3DP Manufacturing Method of Alumina Ceramic Parts Based on Aluminum Chloride as Binder

Abstract

The present invention relates to the field of additive manufacturing, and particularly to a 3DP manufacturing method for alumina ceramic parts using aluminum chloride as a binder, comprising the following steps: mixing alumina, aluminum chloride and a mineralizer to obtain 3DP prefabricated powder; mixing absolute ethanol and deionized water and degassing to obtain a printing binder; using the 3DP prefabricated powder and the binder to print a ceramic part to obtain a green body of the ceramic part; and sintering the green body of the ceramic part to obtain a formed ceramic part. The present invention uses aluminum chloride as a binder to form ceramic parts with controllable porosity, and obtains ceramic parts with excellent properties through a suitable post-treatment process.

Description

Technical Field

[0001] The present invention relates to the field of additive manufacturing, and particularly to a 3DP manufacturing method for alumina ceramic parts using aluminum chloride as a binder. Background Art

[0002] Electrofused corundum has the characteristics of stable high-temperature chemical properties and high high-temperature strength, so it has a wide range of applications in the investment casting field of superalloys and is widely used as core and shell mold materials in the investment casting field. Activated alumina has the characteristics of high dispersion, high adsorption performance, high surface activity, excellent thermal stability and reusability, and is widely used in the field of new filters. With the development of engineering technology, the structure of ceramic parts shows a trend of integration and complexity, mainly manifested in complex external shapes and complex internal channels. However, due to the high hardness and brittleness of ceramic materials, traditional processing methods need to use molds to process ceramic parts. The higher the complexity of the parts, the greater the mold opening cost, and the process flow is complex, with low productivity and low finished product rate. Therefore, it is difficult to be competent for the processing of complex ceramic parts.

[0003] Binder Jetting (BJ) technology, usually also known as the 3DP technology. Compared with other additive manufacturing technologies, its advantages are high manufacturing precision, fast printing speed, material recyclability, good manufacturing economy and a wide range of material selection. The principle of this technology is to first use slicing software to convert the CAD model into a two-dimensional model. After each layer of powder spreading is completed, the nozzle sprays according to a predetermined path to bond the sprayed powder together, and layer-by-layer printing is carried out until completion.

[0004] At present, there are mainly two types of binders used in 3DP technology for manufacturing ceramics: one is organic binders such as furan resin and phenolic resin. Because of its high curing efficiency and good effect, it is widely used in the current ceramic additive manufacturing field. However, organic binders will pyrolyze to produce harmful gases during the high-temperature sintering of ceramics, causing environmental pollution. After pyrolysis, carbon residues will be produced, resulting in a decline in the surface performance of castings. The effective alumina content of the formed parts is relatively low, and the ceramic parts may collapse during the high-temperature sintering process, resulting in a decrease in the finished product rate of the product. The other is inorganic binders such as silicate. Because of its low gas evolution and reliable performance, it is widely used in the field of non-ferrous metal casting. However, such binders will cause high-temperature creep of parts at temperatures above 1000°C. In addition, during the printing process, ink clogging of the nozzle will cause the printing process to be discontinuous and the ink to penetrate into the powder bed, which will have an adverse impact on the accuracy of the final ceramic parts. Therefore, it is of great scientific significance, major engineering applications and broad market value to develop an alumina ceramic 3DP manufacturing process method with high precision and strength, high alumina composition content in the formed parts, good high-temperature adhesiveness, and harmless to the human body and the environment during the production process.

[0005] Aluminum chloride is widely sourced, low in cost, soluble in water and absolute ethanol, and in high-temperature sintering, the mineralizer and alumina can form a reinforcing phase. However, there is currently no report on applying aluminum chloride as a binder in the 3DP technology for ceramic parts. Therefore, the present invention aims to provide a 3DP manufacturing method based on aluminum chloride as a binder that can effectively improve the performance of parts. Summary of the Invention

[0006] To overcome the above technical problems, the present invention provides a 3DP manufacturing method for alumina ceramic parts based on aluminum chloride as a binder, with the aim of obtaining 3DP ceramic parts with good performance and no carbon residue.

[0007] The present invention provides a 3DP manufacturing method for alumina ceramic parts based on aluminum chloride as a binder, comprising the following steps:

[0008] Mix alumina, aluminum chloride, and a mineralizer to obtain 3DP prefabricated powder;

[0009] Mix absolute ethanol and deionized water and degas to obtain a printing binder;

[0010] Use the 3DP prefabricated powder and the binder to print a ceramic part to obtain a green ceramic part;

[0011] Sinter the green ceramic part to obtain a formed ceramic part.

[0012] Preferably, based on the total mass of the 3DP prefabricated powder, the content of alumina is 80% - 90%, the content of aluminum chloride is 8% - 15%, and the content of the mineralizer is 2% - 5%.

[0013] Preferably, the particle size of the alumina is 150 - 320 mesh, the particle size of the aluminum chloride is 120 - 200 mesh, and the particle size of the mineralizer is 2000 - 3000 mesh.

[0014] Preferably, the volume ratio of the absolute ethanol to the deionized water is 1.45 - 1.55:1.

[0015] Preferably, alumina, aluminum chloride, and the mineralizer are dried separately before mixing;

[0016] The degassing is to degas the mixed solution of absolute ethanol and deionized water under vacuum conditions, and the apparent viscosity value of the mixed solution after degassing at 20°C and a shear rate of 1 s -1 is not higher than 8 mPa·s.

[0017] Preferably, the alumina is selected from one or more of white fused alumina, fused alumina, α-alumina, and activated alumina;

[0018] The aluminum chloride is anhydrous aluminum chloride or aluminum chloride hexahydrate;

[0019] The mineralizer is selected from one or a mixture of several of silicon oxide, magnesium oxide, yttrium oxide, zirconium oxide, boehmite, kyanite, fused mullite powder.

[0020] Preferably, during the printing process, the printed layer is subjected to real-time heating treatment, and the heating power is 1000W - 2400W.

[0021] Preferably, the powder bed after printing is subjected to baking and curing treatment, the baking temperature is 120 - 200 °C, and the baking time is 1 - 2 hours.

[0022] Preferably, the ceramic part obtained after baking and curing is subjected to powder cleaning treatment, and then sintered in a programmed heating manner;

[0023] The programmed heating process is as follows: heating to 1400 °C at a heating rate of 5 - 10 °C / min, holding for 30 - 60 min, then heating to the sintering temperature point at 2 - 5 °C / min, and holding for 45 - 80 min.

[0024] Preferably, when printing the green body of the ceramic part, the printing layer height is 0.10 mm - 0.30 mm, and the inkjet concentration is 30% - 75%.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention uses aluminum chloride as a binder, which has the following advantages: (1) When aluminum chloride is used as a binder, the curing time is shorter than that of traditional resin binders; (2) Aluminum chloride is an inorganic compound and will not generate harmful gases like resin pyrolysis in a high-temperature sintering environment; (3) The product after sintering of aluminum chloride is alumina, which will not introduce other substances into the ceramic part, and the final part has a high alumina content; (4) Aluminum chloride will form aluminum hydroxide after hydrolysis, and aluminum hydroxide can form pores when decomposed at high temperature, so the porosity of the ceramic part can be controlled within a certain range by controlling the content of the binder aluminum chloride.

[0027] 2. The present invention uses a mixed solution of absolute ethanol and deionized water as printing ink, which has the following advantages: (1) Ethanol is volatile, which can accelerate the drying and curing speed of the printed ceramic, and avoid the problem of reduced forming accuracy caused by too far penetration distance and too large penetration depth of the ink in the powder bed; (2) It forms aluminum hydroxide colloid with part of the aluminum chloride in the powder bed and forms an aluminum hydroxide connection bridge after drying, generating low-temperature bonding strength; (3) This mixed solution has no other solutes and particles, is simple to prepare, and has no risk of blocking the nozzle; (4) Absolute ethanol and deionized water are widely available and low in cost.

[0028] 3. The use of a mineralizer has the following three advantages: (1) The mineralizer can fill the voids between alumina powder particles, increasing the packing density of the powder bed and thus enhancing the density of the manufactured part; (2) The mineralizer can form a reinforcing phase with the alumina powder during high-temperature sintering, improving the high-temperature service strength of the manufactured part; (3) When used in ceramic core parts, the presence of the mineralizer can improve the chemical leachability of the core.

[0029] 4. The real-time heating treatment of the printed layer has the following two advantages: (1) The increase in the temperature of the printing area will shift the chemical equilibrium of the reaction between aluminum chloride and water to the right, increasing the degree of hydrolysis of aluminum chloride and generating more aluminum hydroxide colloids, thereby enhancing the bonding strength; (2) The increase in the temperature of the printing area will accelerate the evaporation of the ink, reducing the penetration distance and thus improving the printing accuracy.

[0030] 5. The use of a baking process can cure the manufactured part at a relatively low temperature and release the residual moisture in the ceramic part, enabling the green body of the ceramic part to have the strength to resist damage during powder cleaning and avoiding cracking during the sintering process.

[0031] 6. The ceramic parts prepared by using the method provided by the present invention have the advantages of high precision, high high-temperature strength, low high-temperature creep, low sintering shrinkage rate, high alumina content, etc. At the same time, they have good chemical stability during the investment casting process, thus avoiding problems such as large shrinkage rate during sintering and insufficient strength after sintering.

[0032] 7. The ceramic parts manufactured by using the ceramic 3DP manufacturing method provided by the present invention can be manufactured into any complex shapes and structures, and are suitable for complex parts such as ceramic cores for investment casting, ceramic mold shells for high-temperature casting, and porous ceramic filters. It can effectively reduce the manufacturing cost, shorten the product manufacturing cycle, and effectively solve the problem of difficult processing of complex ceramics. These difficulties include both the difficulties in traditional injection molding of ceramics, such as long mold opening time, high cost, precision dependence on the mold, and high scrap rate, and the difficulties in current stereolithography, such as the need for a support structure, slow printing speed, high cost, and high sintering shrinkage rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is the process flow chart of the alumina ceramic 3DP manufacturing method using aluminum chloride as a binder according to the present invention;

[0034] Figure 2 is a schematic diagram of the alumina ceramic core for investment casting of a hollow turbine blade in Example 1 of the present invention;

[0035] Figure 3 is a schematic diagram of the alumina ceramic filter in Example 4 of the present invention;

[0036] Figure 4It is a schematic diagram of the mold shell for casting hollow turbine blades in Embodiment 8 of the present invention;

[0037] Figure 5 It is a schematic diagram of a printer provided with a follow-up heating device in an embodiment of the present invention; 1. Powder spreading device; 2. Feeding bin; 3. Print head; 4. Follow-up heating device; 5. Powder bed; 11. Moving track; 12. Mounting frame;

[0038] Figure 6 It is a schematic structural diagram of the follow-up heating device provided in an embodiment of the present invention; 6. Housing; 7. Heating wire; 8. Reflective film; 9. Heat insulation cotton; 10. Control switch. Detailed implementation manners

[0039] The present invention will be further described below with reference to the drawings and embodiments.

[0040] Refer to Figure 1 As shown, the present invention is realized through the following technical solutions:

[0041] The alumina ceramic 3DP manufacturing method using aluminum chloride as a binder provided by the present invention includes the following steps:

[0042] S1. After drying the alumina powder (substituted by selectable white fused alumina powder in the figure, but it does not mean that the alumina powder can only be selected from white fused alumina powder), aluminum chloride powder and mineralizer respectively, they are fully stirred and mixed evenly to obtain a 3DP forming material; wherein the particle size of the alumina powder is 150 - 320 mesh, the particle size of the aluminum chloride powder is 120 - 200 mesh, the effective component of the aluminum chloride powder ≥ 90wt%, the particle size of the mineralizer is 2000 - 3000 mesh, the mass of the alumina powder accounts for 80% - 90% of the total mass of the 3DP printing material, the mass of the aluminum chloride powder accounts for 8% - 15% of the total mass of the 3DP printing material, and the mass of the mineralizer accounts for 2% - 5% of the total mass of the 3DP printing material.

[0043] S2. Mix anhydrous ethanol and deionized water evenly according to the volume ratio of (1.45:1) - (1.55:1), and then place the solution in a vacuum box for degassing. When degassing, the vacuum degree ≤ 130 Pa, the degassing time is 10 - 20 minutes. After degassing, the apparent viscosity value of the printing ink at 20°C and a shear rate of 1s -1 is not higher than 8 mPa·s to obtain a printing binder (i.e., printing ink).

[0044] S3. Import the ceramic part model data to be printed into a 3D printer, and use the 3DP forming material prepared in S1 and the printing ink prepared in S2 to perform 3DP forming preparation of ceramics to obtain a green ceramic part. During the printing process, the printing layer height is 0.10 mm to 0.30 mm, and the inkjet concentration is 30% to 75%. During the printing process, the accompanying heating device works, and the heating power ≥ 1000 W.

[0045] S4. After S3 is completed, move the entire powder bed into a blast drying oven for heat curing. The heating temperature is 120 - 200 °C, and the baking time is 1 - 2 hours.

[0046] S5. After the powder bed cools down in the furnace, take out the cured green ceramic part and perform powder cleaning. Use a brush to clean the powder on the outer surface and high-pressure gas to clean the powder in the inner hole.

[0047] S6. Sinter the ceramic specimen after the above powder cleaning. The sintering temperature ≥ 1500 °C. Among them, the heating rate from room temperature to 1400 °C is 5 - 10 °C / minute, hold at 1400 °C for 30 - 60 minutes, the heating rate from 1400 °C to the sintering temperature point is 2 - 5 °C / minute, hold at the sintering temperature for 45 - 80 minutes, and then cool down in the furnace to obtain the described ceramic part.

[0048] Among them, the accompanying heating device is installed on an existing printer. In the embodiment of the present invention, the Wuhan EasyFab Easy3DP-M450 printer is used. There is a moving track 11 set on this printer, and an accompanying heating device is set on the moving track 11, as Figure 5 shown.

[0049] The specific structure of the accompanying heating device in the embodiment of the present invention ( Figure 6 ) is: The accompanying heating device includes an aluminum alloy housing 6. There are 6 heating wires 7 with a power of 400 W arranged inside the aluminum alloy housing 6. A reflective film 8 is pasted on the inner wall of the aluminum alloy housing 6. There is a six-way control switch 10 for controlling the operation of the heating wire 7 on the aluminum alloy housing 6. There is also a heat insulation cotton 9 (Golden Cicada Heat Insulation Material Company, thickness 10 mm) between the reflective film 8 and the inner wall of the aluminum alloy housing 6. The aluminum alloy housing 6 slides along the moving track 11 through a mounting frame 12 slidably connected to the moving track 11.

[0050] The parameters are as follows: Heating wire 7 (brand: Tempered brand; material: FeCrAl; power: 400 W; voltage 220 V; length 360 mm; outer diameter 3.9 mm), control switch 10 (CHNT 1P, 10A) × 6; housing 6 material: aluminum alloy 5052-H112. The reflective film 8 uses heat-insulating aluminum skin and is resistant to high temperatures of 500 °C.

[0051] Working principle: The six-way control switch 10 controls six heating wires 7 respectively, realizing the change of heating power from 400 to 2400W; the reflective film 8 makes the heat concentrate downward; the heat insulation cotton 9 protects the shell and makes the equipment safer during operation. The whole is fixed by the mounting bracket 12, so as to realize the follow-up heating function on the moving track 11.

[0052] The alumina powder used in the present invention can be obtained by mixing different particle size grades of one material among white fused alumina powder, fused alumina powder, α-alumina powder, activated alumina powder, or by mixing different particle size grades of several materials.

[0053] The mineralizer used in the present invention can be one or a mixture of several of silicon oxide, magnesium oxide, yttrium oxide, zirconium oxide, boehmite, kyanite, fused mullite powder.

[0054] The aluminum chloride powder used in the present invention can be anhydrous aluminum chloride and aluminum chloride hexahydrate, and the effective component content is ≥90% wt%.

[0055] The sintering temperature point described in the present invention is determined by the type of the selected mineralizer and the sintering shrinkage rate. Those skilled in the art can set the sintering temperature according to the specifically selected mineralizer and sintering shrinkage rate during specific implementation. For example, for the alumina ceramic parts in the present invention, the sintering temperature point is 1450 - 1700°C, and the specific sintering temperature point is selected according to the mineralizer. For example, if the mineralizer is silicon dioxide, the recommended sintering temperature is 1350 - 1500°C, and the reinforcing phase is mullite phase; if the mineralizer is calcium oxide, the recommended sintering temperature is

[0056] 1500 - 1700°C, and the reinforcing phase is CaAl 12 O 19 ; if the mineralizer is magnesium oxide, the recommended sintering temperature is 1350 - 1550°C, and the reinforcing phase is magnesium aluminate spinel, etc. Different sintering temperatures and sintering times will regulate the shrinkage rate and porosity. Generally speaking, the higher the temperature and the longer the time, the greater the shrinkage rate, the lower the porosity, and the higher the strength.

[0057] It can be seen from the above scheme of the present invention that:

[0058] 1. The present invention uses 3DP printing to manufacture ceramic parts. The 3DP printing technology can form cores and molds with any complex structure, and has the advantages of high precision, short manufacturing cycle, and high productivity. Compared with the traditional complex ceramic preparation with long mold manufacturing cycle, high cost, and long iteration cycle, it has obvious advantages.

[0059] 2. Using aluminum chloride as a binder has the following advantages: (1) When aluminum chloride is used as a binder, the curing time is shorter than that of traditional resin binders; (2) Aluminum chloride is an inorganic compound and will not produce harmful gases like resin pyrolysis in a high-temperature sintering environment; (3) The product after sintering aluminum chloride is alumina, which will not introduce other substances into the ceramic parts, and the final parts have a high alumina content; (4) Aluminum chloride will form aluminum hydroxide after hydrolysis, and aluminum hydroxide can form pores when decomposed at high temperature. Therefore, the porosity of the ceramic parts can be controlled within a certain range by controlling the content of the binder aluminum chloride.

[0060] 3. Using a mineralizer has the following three advantages: (1) The mineralizer can fill the gaps between alumina powder particles and improve the density of the parts; (2) The mineralizer can form a reinforcing phase with alumina powder during high-temperature sintering to improve the strength of the parts; (3) When the parts are used as ceramic cores, the presence of the mineralizer can improve the chemical leachability of the cores.

[0061] 4. Using a mixed solution of absolute ethanol and deionized water as printing ink has the following advantages: (1) Absolute ethanol and deionized water are widely sourced and low-cost; (2) This mixed solution has no other solutes and particles, and there is no risk of clogging the nozzle; (3) Ethanol is volatile, which can accelerate the drying and curing speed of the printed ceramics and avoid the problem of reduced forming accuracy caused by excessive penetration distance and depth in the powder bed; (4) It forms aluminum hydroxide colloid with part of aluminum chloride in the powder bed and forms an aluminum hydroxide connecting bridge after drying, generating low-temperature bonding strength.

[0062] 5. Using a follow-up heating device has the following two advantages: (1) The increase in temperature in the printing area will shift the chemical equilibrium of the reaction between aluminum chloride and water to the right, increasing the degree of hydrolysis of aluminum chloride and generating more aluminum hydroxide colloid, thereby improving the bonding strength; (2) The increase in temperature in the printing area will accelerate the evaporation of the ink, reduce the penetration distance, and thus improve the printing accuracy.

[0063] 6. Using a baking process can cure the parts at a lower temperature, release the residual moisture in the ceramic parts, facilitate powder cleaning, and avoid cracking during the sintering process. Placing the entire powder bed in a forced-air drying oven can not only provide a support structure during the drying and curing process in the printing area but also dry the remaining powder, facilitating subsequent printing and manufacturing; when using a sintering process, the heating rate in the first stage should not be too large, otherwise it will cause the specimen to crack, and it is necessary to keep the temperature for a period of time during high-temperature sintering to allow the mineralizer and alumina to fully react to form a reinforcing phase.

[0064] The 3DP powder that is uniformly mixed after separate drying avoids the problem of powder aggregation caused by the humidity in the powder, which is beneficial for powder spreading.

[0065] The complex ceramic parts produced by the method of the present invention have the advantages of high precision, high high-temperature strength, small high-temperature creep, low sintering shrinkage, and high alumina content. At the same time, the casting process is chemically stable after investment casting, thereby avoiding problems such as large shrinkage during sintering and insufficient strength after sintering.

[0066] Ceramic parts manufactured using the ceramic 3DP manufacturing method provided by the present invention can be produced in arbitrarily complex shapes and structures. They are suitable for complex parts such as ceramic cores for investment casting, ceramic mold shells for high-temperature casting, and porous ceramic filters. This method can effectively reduce manufacturing costs and shorten product manufacturing cycles. It effectively addresses the difficulties in processing complex ceramics, including the long mold opening time, high cost, mold-dependence, and high scrap rates in traditional injection molding, as well as the current difficulties in stereolithography, such as the need for support structures, slow printing speeds, high costs, and high sintering shrinkage.

[0067] Example 1

[0068] The 3DP manufacturing method provided by the present invention is used to manufacture a ceramic core for investment casting of a hollow turbine blade having a thin-walled curved surface structure and fine features, comprising the following steps:

[0069] S1. Fused corundum powders with a particle size of 150-180 mesh and 290-320 mesh are uniformly mixed in a mass ratio of 3:7, and then mixed with aluminum chloride hexahydrate powder with a particle size of 120-200 mesh and an active ingredient content of 95% and magnesium oxide powder with a particle size of 2000-3000 mesh to obtain a 3DP prefabricated powder. The mass ratio of the fused corundum graded mixed powder, aluminum chloride hexahydrate powder, and magnesium oxide powder is 87:8:5. The fused corundum graded mixed powder, aluminum chloride hexahydrate powder, and magnesium oxide powder are dried separately before mixing.

[0070] S2, anhydrous ethanol and deionized water were mixed evenly in a volume ratio of 1.45:1, and then the solution was placed in a vacuum box for degassing. The vacuum degree during degassing was 120Pa, and the degassing time was 20 minutes. After degassing, the printing ink was heated at 20°C and the shear rate was 1s -1 The apparent viscosity value at this time was 5 mPa·s, and a printing ink was obtained.

[0071] S3, will be Figure 2 The alumina ceramic core model data for the investment casting of the hollow turbine blade shown is imported into a 3D printer for 3DP molding preparation of the ceramic to obtain a ceramic core green body; during the printing process, the printing layer height is 0.10mm, the inkjet concentration is 30%, and the accompanying heating device is used to perform real-time heating treatment on the printed layer during the printing process, with a heating power of 1300W.

[0072] S4. After S3 is completed, the entire powder bed is transferred into a blast drying oven for heat curing. The heating temperature is 200 °C and the baking time is 1 hour.

[0073] S5. After the powder bed is cooled in the furnace, the cured ceramic core is taken out and powder cleaning is carried out. The outer surface is cleaned with a brush, and the inner hole can be cleaned with high-pressure gas.

[0074] S6. The ceramic sample after the above powder cleaning is sintered. The sintering temperature is 1550 °C. It is heated from room temperature to 1400 °C at a heating rate of 5 °C / minute and held for 30 minutes, then heated to 1550 °C at a heating rate of 2 °C / minute and held for 80 minutes, and then cooled in the furnace to obtain a high-performance complex ceramic part.

[0075] Example 2

[0076] Using the 3DP manufacturing method provided by the present invention to manufacture a ceramic core for investment casting of a hollow turbine blade with a thin-walled curved surface structure and fine features, comprising the following steps:

[0077] S1. The fused alumina powders with particle sizes of 150 - 180 mesh and 290 - 320 mesh are mixed evenly according to a mass ratio of 3:7, and then mixed with the aluminum chloride hexahydrate powder with a particle size of 120 - 200 mesh and an effective component of 95% and the magnesium oxide powder with a particle size of 2000 - 3000 mesh to obtain a 3DP prefabricated powder. The mass ratio of the fused alumina graded mixed powder, the aluminum chloride hexahydrate powder, and the magnesium oxide powder is 80:15:5. The fused alumina graded mixed powder, the aluminum chloride hexahydrate powder, and the magnesium oxide powder are dried separately and then mixed.

[0078] S2. Absolute ethanol and deionized water are mixed evenly according to a volume ratio of 1.45:1. Then the solution is placed in a vacuum chamber for degassing. The vacuum degree during degassing is 120 Pa and the degassing time is 20 minutes. After degassing, the apparent viscosity value of the printing ink at 20 °C and a shear rate of 1 s -1 is 5 mPa·s to obtain the printing ink.

[0079] S3. The model data of the alumina ceramic core for investment casting of the hollow turbine blade as Figure 2 shown is imported into a 3D printer for 3DP forming preparation of ceramics to obtain a green body of the ceramic core. During the printing process, the printing layer height is 0.10 mm, the inkjet concentration is 30%, and a follow-up heating device is used to perform real-time heating treatment on the printing layer during the printing process, and the heating power is 1300 W.

[0080] S4. After S3 is completed, the entire powder bed is transferred into a blast drying oven for heat curing. The heating temperature is 200 °C and the baking time is 1 hour.

[0081] In S5, after the powder bed is cooled with the furnace, the solidified ceramic core is taken out and powder cleaning is carried out. The outer surface is cleaned with a brush, and the inner hole can be cleaned with high-pressure gas.

[0082] In S6, the ceramic sample after the above powder cleaning is sintered. The sintering temperature is 1550 °C. It is heated from room temperature to 1400 °C at a heating rate of 5 °C per minute and held for 30 minutes, then heated to 1550 °C at a heating rate of 2 °C per minute and held for 80 minutes, and then cooled with the furnace to obtain a high-performance complex ceramic part.

[0083] Example 3

[0084] Using the 3DP manufacturing method provided by the present invention to manufacture a ceramic core for investment casting of a hollow turbine blade with a thin-walled curved surface structure and fine features, comprising the following steps:

[0085] In S1, electrofused corundum powders with particle sizes of 150 - 180 mesh and 290 - 320 mesh are mixed evenly in a mass ratio of 3:7, and then mixed with aluminum chloride hexahydrate powder with a particle size of 120 - 200 mesh and an effective component of 95% and magnesium oxide powder with a particle size of 2000 - 3000 mesh to obtain 3DP prefabricated powder. The mass ratio of the electrofused corundum graded mixed powder, aluminum chloride hexahydrate powder, and magnesium oxide powder is 87:8:5. The electrofused corundum graded mixed powder, aluminum chloride hexahydrate powder, and magnesium oxide powder are dried separately and then mixed.

[0086] In S2, absolute ethanol and deionized water are mixed evenly in a volume ratio of 1.45:1. Then the solution is placed in a vacuum box for degassing. The vacuum degree during degassing is 120 Pa, and the degassing time is 20 minutes. After degassing, the apparent viscosity value of the printing ink at 20 °C and a shear rate of 1 s -1 is 5 mPa·s to obtain the printing ink.

[0087] In S3, the model data of the alumina ceramic core for investment casting of the hollow turbine blade as Figure 2 shown is imported into a 3D printer for 3DP forming preparation of the ceramic to obtain a green body of the ceramic core. During the printing process, the printing layer height is 0.10 mm, the inkjet concentration is 30%, and a follow-up heating device is used to perform real-time heating treatment on the printing layer during the printing process, and the heating power is 1300 W.

[0088] In S4, after S3 is completed, the entire powder bed is moved into a blast drying oven for heating and curing. The heating temperature is 200 °C, and the baking time is 1 hour. 9]

[0089] S5, after the powder bed cools down with the furnace, the solidified ceramic core is taken out and the powder is cleaned. The outer surface is cleaned with a brush, and the inner hole can be cleaned with high-pressure gas.

[0090] S6, sintering the ceramic sample after the powder cleaning, the sintering temperature is 1550℃, heating from room temperature to 1400℃ at a heating rate of 10℃ / min, maintaining for 60 minutes, then heating to 1550℃ at a heating rate of 5℃ / min, maintaining for 45 minutes, and then cooling with the furnace to obtain high-performance complex ceramic parts.

[0091] Example 4

[0092] The 3DP manufacturing method provided by the present invention is used to manufacture a reusable alumina ceramic filter with high porosity, comprising the following steps:

[0093] S1. Activated alumina powder with a particle size of 150-190 mesh, anhydrous aluminum chloride powder with a particle size of 120-200 mesh and an active ingredient content of 90%, and silicon dioxide powder with a particle size of 2000-3000 mesh are dried separately and then thoroughly stirred and mixed to obtain a 3DP preformed powder, wherein the mass ratio of activated alumina powder, aluminum chloride powder, and silicon dioxide is 83:15:2.

[0094] S2, anhydrous ethanol and deionized water were mixed evenly in a volume ratio of 1.55:1, and then the solution was placed in a vacuum box for degassing. The vacuum degree during degassing was 120 Pa, and the degassing time was 10 minutes. After degassing, the printing ink was heated at 20 ° C and the shear rate was 1s -1 The apparent viscosity value at this time was 8 mPa·s, and a printing ink was obtained.

[0095] S3, will be Figure 3 The alumina ceramic filter model data shown was imported into a 3D printer for 3DP molding preparation of the ceramic to obtain a ceramic part green body. During the printing process, the printing layer height was 0.30 mm, the inkjet concentration was 75%, and the printing layer was heated in real time using an accompanying heating device during the printing process, with a heating power of 1600 W.

[0096] S4, after S3 is completed, the powder bed is moved as a whole into a blast drying oven for heating and curing. The heating temperature is 120° C. and the baking time is 2 hours.

[0097] S5, after the powder bed cools down with the furnace, the solidified ceramic filter is taken out and the powder is cleaned using a brush.

[0098] S6. Sinter the ceramic sample after the above-mentioned deflouring process. The sintering temperature is 1500 °C. Specifically, heat from room temperature to 1400 °C at a heating rate of 10 °C per minute, hold for 60 minutes, then heat to 1500 °C at a heating rate of 5 °C per minute, hold for 45 minutes, and then cool with the furnace. In this way, a reusable ceramic filter can be obtained.

[0099] Example 5

[0100] The reusable alumina ceramic filter with a relatively high porosity manufactured by the 3DP manufacturing method provided by the present invention includes the following steps:

[0101] S1. Dry the activated alumina powder with a particle size of 150 - 190 mesh, the anhydrous aluminum chloride powder with a particle size of 120 - 200 mesh and an effective ingredient of 90%, and the silica powder with a particle size of 2000 - 3000 mesh respectively, and then stir and mix them evenly to obtain the 3DP prefabricated powder. The mass ratio of the activated alumina powder, aluminum chloride powder to silica powder is 90:8:2.

[0102] S2. Mix anhydrous ethanol and deionized water evenly according to a volume ratio of 1.55:1. Then place the solution in a vacuum chamber for degassing. The vacuum degree during degassing is 120 Pa, and the degassing time is 10 minutes. After degassing, the apparent viscosity value of the printing ink at 20 °C and a shear rate of 1 s -1 is 8 mPa·s, obtaining the printing ink.

[0103] S3. Import the alumina ceramic filter model data as Figure 3 shown into a 3D printer to perform 3DP forming preparation of ceramics, obtaining a green ceramic part. During the printing process, the printing layer height is 0.30 mm, the inkjet concentration is 75%, and a follow-up heating device is used to perform real-time heating treatment on the printing layer during the printing process, and the heating power is 1600 W.

[0104] S4. After S3 is completed, move the entire powder bed into a blast drying oven for heat curing. The heating temperature is 120 °C, and the baking time is 2 hours.

[0105] S5. After the powder bed cools with the furnace, take out the solidified ceramic filter and perform deflouring treatment, using a brush for deflouring.

[0106] S6. Sinter the ceramic sample after the above-mentioned deflouring process. The sintering temperature is l500 °C. Specifically, heat from room temperature to 1400 °C at a heating rate of 10 °C per minute, hold for 60 minutes, then heat to 1500 °C at a heating rate of 5 °C per minute, hold for 45 minutes, and then cool with the furnace. In this way, a reusable ceramic filter can be obtained.

[0107] Example 6

[0108] The reusable alumina ceramic filter with a relatively high porosity fabricated by the 3DP manufacturing method provided by the present invention comprises the following steps:

[0109] S1. Respectively dry the activated alumina powder with a particle size of 150 - 190 mesh, the anhydrous aluminum chloride powder with a particle size of 120 - 200 mesh and an effective ingredient of 90%, and the silica powder with a particle size of 2000 - 3000 mesh, and then fully stir and mix them evenly to obtain the 3DP prefabricated powder, wherein the mass ratio of the activated alumina powder, the aluminum chloride powder to the silica is 83:15:2.

[0110] S2. Mix anhydrous ethanol and deionized water evenly according to a volume ratio of 1.55:1, then place the solution in a vacuum chamber for degassing. When degassing, the vacuum degree is 120 Pa and the degassing time is 10 minutes. After degassing, the apparent viscosity value of the printing ink at 20 °C and a shear rate of 1 s -1 is 8 mPa·s to obtain the printing ink.

[0111] S3. Import the alumina ceramic filter model data as Figure 3 shown into a 3D printer to perform 3DP forming preparation of the ceramic to obtain a green ceramic part; during the printing process, the printing layer height is 0.30 mm, the inkjet concentration is 75%, and a follow - up heating device is used to perform real - time heating treatment on the printing layer during the printing process, and the heating power is 1600 W.

[0112] S4. After S3 is completed, move the entire powder bed into a blast drying oven for heating and curing. The heating temperature is 180 °C and the baking time is 2 hours.

[0113] S5. After the powder bed cools down with the furnace, take out the solidified ceramic filter and perform powder cleaning treatment, using a brush to clean the powder.

[0114] S6. Sinter the ceramic sample after the above powder cleaning is completed. The sintering temperature is 1500 °C. Specifically, heat from room temperature to 1400 °C at a heating rate of 10 °C / minute, hold for 60 minutes, then heat to 1500 °C at a heating rate of 5 °C / minute, hold for 45 minutes, and then cool down with the furnace to obtain the reusable ceramic filter.

[0115] Example 7

[0116] The reusable alumina ceramic filter with a relatively high porosity fabricated by the 3DP manufacturing method provided by the present invention comprises the following steps:

[0117] S1. Dry the activated alumina powder with a particle size of 150 - 190 mesh, the anhydrous aluminum chloride powder with a particle size of 120 - 200 mesh and an effective ingredient of 90%, and the silicon dioxide powder with a particle size of 2000 - 3000 mesh respectively, and then stir and mix them evenly to obtain the 3DP prefabricated powder. The mass ratio of the activated alumina powder, aluminum chloride powder and silicon dioxide is 83:15:2.

[0118] S2. Mix anhydrous ethanol and deionized water evenly according to a volume ratio of 1.55:1. Then place the solution in a vacuum chamber for degassing. The vacuum degree during degassing is 120 Pa, and the degassing time is 10 minutes. After degassing, the apparent viscosity value of the printing ink at 20 °C and a shear rate of 1 s -1 is 8 mPa·s to obtain the printing ink.

[0119] S3. Import the alumina ceramic filter model data as shown in Figure 3 into a 3D printer to carry out 3DP forming preparation of ceramics to obtain a green body of a ceramic part. During the printing process, the printing layer height is 0.30 mm, the inkjet concentration is 75%, and a follow-up heating device is used to perform real-time heating treatment on the printing layer during the printing process, and the heating power is 1600 W.

[0120] S4. After S3 is completed, move the entire powder bed into a blast drying oven for heating and curing. The heating temperature is 120 °C, and the baking time is 2 hours.

[0121] S5. After the powder bed cools down with the furnace, take out the solidified ceramic filter and perform powder cleaning treatment, using a brush to clean the powder.

[0122] S6. Sinter the ceramic sample after the above powder cleaning. The sintering temperature is 1500 °C. Heat from room temperature to 1400 °C at a heating rate of 5 °C / minute and hold for 30 minutes, then heat to 1500 °C at a heating rate of 2 °C / minute and hold for 80 minutes, and then cool down with the furnace to obtain a reusable ceramic filter.

[0123] Example 8

[0124] The alumina casting mold shell for superalloy casting manufactured by using the 3DP manufacturing method provided by the present invention includes the following steps:

[0125] S1. Dry the fused corundum powder with a particle size of 150 - 320 mesh, the hexahydrate aluminum chloride powder with a particle size of 120 - 200 mesh and an effective ingredient of 98%, and the magnesium oxide powder with a particle size of 2000 - 3000 mesh respectively, and then stir and mix them evenly to obtain the 3DP prefabricated powder. The mass ratio of the fused corundum powder, aluminum chloride powder and magnesium oxide powder is 85:12:3;

[0126] S2. Mix absolute ethanol and deionized water evenly according to a volume ratio of 1.50:1. Then place the solution in a vacuum chamber for degassing. The vacuum degree during degassing is 120 Pa, and the degassing time is 15 minutes. After degassing, the printing ink has an apparent viscosity value of 6.5 mPa·s at 20 °C and a shear rate of 1 s -1 to obtain the printing ink.

[0127] S3. Import the data of the alumina casting mold shell model for superalloy casting as shown Figure 4 into a 3D printer, and perform 3DP forming preparation of ceramics to obtain a green ceramic part. During the printing process, the printing layer height is 0.15 mm, the inkjet concentration is 45%, and a follow-up heating device is used to perform real-time heating treatment on the printing layer during the printing process, with a heating power of 1400 W.

[0128] S4. After S3 is completed, move the entire powder bed into a blast drying oven for heating and curing. The heating temperature is 180 °C, and the baking time is 1.5 hours.

[0129] S5. After the powder bed cools down with the furnace, take out the solidified alumina casting mold shell for superalloy casting, and perform powder cleaning. Use a brush to clean the powder on the outer surface and high-pressure gas to clean the powder in the inner hole.

[0130] S6. Sinter the above-mentioned ceramic sample after powder cleaning. The sintering temperature is 1550 °C. Specifically, heat from room temperature to 1400 °C at a heating rate of 7 °C / minute, hold for 50 minutes, then continue to heat to 1550 °C at a heating rate of 3 °C / minute, hold for 60 minutes, and then cool down with the furnace to obtain a high-performance alumina casting mold shell for superalloy casting.

[0131] Example 9

[0132] The alumina casting mold shell for superalloy casting manufactured by the 3DP manufacturing method provided by the present invention includes the following steps:

[0133] S1. Dry the fused alumina powder with a particle size of 150 - 320 mesh, the aluminum chloride hexahydrate powder with a particle size of 120 - 200 mesh and an effective ingredient of 98%, and the magnesium oxide powder with a particle size of 2000 - 3000 mesh respectively, and then stir and mix them evenly to obtain the 3DP prefabricated powder. The mass ratio of the fused alumina powder, the aluminum chloride powder, and the magnesium oxide powder is 85:12:3;

[0134] S2. Mix absolute ethanol and deionized water evenly according to a volume ratio of 1.45:1. Then place the solution in a vacuum chamber for degassing. The vacuum degree during degassing is 120 Pa, and the degassing time is 10 minutes. After degassing, the printing ink has an apparent viscosity value of 6.5 mPa·s at 20 °C and a shear rate of 1 s -1The apparent viscosity value at this time is 6.5 mPa·s, and printing ink is obtained.

[0135] S3, import the alumina casting mold shell model data for superalloy casting as Figure 4 shown into a 3D printer, and perform 3DP forming preparation of ceramics to obtain a green ceramic part; during the printing process, the printing layer height is 0.15 mm, the inkjet concentration is 45%, and a follow-up heating device is used to perform real-time heating treatment on the printing layer during the printing process, and the heating power is 1400 W.

[0136] S4, after S3 is completed, move the entire powder bed into a blast drying oven for heating and curing. The heating temperature is 180 °C, and the baking time is 1.5 hours.

[0137] S5, after the powder bed cools with the furnace, take out the solidified alumina casting mold shell for superalloy casting, perform powder cleaning. Use a brush to clean the powder on the outer surface and high-pressure gas to clean the powder in the inner hole.

[0138] S6, sinter the ceramic sample after the above powder cleaning. The sintering temperature is 1550 °C. Among them, it is heated from room temperature to 1400 °C at a heating rate of 7 °C / minute and held for 50 minutes, then continue to heat to 1550 °C at a heating rate of 3 °C / minute and hold for 60 minutes, and then cool with the furnace to obtain a high-performance alumina casting mold shell for superalloy casting.

[0139] Example 10

[0140] The alumina casting mold shell for superalloy casting manufactured by the 3DP manufacturing method provided by the present invention includes the following steps:

[0141] S1, dry the fused alumina powder with a particle size of 150 - 320 mesh, the aluminum chloride hexahydrate powder with a particle size of 120 - 200 mesh and an effective ingredient of 98%, and the magnesium oxide powder with a particle size of 2000 - 3000 mesh respectively, and then stir and mix them evenly to obtain 3DP prefabricated powder. The mass ratio of the fused alumina powder, aluminum chloride powder and magnesium oxide powder is 85:12:3;

[0142] S2, mix anhydrous ethanol and deionized water evenly according to a volume ratio of 1.50:1, then place the solution in a vacuum box for degassing. The vacuum degree during degassing is 120 Pa, and the degassing time is 15 minutes. After degassing, the printing ink has an apparent viscosity value of 6.5 mPa·s at 20 °C and a shear rate of 1 s -1 The apparent viscosity value at this time is 6.5 mPa·s, and printing ink is obtained.

[0143] S3, import the alumina casting mold shell model data for superalloy casting as Figure 4The model data of the alumina casting mold shell for superalloy casting shown is imported into a 3D printer for 3DP forming preparation of ceramics to obtain a green ceramic part. During the printing process, the printing layer height is 0.15 mm, the inkjet concentration is 45%, and a follow-up heating device is used to perform real-time heating treatment on the printing layer during the printing process, with a heating power of 1400 W.

[0144] S4, after S3 ends, the entire powder bed is moved into a blast drying oven for heating and curing. The heating temperature is 120 °C, and the baking time is 1 hour.

[0145] S5, after the powder bed cools down with the furnace, the cured alumina casting mold shell for superalloy casting is taken out for powder cleaning. The outer surface is cleaned with a brush, and the inner hole is cleaned with high-pressure gas.

[0146] S6, the above-mentioned ceramic sample after powder cleaning is sintered. The sintering temperature is 1550 °C, where it is heated from room temperature to 1400 °C at a heating rate of 7 °C per minute and held for 50 minutes, then continued to be heated to 1550 °C at a heating rate of 3 °C per minute and held for 60 minutes, and then cooled down with the furnace to obtain a high-performance alumina casting mold shell for superalloy casting.

[0147] Example 11

[0148] The alumina casting mold shell for superalloy casting manufactured by the 3DP manufacturing method provided by the present invention includes the following steps:

[0149] S1, the fused alumina powder with a particle size of 150 - 320 mesh, the aluminum chloride hexahydrate powder with a particle size of 120 - 200 mesh and an effective component of 98%, and the magnesium oxide powder with a particle size of 2000 - 3000 mesh are respectively dried and then fully stirred and mixed evenly to obtain 3DP prefabricated powder, where the mass ratio of the fused alumina powder, aluminum chloride powder, and magnesium oxide powder is 85:12:3;

[0150] S2, anhydrous ethanol and deionized water are mixed evenly according to a volume ratio of 1.50:1, and then the solution is placed in a vacuum box for degassing. The vacuum degree during degassing is 120 Pa, and the degassing time is 15 minutes. After degassing, the apparent viscosity value of the printing ink at 20 °C and a shear rate of 1 s -1 is 6.5 mPa·s to obtain the printing ink.

[0151] S3, the model data of the alumina casting mold shell for superalloy casting shown as Figure 4 is imported into a 3D printer for 3DP forming preparation of ceramics to obtain a green ceramic part. During the printing process, the printing layer height is 0.1 mm, the inkjet concentration is 45%, and a follow-up heating device is used to perform real-time heating treatment on the printing layer during the printing process, with a heating power of 1400 W.

[0152] S4. After S3 is completed, the entire powder bed is moved into a blast drying oven for heat curing. The heating temperature is 180 °C and the baking time is 1.5 hours.

[0153] S5. After the powder bed is cooled in the furnace, the solidified alumina casting mold shell for superalloy casting is taken out and subjected to powder cleaning. The outer surface is cleaned with a brush and the inner hole is cleaned with high-pressure gas.

[0154] S6. The ceramic sample after the above powder cleaning is sintered. The sintering temperature is 1550 °C. It is heated from room temperature to 1400 °C at a heating rate of 10 °C / minute and held for 30 minutes, then continued to be heated to 1550 °C at a heating rate of 5 °C / minute and held for 45 minutes, and then cooled in the furnace. Thus, a high-performance alumina casting mold shell for superalloy casting can be obtained.

[0155] Example 12

[0156] The alumina casting mold shell for superalloy casting manufactured by the 3DP manufacturing method provided by the present invention comprises the following steps:

[0157] S1. The fused alumina powder with a particle size of 150 - 320 mesh, the aluminum chloride hexahydrate powder with a particle size of 120 - 200 mesh and an effective component of 98%, and the magnesium oxide powder with a particle size of 2000 - 3000 mesh are respectively dried and then sufficiently stirred and mixed evenly to obtain 3DP prefabricated powder. The mass ratio of the fused alumina powder, the aluminum chloride powder and the magnesium oxide powder is 85:12:3.

[0158] S2. Absolute ethanol and deionized water are mixed evenly according to a volume ratio of 1.50:1. Then the solution is placed in a vacuum chamber for degassing. The vacuum degree during degassing is 120 Pa and the degassing time is 15 minutes. After degassing, the apparent viscosity value of the printing ink at 20 °C and a shear rate of 1 s -1 is 6.5 mPa·s to obtain the printing ink.

[0159] S3. The model data of the alumina casting mold shell for superalloy casting as shown Figure 4 is imported into a 3D printer for 3DP forming preparation of ceramics to obtain a green ceramic part. During the printing process, the printing layer height is 0.15 mm, the inkjet concentration is 45%, and a follow-up heating device is used to perform real-time heating treatment on the printing layer during the printing process, and the heating power is 2400 W.

[0160] S4. After S3 is completed, the entire powder bed is moved into a blast drying oven for heat curing. The heating temperature is 180 °C and the baking time is 1.5 hours.

[0161] S5. After the powder bed is cooled with the furnace, take out the solidified alumina casting mold shell for superalloy casting, and perform powder cleaning. Use a brush to clean the powder on the outer surface and high-pressure gas to clean the powder in the inner hole.

[0162] S6. Sinter the ceramic sample after the above powder cleaning. The sintering temperature is 1550 °C. Heat from room temperature to 1400 °C at a heating rate of 10 °C per minute, hold for 30 minutes, then continue to heat to 1550 °C at a heating rate of 5 °C per minute, hold for 45 minutes, and then cool with the furnace to obtain a high-performance alumina casting mold shell for superalloy casting.

[0163] Example 13

[0164] The alumina casting mold shell for superalloy casting manufactured by the 3DP manufacturing method provided by the present invention includes the following steps:

[0165] S1. Dry the fused alumina powder with a particle size of 150 - 320 mesh, the aluminum chloride hexahydrate powder with a particle size of 120 - 200 mesh and an effective ingredient of 98%, and the magnesium oxide powder with a particle size of 2000 - 3000 mesh respectively, and then stir and mix them evenly to obtain 3DP prefabricated powder. The mass ratio of the fused alumina powder, aluminum chloride powder and magnesium oxide powder is 85:12:3.

[0166] S2. Mix anhydrous ethanol and deionized water evenly according to a volume ratio of 1.50:1. Then place the solution in a vacuum box for degassing. The vacuum degree during degassing is 120 Pa, and the degassing time is 15 minutes. After degassing, the apparent viscosity value of the printing ink at 20 °C and a shear rate of 1 s -1 is 6.5 mPa·s to obtain the printing ink.

[0167] S3. Import the model data of the alumina casting mold shell for superalloy casting as Figure 4 shown into a 3D printer to perform 3DP forming preparation of ceramics to obtain a green ceramic part. During the printing process, the printing layer height is 0.15 mm, the inkjet concentration is 45%, and a follow-up heating device is used to perform real-time heating treatment on the printing layer during the printing process, and the heating power is 2000 W.

[0168] S4. After S3 is completed, move the entire powder bed into a blast drying oven for heating and curing. The heating temperature is 180 °C, and the baking time is 1.5 hours.

[0169] S5. After the powder bed is cooled with the furnace, take out the solidified alumina casting mold shell for superalloy casting, and perform powder cleaning. Use a brush to clean the powder on the outer surface and high-pressure gas to clean the powder in the inner hole.

[0170] S6. Sinter the ceramic specimen after the above-mentioned sizing process is completed. The sintering temperature is 1550 °C. Specifically, heat it from room temperature to 1400 °C at a heating rate of 10 °C per minute, hold for 30 minutes, then continue to heat to 1550 °C at a heating rate of 5 °C per minute, hold for 45 minutes, and then cool it in the furnace. In this way, an alumina casting mold shell for high-performance superalloy casting can be obtained.

[0171] Since the properties of the ceramic parts prepared in Examples 1 to 13 are basically the same, the present invention will only take the ceramic core provided in Example 1 as an example to illustrate the effects.

[0172] 1. Precision test

[0173] The precision is carried out in accordance with GB / T6414-1999.

[0174] The basic dimension of the length of this specimen is greater than 40 mm and less than 63 mm. The errors in the six measurements are 0.29, 0.28, 0.33, 0.29, 0.30, and 0.28 mm respectively. The average error is 0.295 mm, which is between 0.26 - 0.36 mm, belonging to CT4 level.

[0175] After testing, the dimensional accuracy can reach ±0.30 mm in the specimen.

[0176] 2. Roughness test

[0177] The experimental instrument used for measuring the roughness is a surface roughness tester (manufactured by Guangzhou Lantai Instrument Co., Ltd.). The size of the specimen is 50×10×8 mm 3 , the top surface size is 50×10 mm 2 , and the side surface size is 50×8 mm 2 . Measure the top surface and end surfaces of six specimens.

[0178] The measurement results of the surface roughness of the top surface are: Ra6.20, Ra6.02, Ra6.10, Ra5.95, Ra6.17, Ra6.23 respectively, and the average value is Ra6.11.

[0179] The measurement results of the end surface roughness are: Ra6.87, Ra6.77, Ra6.76, Ra6.82, Ra6.80, Ra6.85 respectively, and the average value is Ra6.81.

[0180] 3. High-temperature strength test

[0181] The experimental instrument is a universal testing machine. The test method is a three-point bending test. Three groups of experiments are carried out. The span is 30 mm for all of them. The widths are 8.61 mm, 8.50 mm, and 7.73 mm respectively, and the corresponding thicknesses are 9.24 mm, 9.04 mm, and 9.33 mm respectively.

[0182] After testing, the flexural strengths are 17.642 MPa, 16.920 MPa, and 16.606 MPa respectively, and the average value is 17.056 MPa. The high-temperature strength can reach above 10 MPa. Moreover, the high-temperature creep is small and the sintering shrinkage rate is low. The sintering shrinkage rates in the x, y, and z directions are all lower than 3%.

[0183] By adopting the method disclosed in the present invention, a high-performance alumina ceramic core with a high alumina content, high strength, high precision, and controllable porosity can be prepared, avoiding the problems of insufficient casting precision and frequent defects caused by high-temperature fracture and high-temperature creep of the core, and also avoiding the carbon residue in the core after the pyrolysis of the organic binder at high temperature. The present invention is a high-performance ceramic preparation technology with high productivity, high quality, and low cost, and has broad market space and great engineering application value.

[0184] As described above, only the preferred embodiments of the present invention are provided. For those of ordinary skill in the art, various corresponding changes and deformations can be made according to the technical solutions and technical concepts of the present invention, and all these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A 3DP manufacturing method for alumina ceramic parts using aluminum chloride as a binder, characterized in that, It includes the following steps: Mix alumina, aluminum chloride and a mineralizer to obtain a 3DP prefabricated powder; Mix absolute ethanol and deionized water and degas them to obtain a printing binder; Use the 3DP prefabricated powder and the binder to print a ceramic part to obtain a green body of the ceramic part; During the printing process, perform real-time heating treatment on the printing layer, and the heating power is 1000W to 2400W; Sinter the green body of the ceramic part to obtain a formed alumina ceramic part; Based on the total mass of the 3DP prefabricated powder, the content of alumina powder is 80% to 90%, the content of aluminum chloride powder is 8% to 15%, and the content of the mineralizer is 2% to 5%.

2. The 3DP manufacturing method according to claim 1, characterized in that, The particle size of the alumina powder is 150 to 320 mesh, the particle size of the aluminum chloride powder is 120 to 200 mesh, and the particle size of the mineralizer is 2000 to 3000 mesh.

3. The 3DP manufacturing method according to claim 1, characterized in that, The volume ratio of the absolute ethanol to the deionized water is 1.45 to 1.55:

1.

4. The 3DP manufacturing method according to claim 1, wherein Alumina, aluminum chloride and the mineralizer are dried separately and then mixed; The degassing is to degas a mixed solution of absolute ethanol and deionized water under vacuum conditions, and the apparent viscosity value of the mixed solution after degassing is not higher than 8 mPa·s at 20 °C and a shear rate of 1 s -1 -1.

5. The 3DP manufacturing method according to claim 1, wherein The alumina is selected from one or more of white fused alumina powder, fused alumina powder, α-alumina powder, activated alumina powder; The aluminum chloride is anhydrous aluminum chloride or aluminum chloride hexahydrate; The mineralizer is selected from one or more mixtures of silicon oxide, magnesium oxide, yttrium oxide, zirconium oxide, boehmite, kyanite, fused mullite powder.

6. The 3DP manufacturing method according to claim 1, characterized in that Perform baking and curing treatment on the powder bed after printing, the baking temperature is 120 to 200 °C, and the baking time is 1 to 2 hours.

7. The 3DP manufacturing method according to claim 6, wherein Perform powder cleaning treatment on the ceramic part obtained after baking and curing, and then sinter it in a programmed heating manner; The programmed heating process is: heat up to 1400 °C at a heating rate of 5 to 10 °C / min, hold for 30 to 60 min, and then heat up to the sintering temperature point at 2 to 5 °C / min and hold for 45 to 80 min.

8. The 3DP manufacturing method according to claim 7, characterized in that, When printing to prepare a green body of a ceramic part, the printing layer height is 0.10 mm to 0.30 mm, and the inkjet concentration is 30% to 75%.

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