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Method for preparing nanocrystalline silicon carbide ceramic by SLS (selective laser sintering) based on phase inversion microspheres

A technology of silicon carbide ceramics and nano-silicon carbide, which is applied in the direction of ceramic molding machines, manufacturing tools, and additive processing, can solve the problems of large porosity, high particle size distribution and sphericity requirements, and low strength of the green body. Achieve the effect of uniform grain size distribution, speed up liquid silicon infiltration process, and high density

Active Publication Date: 2022-04-26
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In summary, the current SLS process for preparing silicon carbide ceramics is based on SiC powder, which requires high particle size distribution and sphericity of the powder, and the green body obtained by printing has the problems of large porosity and low strength.

Method used

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  • Method for preparing nanocrystalline silicon carbide ceramic by SLS (selective laser sintering) based on phase inversion microspheres

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] (1) The average particle diameter is 40nm and the nano-silicon carbide ceramic powder with a mass fraction of 70%, polyvinyl alcohol with a mass fraction of 4%, and distilled water with a mass fraction of 26% are added into a ball mill and mixed uniformly to prepare a slurry;

[0027] (2) Perform spray ionization granulation on the slurry configured in step (1), and the tiny liquid droplets that are sprayed and ionized enter the curing pool to undergo cross-linking and curing reactions to form ceramic particles. The solution in the curing pool is glycerol and boric acid, wherein The massfraction of boric acid is 10%;

[0028] (3) Wash the ceramic particles prepared in step (2) with an alcohol solution and dry them naturally in the atmosphere, then sinter and degrease the ceramic particles in a muffle furnace, the temperature is controlled at 1000°C, and the heating rate is controlled at 10°C / min;

[0029] In this example, silicon carbide ceramic microspheres with a pa...

Embodiment 2

[0036] (1) adding nano-silicon carbide ceramic powder with an average particle diameter of 50 nm and a mass fraction of 65%, polyvinyl alcohol with a mass fraction of 5%, and distilled water with a mass fraction of 30% in a ball mill and mixing uniformly to prepare a slurry;

[0037] (2) Perform spray ionization granulation on the slurry configured in step (1), and the tiny liquid droplets that are sprayed and ionized enter the curing pool to undergo cross-linking and curing reactions to form ceramic particles. The solution in the curing pool is glycerol and boric acid, wherein The massfraction of boric acid is 12%;

[0038] (3) Wash the ceramic particles prepared in step (2) with an alcohol solution and dry them naturally in the atmosphere, then sinter and degrease the ceramic particles in a muffle furnace, the temperature is controlled at 1200°C, and the heating rate is controlled at 5°C / min;

[0039] In this embodiment, silicon carbide ceramic microspheres with a particle...

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Abstract

The invention discloses a method for preparing nanocrystalline silicon carbide ceramic by SLS (selective laser sintering) based on phase inversion microspheres. The preparation method comprises the following steps: firstly, preparing silicon carbide ceramic microspheres with the particle size of 40-100 microns by taking nano silicon carbide powder as a raw material and adopting a phase inversion technology, then forming silicon carbide ceramic by adopting an SLS technology, and finally densifying through degreasing, carbonizing, presintering and liquid silicon infiltration to prepare the silicon carbide ceramic. The silicon carbide ceramic microspheres prepared on the basis of a phase inversion method have the characteristics of low organic matter residual quantity, good particle sphericity, excellent fluidity, high additive adaptability, simple process and low manufacturing cost. The silicon carbide ceramic prepared from the silicon carbide microspheres through SLS retains a nanocrystalline structure, is excellent in bending strength, elasticity modulus and fracture toughness, and meets the use requirements of high-performance complex structural parts in the aerospace field.

Description

technical field [0001] The invention relates to the field of additive manufacturing of silicon carbide ceramics, in particular to a method for preparing nanocrystalline silicon carbide ceramics based on SLS of phase inversion microspheres. Background technique [0002] Silicon carbide ceramic materials have the characteristics of high temperature resistance, high temperature mechanical properties, thermal stability and chemical corrosion resistance, and are widely used in aerospace, automobile manufacturing, petrochemical and other fields. Traditional nanocrystalline silicon carbide ceramics are prepared by processes such as recrystallization and nanopowder sintering, which cannot meet the application needs of special-shaped nanocrystalline silicon carbide structural parts. SLS technology is an additive manufacturing technology based on powder printing. By uniformly mixing ceramic powder with a low-melting binder, and then using laser heating to melt the binder, the ceramic ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/573C04B35/626B28B1/00B33Y70/00B33Y10/00
CPCC04B35/573C04B35/62695B28B1/001B33Y70/00B33Y10/00C04B2235/6026
Inventor 杨丽霞温国强刘天龙陈照峰
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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