Deformation-controllable photocuring 3D printing ceramic core slurry and preparation method thereof

Abstract

The invention provides deformation-controllable photocuring 3D printing ceramic core slurry and a preparation method thereof.The deformation-controllable photocuring 3D printing ceramic core slurry is prepared from, by mass, 62%-83% of modified ceramic powder, 15%-30% of acrylic photosensitive resin, 1%-4% of photoinitiator and the balance other auxiliaries; the preparation method comprises the following steps: adding a dispersing agent into absolute ethyl alcohol, and uniformly stirring to prepare a solution; mixing the graded ceramic matrix powder and the deformation control agent with absolute ethyl alcohol and a dispersing agent, and carrying out ball milling to obtain a slurry mixture; naturally drying the mixture, drying in a drying oven, and sieving to obtain modified ceramic powder; and adding the modified ceramic powder, acrylic photosensitive resin, a photoinitiator and other auxiliaries into a homogenizer, and homogenizing to obtain the ceramic core slurry. The method has the advantages that the method is suitable for preparing the photocuring 3D printing ceramic core slurry which is high in solid phase content, good in stability, controllable in sintering deformation and good in physical performance.

Description

Technical Field

[0001] The present invention relates to the technical field of photocurable 3D printing ceramic materials, and in particular to a photocurable 3D printing ceramic core slurry with controllable deformation and a preparation method thereof. Background Art

[0002] Aircraft engines are core components that provide power for aircraft, and their future development direction is to improve thrust-to-weight ratio. Therefore, hollow turbine blades, which are the most important factors in determining engine performance, have become the top priority in research and development. Ceramic cores are the key to forming the complex cooling structure of the inner cavity of hollow turbine blades. At present, the internal cooling structure of hollow blades has developed from single convection air cooling to double-wall super air cooling. For the development of such complex new blades, traditional core preparation methods such as gel injection molding and hot injection molding require the preparation of multiple sets of molds in advance, resulting in a long production cycle for blade development. Therefore, an efficient ceramic core preparation method is urgently needed.

[0003] In recent years, additive manufacturing technology, also known as 3D printing technology, has developed rapidly and has been applied to the production of parts of various complex shapes. 3D printing technology has the advantages of fast molding speed, high model freedom, less material waste, and high dimensional accuracy of finished products. At present, the most widely studied and applied 3D printing technology for ceramic materials is light-curing 3D printing technology, which mainly includes stereolithography (SLA) and digital light processing (DLP).

[0004] Photocuring 3D printing technology has the advantages of high printing accuracy and the ability to form complex structural models. Since ceramic powder cannot solidify by itself, it needs to be mixed with organic photosensitive resin to form slurry. The current mainstream ceramic core printing materials include silicon oxide, aluminum oxide and zirconium oxide, etc., and the existing ceramic slurry has the following problems: single ceramic powder particle size, low slurry solid content, poor stability, etc. In addition, the removal of photosensitive resin and the densification of ceramic particles during degreasing-sintering cause the ceramic core to have a larger dimensional deformation than the three-dimensional model, and it is impossible to retain the dimensional accuracy advantage of 3D printing; in addition, the ceramic core has poor physical properties and poor high-temperature creep resistance, so it has not been widely used in the field of investment casting.

[0005] Therefore, it is urgently necessary to develop a deformation-controllable photocuring 3D printing ceramic core slurry and its preparation method, control the deformation caused by the sintering process of the ceramic core from the perspective of raw materials, thereby improving the dimensional accuracy and physical properties of the 3D printed ceramic core, solving the existing problems in the preparation of ceramic cores by photocuring 3D printing, and promoting the further development of 3D printed ceramic cores. Summary of the invention

[0006] The purpose of the present invention is to solve the problems of poor slurry performance, uncontrollable deformation and poor physical properties of photocurable 3D printing ceramic cores, and to provide a photocurable 3D printing ceramic core slurry with high solid content, good stability, controllable sintering deformation, good physical properties and controllable deformation, and a preparation method thereof.

[0007] The present invention provides a light-cured 3D printing ceramic core slurry with controllable deformation, which comprises, by mass ratio:

[0008] Modified ceramic powder 62%~83%;

[0009] Acrylic photosensitive resin 15% to 30%;

[0010] Photoinitiator 1% to 4%;

[0011] The balance is other additives;

[0012] Wherein, the modified ceramic powder comprises, by mass ratio:

[0013] Ceramic matrix powder 65% to 88%;

[0014] Deformation control agent 10% to 30%;

[0015] The balance is dispersant.

[0016] A method for preparing a deformation-controllable light-cured 3D printing ceramic core slurry comprises the following steps:

[0017] S1. Ceramic powder modification: mixing graded ceramic matrix powder and deformation control agent with anhydrous ethanol and dispersant, ball milling to obtain a slurry mixture, drying the mixture naturally, drying in an oven, and sieving to obtain modified ceramic powder;

[0018] S2, preparing ceramic core slurry: adding the ceramic powder obtained in step S1, acrylic photosensitive resin, photoinitiator and other additives into a homogenizer, and homogenizing to obtain ceramic core slurry.

[0019] In step S1, the ceramic matrix powder is one or more of SiO2, Al2O3, ZrO2, and Y2O3, and the ceramic matrix powder is composed of powders with a particle size of 5μm to 10μm and a particle size of 25μm to 35μm, wherein the powders with a particle size of 5μm to 10μm account for 10% to 40% of the total mass of the ceramic matrix powder, and the powders with a particle size of 25μm to 35μm account for 60% to 90% of the total mass of the ceramic matrix powder; the deformation controller is one or more of SiO2, Al2O3, ZrO2, Y2O3, MgO, and TiO2, and the particle size of the deformation controller is 10nm to 500nm.

[0020] In step S1, the dispersant includes a mixture of one or more of DISPERBYK-110, methacrylic acid, ammonium polymethacrylate, polyoxypropyl polyoxyethyl glycerol ether and polyvinyl pyrrolidone, and the amount of anhydrous ethanol added is 30% to 40% of the total mass of the ceramic powder.

[0021] In step S1, the process parameters of the ball milling are: the ball milling speed is 400r / min-600r / min, the ball milling time is 1h-3h, the ball milling equipment is a planetary ball mill, the ball milling medium is zirconium silicate balls, the natural drying time is 18h-24h, the drying temperature is 100℃-150℃, the drying time is 1h-3h, and the sieving is 80-mesh sieve 150-mesh sieve.

[0022] In step S1, the acrylic photosensitive resin is a mixture of one or more of polyurethane acrylate, propoxylated neopentyl glycol diacrylate, trimethylolpropane triacrylate and 1,6-hexanediol diacrylate;

[0023] The photoinitiator is a mixture of one or more of 1-hydroxycycloethyl benzophenone, phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide and 2,4,6-trimethylbenzoyl-ethoxy-phenyl phosphine oxide;

[0024] The other auxiliary agent is a mixture of one or more of polyethylene glycol, stearic acid, oleic acid and dimethylsiloxane.

[0025] In step S1, the process parameters of the homogenization are: a homogenization speed of 1000 r / min to 1500 r / min, and a homogenization time of 1 h to 3 h.

[0026] During the sintering process of the ceramic core slurry prepared by the present invention, the nano-scale deformation control agent is filled in the pores of the ceramic matrix powder. Depending on the selected deformation control agent and the ceramic matrix powder material, the deformation control agent itself or reacts with the ceramic matrix powder to generate a new compound, which shrinks or expands in volume during high-temperature sintering and cooling. By adjusting the type, particle size and addition amount of the ceramic matrix powder and the deformation control agent, the deformation of the ceramic core can be controlled.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention provides a deformation-controllable photocurable 3D printing ceramic core slurry and a preparation method thereof. The ceramic core slurry comprises, by mass ratio, 62% to 83% of modified ceramic powder, 15% to 30% of acrylic photosensitive resin, 1% to 4% of photoinitiator and 1% to 4% of other additives, wherein the modified ceramic powder comprises, by mass ratio, 65% to 88% of ceramic matrix powder, 10% to 30% of deformation control agent and 2% to 5% of dispersant; by controlling and designing the ratio of each component, the ceramic slurry is ensured to have a high solid content, good stability and meet the fluidity required for printing.

[0029] By designing the ceramic matrix powder grading and introducing deformation control agents, regulating the slurry viscosity and the sintering process of the ceramic core, the volume change caused by the sintering and densification of the ceramic particles is controlled, ensuring that the ceramic core has sufficient bending strength while reducing the deformation caused by sintering, solving the main problems existing in the existing technology of 3D printing ceramic cores, and can be applied to the production field of 3D printing ceramic cores.

[0030] The existing light-cured 3D printed ceramic cores have problems such as the removal of photosensitive resin and densification of ceramic particles during degreasing and sintering, which result in larger dimensional deformation of the ceramic core compared with the three-dimensional model, the inability to retain the dimensional accuracy advantage of 3D printing, and poor physical properties of the ceramic core. The present invention controls the deformation of the ceramic core during sintering from the perspective of raw materials, and the resulting ceramic core has high dimensional accuracy and good physical properties.

[0031] The present invention introduces deformation control agents such as nano-SiO2, Al2O3, ZrO2, Y2O3, MgO, TiO2, etc., and selects corresponding deformation control agents according to the different degrees of deformation (volume shrinkage or expansion) generated during sintering of different ceramic matrix powder materials. During sintering, the deformation control agent is filled in the pores of the ceramic matrix powder, and reacts with the ceramic matrix powder to generate new compounds, which shrink or expand in volume during high-temperature sintering and cooling, thereby compensating for the deformation generated by the ceramic matrix powder. By adjusting the type, particle size and addition amount of the ceramic matrix powder and the deformation control agent, the deformation of the ceramic core can be controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention is further described in detail below with reference to the accompanying drawings and embodiments:

[0033] Figure 1 This is a SEM morphology image of the ceramic core slurry prepared in Example 1 after being formed using a light-curing 3D printing device and then degreased and sintered. DETAILED DESCRIPTION

[0034] The present invention will be further explained below in conjunction with specific implementation plans, but the present invention is not limited thereto. The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the restrictive conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0035] Embodiment 1:

[0036] A deformation controllable photocurable 3D printing ceramic core slurry and preparation method, 25 micron SiO2, 5 micron SiO2, 50 nm ZrO2 and 50 nm Y2O3 are mixed in a mass ratio of 60:30:9:1 to obtain a ceramic powder, 30% of anhydrous ethanol and 2% of DISPERBYK-110 are added, and the slurry mixture is obtained by ball milling at a speed of 400 r / min for 2 hours. The mixture is naturally dried for 18 hours, dried at 100°C for 2 hours, and passed through a 100-mesh sieve to obtain a modified ceramic powder. 20% of polyurethane acrylate, 1% of phenyl bis (2, 4, 6-trimethylbenzoyl) phosphine oxide, and 1% of polyethylene glycol are added to the modified ceramic powder, and the silicon oxide ceramic core slurry is obtained by homogenizing at a speed of 1500 r / min for 1 hour.

[0037] The ceramic core slurry is used to form a ceramic core blank through photocuring, and a ceramic core blank is obtained after degreasing and sintering. According to experimental measurements, the sintering deformation rate is 0.78% in the Z direction and 0.56% in the X / Y direction, the apparent porosity is 33.27%, and the flexural strength is 16.04MPa.

[0038] Embodiment 2:

[0039] A deformation controllable photocurable 3D printing ceramic core slurry and preparation method, 30 micron Al2O3, 6 micron Al2O3 and 200nm SiO2 are mixed in a mass ratio of 70:20:10 to obtain a ceramic powder, 35% of anhydrous ethanol and 1.5% of ammonium polymethyl acrylate are added, and the slurry mixture is obtained by ball milling at a speed of 500r / min for 2.5h. The mixture is naturally dried for 20h, dried at 120°C for 2h, and passed through a 90-mesh sieve to obtain a modified ceramic powder. 25% of polyurethane acrylate, 1.5% of 1-hydroxycycloethyl benzophenone, and 1.5% of oleic acid are added to the modified ceramic powder, and the alumina ceramic core slurry is obtained by homogenizing at a speed of 1200r / min for 1.5h.

[0040] The ceramic core slurry is used to form a ceramic core blank through photocuring, and a ceramic core blank is obtained after degreasing and sintering. According to experimental measurements, the sintering deformation rate is 0.61% in the Z direction and 0.47% in the X / Y direction, the apparent porosity is 23.60%, and the flexural strength is 20.23MPa.

[0041] Embodiment 3:

[0042] A deformation controllable photocurable 3D printing ceramic core slurry and preparation method, 35 micron ZrO2, 7 micron ZrO2, 500nm MgO and 500nm TiO2 are mixed in a mass ratio of 35:30:30:5 to obtain a ceramic powder, 40% of anhydrous ethanol and 3% of ammonium polymethyl acrylate are added, and the slurry mixture is obtained by ball milling at a speed of 600r / min for 3h. The mixture is naturally dried for 24h, dried at 130°C for 2.5h, and passed through an 80-mesh sieve to obtain a modified ceramic powder. 30% of trimethylolpropane triacrylate, 3% of 2,4,6-trimethylbenzoyl-ethoxy-phenylphosphine oxide, and 2% of stearic acid are added to the modified ceramic powder, and the zirconia ceramic core slurry is obtained by homogenizing at a speed of 1500r / min for 2h.

[0043] The ceramic core slurry is used to form a ceramic core blank through photocuring, and a ceramic core blank is obtained after degreasing and sintering. According to experimental measurements, the sintering deformation rate of the blank is 0.52% in the Z direction and 0.60% in the X / Y direction, the apparent porosity is 37.88%, and the flexural strength is 26.79 MPa.

[0044] Matters not covered by the present invention are known technologies.

[0045] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A deformation-controllable light-cured 3D printing ceramic core slurry, characterized in that: By mass ratio, including: Modified ceramic powder 62%~83%; Acrylic photosensitive resin 15% to 30%; Photoinitiator 1% to 4%; The balance is other additives; Wherein, the modified ceramic powder comprises, by mass ratio: Ceramic matrix powder 65% to 88%; Deformation control agent 10% to 30%; The balance is dispersant.

2. A method for preparing a deformation-controllable light-cured 3D printing ceramic core slurry according to claim 1, characterized in that: The following steps are involved: S1. Ceramic powder modification: mixing graded ceramic matrix powder and deformation control agent with anhydrous ethanol and dispersant, ball milling to obtain a slurry mixture, drying the mixture naturally, drying in an oven, and sieving to obtain modified ceramic powder; S2, preparing ceramic core slurry: adding the ceramic powder obtained in step S1, acrylic photosensitive resin, photoinitiator and other additives into a homogenizer, and homogenizing to obtain ceramic core slurry.

3. The method for preparing the deformation controllable light-cured 3D printing ceramic core slurry according to claim 2, characterized in that: In step S1, the ceramic matrix powder is one or more of SiO2, Al2O3, ZrO2, and Y2O3, and the ceramic matrix powder is composed of powders with a particle size of 5μm to 10μm and a particle size of 25μm to 35μm, wherein the powders with a particle size of 5μm to 10μm account for 10% to 40% of the total mass of the ceramic matrix powder, and the powders with a particle size of 25μm to 35μm account for 60% to 90% of the total mass of the ceramic matrix powder; the deformation controller is one or more of SiO2, Al2O3, ZrO2, Y2O3, MgO, and TiO2, and the particle size of the deformation controller is 10nm to 500nm.

4. The method for preparing the deformation controllable light-cured 3D printing ceramic core slurry according to claim 2, characterized in that: In step S1, the dispersant includes a mixture of one or more of DISPERBYK-110, methacrylic acid, ammonium polymethacrylate, polyoxypropyl polyoxyethyl glycerol ether and polyvinyl pyrrolidone, and the amount of anhydrous ethanol added is 30% to 40% of the total mass of the ceramic powder.

5. The method for preparing the deformation controllable light-cured 3D printing ceramic core slurry according to claim 2, characterized in that: In step S1, the process parameters of the ball milling are: the ball milling speed is 400r / min-600r / min, the ball milling time is 1h-3h, the ball milling equipment is a planetary ball mill, the ball milling medium is zirconium silicate balls, the natural drying time is 18h-24h, the drying temperature is 100℃-150℃, the drying time is 1h-3h, and the sieving is 80-mesh sieve 150-mesh sieve.

6. The method for preparing the deformation controllable light-cured 3D printing ceramic core slurry according to claim 2, characterized in that: In step S1, the acrylic photosensitive resin is a mixture of one or more of polyurethane acrylate, propoxylated neopentyl glycol diacrylate, trimethylolpropane triacrylate and 1,6-hexanediol diacrylate; The photoinitiator is a mixture of one or more of 1-hydroxycycloethyl benzophenone, phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide and 2,4,6-trimethylbenzoyl-ethoxy-phenyl phosphine oxide; The other auxiliary agent is a mixture of one or more of polyethylene glycol, stearic acid, oleic acid and dimethylsiloxane.

7. The method for preparing the deformation controllable light-cured 3D printing ceramic core slurry according to claim 2, characterized in that: In step S1, the process parameters of the homogenization are: a homogenization speed of 1000 r / min to 1500 r / min, and a homogenization time of 1 h to 3 h.

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