阅读说明：本技术 一种光固化3d打印氮化硅陶瓷前驱体、其制备及成形方法 (Photocuring 3D printing silicon nitride ceramic precursor, and preparation and forming methods thereof ) 是由 连芩 刘小栋 李涤尘 何晓宁 陈锐光 孟佳丽 武向权 于 2019-09-20 设计创作，主要内容包括：本发明公开了一种光固化3D打印氮化硅陶瓷前驱体、其制备及成形方法,由单体、光引发剂、陶瓷前驱体预聚物及光吸收剂制备而成；单体为1,6己二醇二丙烯酸酯、甲基丙烯酸异氰基乙酯及1,2二硫氰酸亚乙酯的一种或多种；陶瓷前驱体预聚物为含有甲基、乙烯基或巯基基团的聚硅氮烷树脂；光引发剂为2,4,6-三甲基苯甲酰基-二苯基氧化膦、IRGACURE 819或安息香二甲醚,该陶瓷前驱体的固化性能良好,且制备及成形较为简单。(The invention discloses a photocuring 3D printing silicon nitride ceramic precursor, a preparation method and a forming method thereof, wherein the photocuring 3D printing silicon nitride ceramic precursor is prepared from a monomer, a photoinitiator, a ceramic precursor prepolymer and a light absorber; the monomer is one or more of 1, 6-hexanediol diacrylate, isocyano ethyl methacrylate and 1,2 ethylene dithiocyanate; the ceramic precursor prepolymer is polysilazane resin containing methyl, vinyl or sulfhydryl groups; the photoinitiator is 2,4, 6-trimethylbenzoyl-diphenyl phosphine oxide, IRGACURE 819 or benzoin dimethyl ether, the ceramic precursor has good curing performance, and the preparation and the forming are simpler.)

1. A photocuring 3D printing silicon nitride ceramic precursor is characterized by being prepared from a monomer, a photoinitiator, a ceramic precursor prepolymer and a light absorber;

the monomer is one or more of 1, 6-hexanediol diacrylate, isocyano ethyl methacrylate and 1,2 ethylene dithiocyanate;

the ceramic precursor prepolymer is polysilazane resin containing methyl, vinyl or sulfhydryl groups;

the photoinitiator is 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide, IRGACURE 819 or benzoin dimethyl ether.

2. The photocuring 3D-printed silicon nitride ceramic precursor as set forth in claim 1, wherein the monomers, the photoinitiator, the ceramic precursor prepolymer and the light absorber are 20-50 parts, 0.1-0.5 part, 50-80 parts and 0.2-0.5 part, respectively, by mass.

3. The photocurable 3D printable silicon nitride ceramic precursor according to claim 1, wherein the light absorber is 2- (2-hydroxy-3, 5-di-tert-butylphenyl) -5-chlorobenzotriazole.

4. A method for preparing the photocuring 3D printing silicon nitride ceramic precursor according to claim 1, comprising the following steps:

1) weighing a monomer and a photoinitiator, placing the photoinitiator in the monomer, and performing ball milling to obtain a mixed solution;

2) adding a ceramic precursor prepolymer and a light absorber into the mixed liquid obtained in the step 1), and performing vacuum pumping treatment after ultrasonic oscillation to obtain the photocuring 3D printing silicon nitride ceramic precursor.

5. A method of forming a photocured 3D printed silicon nitride ceramic precursor of claim 1, comprising the steps of:

1) pouring the photocuring 3D printing silicon nitride ceramic precursor into a slurry tank of a ceramic photocuring forming system, and leveling by using a coating scraper;

2) moving the workbench to the bottom of the liquid tank and contacting with the photocuring 3D printing silicon nitride ceramic precursor, setting a zero position, and selecting exposure parameters for printing to obtain a ceramic precursor curing sample piece;

3) and ultrasonically cleaning the ceramic precursor curing sample, and then putting the sample into an argon atmosphere for pyrolysis to obtain the silicon nitride ceramic piece.

6. The method of forming a photocured 3D printed silicon nitride ceramic precursor of claim 5, further comprising: and carrying out a thermogravimetric experiment on the ceramic precursor curing sample, and analyzing a thermogravimetric-differential thermal curve of the ceramic precursor curing sample to determine a pyrolysis process curve of the photocuring 3D printed silicon nitride ceramic precursor.

7. The method for forming the photocuring 3D printing silicon nitride ceramic precursor as claimed in claim 5, wherein the specific process of pyrolysis in the step 3) is as follows: heating the ceramic precursor curing sample piece from 50 ℃ to 600 ℃ at the speed of 3 ℃/min, heating to the preset maximum temperature at the speed of 1 ℃/min, preserving the heat at the preset maximum temperature for 120min, and cooling to the room temperature at the cooling speed of 3 ℃/min to obtain the silicon nitride ceramic piece.

8. The method for forming the photocuring 3D printing silicon nitride ceramic precursor as recited in claim 7, wherein the preset maximum temperature is 700-.

9. The method for forming the photocured 3D-printed silicon nitride ceramic precursor as recited in claim 5, wherein the yield of the ceramic after pyrolysis of the ceramic precursor cured sample is 60% to 82%.

10. The method for forming the photocured 3D printed silicon nitride ceramic precursor as claimed in claim 5, wherein the linear shrinkage of the ceramic precursor cured sample after pyrolysis is 17-35%.

Technical Field

The invention belongs to the field of additive manufacturing in machine manufacturing, and relates to a photocuring 3D printing silicon nitride ceramic precursor, and a preparation and forming method thereof.

Background

Silicon nitride ceramics have high mechanical strength, good thermal stability, small thermal expansion coefficient, good heat conductivity, oxidation resistance, wear resistance and corrosion resistance, so the silicon nitride ceramics are widely applied to mechanical industry, metallurgical industry, electronics, aerospace and military, for example, parts of high temperature engineering, such as aircraft engines, novel ceramic cutters, ball valves, pump bodies and the like. But the hardness is high, the brittleness is large, defects are easy to occur in the manufacturing process, the forming precision influence factors are numerous, and the complex structure is more difficult to form and process. The traditional processing methods such as isostatic pressing, hot-pressing sintering molding, gel injection molding and the like depend on complex molds, the development period is long, the cost is high, the product is not suitable for updating, and the complex thin-wall structure is more difficult to form and process.

Therefore, the additive manufacturing technology has wide application space in the field of ceramic manufacturing. The additive manufacturing technology applied to ceramic manufacturing at present mainly comprises three-dimensional printing (3DP), Selective Laser Sintering (SLS), Selective Laser Melting (SLM) and photocuring forming (SLA), wherein the surface forming technology in the photocuring forming is used for forming a section at one time, the forming efficiency is high, and the forming precision and the surface quality have great advantages.

However, since silicon nitride ceramics have a high refractive index (n is 2.2), light is scattered when irradiated into a ceramic slurry in which silicon nitride powder and a photosensitive resin are mixed, resulting in a too small molding thickness and difficulty in adhesion to a table, and the slurry is difficult to mold due to severe scattering. The ceramic precursor conversion ceramic technology is a novel ceramic part manufacturing method developed in recent years, and ceramic parts are obtained by preparing a ceramic precursor, forming a precursor solidified part through a 3D printing technology and then performing pyrolysis. The precursor pyrolysis method solves the problem of scattering of ultraviolet light incidenceEffect, making it possible to shape high refractive index ceramic complex structures, e.g. SiC ceramics, Si, by photocuring 3D printing techniques₃N₄However, the curing performance of the existing ceramic precursor is poor, and the development of the industry is seriously influenced.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a photocuring 3D printing silicon nitride ceramic precursor, and a preparation and forming method thereof.

In order to achieve the purpose, the photocuring 3D printing silicon nitride ceramic precursor is prepared from a monomer, a photoinitiator, a ceramic precursor prepolymer and a light absorber;

the monomer is one or more of 1, 6-hexanediol diacrylate, isocyano ethyl methacrylate and 1,2 ethylene dithiocyanate;

the ceramic precursor prepolymer is polysilazane resin containing methyl, vinyl or sulfhydryl groups;

the photoinitiator is 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide, IRGACURE 819 or benzoin dimethyl ether.

The mass portions of the monomer, the photoinitiator, the ceramic precursor prepolymer and the light absorbent are 20-50 parts, 0.1-0.5 part, 50-80 parts and 0.2-0.5 part respectively.

The light absorbent is 2- (2-hydroxy-3, 5-dibutyl tertiary phenyl) -5-chloro benzotriazole.

The preparation method of the photocuring 3D printing silicon nitride ceramic precursor comprises the following steps:

1) weighing a monomer and a photoinitiator, placing the photoinitiator in the monomer, and performing ball milling to obtain a mixed solution;

2) adding a ceramic precursor prepolymer and a light absorber into the mixed liquid obtained in the step 1), and performing vacuum pumping treatment after ultrasonic oscillation to obtain the photocuring 3D printing silicon nitride ceramic precursor.

The forming method of the photocuring 3D printing silicon nitride ceramic precursor comprises the following steps:

1) pouring the photocuring 3D printing silicon nitride ceramic precursor into a slurry tank of a ceramic photocuring forming system, and leveling by using a coating scraper;

2) moving the workbench to the bottom of the liquid tank, enabling the photocuring 3D printing silicon nitride ceramic precursor to be in contact with the liquid tank, setting a zero position, and selecting exposure parameters for printing to obtain a ceramic precursor curing sample piece;

3) and ultrasonically cleaning the ceramic precursor curing sample, and then putting the sample into an argon atmosphere for pyrolysis to obtain the silicon nitride ceramic piece.

Further comprising: and carrying out a thermogravimetric experiment on the ceramic precursor curing sample, and analyzing a thermogravimetric-differential thermal curve of the ceramic precursor curing sample to determine a pyrolysis process curve of the photocuring 3D printed silicon nitride ceramic precursor.

The pyrolysis in the step 3) comprises the following specific processes: heating the ceramic precursor curing sample piece from 50 ℃ to 600 ℃ at the speed of 3 ℃/min, heating to the preset maximum temperature at the speed of 1 ℃/min, preserving the heat at the preset maximum temperature for 120min, and cooling to the room temperature at the cooling speed of 3 ℃/min to obtain the silicon nitride ceramic piece.

The preset maximum temperature is 700-1500 ℃.

The yield of the ceramic after pyrolysis of the ceramic precursor solidified sample piece is 60-82%.

The linear shrinkage rate of the ceramic precursor solidified sample piece after pyrolysis is 17-35%.

The invention has the following beneficial effects:

the photocuring 3D printing silicon nitride ceramic precursor and the preparation and forming method thereof are characterized in that during specific operation, the photocuring 3D printing silicon nitride ceramic precursor is prepared from a monomer, a photoinitiator, a ceramic precursor prepolymer and a light absorber, wherein the monomer is one or more of 1, 6-hexanediol diacrylate, isocyano ethyl methacrylate and 1, 2-ethylene dithiocyanate; the ceramic precursor prepolymer is polysilazane resin containing methyl, vinyl or sulfhydryl groups; the photoinitiator is 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide, IRGACURE 819 or benzoin dimethyl ether, thermogravimetric analysis on a cured sample shows that the weight loss process mainly occurs at 500 ℃ of 360-. In addition, during preparation, only traditional mixing, ball milling, ultrasonic oscillation and vacuumizing treatment are needed, and the preparation method is simple. Meanwhile, during forming, printing is carried out by selecting exposure parameters to obtain a ceramic precursor curing sample, and then ultrasonic cleaning and pyrolysis are carried out on the ceramic precursor curing sample to obtain the silicon nitride ceramic piece, wherein the forming process is simple.

Drawings

FIG. 1 is a flow chart of the present invention for preparing a ceramic precursor;

FIG. 2 is a drawing of a photo-cured molded sample of the ceramic precursor prepared in the first example;

FIG. 3 is a drawing of a photo-cured molded sample of the ceramic precursor prepared in example two;

FIG. 4 is a thermogravimetric analysis graph of a ceramic precursor photocured sample prepared in example two;

FIG. 5 is a drawing of a ceramic sample after pyrolysis of a ceramic precursor photocurable sample prepared in accordance with example one;

fig. 6 is a diagram of a ceramic sample after pyrolysis of the ceramic precursor photocured sample prepared in example two.

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings:

referring to fig. 1, the photocuring 3D printing silicon nitride ceramic precursor is prepared from a monomer, a photoinitiator, a ceramic precursor prepolymer and a light absorber;

the monomer is one or more of 1, 6-hexanediol diacrylate, isocyano ethyl methacrylate and 1,2 ethylene dithiocyanate;

the ceramic precursor prepolymer is polysilazane resin containing methyl, vinyl or sulfhydryl groups;

the photoinitiator is 2,4, 6-trimethylbenzoyl-diphenyl phosphine oxide, IRGACURE 819 or benzoin dimethyl ether;

the light absorbent is 2- (2-hydroxy-3, 5-dibutyl tertiary phenyl) -5-chloro benzotriazole;

the mass portions of the monomer, the photoinitiator, the ceramic precursor prepolymer and the light absorbent are 20-50 parts, 0.1-0.5 part, 50-80 parts and 0.2-0.5 part respectively.

The preparation method of the photocuring 3D printing silicon nitride ceramic precursor comprises the following steps:

1) weighing a monomer and a photoinitiator, placing the photoinitiator in the monomer, and performing ball milling for 30min to obtain a mixed solution, wherein the rotating speed during ball milling is 160 r/min;

2) adding a ceramic precursor prepolymer and a light absorber into the mixed liquid obtained in the step 1), performing ultrasonic oscillation for 30min, and then performing vacuum pumping for 1min to obtain the photocuring 3D printing silicon nitride ceramic precursor.

The forming method of the photocuring 3D printing silicon nitride ceramic precursor comprises the following steps:

1) pouring the photocuring 3D printing silicon nitride ceramic precursor into a slurry tank of a ceramic photocuring forming system, and leveling by using a coating scraper;

2) moving the workbench to the bottom of the liquid tank, enabling the photocuring 3D printing silicon nitride ceramic precursor to be in contact with the liquid tank, setting a zero position, and selecting exposure parameters for printing to obtain a ceramic precursor curing sample piece;

3) and placing the ceramic precursor solidified sample piece into DBE cleaning solution for ultrasonic cleaning for 2min, and then placing the sample piece into argon atmosphere for pyrolysis to obtain the silicon nitride ceramic piece.

Further comprising: and carrying out a thermogravimetric experiment on the ceramic precursor curing sample, and analyzing a thermogravimetric-differential thermal curve of the ceramic precursor curing sample to determine a pyrolysis process curve of the photocuring 3D printed silicon nitride ceramic precursor.

The pyrolysis in the step 3) comprises the following specific processes: heating the ceramic precursor curing sample piece from 50 ℃ to 600 ℃ at the speed of 3 ℃/min, heating to 700-.

The yield of the ceramic after pyrolysis of the ceramic precursor solidified sample piece is 60-82%; the linear shrinkage rate of the ceramic precursor solidified sample piece after pyrolysis is 17-35%.