Silicon carbide reinforced silicon nitride ceramic and preparation method thereof

A technology of silicon nitride ceramics and silicon carbide, which is applied in the field of ceramic materials, can solve the problems of difficulty in guaranteeing the dimensional accuracy of parts, low relative density of silicon nitride body, and high exposure power, so as to avoid the reduction of mechanical properties and improve photocuring Ability to reduce the effect of exposure energy

Active Publication Date: 2021-10-26
GUANGDONG UNIV OF TECH
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Problems solved by technology

[0003]Compared with other 3D printing technologies, the light curing molding technology has high molding precision and is suitable for the preparation of tiny ceramic parts, but due to the optical properties of silicon nitride powder characteristics, which greatly limit the solid content of the ceramic slurry, so that the relative density of the obtained silicon nitride body is low, and finally it is difficult to obtain dense silicon nitride ceramics, and there is a large deformation and shrinkage during the sintering process, which makes the parts. Dimensional accuracy is difficult to guarantee
Using silicon powder as raw material, dense silicon nitride ceramics can be prepared by reaction sintering, which can reduce the shrinkage of the sintering process and greatly improve the dimensional accuracy of parts. Low, which makes the exposure time of photocuring molding process long and the exposure power is high, it is difficult to directly prepare photocurable high solid content slurry

Method used

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preparation example Construction

[0028] The embodiment of the present invention provides a silicon carbide reinforced silicon nitride ceramic and a preparation method thereof, and the preparation steps are as follows:

[0029] (1) Surface treatment of powder: place silicon powder in an air sintering furnace for surface oxidation treatment, wherein the oxidation temperature is 900-1400°C, the holding time is 30min-6h, and the heating rate is 5-15°C / min to obtain the surface Oxidized silica fume;

[0030] Specifically, the silicon powder of the present invention refers to Si powder, which is a single component and generally contains a very small amount of impurities such as Al and Fe. Preferably, the silicon powder has a particle size of 0.1-2 μm and a purity of 97%-99.5%.

[0031] (2) Mixing the powder by ball milling: the surface oxidized silicon powder and sintering aid obtained in (1) are mixed by ball milling, dried and sieved to obtain the mixed powder, wherein the ball milling medium is absolute ethanol,...

Embodiment 1

[0045] (1) Powder surface treatment: put silicon powder with a particle size of 0.5 μm and a purity of 99% into an air sintering furnace, heat it to 1200 °C at a heating rate of 10 °C / min, and keep it for 2 hours to obtain an oxide layer with a thickness of 50 nm. Surface oxidized silicon powder;

[0046] (2) Powder ball milling and mixing: use absolute ethanol as the medium and silicon nitride balls as the ball milling balls to make 90g of surface oxidized silicon powder, 5g of MgO and 5g of Y 2 o 3 Ball milling and mixing for 6 hours, drying and sieving to obtain mixed powder.

[0047] (3) Slurry preparation: Take 65g of mixed powder, 17.5g of 1,6-hexanediol diacrylate (HDDA), 17.5g of ethoxylated pentaerythritol tetraacrylate (PPTTA), 1.3g of BYK-9077 , 0.7 g of diphenyl-(2,4,6-trimethylbenzoyl)phosphine (TPO) was uniformly mixed to obtain a slurry.

[0048] (4) Photocuring molding: add the above slurry to the photocuring molding equipment, load the 3D model data, set th...

Embodiment 2

[0054] (1) Powder surface treatment: Put silicon powder with a particle size of 0.5 μm and a purity of 99% into an air sintering furnace, heat it to 1200 °C at a heating rate of 10 °C / min, and keep it for 4 hours to obtain an oxide layer with a thickness of 100 nm. Surface oxidized silicon powder;

[0055] (2) Powder ball milling and mixing: use absolute ethanol as the medium and silicon nitride balls as the ball milling balls to make 90g of surface oxidized silicon powder, 5g of MgO and 5g of Y 2 o 3 Ball milling and mixing for 6 hours, drying and sieving to obtain mixed powder.

[0056] (3) Slurry preparation: Take 70g of mixed powder, 15g of 1,6-hexanediol diacrylate (HDDA), 15g of ethoxylated pentaerythritol tetraacrylate (PPTTA), 1.4g of BYK-9077, 0.6 g of diphenyl-(2,4,6-trimethylbenzoyl)phosphine (TPO) were uniformly mixed to obtain a slurry.

[0057] (4) Photocuring molding: add the above slurry to the photocuring molding equipment, load the 3D model data, set the l...

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Abstract

The invention discloses silicon carbide reinforced silicon nitride ceramic and a preparation method thereof, and relates to the technical field of ceramic materials. According to the preparation method, the silicon powder is subjected to heating surface oxidation treatment, so that a SiO2 layer with relatively low absorbance and refractive index is formed on the surface of the silicon powder, the introduced oxygen content is removed through carbon thermal reduction, and meanwhile, the silicon carbide phase reinforced silicon nitride ceramic is generated. The silicon nitride ceramic prepared by taking the silicon powder as the raw material through a reaction sintering method has the characteristic of low shrinkage distortion, and the preparation of the silicon carbide reinforced silicon nitride ceramic with a complex shape can be realized by matching with a photocuring molding technology.

Description

technical field [0001] The invention relates to the technical field of ceramic materials, in particular to a silicon carbide reinforced silicon nitride ceramic and a preparation method thereof. Background technique [0002] Silicon nitride ceramics is a structural ceramic with great application prospects. It has excellent mechanical properties, good chemical stability, wear resistance, and good thermal shock resistance. It is used in aerospace, machinery, automobiles, chemical metallurgy, and electronics. field is widely used. The traditional molding method of ceramics can only produce ceramic parts with simple structure, but because of the high strength, high hardness and inherent brittleness of silicon nitride ceramics, its machinability is low, and it is difficult to prepare complex shapes by mechanical processing. silicon nitride ceramics. In recent years, additive manufacturing technologies such as stereolithography (SLA), selective laser sintering (SLS) and three-dim...

Claims

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Application Information

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IPC IPC(8): C04B35/80C04B35/591C04B35/622C04B35/64
CPCC04B35/591C04B35/622C04B35/64C04B2235/3224C04B2235/3225C04B2235/3229C04B2235/3227C04B2235/6026C04B2235/6562C04B2235/6567C04B2235/658C04B2235/661C04B2235/3826C04B2235/77C04B2235/96Y02P10/25
Inventor 伍尚华黄兆权林立甫伍海东
Owner GUANGDONG UNIV OF TECH
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