Organic carbon source for pouring and molding silicon carbide aqueous gel and molding technique

A water-based gel and pouring molding technology, which is applied in the field of silicon carbide ceramics, can solve the problems of unfavorable silicon carbide powder dispersion, phenolic resin failure, and high viscosity, and achieve the effect of easy process, easy realization, and low cost

Active Publication Date: 2013-03-13
中科西卡思(苏州)科技发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, phenolic resins are not soluble in aqueous solutions
The viscosity of starch is too high after dissolving, and it is not conducive to the dispersion of silicon carbide powder

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Dissolve maltodextrin in deionized water at a content of 1.3-44.3 wt%, and add an appropriate amount of dimethyl sulfoxide. The monomer acrylamide (MA) and the crosslinking agent N,N'-methylenebisacrylamide (MBAM) are dissolved in deionized water at a ratio of 6:1, and then the dispersant TMAH is added to prepare a premix. Silicon carbide and boron carbide powder are added, and boron carbide is used as a sintering aid, and the addition amount is 0.5 to 1 wt% (based on SiC). Ball milling obtains a slurry with a solid content of 50 vol%, and the viscosity of the slurry is about 300-600 mPa.s. Add initiator azobisimidazoline propane hydrochloride, the content is 1 / 10-1 / 15 of the monomer. Add while stirring vigorously and degas. Then pour it into the mold as needed. Cure at 45°C for 30-60min. Take it out and get a blank after demoulding. The relative density of the green is 57%.

Embodiment 2

[0021] Dissolve α, β or γ cyclodextrin or their mixture in deionized water as needed, and add appropriate amount of dimethyl sulfoxide. The monomer N,N-dimethylacrylamide (DMAA) and the crosslinking agent N,N'-methylenebisacrylamide (MBAM) are dissolved in deionized water at a ratio of 6:1, and then the dispersant TMAH is added. Prepare a premix. Silicon carbide and boron carbide powder are added and ball milled to obtain a slurry with a solid content of 50 vol%, and the viscosity of the slurry is about 300-600 mPa.s. Add initiator azobisimidazoline propane hydrochloride, the content is 1 / 10-1 / 15 of the monomer. Add while stirring vigorously and degas. Then pour it into the mold as needed. Cure at 45°C for 30-60min. Take it out and get a blank after demoulding. The rest is the same as in Example 1.

Embodiment 3

[0023] Dissolve white dextrin in deionized water as needed, and add appropriate amount of dimethyl sulfoxide. The monomer methacrylamide and the crosslinking agent N,N'-methylenebisacrylamide (MBAM) are dissolved in deionized water at a ratio of 12:1, and then the dispersant TMAH is added to prepare a premix. Silicon carbide and boron carbide powder are added and ball milled to obtain a slurry with a solid content of 50 vol%, and the viscosity of the slurry is about 300-600 mPa.s. Add initiator ammonium persulfate, the content is 1 / 10-1 / 15 of the monomer. Add while stirring vigorously and degas. Then pour it into the mold as needed. Cure at 40°C for 30-60min. Take it out and get a blank after demoulding. The rest is the same as in Example 1.

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Abstract

The invention relates to selecting a novel organic carbon source which is suitable for a gel casting molding process of silicon carbide and can meet the requirements of the dispersion, stability and a subsequent curing process of slurry with high solid content in water-base gel casting as well as provide carbon powder after cracking. The invention adopts dextrin as the organic carbon source and adds dimethyl sulfoxide to improve the stability of the dextrin. According to conventional gel casting process, the SiC slurry with solid content to be 50vol percent can be prepared and the viscosity can be about 300 to 600MPa*s; gel casting bisques with uniform structures and 55 to 60 percent of relative density can be prepared by the slurry according to needs; the bisques are further de-glued and sintered to obtain compact silica carbide ceramic. By adopting the dextrin as the organic carbon source in the invention, the cost is low; the gel casting process can be easily realized and the technological process can be easily controlled. The novel carbon source can prepare silicon carbide ceramic materials with high performance and complex shapes with low cost and is suitable for the preparation of block or porous silicon carbide ceramics.

Description

Technical field [0001] The present invention provides an organic carbon source and molding process for silicon carbide water-based gel casting, which meets the requirements of being a silicon carbide solid-phase sintering aid, and at the same time meets the requirements of the water-based gel casting process, and is suitable for passing water-based gels. Silicon carbide ceramics are prepared by casting. It belongs to the preparation process and application field of silicon carbide ceramics. Background technique [0002] Silicon carbide (SiC) ceramics have excellent mechanical properties, high temperature oxidation resistance, wear resistance, corrosion resistance, radiation resistance and special electrical and thermal properties. It is the preferred high-temperature thermomechanical material and can be used as engine parts, Combustion chambers of gas turbines, moving and static blades of turbines, nozzles of rocket engines, etc. In addition, it can also be used as precision be...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/632C04B35/624
Inventor 张景贤江东亮林庆玲陈忠明黄政仁
Owner 中科西卡思(苏州)科技发展有限公司
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