Thermoplastic powder adhesive injection molding ceramic manufacturing method and ceramic

Abstract

The application provides a thermoplastic powder adhesive injection molding ceramic manufacturing method and ceramic, and the method comprises the following steps: providing thermoplastic adhesive powder and ceramic powder and mixing to obtain mixed powder; dissolving polyvinyl alcohol powder into deionized water, then adding polyethylene glycol 400, glycerol and FS-8 fluorocarbon surfactant to obtain a mixed solution; using the mixed solution as an adhesive and the mixed powder as a substrate to carry out ceramic adhesive injection molding; taking out a molding cylinder containing ceramic blanks and drying; secondary curing, then naturally cooling the ceramic blanks; impregnation treatment in an impregnation solution; baking and drying, and high-temperature sintering treatment to obtain the thermoplastic powder adhesive injection molding ceramic. The application solves the problems of low blank strength, poor high-temperature resistance and acid and alkali resistance, poor sintering performance and the like in ceramic adhesive injection molding, and can be used for preparing ceramic products with complex structures and high requirements of precision, strength and porosity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic manufacturing, in particular, to a thermoplastic powder binder jetting ceramic manufacturing method and ceramic. BACKGROUND

[0002] The development of engineering technology puts forward higher requirements for ceramic products. Some application scenarios require complex shape ceramic product forming, high porosity, and low sintering shrinkage ceramic product forming. Binder jetting method as a new type of additive manufacturing method has the advantages of high manufacturing precision, complex part forming, fast manufacturing, short manufacturing cycle, etc. However, the binder jetting method is not widely used in ceramic manufacturing. The main reason is that the green body density of the binder jetting ceramic is low, and it is difficult to realize sintering densification. At the same time, the internal binder of the binder jetting ceramic green body volatilizes at high temperature during the sintering process, resulting in cracking and direct collapse of the binder jetting ceramic after high temperature sintering. Therefore, it is of great significance to study a ceramic binder forming method with high manufacturing precision, good high temperature resistance and good sintering performance.

[0003] Thermoplastic powder is commonly used in injection molding of ceramics and metals, and has a long history in the ceramic production industry. Its advantages are good strength, high precision, strong high temperature deformation resistance, and good sintering performance, but it cannot be directly applied to binder jetting ceramic forming. Polyvinyl alcohol solution is a commonly used binder in binder jetting, which has the advantages of high printing precision and low diffusion. However, due to the low bonding strength of polyvinyl alcohol itself and the problem of serious water absorption in air, the formed green body has low strength, is difficult to process after forming, has low sintering strength, and cannot be stored for a long time in humid air, which makes it difficult to directly form binder jetting ceramics.

[0004] After searching, it is found that a Chinese invention patent with application publication number CN116986910A discloses a method for preparing aluminum nitride ceramic by binder jetting forming technology. The prior art uses submicron aluminum nitride powder for preparation, and modifies the powder with polyvinyl butyral and hydrophobic agent in sequence. After debinding the green body, the green body is infiltrated with metal ions by infiltration process, and the aluminum nitride ceramic green body is successfully printed by using the binder jetting technology, which can prepare aluminum nitride ceramic with high performance. The above-mentioned patent uses polyvinyl butyral as a binder for forming, and uses the method of infiltrating metal ions to catalyze the reaction sintering process of aluminum nitride ceramic, which is essentially still the conventional application of binder jetting ceramic. SUMMARY

[0005] Aiming at the defects in the prior art, the present application aims to provide a thermoplastic powder adhesive injection molding ceramic manufacturing method and ceramic.

[0006] According to one aspect of the present application, a thermoplastic powder adhesive injection molding ceramic manufacturing method is provided, the method comprising:

[0007] Providing thermoplastic adhesive powder and ceramic powder, and mixing them uniformly to obtain mixed powder;

[0008] Dissolving polyvinyl alcohol powder in deionized water at a preset temperature, adding polyethylene glycol 400, glycerol and FS-8 fluorocarbon surfactant after the solution is cooled, and mixing uniformly to obtain a mixed solution;

[0009] Using the mixed solution as an adhesive and the mixed powder as a substrate to perform ceramic adhesive injection manufacturing;

[0010] Taking out the molding cylinder containing the printed ceramic body, and drying it;

[0011] Performing secondary curing on the ceramic body, and then naturally cooling the ceramic body;

[0012] Performing infiltration treatment on the cooled ceramic body in an infiltration liquid;

[0013] Performing baking and drying on the ceramic body after infiltration treatment, and performing high-temperature sintering treatment to obtain a thermoplastic powder adhesive injection molding ceramic.

[0014] Optionally, the thermoplastic adhesive powder and the ceramic powder have a particle size of 20-100 µm, and the thermoplastic adhesive powder accounts for 3-15 wt% of the mixed powder.

[0015] Optionally, in the mixed solution, the mass ratio of polypropylene alcohol is 3-10 wt%.

[0016] Optionally, the solution viscosity of the mixed solution is 6-12 mPa·s, and the surface tension is 26-42 N / m.

[0017] Optionally, using the mixed solution as an adhesive and the mixed powder as a substrate to perform ceramic adhesive injection manufacturing, wherein the printing layer thickness is 0.03-0.30 mm, and the adhesive injection saturation is 30-70%.

[0018] Optionally, taking out the molding cylinder containing the printed ceramic body, and drying it, wherein the drying temperature is 120-145 ℃, and the drying time is 4-8 hours.

[0019] Optionally, the green body is subjected to secondary solidification, wherein the solidification temperature is 5-8℃ higher than the melting point of the thermoplastic adhesive powder and the holding time is 1-1.5 hours.

[0020] Optionally, the green body is subjected to impregnation treatment in the impregnation solution, wherein the impregnation solution is any one of titanium dioxide sol, aluminum sol and ethyl silicate.

[0021] Optionally, the green body is subjected to impregnation treatment in the impregnation solution, wherein the impregnation treatment time is 1-3 hours and the impregnation treatment is carried out in a vacuum environment.

[0022] According to another aspect of the present application, there is provided a ceramic prepared by the above-mentioned method for manufacturing ceramic by thermoplastic powder adhesive spray forming.

[0023] Compared with the prior art, the present application has at least one of the following beneficial effects:

[0024] 1. The ceramic manufacturing method provided by the present application uses polyvinyl alcohol solution and thermoplastic adhesive powder as a secondary composite adhesive system for adhesive spray ceramic manufacturing, which can ensure that the adhesive spray green body has high precision and good water resistance, solvent resistance, acid and alkali resistance and high temperature resistance, so that the green body can be stored for a long time, sintered at high temperature and subjected to impregnation solution. Then, the adhesive spray green body is subjected to impregnation treatment. First, the impregnation treatment increases the inorganic adhesive bridge in the green body, which increases the high temperature resistance of the green body during sintering. Second, the adhesive bridge between the ceramic particles helps the atomic diffusion on the surface of the ceramic particles, which increases the sintering performance. Third, the inorganic adhesive bridge between the ceramic powders is a low-melting-point liquid phase material, which can promote ceramic sintering. At the same time, the thermoplastic component is oxidized and disappears during high-temperature sintering, forming pores and ensuring that the final product has high porosity.

[0025] 2. The adhesive spray ceramic product prepared by the present application has the advantages of high green body strength and high dimensional accuracy, and the green body has good water resistance, solvent resistance and acid and alkali resistance, and can be stored for a long time in a humid environment. The sintered product has high dimensional accuracy and high strength, and has high porosity to meet related requirements.

[0026] 3. The present application can manufacture ceramic products of any complex shape and structure, which is suitable for the production of structural ceramics and functional ceramics of complex shape, and can greatly reduce the production cycle and save the manufacturing cost. BRIEF DESCRIPTION OF DRAWINGS

[0027] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments with reference to the following drawings:

[0028] Figure 1 A flowchart of a thermoplastic powder adhesive spray forming ceramic manufacturing method according to an embodiment of the present application;

[0029] Figure 2 A schematic diagram of a printed model according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] The present application will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made. These are within the scope of the present application.

[0031] An embodiment of the present application provides a thermoplastic powder adhesive spray forming ceramic manufacturing method, referring to the flowchart shown in Figure 1 The method comprises the following steps:

[0032] S1, providing thermoplastic adhesive powder and ceramic powder, and mixing the two to obtain a mixed powder;

[0033] S2, dissolving polyvinyl alcohol powder into 60-80℃ deionized water, adding polyethylene glycol 400, glycerol and FS-8 fluorocarbon surfactant after the solution is cooled, and mixing uniformly to obtain a mixed solution;

[0034] S3, using the mixed solution as an adhesive and the mixed powder as a substrate to perform ceramic adhesive spray forming;

[0035] S4, taking out the forming cylinder containing the printed ceramic body, and drying it;

[0036] S5, performing secondary curing on the ceramic body, and then naturally cooling the ceramic body to room temperature;

[0037] S6, immersing the cooled ceramic body in an impregnation solution for impregnation treatment;

[0038] S7, baking and drying the ceramic body after impregnation treatment, and performing high-temperature sintering treatment to obtain a thermoplastic powder adhesive spray forming ceramic.

[0039] The method provided by the embodiment of the application adopts polyvinyl alcohol solution and thermoplastic powder as a composite adhesive system, realizes high-strength, high-precision, acid, alkali and salt water resistance and long-term storage of the adhesive sprayed ceramic body, and finally realizes high-strength and variable high-porosity ceramic forming, solves the problems of low body strength, inability to perform infiltration treatment, poor high-temperature resistance, poor acid and alkali resistance and poor sintering performance in the ceramic adhesive spray forming, and can be used for adhesive spray preparation of ceramic products with complex structures and high requirements for precision, strength and porosity.

[0040] In some embodiments, in step S1, the thermoplastic adhesive powder can adopt any one of polypropylene (PP), polylactic acid (PLA), acrylonitrile-butadiene-styrene copolymer (ABS) and industrial paraffin; the ceramic powder can adopt any one of alumina, zirconia, aluminum nitride, silicon carbide and boron nitride. The particle size of the thermoplastic adhesive powder and the ceramic powder is 20-100 μm, the particle size of the thermoplastic adhesive powder is selected to be the same as or similar to that of the ceramic powder, and the specific particle size value is determined by the application scenario. To realize uniform mixing of the thermoplastic adhesive powder and the ceramic powder, the two are placed in a blender and fully stirred. The thermoplastic adhesive powder accounts for 3-15 wt% of the mixed powder, and the body strength and porosity increase with the mass ratio of the thermoplastic adhesive.

[0041] In step S2, after adding each component, fully stir until the solution is uniformly mixed. In some embodiments, in the mixed solution, the mass ratio of polyvinyl alcohol is 3-10 wt%. According to the performance properties of the solution, polyethylene glycol 400, glycerol, FS-8 fluorocarbon surfactant and the like are added, polyethylene glycol 400 mainly adjusts the surface tension of the solution, glycerol adjusts the viscosity of the solution, and FS-8 adjusts the surface tension of the solution as an auxiliary, so that the viscosity of the mixed solution is 6-12 mPa·s and the surface tension is 26-42 N / m, thereby ensuring that the mixed solution has appropriate viscosity and surface tension to meet the requirements of piezoelectric nozzle printing of the adhesive spray equipment, and at the same time, the above liquid viscosity and surface tension can ensure that the solution produces less bleeding diffusion phenomenon after being sprayed onto the powder bed, so that it can be used as a liquid adhesive in adhesive spraying.

[0042] In step S3, the above mixed powder is used as a printing substrate, and the above mixed solution is used as a printing adhesive to perform printing. In some embodiments, the printing layer thickness is 0.03-0.30 mm, and the adhesive spray saturation is 30-70%. The printing layer thickness mainly determines the interlayer dimensional accuracy of the adhesive spray forming body, and is matched with the powder particle size, and the adhesive spray saturation mainly determines the strength of the dried body, so as to ensure that the body is not damaged during powder cleaning.

[0043] In step S4, the forming cylinder containing the printed ceramic green body is placed in a blast drying oven for drying, and in some embodiments, the drying temperature is 120-145℃ and the drying time is 4-8 hours to ensure that the dried and solidified green body is achieved without melting the thermoplastic adhesive powder.

[0044] In some embodiments, before step S5, the method further comprises: taking out the dried and solidified ceramic green body and performing meticulous powder cleaning to ensure that there is no residual powder inside the ceramic green body.

[0045] In some embodiments, in step S5, the ceramic green body is placed in the glass microbead powder for secondary solidification, and the solidification temperature is 5-8℃ higher than the melting point of the thermoplastic adhesive powder in the mixed powder, and the temperature is maintained for 1-1.5 hours. Taking polypropylene (PP) as an example, the melting point is 155℃, and the secondary solidification temperature is 160℃ to ensure that the polypropylene powder is re-melted and forms a bonding bridge between the powders, thereby making the ceramic green body have high strength, solvent resistance, water resistance, acid and alkali resistance, and long-term storage capability.

[0046] In some embodiments, in step S6, the substance infiltrated into the green body is an inorganic bonding bridge formed after the infiltration liquid is dried. The bonding bridge itself is a low-melting-point substance. The infiltration liquid used in the infiltration treatment is any one of titanium dioxide sol, aluminum sol, and ethyl silicate. The titanium dioxide sol, aluminum sol, and ethyl silicate can provide the ceramic green body with an inorganic bonding bridge. The inorganic bonding bridge acts as a low-melting-point phase to assist in melting and promote sintering during the sintering process. Further, the infiltration liquid also includes phenolic resin, which acts as a reinforcing phase of the green body and can enhance the strength performance of the ceramic green body at room temperature. The infiltration time is 1-3 hours, and the infiltration treatment is performed in a vacuum environment to ensure that the infiltration liquid is fully infiltrated into the ceramic green body.

[0047] In some embodiments, in step S7, the drying temperature is 120-150℃, the high-temperature sintering treatment temperature is 900-1550℃, and the high-temperature sintering temperature is determined by the ceramic powder and the application field of the ceramic to obtain the desired ceramic product.

[0048] Another embodiment of the present application provides a ceramic prepared by the above-mentioned thermoplastic powder adhesive spray forming ceramic manufacturing method.

[0049] The above-mentioned embodiment of the present application uses polyvinyl alcohol solution and thermoplastic powder as a secondary composite adhesive system to carry out adhesive spray ceramic manufacturing, so that the adhesive spray ceramic green body has high precision and good water resistance, solvent resistance, acid and alkali resistance and high temperature resistance, and the ceramic green body has the ability of long-term storage, high temperature sintering and solution infiltration. The ceramic green body is infiltrated with the infiltration solution, which has the following advantages: (1) increasing the inorganic adhesive bridge in the ceramic green body to increase the high temperature resistance of the ceramic green body during sintering; (2) increasing the adhesive bridge between the ceramic green body particles, which helps the atomic diffusion on the surface of the ceramic particles and increases the sintering performance; (3) increasing the low-melting-point liquid phase material between the ceramic powder, which promotes ceramic sintering, and the thermoplastic component is oxidized and disappears during high temperature sintering, forming pores and ensuring that the final product has high porosity.

[0050] The above-mentioned embodiment of the present application selects thermoplastic powder and polyvinyl alcohol solution as a secondary composite adhesive, and enhances it through a post-processing method of infiltration, which is beneficial to reduce the cost of ceramic manufacturing, improve the working environment of ceramic manufacturing, reduce the sintering temperature of ceramic, and reduce the cost of ceramic manufacturing.

[0051] By using the method of the above-mentioned embodiment of the present application, the adhesive spray ceramic product prepared by mutual cooperation of each step and each process parameter has the advantages of high green body strength and high dimensional precision, the green body has water resistance, solvent resistance and acid and alkali resistance, and can be stored for a long time in a humid environment. The sintered product has high dimensional precision and strength, and has high porosity, so as to meet the related requirements.

[0052] The ceramic product manufactured by using the adhesive spray forming method of the above-mentioned embodiment of the present application can be manufactured into any complex shape and structure, and is suitable for the production of complex-shaped structural ceramics and functional ceramics, which can greatly reduce the production cycle and save the manufacturing cost.

[0053] The scheme of the present application will be explained below in combination with specific embodiments. Those skilled in the art can understand that the following embodiments are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. If the specific technology or condition is not specified in the embodiments, the technology or condition described in the literature in the art or according to the product instruction is used. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be obtained through market channels.

[0054] Embodiment 1

[0055] The present embodiment provides a thermoplastic powder adhesive spray forming ceramic manufacturing method, which is used for manufacturing a turbine blade alumina ceramic formwork, and includes the following steps:

[0056] Step 1, polypropylene powder with a particle size of 30 μm and alumina ceramic powder with a particle size of 20-50 μm are placed in a blender and mixed well;

[0057] Step 2, 5wt% polyvinyl alcohol powder is dissolved in hot deionized water, after the solution is cooled, 10wt% polyethylene glycol 400, 5wt% glycerol, 0.2wt% FS-8 fluorocarbon surfactant are added, and the solution is stirred well to mix evenly;

[0058] Step 3, using the above mixed solution as the binder, mixing the powder as the substrate, ceramic binder jetting manufacturing is carried out in the binder jetting equipment, the printing layer thickness is selected as 0.10mm, the binder jetting saturation is 70%, and the printing model is as shown in Figure 2 ;

[0059] Step 4, the forming cylinder containing the printed ceramic body is taken out and placed in a forced air drying oven for drying, the drying temperature is 120℃, and the drying time is 4 hours;

[0060] Step 5, the dried and solidified ceramic body is taken out and carefully cleaned to remove any residual powder from the inside of the body;

[0061] Step 6, the ceramic body after cleaning is subjected to secondary solidification at a temperature of 160℃ for 1 hour, and then naturally cooled, the obtained body has high strength, high dimensional accuracy, and resistance to acid, alkali, salt and water, and can be stored for a long time in various environments;

[0062] Step 7, the cooled body is immersed in ethyl silicate for 1 hour, and vacuum is applied during the immersion;

[0063] Step 8, the immersed body sample is baked and dried at a temperature of 150℃ for 2 hours, the sample is heated to 1180℃ at a rate of 2℃ / min and held for 4 hours for high temperature sintering treatment, and the desired binder jetting ceramic product is obtained, which has a room temperature bending strength of 30-50MPa, a high temperature bending strength of 10MPa or more, and a porosity of more than 55%, the bending strength and high porosity of conventional binder jetting ceramic products are difficult to coexist, while ensuring the bending strength of the ceramic product in the embodiment is similar, the porosity is generally 35% or less, and it is difficult to achieve high strength and high porosity at the same time.

[0064] The specific embodiments of the present application are described above. It needs to be understood that the present application is not limited to the specific embodiments described above, and various modifications or changes can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application. The above preferred features can be combined in any manner without conflict, and used.

Claims

1. A thermoplastic powder adhesive injection molding ceramic manufacturing method characterized by, The application relates to a thermoplastic powder adhesive injection molding ceramic manufacturing method. The thermoplastic adhesive powder and the ceramic powder are mixed to obtain a mixed powder, wherein the thermoplastic adhesive powder accounts for 3-15 wt% of the mixed powder; polyethylene glycol 400, glycerol and FS-8 fluorocarbon surfactant are added into the solution after the solution is cooled, and mixed uniformly to obtain a mixed solution; in the mixed solution, the mass ratio of polyvinyl alcohol is 3-10 wt%; the solution viscosity of the mixed solution is 6-12 , and the surface tension is 26-42 N / m; The mixed solution is used as an adhesive, and the mixed powder is used as a substrate to perform ceramic adhesive injection molding, and the adhesive injection saturation is 30-70%; The forming cylinder containing the printed ceramic blank is taken out and dried; The ceramic blank is secondarily solidified, and then naturally cooled; The cooled ceramic blank is immersed in an impregnation solution, and the impregnation solution is any one of a titanium dioxide sol, an aluminum sol and ethyl silicate; The impregnated ceramic blank is baked and dried, and high-temperature sintering treatment is performed, the baking and drying temperature is 120-150 DEG C, the high-temperature sintering treatment temperature is 900-1550 DEG C, and a thermoplastic powder adhesive injection molding ceramic is obtained.

2. The thermoplastic powder adhesive injection molding ceramic manufacturing method according to claim 1, characterized by, The thermoplastic adhesive powder and the ceramic powder have a particle size of 20-100 mu m.

3. The thermoplastic powder adhesive injection molding ceramic manufacturing method according to claim 1, characterized by, The mixed solution is used as an adhesive, and the mixed powder is used as a substrate to perform ceramic adhesive injection molding, and the printing layer thickness is 0.03-0.30 mm.

4. The thermoplastic powder adhesive injection molding ceramic manufacturing method according to claim 1, characterized by, The forming cylinder containing the printed ceramic blank is taken out and dried, and the drying temperature is 120-145 DEG C and the drying time is 4-8 hours.

5. The thermoplastic powder adhesive injection molding ceramic manufacturing method according to claim 1, wherein The ceramic blank is secondarily solidified, and the solidification temperature is 5-8 DEG C higher than the melting point of the thermoplastic adhesive powder, and the temperature is kept for 1-1.5 hours.

6. The thermoplastic powder adhesive injection molding ceramic manufacturing method according to claim 1, wherein The cooled ceramic blank is immersed in an impregnation solution, and the immersion treatment time is 1-3 hours, and the immersion treatment is performed in a vacuum environment.

7. A ceramic, characterized by, The thermoplastic powder adhesive injection molding ceramic manufacturing method is used to prepare the thermoplastic powder adhesive injection molding ceramic.

Images