Electron beam curing method, materials and equipment for complex ceramic components

Abstract

An electron beam curing method, materials, and equipment for complex ceramic components are disclosed. This method employs a focused electron beam with a variable beam diameter to selectively cure and form ceramic materials containing photosensitive resin, layer by layer, to create complex components. These components are then sintered to obtain the final complex ceramic component. Due to the high penetration of the electron beam and the real-time control of the beam diameter, this method can not only form complex, irregularly shaped, high-density components such as ultrafine carbides, nitrides, and ultra-high temperature ceramics, but also reduce the difficulty of sintering. Simultaneously, the real-time adjustment of the beam diameter allows for efficient filling of large areas within complex components and precise shaping of fine contours. Furthermore, the high vacuum requirement during electron beam curing significantly reduces defects such as pores within the material. Since electron beam curing can reduce or eliminate the need for initiators, the storage stability of the prepared ceramic materials is also greatly improved. This represents a novel additive manufacturing process for high-performance complex ceramic components.

Description

Technical Field

[0001] This invention belongs to the field of ceramic additive manufacturing technology, specifically relating to an electron beam curing method, materials, and equipment for complex ceramic components. Background Technology

[0002] Ceramic materials possess a range of advantages, including high mechanical strength, high elastic modulus, good high-temperature resistance, high thermal conductivity, and high thermal shock resistance. Therefore, they are widely used in ceramic armor plates, space mirrors, high-precision components for semiconductors, and reactor cladding. Taking silicon carbide used in extreme environments as an example, the silicon carbide wall thickness required for heat exchangers used in chemical corrosion applications is typically less than 2.0 mm, with a minimum feature size as low as 0.4 mm and an overall size exceeding 400 mm. Furthermore, these components possess complex flow channels, curved surfaces, and thin walls, presenting significant challenges to traditional die-dependent forming processes such as compression molding, slip casting, and extrusion molding in the fabrication of these components. Ceramic additive manufacturing technology, with its dieless forming capabilities and high process flexibility, is an effective technical method for manufacturing complex ceramic components.

[0003] Currently, various additive manufacturing processes are applied to the forming of complex ceramic parts, such as selective laser sintering (SLS), photopolymerization, and fused deposition modeling (FDM). Among these, ceramics prepared by SLS are difficult to use for the preparation of high-performance ceramic components, and their low bulk density, mechanical properties, and precision fail to meet the requirements of high-precision, high-performance components. FDM faces challenges in forming complex internal structures and asymmetric thin-walled structures due to limitations in precision imposed by the printhead. Photopolymerization, with its advantages of high forming precision and component performance close to that of traditional processes, has become one of the most mature additive manufacturing processes for preparing complex ceramic parts.

[0004] The principle of photopolymerization molding process is to mix ceramic powder with photosensitive resin to prepare ceramic material. After each layer of material is spread by an auxiliary system, it is irradiated by light of a certain wavelength to induce cross-linking polymerization reaction and complete curing. Then, the ceramic green body is cured layer by layer by repeating the material spreading and photocuring process to finally obtain the target sample. After that, the printed part is subjected to high temperature degreasing and sintering processes to further densify the ceramic sample and finally obtain the ceramic sample (Liu Yu, Chen Zhangwei. Research progress of ceramic photopolymerization 3D printing technology [J]. Materials Engineering, 2020, 48(09):1-12.). At present, there are still several disadvantages: (1) The extremely high refractive index of ceramics leads to a huge refractive index difference between it and photosensitive resin, which further leads to problems such as low curing depth, large lateral dimensional error and low printing efficiency in the prepared material; (2) The smaller the particle size of ceramic powder, the higher its sintering activity, but small particle size ceramic powder will further reduce the curing depth. This makes additive manufacturing of ceramic components with high mechanical properties and high elastic modulus extremely difficult, severely restricting the application and development of advanced ceramic components in cutting-edge technology fields. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide an electron beam curing forming method, material and equipment for complex ceramic components. The electron beam mass decay mechanism is used in the curing process of the forming material, and a vacuum atmosphere is used in the curing process of the forming material, which greatly improves the chemical stability of the material; ceramic components with high mechanical properties and high elastic modulus can be manufactured.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] An electron beam curing method for complex ceramic components involves selectively curing a ceramic material containing photosensitive resin using a focused electron beam with a variable beam diameter, layer by layer to form a complex component, which is then sintered to obtain the complex ceramic component.

[0008] The ceramic material comprises ceramic powder, sintering aid, and resin mixture. By volume fraction, the solid content of the material formed by mixing ceramic powder and sintering aid is 35 vol% to 55 vol, and the resin mixture accounts for 45 vol% to 65 vol.

[0009] The ceramic powder is one or more of silicon carbide, silicon nitride, aluminum nitride, tungsten carbide, etc., with a particle size of 10nm to 10μm and a purity of more than 99.5%. The ceramic powder is 80 to 99.5 parts by weight.

[0010] The sintering aid is one or more of the following: carbon powder, boron carbide or alumina, yttrium oxide, etc., with a particle size of 20nm to 1000nm and a purity greater than 99.5%. The sintering aid is 0.5 to 20 parts by weight.

[0011] The resin mixture does not contain a photoinitiator and is a mixture of photosensitive resin, surface-modified dispersant, defoamer, and leveling agent. The photosensitive resin is one or more of acrylate resin or epoxy acrylate resin, and its amount is 80%–95% of the total resin mixture. The surface-modified dispersant is one or more of organic acid, silane coupling agent, or hyperdispersant, and its total amount is 1%–10% of the total resin mixture. The defoamer is one or more of polysiloxane defoamer, silicone emulsion defoamer, polyether defoamer, non-silicone defoamer, and higher alcohol defoamer, and its total amount is 0.5%–5% of the total resin mixture. The leveling agent is one or more of acrylic leveling agent, silicone leveling agent, and fluorocarbon compound leveling agent, and its total amount is 0.5%–5% of the total resin mixture. The photosensitive resin, surface-modified dispersant, defoamer, and leveling agent are thoroughly mixed using a mixing device to obtain the resin mixture.

[0012] The method for preparing the ceramic material includes: adding the mixed ceramic powder and sintering aid to the resin mixture one by one, and then mixing and defoaming the mixture thoroughly using a planetary homogenizer to obtain the ceramic material.

[0013] An electron beam curing molding device for complex ceramic components includes a housing 1 and an electron gun housing 6 sealed to it. A printing chamber vacuum pump 4 is connected to the side wall of the housing 1. A molding platform 2 is connected to the middle of the bottom of the housing 1. A printing chamber is provided above the molding platform 2. Material hoppers 3 are connected to both sides of the bottom of the housing 1. Ceramic material 13 is provided in the material hoppers 3. A scraper 5 is provided on the top of the material hoppers 3. The top of the housing 1 is connected to the electron gun housing 6. An electron gun vacuum pump 11 is connected to the upper side wall of the electron gun housing 6. An electron gun 7 is connected to the top of the electron gun housing 6. The input of the electron gun 7 is connected to a high voltage input 12. A focusing system 8 is connected to the lower side wall of the electron gun housing 6. A deflection coil 9 is connected to the bottom side wall of the electron gun housing 6.

[0014] A forming method using an electron beam curing forming apparatus for complex ceramic components includes the following steps:

[0015] 1) Printing process: The printing chamber is filled with ceramic material 13, and the ceramic material is cured by irradiation from top to bottom with an electron beam. After the printing chamber is evacuated, the forming process begins. The forming platform 2 is positioned below the horizontal plane of the ceramic material by a height equal to the thickness of a cross section, i.e., the layer thickness, which is 10μm to 200μm. The electron beam, focused by the focusing system 8, is accelerated. The electron beam acceleration voltage is 3KV to 60KV, the current is 0.02μA to 200μA, the beam spot diameter ranges from 0.01μm to 500μm, and the electron beam scanning overlap ratio is 10% to 30%. According to the equipment instructions, the cross section contour is scanned along the horizontal plane of the ceramic material at a scanning speed of 400mm / s to 8000mm / s. Different beam spot diameters are used to fill the contour and internal areas according to the shape of the part. The ceramic material in the scanned area is rapidly cured, thus completing the processing of one cross section and obtaining one forming layer. Then, the lifting worktable is lowered by another layer of cross section thickness, and the above process is repeated. In this way, layers are stacked to form a three-dimensional solid green body 10.

[0016] 2) Degreasing process: The three-dimensional solid green body 10 is degreased in argon atmosphere. The degreasing process is divided into 6 stages: 0-200℃, 200-300℃, 300-400℃, 400-450℃, 450-600℃, and 600-800℃. The heating rate at 400-450℃ is 0.2-0.5℃ / min, and the final temperature of 450℃ is held for 4-8 hours. The heating rate at the remaining stages is 0.5-3℃ / min, and the holding time at the final temperature of each stage is 1-4 hours.

[0017] 3) Sintering process: The sintering of the degreased three-dimensional solid green body is divided into four stages: 0-150℃, 150-320℃, 320-600℃, and 600-1800℃. The heating rate for the 320-600℃ stage is 0.5-2℃ / min, and the heating rate for the other stages is 3-5℃ / min. The holding time at the final temperature of each stage is 1-3 hours. Sintering is carried out in a vacuum atmosphere furnace or a pressure furnace. When using a vacuum atmosphere furnace, the vacuum degree is 10. -3 MPa, the corresponding nitrogen or argon pressure in the gas pressure sintering furnace is 2-5 MPa, and the sintering is completed by holding at 1600-2100℃ for 1-6 hours.

[0018] The beneficial effects of this invention are as follows:

[0019] This invention uses an electron beam instead of ultraviolet light, transforming the light density attenuation mechanism of ultraviolet light during the curing process of ceramic materials into a mass attenuation mechanism of the electron beam. This offers advantages such as curing and forming not being limited by ceramic powder characteristics (e.g., particle size, color, refractive index, and state), high forming speed, and high efficiency. The variable beam diameter significantly improves efficiency, while a smaller lower limit for the beam diameter means a substantial improvement in formability precision. These improvements can be achieved by software-controlled current and voltage of the magnetic lens, whereas traditional photopolymerization struggles to control the laser beam size in real time. Additive manufacturing of complex ceramic components based on electron beam curing can be performed without initiators, and the high vacuum environment significantly reduces the impact of oxygen inhibition. Furthermore, the absence of initiators extends material shelf life to several years. Electron beam forming time is only one-tenth that of photopolymerization, resulting in higher efficiency. Moreover, changing the ceramic curing process from an air atmosphere to a vacuum atmosphere avoids oxygen inhibition problems during the lamination process.

[0020] This invention is expected to completely break through the bottleneck of high-performance ceramic material forming, expand the range of formable materials for high-precision ceramic components, avoid the forming constraints caused by the light absorption characteristics and oxygen inhibition characteristics of ultraviolet curing forming technology, and greatly expand the application range of high-precision ceramic additive manufacturing materials; it can manufacture ceramic components with high mechanical properties and high elastic modulus. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the forming equipment according to an embodiment of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0023] Example 1: An electron beam curing method for complex ceramic components. A focused electron beam with a variable beam diameter is used to selectively cure and form a ceramic material containing photosensitive resin. The complex components are formed by layering and then sintering.

[0024] The ceramic material includes ceramic powder, sintering aid and resin mixture. By volume fraction, the solid content of the material formed by mixing ceramic powder and sintering aid is 50 vol%, and the resin mixture accounts for 50 vol%.

[0025] The ceramic powder is silicon carbide with a particle size of 10 nm and a purity greater than 99.5%. By weight, the ceramic powder is 96 parts.

[0026] The sintering aid is carbon powder with a particle size of 500 nm and a purity greater than 99.5%. By weight, the sintering aid is 4 parts.

[0027] The resin mixture does not contain a photoinitiator and is a mixture of photosensitive resin, surface-modifying dispersant, defoamer, and leveling agent. The photosensitive resin is an acrylate resin, comprising 89% of the total resin mixture. The surface-modifying dispersant is a silane coupling agent, comprising 10% of the total resin mixture. The defoamer is a polysiloxane defoamer, comprising 0.5% of the total resin mixture. The leveling agent is an acrylic leveling agent, comprising 0.5% of the total resin mixture. The photosensitive resin, surface-modifying dispersant, defoamer, and leveling agent are thoroughly mixed using a mixing device to obtain the resin mixture.

[0028] The method for preparing the ceramic material includes: adding the mixed ceramic powder and sintering aid to the resin mixture one by one, and then mixing and defoaming the mixture thoroughly using a planetary homogenizer to obtain the ceramic material.

[0029] Reference Figure 1 An electron beam curing molding device for complex ceramic components includes a housing 1 and an electron gun housing 6 sealed thereto. A printing chamber vacuum pump 4 is connected to the side wall of the housing 1. A molding platform 2 is connected to the middle of the bottom of the housing 1. A printing chamber is provided above the molding platform 2. Material hoppers 3 are connected to both sides of the bottom of the housing 1. Ceramic material 13 is provided in the material hoppers 3. A scraper 5 is provided on the top of the material hoppers 3. An electron gun housing 6 is connected to the top of the housing 1. An electron gun vacuum pump 11 is connected to the upper side wall of the electron gun housing 6. An electron gun 7 is connected to the top of the electron gun housing 6. The input of the electron gun 7 is connected to a high voltage input 12. A focusing system 8 is connected to the lower side wall of the electron gun housing 6. A deflection coil 9 is connected to the bottom side wall of the electron gun housing 6.

[0030] Reference Figure 1 A forming method using an electron beam curing forming apparatus for complex ceramic components includes the following steps:

[0031] 1) Printing process: The printing chamber is filled with ceramic material 13, and the ceramic material is solidified by irradiation from top to bottom with an electron beam. After the printing chamber is evacuated, the forming process begins. The forming platform 2 is positioned below the horizontal plane of the ceramic material by a height equal to the thickness of a cross section, i.e., the layer thickness, which is 50 μm. The electron beam, focused by the focusing system 8, is accelerated at a voltage of 3 KV, a current of 100 μA, a beam spot diameter of 50 μm, and an overlap ratio of 10%. According to the equipment instructions, the cross section contour is scanned along the horizontal plane of the ceramic material at a scanning speed of 5000 mm / s. Different beam spot diameters are used to fill the contour and internal areas according to the shape of the part. The horizontal plane of the ceramic material in the scanned area is rapidly solidified, thus completing the processing of one cross section and obtaining one forming layer. Subsequently, the lifting platform is lowered by another layer of cross section thickness, and the above process is repeated. In this way, layers are stacked to form a three-dimensional solid green body 10. The electron beam forming accuracy can reach the nanometer level.

[0032] 2) Degreasing process: The three-dimensional solid green body 10 is degreased in argon atmosphere. The degreasing process is divided into 6 stages: 0-200℃, 200-300℃, 300-400℃, 400-450℃, 450-600℃, and 600-800℃. The heating rate in the 400-450℃ stage is 0.2℃ / min, and the final temperature of 450℃ is held for 4 hours. The heating rate in the other stages is 1℃ / min, and the holding time at the final temperature of each stage is 2 hours.

[0033] 3) Sintering process: The sintering of the degreased three-dimensional solid green body 10 is divided into 4 stages: 0-150℃, 150-320℃, 320-600℃, and 600-1800℃. The heating rate of 320-600℃ is 1℃ / min, and the heating rate of the other stages is 4℃ / min. The holding time at the final temperature of each stage is 1h. Sintering is carried out in a pressure furnace. The nitrogen gas in the pressure sintering furnace is at atmospheric pressure. Finally, the sintering is completed by holding at 1800℃ for 3h.

[0034] The beneficial effects of this embodiment are as follows: This embodiment avoids the problem that nano-carbon powder cannot be added as an additive in the curing process of silicon carbide photocuring molding. The curing depth can reach more than 120μm, the solid content can reach 50vol%, the single-layer curing time is less than 2s, and the molded sample has no cracking or deformation.

[0035] Example 2: An electron beam curing method for complex ceramic components. A focused electron beam with a variable beam diameter is used to selectively cure and form a ceramic material containing photosensitive resin, layer by layer to form a complex component, which is then sintered to obtain the complex ceramic component.

[0036] The ceramic material comprises ceramic powder, sintering aid, and resin mixture. By volume fraction, the solid content of the material formed by mixing ceramic powder and sintering aid is 55 vol%, and the resin mixture accounts for 45 vol%.

[0037] The ceramic powder is silicon nitride with a particle size of 10 μm and a purity greater than 99.5%. By weight, the ceramic powder is 80 parts.

[0038] The sintering aid is a mixture of alumina and yttrium oxide in a mass ratio of 1:1, with a particle size of 500 nm and a purity greater than 99.5%. The sintering aid is 20 parts by weight.

[0039] The resin mixture does not contain a photoinitiator and is a mixture of photosensitive resin, surface-modified dispersant, defoamer, and leveling agent. The photosensitive resin is epoxy acrylate, accounting for 95% of the total resin mixture. The surface-modified dispersant is an organic acid, accounting for 4% of the total resin mixture. The defoamer is one or more of polysiloxane defoamers, silicone emulsion defoamers, polyether defoamers, non-silicone defoamers, and higher alcohol defoamers, accounting for 0.5% of the total resin mixture. The leveling agent is a silicone leveling agent, accounting for 0.5% of the total resin mixture. The photosensitive resin, surface-modified dispersant, defoamer, and leveling agent are thoroughly mixed using a mixing device to obtain the resin mixture.

[0040] The preparation method of the ceramic material is the same as that in Example 1.

[0041] The electron beam curing equipment for complex ceramic components is the same as that used in Example 1.

[0042] A forming method using an electron beam curing forming apparatus for complex ceramic components includes the following steps:

[0043] 1) Printing process: The printing chamber is filled with ceramic material 13, and the ceramic material is cured by irradiation from top to bottom with an electron beam. After the printing chamber is evacuated, the forming process begins. The forming platform 2 is positioned below the horizontal plane of the ceramic material by a height equal to the thickness of a cross section, i.e., the layer thickness, which is 10 μm. The electron beam, focused by the focusing system 8, is accelerated at a voltage of 60 kV, a current of 200 μA, a beam spot diameter of 30 μm, and an overlap ratio of 30%. According to the equipment instructions, the cross section contour is scanned along the horizontal plane of the ceramic material at a scanning speed of 1000 mm / s. Different beam spot diameters are used to fill the contour and internal areas according to the shape of the part. The ceramic material in the scanned area is rapidly cured, thus completing the processing of one cross section and obtaining one forming layer. Subsequently, the lifting platform is lowered by another layer of cross section thickness, and the above process is repeated. In this way, layers are stacked to form a three-dimensional solid green body 10. The electron beam forming accuracy can reach the nanometer level.

[0044] 2) Degreasing process: The three-dimensional solid green body 10 is degreased in an argon atmosphere. The degreasing process is divided into 6 stages: 0-200℃, 200-300℃, 300-400℃, 400-450℃, 450-600℃, and 600-800℃. The heating rate at 400-450℃ is 0.5℃ / min, and the final temperature of 450℃ is held for 8 hours. The heating rate at the remaining stages is 0.5℃ / min, and the holding time at the final temperature of each stage is 4 hours.

[0045] 3) Sintering process: The sintering of the degreased three-dimensional solid green body 10 is divided into 4 stages: 0-150℃, 150-320℃, 320-600℃, and 600-1750℃. The heating rate of 320-600℃ is 0.5℃ / min, and the heating rate of the other stages is 3℃ / min. The holding time at the final temperature of each stage is 3h. Sintering is carried out in a gas pressure sintering furnace with a corresponding nitrogen pressure of 5MPa. Finally, sintering is completed at 1750℃ for 6h.

[0046] The beneficial effects of this embodiment are as follows: This embodiment avoids the problem that the curing process in silicon nitride photocuring is limited by the strong ultraviolet absorption of silicon nitride. The curing depth can reach more than 150μm, the solid content can reach 55vol%, the single-layer curing time is less than 2s, and the molded sample has no cracking or deformation.

[0047] Example 3: An electron beam curing method for complex ceramic components. A focused electron beam with a variable beam diameter is used to selectively cure and form a ceramic material containing photosensitive resin, layer by layer to form a complex component, which is then sintered to obtain the complex ceramic component.

[0048] The ceramic material comprises ceramic powder, sintering aid, and resin mixture. By volume fraction, the solid content of the material formed by mixing ceramic powder and sintering aid is 55 vol%, and the resin mixture accounts for 45 vol%.

[0049] The ceramic powder is aluminum nitride with a particle size of 0.1 μm and a purity greater than 99.5%. By weight, the ceramic powder is 99.5 parts.

[0050] The sintering aid is alumina and yttrium oxide powder in a mass ratio of 2:1, with a particle size of 1000 nm and a purity greater than 99.5%. The sintering aid is 0.5 parts by weight.

[0051] The resin mixture does not contain a photoinitiator and is a mixture of photosensitive resin, surface-modifying dispersant, defoamer, and leveling agent. The photosensitive resin is composed of acrylate resin and epoxy acrylate resin in a 1:1 mass ratio, accounting for 80% of the total resin mixture. The surface-modifying dispersant is one or more super-dispersants, with a total usage of 10% of the total resin mixture. The defoamer is a higher alcohol defoamer, with a total usage of 5% of the total resin mixture. The leveling agent is a fluorocarbon compound leveling agent, with a total usage of 5% of the total resin mixture. The photosensitive resin, surface-modifying dispersant, defoamer, and leveling agent are thoroughly mixed using a mixing device to obtain the resin mixture.

[0052] The preparation method of the ceramic material is the same as that in Example 1.

[0053] The electron beam curing equipment for complex ceramic components is the same as that used in Example 1.

[0054] A forming method using an electron beam curing forming apparatus for complex ceramic components includes the following steps:

[0055] 1) Printing process: The printing chamber is filled with ceramic material 13, and the material is cured by irradiation from top to bottom with an electron beam. After the printing chamber is evacuated, the forming process begins. The forming platform 2 is positioned below the horizontal plane of the ceramic material by a height equal to the thickness of a cross section, i.e., the layer thickness, which is 200 μm. The electron beam, focused by the focusing system 8, is accelerated at a voltage of 50 kV, a current of 0.02 μA, a beam spot diameter of 0.01 μm, and an overlap ratio of 15%. According to the equipment instructions, the cross section contour is scanned along the horizontal plane of the ceramic material at a scanning speed of 400 mm / s. Different beam spot diameters are used to fill the contour and internal areas according to the shape of the part. The ceramic material in the scanned area is rapidly cured, thus completing the processing of one cross section and obtaining one forming layer. Subsequently, the lifting platform is lowered by another layer of cross section thickness, and the above process is repeated. In this way, layers are stacked to form a three-dimensional solid green body 10. The electron beam forming accuracy can reach the nanometer level.

[0056] 2) Degreasing process: The three-dimensional solid green body 10 is degreased in argon atmosphere. The degreasing process is divided into 6 stages: 0-200℃, 200-300℃, 300-400℃, 400-450℃, 450-600℃, and 600-800℃. The heating rate at 400-450℃ is 0.2℃ / min, and the final temperature of 450℃ is held for 4 hours. The heating rate at the remaining stages is 3℃ / min, and the holding time at the final temperature of each stage is 1 hour.

[0057] 3) Sintering process: The sintering of the degreased three-dimensional solid green body 10 is divided into 4 stages: 0-150℃, 150-320℃, 320-600℃, and 600-1800℃. The heating rate of 320-600℃ is 2℃ / min, and the heating rate of the other stages is 5℃ / min. The holding time at the final temperature of each stage is 1h. Sintering is carried out in a gas pressure sintering furnace with a corresponding nitrogen pressure of 2MPa. Finally, sintering is completed at 1800℃ for 6h.

[0058] The beneficial effects of this embodiment are as follows: This embodiment avoids the problem that the curing process in aluminum nitride photocuring is limited by the strong ultraviolet absorption of aluminum nitride nanoparticles. The curing depth can reach more than 150μm, the solid content can reach 55vol%, the single-layer curing time is less than 3s, and the molded sample has no cracking or deformation.

[0059] Example 4: An electron beam curing method for complex ceramic components. A focused electron beam with a variable beam diameter is used to selectively cure and form ceramic materials containing photosensitive resin, layer by layer to form complex components, which are then sintered to obtain the complex ceramic components.

[0060] The ceramic material comprises ceramic powder, sintering aid, and resin mixture. By volume fraction, the solid content of the material formed by mixing ceramic powder and sintering aid is 52 vol, and the resin mixture accounts for 48 vol.

[0061] The ceramic powder is boron carbide powder with a particle size of 10 μm and a purity greater than 99.5%. By weight, the ceramic powder is 84 parts.

[0062] The sintering aid is carbon, alumina and yttrium oxide powder in a mass ratio of 1:2:3, with a particle size of 800 nm and a purity greater than 99.5%. The sintering aid is 16 parts by weight.

[0063] The resin mixture does not contain a photoinitiator and is a mixture of photosensitive resin, surface-modified dispersant, defoamer, and leveling agent. The photosensitive resin is composed of acrylate resin and epoxy acrylate resin in a mass ratio of 3:6, accounting for 90% of the total resin mixture. The surface-modified dispersant is a silane coupling agent or a superdispersant in a mass ratio of 2:1, with a total usage of 1% of the total resin mixture. The defoamer is a polysiloxane defoamer, a non-silicone defoamer, and a higher alcohol defoamer in a mass ratio of 1:1:1, with a total usage of 5% of the total resin mixture. The leveling agent is an acrylic leveling agent and a fluorocarbon leveling agent in a mass ratio of 1:2, with a total usage of 4% of the total resin mixture. The photosensitive resin, surface-modified dispersant, defoamer, and leveling agent are thoroughly mixed using a mixing device to obtain the resin mixture.

[0064] The preparation method of the ceramic material is the same as that in Example 1.

[0065] The electron beam curing equipment for complex ceramic components is the same as that used in Example 1.

[0066] A forming method using an electron beam curing forming apparatus for complex ceramic components includes the following steps:

[0067] 1) Printing process: The printing chamber is filled with ceramic material 13, and the ceramic material is cured by irradiation from top to bottom with an electron beam. After the printing chamber is evacuated, the forming process begins. The forming platform 2 is positioned below the horizontal plane of the ceramic material by a height equal to the thickness of a cross section, i.e., the layer thickness, which is 100 μm. The electron beam, focused by the focusing system 8, is accelerated at a voltage of 20 kV, a current of 10 μA, a beam spot diameter of 100 μm, and an overlap ratio of 20%. According to the equipment instructions, the cross section contour is scanned along the horizontal plane of the ceramic material at a scanning speed of 8000 mm / s. Different beam spot diameters are used to fill the contour and internal areas according to the shape of the part. The ceramic material in the scanned area is rapidly cured, thus completing the processing of one cross section and obtaining one forming layer. Subsequently, the lifting platform is lowered by another layer of cross section thickness, and the above process is repeated. In this way, layers are stacked to form a three-dimensional solid green body 10. The electron beam forming accuracy can reach the nanometer level.

[0068] 2) Degreasing process: The three-dimensional solid green body 10 is degreased in argon atmosphere. The degreasing process is divided into 6 stages: 0-200℃, 200-300℃, 300-400℃, 400-450℃, 450-600℃, and 600-800℃. The heating rate at 400-450℃ is 0.4℃ / min, and the final temperature of 450℃ is held for 6 hours. The heating rate at the remaining stages is 1.5℃ / min, and the holding time at the final temperature of each stage is 1 hour.

[0069] 3) Sintering process: The sintering of the degreased three-dimensional solid green body is divided into four stages: 0-150℃, 150-320℃, 320-600℃, and 600-1900℃. The heating rate for the 320-600℃ stage is 1.5℃ / min, and the heating rate for the other stages is 5℃ / min. The holding time at the final temperature of each stage is 2 hours. Sintering is carried out in a vacuum atmosphere furnace with a vacuum degree of 10. -3 MPa, and finally sintering was completed at 1900℃ for 1 hour.

[0070] The beneficial effects of this embodiment are as follows: This embodiment avoids the problem of boron carbide being difficult to cure in traditional photocuring, the curing depth can reach more than 150μm, the solid content can reach 52vol%, the single-layer curing time is less than 2s, and the formed sample has no cracking or deformation.

[0071] Example 5: An electron beam curing method for complex ceramic components. A focused electron beam with a variable beam diameter is used to selectively cure and form a ceramic material containing photosensitive resin, layer by layer to form a complex component, which is then sintered to obtain the complex ceramic component.

[0072] The ceramic material comprises ceramic powder, sintering aid, and resin mixture. By volume fraction, the solid content of the material formed by mixing ceramic powder and sintering aid is 60 vol, and the resin mixture accounts for 40 vol.

[0073] The ceramic powder is tungsten carbide with particle sizes of 10 μm and 200 nm, in a ratio of 7:3, and a purity greater than 99.5%. The ceramic powder comprises 85 parts by weight.

[0074] The sintering aid is cobalt oxide powder with a particle size of 500 nm and a purity greater than 99.5%. By weight, the sintering aid is 15 parts.

[0075] The resin mixture does not contain a photoinitiator and is a mixture of photosensitive resin, surface-modifying dispersant, defoamer, and leveling agent. The photosensitive resin is composed of acrylic acid and epoxy acrylate in a 3:1 mass ratio, accounting for 93% of the total resin mixture. The surface-modifying dispersant is composed of organic acid, silane coupling agent, and superdispersant in a 1:1:1 mass ratio, accounting for 1% of the total resin mixture. The defoamer is composed of silicone emulsion defoamer, polyether defoamer, and non-silicone defoamer in a 2:1:1 mass ratio, accounting for 3% of the total resin mixture. The leveling agent is composed of silicone leveling agent and fluorocarbon leveling agent in a 3:1 mass ratio, accounting for 3% of the total resin mixture. The photosensitive resin, surface-modifying dispersant, defoamer, and leveling agent are thoroughly mixed using a mixing device to obtain the resin mixture.

[0076] The preparation method of the ceramic material is the same as that in Example 1.

[0077] The electron beam curing equipment for complex ceramic components is the same as that used in Example 1.

[0078] A forming method using an electron beam curing forming apparatus for complex ceramic components includes the following steps:

[0079] 1) Printing process: The printing chamber is filled with ceramic material 13, and the ceramic material is solidified by irradiation from top to bottom with an electron beam. After the printing chamber is evacuated, the forming process begins. The forming platform 2 is positioned below the horizontal plane of the ceramic material by a height equal to one cross-sectional thickness, i.e., the layer thickness, which is 200 μm. The electron beam, focused by the focusing system 8, is accelerated at a voltage of 60 KV, a current of 200 μA, a beam spot diameter of 100 μm, and an electron beam scanning overlap ratio of 25%. According to the equipment instructions, the cross-sectional contour is scanned along the horizontal plane of the ceramic material at a scanning speed of 400 mm / s. Different beam spot diameters are used to fill the contour and internal areas according to the shape of the part. The ceramic material in the scanned area is rapidly solidified, thus completing the processing of one cross-section and obtaining one forming layer. Subsequently, the lifting platform is lowered by another layer of cross-sectional thickness, and the above process is repeated. In this way, layers are stacked to form a three-dimensional solid green body 10. The electron beam forming accuracy can reach the nanometer level.

[0080] 2) Degreasing process: The three-dimensional solid green body 10 is degreased in an argon atmosphere. The degreasing process is divided into 6 stages: 0-200℃, 200-300℃, 300-400℃, 400-450℃, 450-600℃, and 600-800℃. The heating rate at 400-450℃ is 0.3℃ / min, and the final temperature of 450℃ is held for 7 hours. The heating rate at the remaining stages is 1℃ / min, and the holding time at the final temperature of each stage is 1 hour.

[0081] 3) Sintering process: The sintering of the degreased three-dimensional solid green body was divided into four stages: 0-150℃, 150-320℃, 320-600℃, and 600-2100℃. The heating rate for the 320-600℃ stage was 1.2℃ / min, and the heating rate for the other stages was 5℃ / min. The holding time at the final temperature of each stage was 2.5h. Sintering was carried out in a vacuum atmosphere furnace with a vacuum degree of 10. -3 MPa, and finally sintering was completed at 2100℃ for 1 hour.

[0082] The beneficial effects of this embodiment are as follows: This embodiment avoids the disadvantages of the curing process in tungsten carbide photocuring being limited by the particle size, color, refractive index and state of ceramic powder. The curing depth can reach more than 120μm, the solid content can reach 60vol%, the single-layer curing time is less than 3s, and the formed sample has no cracking or deformation.

Claims

1. A method for electron beam curing of complex ceramic components, characterized in that: A focused electron beam with a variable spot diameter is used to selectively cure and form ceramic materials containing photosensitive resin. The curing depth in photocuring reaches more than 120μm. Complex components are formed by layering and then sintering to obtain complex ceramic components. The ceramic material comprises ceramic powder, sintering aid, and resin mixture. By volume fraction, the solid content of the material formed by mixing the ceramic powder and sintering aid is 35 vol% to 55 vol%, and the resin mixture accounts for 45 vol% to 65 vol%. The resin mixture comprises a photosensitive resin, a surface-modified dispersant, a defoamer, and a leveling agent. The photosensitive resin is one or more of acrylate resin or epoxy acrylate resin, and its dosage is 80%–95% of the total resin mixture. The surface-modified dispersant is one or more of organic acid, silane coupling agent, or hyperdispersant, and its total dosage is 1%–10% of the total resin mixture. The defoamer is one or more of polysiloxane defoamer, silicone emulsion defoamer, polyether defoamer, non-silicone defoamer, and higher alcohol defoamer, and its total dosage is 0.5%–5% of the total resin mixture. The leveling agent is one or more of acrylic leveling agent, silicone leveling agent, and fluorocarbon compound leveling agent, and its total dosage is 0.5%–5% of the total resin mixture. The photosensitive resin, surface-modified dispersant, defoamer, and leveling agent are thoroughly mixed using a mixing device to obtain the resin mixture.

2. The method according to claim 1, characterized in that: The ceramic powder is one or more of silicon carbide, silicon nitride, aluminum nitride, and tungsten carbide powders, with a particle size of 10nm~10μm and a purity greater than 99.5%. By weight, the ceramic powder is 80~99.5 parts.

3. The method according to claim 1, characterized in that: The sintering aid is one or more of carbon powder, boron carbide or aluminum oxide, and yttrium oxide powder, with a particle size of 20nm~1000nm and a purity greater than 99.5%. The sintering aid is 0.5 parts to 20 parts by weight.

4. The method for preparing the ceramic material according to any one of claims 1-3, characterized in that, include: The mixed ceramic powder and sintering aid are added to the resin mixture in sequence, and the mixture is thoroughly mixed and defoamed using a planetary homogenizer to obtain the ceramic material.

5. An electron beam curing apparatus for complex ceramic components that implements the method of claim 1, characterized in that: The device includes a housing (1) and an electron gun housing (6) sealed to it. A printing chamber vacuum pump (4) is connected to the side wall of the housing (1). A forming platform (2) is connected to the middle of the bottom of the housing (1). A printing chamber is provided above the forming platform (2). A material hopper (3) is connected to both sides of the bottom of the housing (1). Ceramic material (13) is provided in the material hopper (3). A scraper (5) is provided on the top of the material hopper (3). An electron gun housing (6) is connected to the top of the housing (1). An electron gun vacuum pump (11) is connected to the upper side wall of the electron gun housing (6). An electron gun (7) is connected to the top of the electron gun housing (6). The input of the electron gun (7) is connected to a high voltage input (12). A focusing system (8) is connected to the lower side wall of the electron gun housing (6). A deflection coil (9) is connected to the bottom side wall of the electron gun housing (6).

6. A forming method using the electron beam curing forming equipment for complex ceramic components as described in claim 5, characterized in that, Includes the following steps: 1) Printing process: The printing chamber is filled with ceramic material (13), and the ceramic material is solidified by irradiation from top to bottom with an electron beam; after the printing chamber is evacuated, the forming process begins. The forming platform (2) is located at the height of a cross-sectional thickness below the horizontal plane of the ceramic material, i.e., the layer thickness, which is 10μm~200μm; the electron beam is accelerated by the focusing system (8), with an electron beam acceleration voltage of 3KV~60KV, a current of 0.02μA~200μA, and a beam spot diameter range of 0.01μm~500μm. The electron beam scanning overlap area ratio is 10%~30%. According to the equipment instructions, the cross-sectional contour is scanned along the horizontal plane of the forming ceramic material at a scanning speed of 400mm / s~8000mm / s. Different beam spot diameters are used to fill the contour and internal area according to the shape of the part. The forming ceramic material in the scanning area is rapidly solidified, thereby completing the processing of a cross-section and obtaining a forming layer. Then the lifting worktable is lowered by the height of another layer of cross-sectional thickness, and the above process is repeated. In this way, layers are stacked to form a three-dimensional solid green body (10). 2) Degreasing process: The three-dimensional solid green body (10) is degreased in argon atmosphere. The degreasing process is divided into 6 stages: 0-200℃, 200-300℃, 300-400℃, 400-450℃, 450-600℃, and 600-800℃. The heating rate at 400-450℃ is 0.2~0.5℃ / min, and the final temperature of 450℃ is held for 4~8h. The heating rate at the other stages is 0.5~3℃ / min, and the holding time at the final temperature of each stage is 1~4h. 3) Sintering process: The three-dimensional solid green body (10) after degreasing is sintered in 4 stages, namely 0-150℃, 150-320℃, 320-600℃, and 600-2100℃. The heating rate of 320-600℃ is 0.5~2℃ / min, and the heating rate of the other stages is 3~5℃ / min. The holding time at the end temperature of each stage is 1~3h. Sintering is carried out in a vacuum atmosphere furnace or a pressure furnace. When using a vacuum atmosphere furnace, the vacuum degree is 10 -3 MPa, the corresponding nitrogen or argon pressure in the gas pressure sintering furnace is 2~5MPa, and the sintering is completed by holding at 1600~2100℃ for 1~6h.

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