Ink-jet 3D printing magnesium oxide ceramic powder material and magnesium oxide ceramic material

Abstract

The invention relates to an ink-jet 3D printing magnesium oxide ceramic powder material and a magnesium oxide ceramic material.The powder material comprises 50-90 parts of dead burned MgO, 10-30 parts of phosphate, 2-7 parts of a precision improving component, 1-10 parts of a sintering aid and 1-10 parts of a sintering shrinkage-reducing flexibilizer. Firstly, an ink-jet 3D printing technology is adopted for preparing a magnesium oxide ceramic green body of a complex structure; and sintering in a high-temperature muffle furnace to obtain the compact high-strength magnesium oxide ceramic. The powder material disclosed by the invention can realize ink-jet 3D printing, has the characteristics of high precision and high degree of freedom, can be used for preparing any ceramic green body in a complex shape, and provides a new way for preparing complex ceramics.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, specifically to an inkjet 3D printing magnesium oxide ceramic powder material and a magnesium oxide ceramic material. The magnesium oxide ceramic material has good flowability and spreadability and can be used to prepare ceramics with complex structures. Background Technology

[0002] Traditional methods for preparing ceramics with complex structures suffer from long production cycles, high costs, and low yields, failing to meet market demands for complex ceramics. Additive manufacturing technology offers a new approach to complex ceramic fabrication, enabling the creation of arbitrarily complex shapes and structures through computer modeling, overcoming the limitations of traditional processes. Among these, inkjet 3D printing technology, with its advantages of high precision, high degree of freedom, low production costs, wide availability of raw materials, and suitability for large-scale manufacturing, shows great promise in the ceramics field. Inkjet 3D printing involves creating a model using a computer, slicing it, laying a layer of powder on a printing platform, and then selectively jetting ink onto the powder surface based on the model information. The jetted areas quickly solidify and harden. After printing, the platform lowers to a certain height, a new layer of powder is laid, and the process is repeated layer by layer to obtain the desired three-dimensional object. This provides a new approach to the refined shaping of complex ceramic models, enabling the printing of detailed, complex, controllable, and reproducible complex ceramic models. Currently, inkjet 3D printing of ceramics mostly uses resin as a binder. Resin bonding relies solely on physical adsorption, resulting in weak interparticle bonding, low strength of the printed blank, and susceptibility to damage during transfer and handling. During the degreasing and sintering stages, the resin decomposes at high temperatures, producing harmful gases that pollute the environment. It is also easy for pores and cracks to form inside ceramic parts. Uneven shrinkage of ceramic particles can lead to uncontrolled shrinkage of printed parts, resulting in deformation and collapse, making it difficult to match the design precision. Therefore, there is an urgent need to develop inorganic binders.

[0003] Magnesium phosphate cement, as a green inorganic cementitious material, mainly contains magnesium oxide and phosphate. It features rapid setting and hardening, and high early strength, providing sufficient forming strength for ceramic blanks. It can be used as an inorganic cementitious material for inkjet 3D printing, and the magnesium oxide can be sintered at high temperatures to form magnesium oxide ceramics. Chinese patent document CN118637892 A discloses a method for manufacturing magnesium oxide ceramics, using high-purity magnesium oxide powder as the main raw material, adding 1-10% auxiliary agents, and employing a granulation-forming-high-temperature sintering process to prepare magnesium oxide ceramics. This method is not suitable for inkjet 3D printing. Chinese patent document CN 112759298 A discloses a material for powder 3D printing experimental models, which is a magnesium phosphate cement cementitious material suitable for powder 3D printing. It has good mechanical properties and printing accuracy. However, models printed using this magnesium phosphate cement cement cement material exhibit significant deformation and cracking after sintering, making it impossible to successfully sinter magnesium oxide ceramics. Magnesium oxide ceramics have a high sintering temperature. Single sintering aids have limited functions during the sintering process and cannot simultaneously solve multiple problems such as densification, grain control, and synergistic performance of multiple properties in magnesium oxide ceramics during sintering. Especially in powder 3D printing materials with high porosity, the mechanical strength and high-temperature stability of the specimen cannot be taken into account. The model printed by magnesium phosphate cementitious material has high porosity, which leads to large deformation and even cracking during sintering.

[0004] Based on the above problems, there is an urgent need to develop a magnesium oxide ceramic material that can be used for inkjet 3D printing. Summary of the Invention

[0005] The purpose of this invention is to provide an inkjet 3D printing magnesium oxide ceramic powder material and a magnesium oxide ceramic material. This powder material has the characteristics of excellent printability, high molding strength and uniform shrinkage after sintering, and can be used to make ceramic models with complex structures.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A magnesium oxide ceramic powder material for inkjet 3D printing, wherein the powder material is formulated in the following weight ratios: 50-90 parts re-fired MgO, 10-30 parts phosphate, 2-7 parts precision improving components, 1-10 parts sintering aids, and 1-10 parts sintering shrinkage reducing and toughening agents. The precision-improving components include PVA powder and diatomaceous earth powder, wherein the mass ratio of PVA powder to diatomaceous earth powder is 1:2-1:5; The sintering aids include titanium dioxide powder (TiO2), magnesium fluoride powder (MgF2), and yttrium oxide powder (Y2O3), wherein the mass ratio of TiO2 powder, MgF2 powder, and Y2O3 powder is (3.8-4.5):(1.8-2.2):(0.8-1.2). The sintering shrinkage-reducing and toughening agent includes nano-SiO2 powder, talc powder and zircon powder, and the mass ratio of nano-SiO2 powder, talc powder and zircon powder is (2.8-3.4):(1.8-2.4):(1.8-2.2).

[0007] Furthermore, the PVA powder is one or more of grades 17-80, 17-88, 17-92, and K30, with a purity greater than 98% and a fineness of 150-200 mesh; the diatomaceous earth powder has a purity greater than 96% and a bulk density of 0.54-0.67 g / cm³. 3 The particle size ranges from 0.075 to 0.125 mm.

[0008] Furthermore, the TiO2 powder is in the rutile phase, with a bulk density of 1.4-1.8 g / cm³. 3 The purity is greater than 98%, and the particle size ranges from 0.045 to 0.125 mm; the MgF2 powder concentration is 1.5-1.8 g / cm³. 3 The particle size ranges from 0.075 to 0.125 mm; the Y₂O₃ powder concentration is 1.6-2.1 g / cm³. 3 The particle size ranges from 0.075 to 0.125 mm.

[0009] Furthermore, the bulk density of the nano-SiO2 powder is 1.2-1.6 g / cm³. 3 The purity is greater than 98%; the bulk density of the talc powder is 2.5-2.8 g / cm³. 3 Particle size less than 45 The zircon powder has a bulk density of 1.0-1.2 g / cm³. 3 Particle size less than 45 .

[0010] The recalcined MgO is obtained by calcining magnesite raw material in a high-temperature furnace at 1600–1950℃ for 50–120 min, followed by ball milling at 1500–1800 r / min for 15–35 min and then sieving. Its bulk density is 1.8–2.0 g / cm³. 3 Specific surface area is 230-287 m² 2 / kg, with a particle size range of 0.075-0.15mm; The phosphate is one or more of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and sodium dihydrogen phosphate powder, and the purity of the phosphate is greater than 96% and the maximum particle size is 0.125 mm.

[0011] A method for using a magnesium oxide ceramic powder material in inkjet 3D printing, the method comprising the following steps: (1) Pass the reburned MgO, phosphate, precision improvement components and sintering aid through a 150-200 mesh sieve, and the sintering shrinkage reduction and toughening agent through a 320 mesh sieve.

[0012] (2) Add 50-90 parts of reburned MgO and 10-30 parts of phosphate to a planetary mixer and stir for 5-10 minutes until the mixture is uniform. Then, add 2-7 parts of precision improving component, 1-10 parts of sintering aid, and 1-10 parts of sintering shrinkage reducing and toughening agent, and continue stirring for 10-15 minutes until the mixture is uniform to obtain the powder material.

[0013] (3) Add the powder material prepared above into the powder material feed hopper of the printer and print using inkjet 3D printing technology. The layer thickness is 0.1-0.3mm and the printing speed is 600-800mm / s. After printing, remove the model and remove any unbonded powder.

[0014] (4) Place a model pad with a height of 2cm-4cm at the bottom of the magnesium oxide ceramic blank. The heating rate of the muffle furnace is 5-10℃ / min. Heat the material to 700-900℃ and hold for 0.5-1h. Then, the heating rate is 1-4℃ / min. Heat the material to 1200-1400℃ and hold for 1-3h. After natural cooling to room temperature, magnesium oxide ceramic is obtained.

[0015] Furthermore, the green body is treated using a segmented heating-powder-support anti-deformation sintering method, the specific process of which is as follows: 1) Pretreatment of embedded powder: 200 mesh alumina powder is selected for embedded powder, pre-calcined in a muffle furnace for 2 hours, cooled to room temperature, and then sieved to break up agglomerated particles; 2) Burying powder in the furnace: Select a corundum sagger, spread 15mm of pre-fired alumina powder on the bottom, put the billet into the sagger, and then bury the powder. When burying the powder, use a sieve to lightly sprinkle until it completely covers the billet by 10mm. 3) Sintering in a muffle furnace: room temperature - 200℃, heating rate 2℃ / min; 200℃ - 800℃, heating rate 3℃ / min, holding time 1~2h; 800℃ - target temperature, heating rate 5℃ / min, holding time 2~3h; target temperature - 1000℃, cooling rate 3~5℃ / min; 1000℃ - room temperature, cooling with the furnace; the target temperature is the sintering temperature. Ceramic cleaning: Use a soft brush to sweep away the alumina powder on the surface. Residual powder can be blown away with an air pump.

[0016] Furthermore, the target temperature is 1300~1350℃.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. The powder materials and inks used in this invention are all inorganic materials, which do not release harmful gases during the sintering process, thus posing no threat to the environment or the health of operators. The sintering process is simple; after printing, there is no need for degreasing or curing steps, and the material can be directly placed in a muffle furnace for sintering. The sintering temperature of this invention is controlled at 1200-1400℃. Within the given formula parameters, by adjusting the ratio of re-fired MgO to phosphate and increasing the sintering temperature, MgO ceramics with excellent mechanical properties can be obtained. The ceramic powder material of this invention does not require resin or other binders, providing both molding bonding and serving as the sintering matrix. This achieves green and low-cost ceramic inkjet 3D printing, overcoming the shortcomings of traditional methods that use resin as a molding binder and ceramic powder as the sintering matrix, requiring complex operations such as degreasing and curing.

[0018] 2. The precision-improving component in this invention consists of highly water-soluble PVA powder and diatomaceous earth powder. PVA powder can effectively improve molding precision, while diatomaceous earth powder has a unique porous honeycomb structure and is rich in silanol groups on its surface, giving it strong water absorption capacity. This allows it to adsorb small amounts of free water in the powder, reducing powder agglomeration and thus improving powder flowability and spreading performance. The active SiO2 produced by the decomposition of diatomaceous earth undergoes a secondary reaction with the hydration products of magnesium phosphate cement. The resulting magnesium silicate gel can strengthen the interfacial bonding of the hydration products, thereby improving the early strength of the printed specimen and achieving a coordinated and simultaneous improvement in the precision and strength of the 3D printed ceramic specimen. Simultaneously, during the sintering process, diatomaceous earth powder can lower the sintering temperature of magnesium oxide ceramics, promoting densification and improving strength and toughness.

[0019] 3. This invention uses a composite of TiO2 powder, MgF2 powder, and Y2O3 powder as a multi-component sintering aid. These three components exhibit excellent synergistic effects during the sintering process of magnesia ceramics: TiO2 forms a solid solution with MgO, effectively refining the grains; MgF2 introduces lattice vacancies, significantly accelerating the ion diffusion rate; and Y2O3 promotes sintering neck growth and optimizes grain boundary bonding. This composite aid system not only significantly reduces the sintering temperature of magnesia ceramics but also increases the compactness of the green body without forming a low-melting-point glass phase, simultaneously enhancing the strength, toughness, and thermal shock resistance of the ceramic. It is particularly suitable for the preparation of high-performance high-temperature refractory magnesia ceramic components.

[0020] 4. This invention incorporates nano-SiO2 powder, talc powder, and zircon powder as sintering shrinkage-reducing and toughening agents in powder materials. The particle size range is smaller than that of magnesium phosphate cement powder. By adjusting the proportions of each component in the sintering shrinkage-reducing and toughening agent, the particle size distribution of the composite powder is optimized, increasing the powder bed density and thus reducing the porosity of the specimen. Each component of the sintering shrinkage-reducing and toughening agent exhibits excellent high-temperature resistance. During sintering, nano-SiO2, with its high activity and small size effect, fills the pores between magnesium oxide particles and reacts with magnesium oxide to form a magnesium silicate phase, reducing sintering porosity. Talc powder decomposes to form magnesium silicate whiskers, which can hinder crack propagation. Zircon maintains a stable particle morphology at the sintering temperature of magnesium oxide ceramics, thereby inhibiting excessive growth of magnesium oxide grains. The three components react synergistically during high-temperature sintering to form an interwoven composite toughening structure. This structure can effectively resist the shrinkage stress generated in the high-porosity magnesium oxide ceramic green body during sintering, successfully solving the problems of model deformation and cracking. Attached Figure Description

[0021] Figure 1 This is a photograph of the specimen printed in Example 2.

[0022] Figure 2 Photographs of the printed specimens prepared for Comparative Example 1.

[0023] Figure 3 This is a photograph of the sintered model prepared according to the formulation in Example 3.

[0024] Figure 4 Photograph of the sintered model with the proportions of Comparative Example 3. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to specific embodiments, but this is not intended to limit the scope of protection of this application. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] The ink formulation used in this invention is based on the ink formulation disclosed in Chinese Patent Document CN 117263647 A, "An Ink for a Bonded 3D Printing Similar Material for Complex Geological Models." The ink used in the following examples is prepared using the ink formulation (all weight percentages) disclosed in Example 1 of Patent Document CN117263647 A, specifically: 8% PVA, 1.2% 2-pyrrolidone, 0.5% nonionic surfactant Surfynol 465, 0.05% silicone defoamer, 4% 1,2-propanediol, and the balance deionized water. The preparation method is as follows: 1) Add PVA to 2-pyrrolidone and stir for 10 minutes until well mixed; 2) Add nonionic surfactant Surfynol 465, silicone defoamer, 1,2-propanediol, and deionized water to the mixture obtained in step 1), and ultrasonically disperse it for 8 minutes using an ultrasonic disperser at a frequency of 50 Hz; to obtain ink; the effective ingredient content of Surfynol 465 is greater than 99%; the effective ingredient content of silicone defoamer is greater than 98%, and the pH is 3~14; 3) The ink was vacuum filtered sequentially using PP material filter membranes of 15μm, 10μm and 0.5μm, with a filtration negative pressure of 0.7MPa; 4) Degas the filtered ink sequentially using a vacuum degassing tank and a vacuum degassing mold, and then inject it into the ink tank.

[0027] Reburned MgO powder and phosphate powder exhibit excellent flowability and spreadability, meeting the requirements of inkjet 3D printing. Their rapid chemical reaction provides molding strength to the magnesia ceramic preform. Precision-improving components significantly enhance model molding accuracy, sintering aids reduce sintering temperature and increase mechanical strength, and sintering shrinkage-reducing and toughening agents optimize powder particle size distribution and improve specimen density. During sintering, they react to form an interwoven composite toughening structure, effectively inhibiting deformation and cracking of the ceramic during sintering. This invention eliminates the need for organic binders like resins, reducing environmental pollution and health hazards to operators during sintering.

[0028] In the following embodiments, the mass ratio of nano-SiO2 powder, talc powder, and zircon powder is 3.0:2.0:2.0. The sintering aids include titanium dioxide powder (TiO2), magnesium fluoride powder (MgF2), and yttrium oxide powder (Y2O3), and the mass ratio of TiO2 powder, MgF2 powder, and Y2O3 powder is 4.0:2.0:1.0. The mass ratio of PVA powder and diatomaceous earth powder is 1:3.

[0029] Example 1 This embodiment uses inkjet 3D printing of magnesium oxide ceramic powder to prepare magnesium oxide ceramics, specifically including the following steps: (1) Pass the reburned MgO, phosphate, precision improvement components and sintering aid through a 150-200 mesh sieve, and the sintering shrinkage reduction and toughening agent through a 320 mesh sieve.

[0030] (2) Add 63 parts of reburned MgO and 15 parts of phosphate to a planetary mixer and stir for 5 minutes until the mixture is uniform. Then, add 5 parts of precision improving component, 3 parts of sintering aid and 5 parts of sintering shrinkage reducing and toughening agent, and continue stirring for 10 minutes until the mixture is uniform to obtain the powder material.

[0031] (3) Add the powder material prepared above into the powder material feed hopper of the printer, and print using inkjet 3D printing technology. The layer thickness is 0.125mm and the printing speed is 600mm / s. After printing, remove the model and remove the unbonded powder to obtain a magnesium oxide ceramic blank.

[0032] (4) Place a 3cm high model pad at the bottom of the magnesium oxide ceramic blank, heat the muffle furnace at a rate of 5℃ / min, heat to 800℃ and hold for 30min, then heat at a rate of 3℃ / min to sintering temperature of 1300℃ and hold for 2h. After natural cooling to room temperature, magnesium oxide ceramic is obtained.

[0033] Example 2 This embodiment uses inkjet 3D printing of magnesium oxide ceramic powder to prepare magnesium oxide ceramics. The steps are the same as in Embodiment 1, except that the sintering temperature in this embodiment is set to 1350℃ to prepare magnesium oxide ceramics.

[0034] Example 3 This embodiment uses inkjet 3D printing of magnesium oxide ceramic powder to prepare magnesium oxide ceramics. The steps are the same as in Embodiment 2, except that the formulation of the inkjet 3D printing magnesium oxide ceramic powder in this embodiment is as follows: 80 parts recalcined MgO, 15 parts phosphate, 5 parts precision improving components, 3 parts sintering aids, and 5 parts sintering shrinkage reducing and toughening agents.

[0035] Example 4 This embodiment uses inkjet 3D printing of magnesium oxide ceramic powder to prepare magnesium oxide ceramics. The steps are the same as in Embodiment 1, except that the ceramic sintering mechanism is different: In this embodiment, the magnesium oxide ceramic green body adopts a segmented heating-powder-support anti-deformation sintering method. The specific process is as follows: 4) Pretreatment of embedded powder: 200-mesh alumina powder is selected for embedded powder, pre-calcined in a muffle furnace for 2 hours, cooled to room temperature, and then sieved to break up agglomerated particles. 5) Burying powder in the furnace: Select a corundum sagger, spread 15mm of pre-fired alumina powder on the bottom, put the billet into the sagger, and then bury the powder. When burying the powder, use a sieve to lightly sprinkle until it completely covers the billet by 10mm. 6) Sintering in a muffle furnace: room temperature - 200℃, heating rate is 2℃ / min; 200℃ - 800℃, heating rate is 3℃ / min, holding time is 1h; 800℃ - target temperature, heating rate is 5℃ / min, holding time is 2h; target temperature - 1000℃, cooling rate is 5℃ / min; 1000℃ - room temperature, cooling with the furnace.

[0036] 7) Ceramic cleaning: Use a soft brush to sweep away the alumina powder on the surface. Residual powder can be blown away with an air pump.

[0037] In this invention, the target temperature is the sintering temperature, which can be taken in the range of 1200-1400℃.

[0038] Pre-sintering with alumina powder is used to avoid deformation of the green body caused by the shrinkage of the powder at high temperatures. During sintering, the process consists of four stages: a first stage is a low-temperature dehydration stage to remove moisture from the green body; a second stage is a medium-temperature desalination stage with a holding time of at least 1 hour to ensure complete decomposition of phosphates and prevent the formation of low-melting-point phases at high temperatures, which could lead to green body deformation; a third stage is a high-temperature sintering stage with a holding time of at least 2 hours to promote the dense sintering of magnesia grains and improve the strength of magnesia; and a fourth stage is a cooling stage, with a cooling rate not exceeding 5℃ / min above 1000℃ to prevent thermal shock cracking of the magnesia ceramic. Compared with traditional sintering methods, this segmented heating-powder-support anti-deformation sintering method is beneficial for improving the strength of magnesia ceramics and also provides support for green bodies with complex thin-walled structures, preventing deformation caused by shrinkage and gravity during sintering.

[0039] Comparative Example 1 This comparative example uses inkjet 3D printing of magnesium oxide ceramic powder to prepare magnesium oxide ceramics. The steps are the same as in Example 2, except that no precision-improving components are added in this comparative example.

[0040] Comparative Example 2 This comparative example uses inkjet 3D printing of magnesium oxide ceramic powder to prepare magnesium oxide ceramics. The steps are the same as in Example 2, except that no sintering aids are added in this comparative example.

[0041] Comparative Example 3 This comparative example uses inkjet 3D printing of magnesium oxide ceramic powder to prepare magnesium oxide ceramics. The steps are the same as in Example 2, except that no sintering shrinkage reducing and toughening agent is added in this comparative example.

[0042] Comparative Example 4 The steps in this comparative example are the same as in Example 2, except that no nano-silica powder is added in this comparative example, and the mass ratio of talc powder to zircon powder is 1:1. After testing, it showed that it produced large deformation and cracking after sintering.

[0043] Comparative Example 5 The steps in this comparative example are the same as in Example 2, except that talc powder is not added in this comparative example, and the mass ratio of nano silica powder to zircon powder is 3:2. After testing, it was found that shrinkage deformation occurred after sintering.

[0044] Comparative Example 6 The steps in this comparative example are the same as in Example 2, except that TiO2 powder is not added in this comparative example, and the mass ratio of MgF2 powder to Y2O3 powder is 2:1. The resulting ceramic material has a rougher surface and significantly reduced strength, toughness and thermal shock resistance.

[0045] Example 2 differs from Comparative Example 1 in that Comparative Example 1 did not include any accuracy-improving components. (See Table 1 and...) Figure 1 , Figure 2 The comparison shows that printing using Example 2 has higher molding accuracy and surface quality. Printing using Comparative Example 1 proceeds smoothly, but the molding accuracy and surface quality of the printed specimen are poor. The printed model needs to meet the requirements of printing accuracy error below 1mm and maintaining a flat surface.

[0046] Table 1

[0047] Table 2 shows that, comparing Examples 1 and 2, increasing the sintering temperature can improve the mechanical strength of the sintered specimens. Comparing Examples 2 and 3, under the same conditions within the given parameter range, increasing the magnesium oxide ratio can reduce the shrinkage of the specimens, with the Z-shrinkage rate controlled below 15%. Comparative Example 2 is the same as Example 2, except that no sintering aid was added, resulting in a significant decrease in the mechanical strength of the specimen. Comparative Example 3 is the same as Example 3, except that no sintering shrinkage-reducing and toughening agent was added. Although it has higher compressive strength, it is prone to cracking after sintering. Figure 3 and Figure 4 As shown, the model underwent significant shrinkage, leading to sintering cracks. Excessive sintering temperature can cause the model structure to collapse and deform.

[0048] Table 2

[0049] The implementation methods of this experiment have been described in detail above. However, this experiment is not limited to the specific details of the above implementation methods. In addition, it should be noted that the various specific technical features described in the above specific implementation methods can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, this experiment will not describe the various possible combinations separately.

[0050] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A magnesium oxide ceramic powder material for inkjet 3D printing, characterized in that, The powder material is formulated in the following weight proportions: 50-90 parts reburned MgO, 10-30 parts phosphate, 2-7 parts precision improving component, 1-10 parts sintering aid, and 1-10 parts sintering shrinkage reducing and toughening agent. The precision-improving components include PVA powder and diatomaceous earth powder, wherein the mass ratio of PVA powder to diatomaceous earth powder is 1:2-1:5; The sintering aids include titanium dioxide powder (TiO2), magnesium fluoride powder (MgF2), and yttrium oxide powder (Y2O3), wherein the mass ratio of TiO2 powder, magnesium fluoride powder (MgF2), and Y2O3 powder is (3.8-4.5):(1.8-2.2):(0.8-1.2). The sintering shrinkage-reducing and toughening agent includes nano-SiO2 powder, talc powder and zircon powder, and the mass ratio of nano-SiO2 powder, talc powder and zircon powder is (2.8-3.4):(1.8-2.4):(1.8-2.2).

2. The inkjet 3D printing magnesium oxide ceramic powder material according to claim 1, characterized in that, The PVA powder is one or more of the following types: 17-80, 17-88, 17-92, and K30, with a purity greater than 98% and a fineness of 150-200 mesh; the diatomaceous earth powder has a purity greater than 96% and a bulk density of 0.54-0.67 g / cm³. 3 The particle size ranges from 0.075 to 0.125 mm.

3. The inkjet 3D printing magnesium oxide ceramic powder material according to claim 1, characterized in that, The TiO2 powder is rutile phase with a bulk density of 1.4-1.8 g / cm³. 3 The purity is greater than 98%, and the particle size range is 0.045-0.125 mm; the MgF2 powder has a concentration of 1.5-1.8 g / cm³. 3 The particle size range is 0.075-0.125 mm; the Y2O3 powder has a concentration of 1.6-2.1 g / cm³. 3 The particle size ranges from 0.075 to 0.125 mm.

4. The inkjet 3D printing magnesium oxide ceramic powder material according to claim 1, characterized in that, The bulk density of the nano-SiO2 powder is 1.2-1.6 g / cm³. 3 The purity is greater than 98%; the bulk density of the talc powder is 2.5-2.8 g / cm³. 3 Particle size less than 45 The zircon powder has a bulk density of 1.0-1.2 g / cm³. 3 Particle size less than 45 ; The recalcined MgO is obtained by calcining magnesite raw material in a high-temperature furnace at 1600–1950℃ for 50–120 min, followed by ball milling at 1500–1800 r / min for 15–35 min and then sieving. Its bulk density is 1.8–2.0 g / cm³. 3 Specific surface area is 230-287 m² 2 / kg, with a particle size range of 0.075-0.15mm; The phosphate is one or more of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and sodium dihydrogen phosphate powder, with a purity greater than 96% and a maximum particle size of 0.125 mm.

5. A magnesium oxide ceramic material prepared using the inkjet 3D printing magnesium oxide ceramic powder material according to any one of claims 1-4, characterized in that, The specific preparation process is as follows: (1) Pass the recalcined MgO, phosphate, precision improvement components and sintering aid through a 150-200 mesh sieve, and the sintering shrinkage reduction and toughening agent through a 320 mesh sieve; (2) Add 50-90 parts of recalcined MgO and 10-30 parts of phosphate to a planetary mixer and stir for 5-10 minutes until the mixture is uniform; then, add 2-7 parts of precision improving component, 1-10 parts of sintering aid, and 1-10 parts of sintering shrinkage reducing and toughening agent, and continue stirring for 10-15 minutes until the mixture is uniform to obtain the powder material. (3) Add the powder material prepared in step (2) into the powder material feed hopper of the printer, add the inorganic material ink into the printing ink cartridge, and print using inkjet 3D printing technology. The layer thickness is 0.1-0.2mm, the printing speed is 600-800mm / s, and after printing, remove the model and remove the unbonded powder to obtain the blank. (4) Place a model pad with a height of 2cm-4cm at the bottom of the blank, heat the muffle furnace at a rate of 5-10℃ / min, heat to 700-900℃ and hold for 0.5-1h, then heat at a rate of 1-4℃ / min to sintering temperature of 1200-1400℃ and hold for 1-3h, and then cool naturally to room temperature to obtain magnesium oxide ceramic.

6. The magnesium oxide ceramic material according to claim 5, characterized in that, The green body is treated using a segmented heating-powder-supported anti-deformation sintering method. The specific process is as follows: 1) Pretreatment of embedded powder: 200 mesh alumina powder is selected for embedded powder, pre-calcined in a muffle furnace for 2 hours, cooled to room temperature, and then sieved to break up agglomerated particles; 2) Burying powder in the furnace: Select a corundum sagger, spread 15mm of pre-fired alumina powder on the bottom, put the billet into the sagger, and then bury the powder. When burying the powder, use a sieve to lightly sprinkle until it completely covers the billet by 10mm. 3) Sintering in a muffle furnace: room temperature - 200℃, heating rate 2℃ / min; 200℃ - 800℃, heating rate 3℃ / min, holding time 1~2h; 800℃ - target temperature, heating rate 5℃ / min, holding time 2~3h; target temperature - 1000℃, cooling rate 3~5℃ / min; 1000℃ - room temperature, cooling with the furnace; the target temperature is the sintering temperature. 4) Ceramic cleaning: Use a soft brush to sweep away the alumina powder on the surface. Residual powder can be blown away with an air pump.

7. The magnesium oxide ceramic material according to claim 6, characterized in that, The target temperature is 1300~1350℃.

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