 particle size ≤5 μm.

3. The high-entropy ceramic slurry for photocuring as described in claim 2, characterized in that: The high-entropy ceramic powder is a high-entropy rare earth zirconate with the composition (Gd,Y,Sm,La,Dy)2Zr2O7.

4. The high-entropy ceramic slurry for photocuring as described in claim 1, characterized in that: The reactive diluent is one or a combination of two of 1,6-hexanediol diacrylate and trimethylolpropane triacrylate; the oligomer is a waterborne polyurethane acrylate with a functionality of 2-3.

5. The high-entropy ceramic slurry for photocuring as described in claim 1, characterized in that: The dispersant is a polycarboxylate-type polymeric dispersant.

6. The high-entropy ceramic slurry for photocuring as described in claim 1, characterized in that: The photoinitiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

7. The high-entropy ceramic slurry for photocuring as described in claim 1, characterized in that: The defoamer is an organosilicon defoamer.

8. A method for preparing the high-entropy ceramic slurry as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Mix all oligomers, reactive diluents, dispersants and defoamers, and stir with a high-speed shear mixer at 800-1200 rpm for 10-15 minutes to obtain a uniform resin matrix; S2: Add the high-entropy ceramic powder to the resin matrix in 2-4 batches. After each batch is added, first use a planetary mixer to mix at a low speed of 100-300 rpm for 10 minutes, and then use a high-speed shear machine to disperse at a speed of 1500-2000 rpm for 5 minutes. S3: The slurry obtained in step S2 is ball-milled for 2-4 hours. S4: Add a photoinitiator to the ball-milled slurry, and under light-protected conditions, use a planetary centrifugal mixer at a revolution speed of 1000-2000 rpm and a rotation speed of 500-1000 rpm to degas and mix for 3-8 minutes to obtain the high-entropy ceramic slurry.

9. The method according to claim 8, characterized in that: In step S3, the ball mill uses zirconia grinding balls with a ball-to-material ratio of 2:1 to 4:

1.

10. The method according to claim 8, characterized in that: In step S4, the degassing and mixing are carried out under vacuum conditions, with a vacuum degree of -0.08 to -0.1 MPa.

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