CN118344159A - A method for producing silicon nitride ceramics based on photocuring 3D printing - Google Patents

Abstract

The invention provides a silicon nitride ceramic generating method based on photo-curing 3D printing, which is characterized in that a silicon nitride ceramic part is subjected to photo-curing through a silicon nitride precursor material, photosensitive resin premix, a diluent and a light absorber to obtain a silicon nitride precursor 3D structure, and then the silicon nitride precursor 3D structure is subjected to heat treatment to obtain a silicon nitride ceramic body, the curing performance of the silicon nitride photo-curing precursor material is better, the problems that the silicon nitride powder has light absorptivity, the obtained curing thickness is lower, the forming process needs higher exposure power and exposure time, and the service life and printing efficiency of equipment are affected are solved by optimizing the raw material selection and forming steps, and the silicon nitride ceramic body with good morphology structure, good surface quality and higher forming precision can be obtained by using the method, so that the reliability of the ceramic body is improved.

Description

A method for producing silicon nitride ceramics based on photocuring 3D printing

Technical Field

The present invention relates to the technical field of silicon nitride ceramics, and in particular to a method for generating silicon nitride ceramics based on photocuring 3D printing.

Background technique

Silicon nitride ceramic components are widely used in the fields of machinery, chemical industry and automobile, such as silicon nitride ceramic gears, turbine rotors, cutting tools and bearings. At present, the molding methods of silicon nitride ceramic components include cold isostatic pressing, dry pressing, slip injection and hot die casting. Among them, although the dry pressing method is more efficient, the molded products have density differences and uneven microstructures, and it is not easy to mold complex shapes and special-shaped products; the cold isostatic pressing method can obtain high-density and high-uniformity molded blanks, but it is still difficult to mold ceramic parts with complex shapes, and the molding efficiency is low and there are many manual operations; although slip injection molding can mold special-shaped products to achieve near-net size, the molded blanks are prone to uneven density and component segregation, as well as low molding dimensional accuracy and reduced product reliability. In addition, this molding method requires manual operation and low blank drying efficiency; the biggest problem with hot die casting is that the production cycle is long and the efficiency is low. It takes dozens or even hundreds of hours to remove organic binders such as paraffin wax, and ceramics are prone to defects such as pores and cracks during the wax removal process.

With the development of industry, these traditional molding processes can no longer meet the requirements of certain special fields. Unlike traditional "subtractive" manufacturing technology, 3D printed ceramics have the advantages of short production cycle, low cost, convenient processing, and strong operability. At present, the main methods for preparing silicon nitride ceramics by 3D printing are fused deposition modeling technology, inkjet printing modeling technology, three-dimensional printing modeling technology and photocuring modeling technology. Among them, photocuring is easier to prepare dense silicon nitride ceramics than other molding technologies. It has the advantages of high precision and printable complex structures. It is the most ideal printing technology for preparing silicon nitride ceramics. With the development of photocuring molding technology, it has become easier to prepare ceramic structures with complex shapes. However, photocuring molding technology also has the following disadvantages: silicon nitride powder is light-absorbing, the obtained solidified thickness is low, and the molding process requires high exposure power and exposure time, which affects the life of the equipment and printing efficiency; these problems limit the development of photocuring molding technology and the application of silicon nitride ceramics.

Summary of the invention

The present invention provides a method for producing silicon nitride ceramics based on photocuring 3D printing, so as to solve the defects in the prior art.

The present invention provides a method for producing silicon nitride ceramics based on photocuring 3D printing, comprising:

S1, material preparation, preparing silicon nitride precursor material, photosensitive resin premix, diluent, and light absorber;

S2, pretreatment, ball milling the photosensitive resin premix, diluent, and light absorber to obtain a premix;

The silicon nitride precursor material and the premixed liquid are uniformly mixed and ultrasonically stirred to obtain a silicon nitride photocurable precursor material;

S3, model design, using computer-aided design software to design the 3D model of silicon nitride ceramic parts to ensure that the geometric shape and size of the model meet actual requirements;

S4, photocuring printing, pouring silicon nitride photocuring precursor material into the slurry tank of the ceramic photocuring forming system and scraping it flat with a coating scraper;

Move the workbench to the bottom of the liquid tank and make it contact with the silicon nitride photocurable precursor material, set the zero position, select the exposure parameters, and irradiate the light source onto the silicon nitride precursor material so that it is cured layer by layer during the printing process to form the final silicon nitride precursor 3D structure;

S5, heat treatment, heat treatment of the photocured silicon nitride precursor 3D structure to promote the formation and ceramicization of silicon nitride to form a silicon nitride ceramic part;

S6, post-processing, after completing the heat treatment, the silicon nitride ceramic parts are subjected to surface treatment or other post-processing steps to meet the final performance and appearance requirements.

According to a method for producing silicon nitride ceramics based on photocuring 3D printing provided by the present invention, the silicon nitride precursor material is a polysilazane resin containing a methyl group, a vinyl group or a mercapto group.

According to a method for producing silicon nitride ceramics based on photocuring 3D printing provided by the present invention, the photosensitive resin premix liquid comprises a photosensitive resin, a plasticizer and a photoinitiator.

According to a method for producing silicon nitride ceramics based on photocuring 3D printing provided by the present invention, the photosensitive resin includes one or more of acryloyl morpholine, cyclotrimethylolpropane formal acrylate, diethoxylated neodiol diacrylate, and ethoxylated trimethylolpropane triacrylate;

The plasticizer includes one or more of polyethylene glycol, 2,2,4-trimethyl-1,3-pentanediol diisocyanate and dimethyl phthalate;

The photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, and 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone.

According to a method for generating silicon nitride ceramics based on photocuring 3D printing provided by the present invention, the light absorber is one or more of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone, and (2-hydroxy-3.5-dibutyl-tert-phenyl)-5-chlorobenzotriazole.

According to a method for generating silicon nitride ceramics based on photocuring 3D printing provided by the present invention, the heat treatment method in step S5 is to heat the material to a preset temperature at a rate of 2°C/min in a nitrogen atmosphere, keep the temperature at the preset maximum temperature for 120 minutes, and then slowly cool the material to room temperature at a cooling rate of 3°C/min to obtain a silicon nitride ceramic part.

According to a method for producing silicon nitride ceramics based on photocuring 3D printing provided by the present invention, the preset temperature is 1200-1800°C.

According to a method for producing silicon nitride ceramics based on photocuring 3D printing provided by the present invention, the post-processing in step S6 includes surface polishing and coating of the silicon nitride ceramic part.

The present invention provides a method for generating silicon nitride ceramics based on photocuring 3D printing. The silicon nitride ceramic piece is photocured through a silicon nitride precursor material, a photosensitive resin premix, a diluent, and a light absorber to obtain a silicon nitride precursor 3D structure, and then the silicon nitride precursor 3D structure is heat-treated to obtain a silicon nitride ceramic body. The silicon nitride photocuring precursor material has good curing performance. By optimizing the raw material selection and molding steps, the problems of silicon nitride powder having light absorption, low cured thickness, and high exposure power and exposure time required for the molding process, which affect the life of the equipment and printing efficiency, are solved. The method can be used to obtain a silicon nitride ceramic body with good morphology and structure, good surface quality, and high molding accuracy, thereby improving the reliability of the ceramic body.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Example 1

S1, material preparation, preparing polysilazane resin, acryloyl morpholine, polyethylene glycol, 2-hydroxy-2-methyl-1-phenylpropanone, diluent, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole;

S2, pretreatment, acryloyl morpholine, polyethylene glycol, 2-hydroxy-2-methyl-1-phenylacetone, diluent, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, and mixing by ball milling to obtain a premixed solution;

The polysilazane resin and the premixed liquid are uniformly mixed and ultrasonically stirred to obtain a silicon nitride photocurable precursor material;

S3, model design, using computer-aided design software to design the 3D model of silicon nitride ceramic parts to ensure that the geometric shape and size of the model meet actual requirements;

S4, photocuring printing, pouring silicon nitride photocuring precursor material into the slurry tank of the ceramic photocuring forming system and scraping it flat with a coating scraper;

Move the workbench to the bottom of the liquid tank and make it contact with the silicon nitride photocurable precursor material, set the zero position, select the exposure parameters, and irradiate the light source onto the silicon nitride precursor material so that it is cured layer by layer during the printing process to form the final silicon nitride precursor 3D structure;

S5, heat treatment, heat treatment of the photocured silicon nitride precursor 3D structure, heating to 1200°C at a rate of 2°C/min in a nitrogen atmosphere, and keeping the temperature at the preset maximum temperature for 120min, and then slowly cooling to room temperature at a cooling rate of 3°C/min to obtain a silicon nitride ceramic part;

S6, post-processing, after completing the heat treatment, the silicon nitride ceramic parts are surface polished and coated to meet the final performance and appearance requirements.

Example 2

S1, material preparation, preparing polysilazane resin, cyclotrimethylolpropane formal acrylate, 2,2,4-trimethyl-1,3-pentanediol diisocyanate, 1-hydroxycyclohexyl phenyl ketone, diluent, (2-hydroxy-3.5-dibutyl-tert-phenyl)-5-chlorobenzotriazole;

S2, pretreatment, cyclotrimethylolpropane methylal acrylate, 2,2,4-trimethyl-1,3-pentanediol diisocyanate, 1-hydroxycyclohexyl phenyl ketone, diluent, (2-hydroxy-3,5-dibutyl-tert-phenyl)-5-chlorobenzotriazole, and ball milling to obtain a premixed solution;

The polysilazane resin and the premixed liquid are uniformly mixed and ultrasonically stirred to obtain a silicon nitride photocurable precursor material;

S3, model design, using computer-aided design software to design the 3D model of silicon nitride ceramic parts to ensure that the geometric shape and size of the model meet actual requirements;

S4, photocuring printing, pouring silicon nitride photocuring precursor material into the slurry tank of the ceramic photocuring forming system and scraping it flat with a coating scraper;

Move the workbench to the bottom of the liquid tank and make it contact with the silicon nitride photocurable precursor material, set the zero position, select the exposure parameters, and irradiate the light source onto the silicon nitride precursor material so that it is cured layer by layer during the printing process to form the final silicon nitride precursor 3D structure;

S5, heat treatment, heat treatment of the photocured silicon nitride precursor 3D structure, heating to 1500°C at a rate of 2°C/min in a nitrogen atmosphere, and keeping the temperature at the preset maximum temperature for 120min, and then slowly cooling to room temperature at a cooling rate of 3°C/min to obtain a silicon nitride ceramic part;

S6, post-processing, after completing the heat treatment, the silicon nitride ceramic parts are surface polished and coated to meet the final performance and appearance requirements.

Example 3

S1, material preparation, preparing polysilazane resin, ethoxylated trimethylolpropane triacrylate, dimethyl phthalate, 2-hydroxy-2-methyl-1-phenylpropanone, diluent, 2-(2ˊ-hydroxy-5ˊ-methylphenyl)benzotriazole;

S2, pretreatment, ethoxylated trimethylolpropane triacrylate, dimethyl phthalate, 2-hydroxy-2-methyl-1-phenylacetone, diluent, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, and mixing by ball milling to obtain a premixed solution;

The polysilazane resin and the premixed liquid are uniformly mixed and ultrasonically stirred to obtain a silicon nitride photocurable precursor material;

S3, model design, using computer-aided design software to design the 3D model of silicon nitride ceramic parts to ensure that the geometric shape and size of the model meet actual requirements;

S4, photocuring printing, pouring silicon nitride photocuring precursor material into the slurry tank of the ceramic photocuring forming system and scraping it flat with a coating scraper;

Move the workbench to the bottom of the liquid tank and make it contact with the silicon nitride photocurable precursor material, set the zero position, select the exposure parameters, and irradiate the light source onto the silicon nitride precursor material so that it is cured layer by layer during the printing process to form the final silicon nitride precursor 3D structure;

S5, heat treatment, heat treatment of the photocured silicon nitride precursor 3D structure, heating to 1800°C at a rate of 2°C/min in a nitrogen atmosphere, and keeping the temperature at the preset maximum temperature for 120min, and then slowly cooling to room temperature at a cooling rate of 3°C/min to obtain a silicon nitride ceramic part;

S6, post-processing, after completing the heat treatment, the silicon nitride ceramic parts are surface polished and coated to meet the final performance and appearance requirements.

Example 4

S1, material preparation, preparing polysilazane resin, cyclotrimethylolpropane formal acrylate, 2,2,4-trimethyl-1,3-pentanediol diisocyanate, 1-hydroxycyclohexyl phenyl ketone, diluent, (2-hydroxy-3.5-dibutyl-tert-phenyl)-5-chlorobenzotriazole;

S2, pretreatment, cyclotrimethylolpropane methylal acrylate, 2,2,4-trimethyl-1,3-pentanediol diisocyanate, 1-hydroxycyclohexyl phenyl ketone, diluent, (2-hydroxy-3,5-dibutyl-tert-phenyl)-5-chlorobenzotriazole, and ball milling to obtain a premixed solution;

The polysilazane resin and the premixed liquid are uniformly mixed and ultrasonically stirred to obtain a silicon nitride photocurable precursor material;

S3, model design, using computer-aided design software to design the 3D model of silicon nitride ceramic parts to ensure that the geometric shape and size of the model meet actual requirements;

S4, photocuring printing, pouring silicon nitride photocuring precursor material into the slurry tank of the ceramic photocuring forming system and scraping it flat with a coating scraper;

Move the workbench to the bottom of the liquid tank and make it contact with the silicon nitride photocurable precursor material, set the zero position, select the exposure parameters, and irradiate the light source onto the silicon nitride precursor material so that it is cured layer by layer during the printing process to form the final silicon nitride precursor 3D structure;

S5, heat treatment, heat treatment of the photocured silicon nitride precursor 3D structure, heating to 1600°C at a rate of 2°C/min in a nitrogen atmosphere, and keeping the temperature at the preset maximum temperature for 120min, and then slowly cooling to room temperature at a cooling rate of 3°C/min to obtain a silicon nitride ceramic part;

S6, post-processing, after completing the heat treatment, the silicon nitride ceramic parts are surface polished and coated to meet the final performance and appearance requirements.

Example 5

S1, material preparation, preparing polysilazane resin, ethoxylated trimethylolpropane triacrylate, dimethyl phthalate, 2-hydroxy-2-methyl-1-phenylpropanone, diluent, and 2-hydroxy-4-methoxybenzophenone;

S2, pretreatment, ball-milling ethoxylated trimethylolpropane triacrylate, dimethyl phthalate, 2-hydroxy-2-methyl-1-phenylacetone, a diluent, and 2-hydroxy-4-methoxybenzophenone to obtain a premixed solution;

The polysilazane resin and the premixed liquid are uniformly mixed and ultrasonically stirred to obtain a silicon nitride photocurable precursor material;

S3, model design, using computer-aided design software to design the 3D model of silicon nitride ceramic parts to ensure that the geometric shape and size of the model meet actual requirements;

S4, photocuring printing, pouring silicon nitride photocuring precursor material into the slurry tank of the ceramic photocuring forming system and scraping it flat with a coating scraper;

Move the workbench to the bottom of the liquid tank and make it contact with the silicon nitride photocurable precursor material, set the zero position, select the exposure parameters, and irradiate the light source onto the silicon nitride precursor material so that it is cured layer by layer during the printing process to form the final silicon nitride precursor 3D structure;

S5, heat treatment, heat treatment of the photocured silicon nitride precursor 3D structure, heating to 1400°C at a rate of 2°C/min in a nitrogen atmosphere, and keeping the temperature at the preset maximum temperature for 120min, and then slowly cooling to room temperature at a cooling rate of 3°C/min to obtain a silicon nitride ceramic part;

S6, post-processing, after completing the heat treatment, the silicon nitride ceramic parts are surface polished and coated to meet the final performance and appearance requirements.

Silicon nitride ceramic parts are photocured through silicon nitride precursor materials, photosensitive resin premix, diluent, and light absorber to obtain a silicon nitride precursor 3D structure, and then the silicon nitride precursor 3D structure is heat-treated to obtain a silicon nitride ceramic body. The curing performance of the silicon nitride photocurable precursor material is good. By optimizing the raw material selection and molding steps, the problems of silicon nitride powder being light-absorbent, the obtained cured thickness being low, and the molding process requiring high exposure power and exposure time, which affect the life of the equipment and printing efficiency, are solved. Thermogravimetric analysis of the cured samples found that when heated to 1000°C, the maximum ceramic yield was 79.45%. The ceramic parts after heat treatment have a dense structure without cracks or other defects. The method can be used to obtain a silicon nitride ceramic body with good morphology and structure, good surface quality, and high forming accuracy, thereby improving the reliability of the ceramic body.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (8)

1. A method for producing silicon nitride ceramics based on photocuring 3D printing, characterized by comprising: S1, material preparation, preparing silicon nitride precursor material, photosensitive resin premix, diluent, and light absorber; S2, pretreatment, ball milling the photosensitive resin premix, diluent, and light absorber to obtain a premix; The silicon nitride precursor material and the premixed liquid are uniformly mixed and ultrasonically stirred to obtain a silicon nitride photocurable precursor material; S3, model design, using computer-aided design software to design the 3D model of silicon nitride ceramic parts to ensure that the geometric shape and size of the model meet actual requirements; S4, photocuring printing, pouring silicon nitride photocuring precursor material into the slurry tank of the ceramic photocuring forming system and scraping it flat with a coating scraper; Move the workbench to the bottom of the liquid tank and make it contact with the silicon nitride photocurable precursor material, set the zero position, select the exposure parameters, and irradiate the light source onto the silicon nitride precursor material so that it is cured layer by layer during the printing process to form the final silicon nitride precursor 3D structure; S5, heat treatment, heat treatment of the photocured silicon nitride precursor 3D structure to promote the formation and ceramicization of silicon nitride to form a silicon nitride ceramic part; S6, post-processing, after completing the heat treatment, the silicon nitride ceramic parts are subjected to surface treatment or other post-processing steps to meet the final performance and appearance requirements. 2. A method for producing silicon nitride ceramics based on photocuring 3D printing according to claim 1, characterized in that the silicon nitride precursor material is a polysilazane resin containing methyl, vinyl or mercapto groups. 3. According to a method for producing silicon nitride ceramics based on photocuring 3D printing according to claim 1, it is characterized in that the photosensitive resin premix liquid comprises a photosensitive resin, a plasticizer and a photoinitiator. 4. A method for producing silicon nitride ceramics based on photocuring 3D printing according to claim 3, characterized in that the photosensitive resin comprises one or more of acryloyl morpholine, cyclotrimethylolpropane formal acrylate, diethoxylated neodiol diacrylate, and ethoxylated trimethylolpropane triacrylate; The plasticizer includes one or more of polyethylene glycol, 2,2,4-trimethyl-1,3-pentanediol diisocyanate and dimethyl phthalate; The photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, and 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone. 5. A method for generating silicon nitride ceramics based on photocuring 3D printing according to claim 1, characterized in that the light absorber is one or more of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone, and (2-hydroxy-3.5-dibutyl-tert-phenyl)-5-chlorobenzotriazole. 6. According to a method for generating silicon nitride ceramics based on photocuring 3D printing according to claim 1, it is characterized in that the heat treatment method in step S5 is to heat the temperature to a preset temperature at a rate of 2°C/min in a nitrogen atmosphere, keep the temperature at the preset maximum temperature for 120 minutes, and then slowly cool to room temperature at a cooling rate of 3°C/min to obtain a silicon nitride ceramic part. 7. A method for producing silicon nitride ceramics based on photocuring 3D printing according to claim 6, characterized in that the preset temperature is 1200-1800°C. 8. The method for producing silicon nitride ceramics based on photocuring 3D printing according to claim 1, characterized in that the post-processing in step S6 includes surface polishing and coating of the silicon nitride ceramic part.