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: 2009-02-04
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] The maltodextrin is dissolved in deionized water according to the content of 1.3-44.3 wt%, and an appropriate amount of dimethyl sulfoxide is added. Monomer acrylamide (MA) and cross-linking agent N,N'-methylenebisacrylamide (MBAM) were dissolved in deionized water at a ratio of 6:1, and then dispersant TMAH was added to prepare a premix. Silicon carbide and boron carbide powder are added, and the boron carbide is used as a sintering aid in an amount of 0.5-1 wt% (based on SiC). A slurry with a solid content of 50vol% is obtained by ball milling, and the viscosity of the slurry is about 300-600mPa.s. Add the initiator azobisimidazoline propane hydrochloride (AZIP·2HCl), the content of which is 1 / 10-1 / 15 of the monomer. Add while stirring vigorously and defoaming. Then pour into molds as needed. Cured at 45°C for 30-60min. Take it out and get the green body after demoulding. The relative density of the green body is 57%.

Embodiment 2

[0021] Dissolve α, β or γ cyclodextrin or their mixture in deionized water as required, and add appropriate amount of dimethyl sulfoxide. The monomer N,N-dimethylacrylamide (DMAA) and the crosslinking agent N,N'-methylenebisacrylamide (MBAM) were dissolved in deionized water according to the ratio of 6:1, and then the dispersant TMAH was added, Prepare a master mix. Add silicon carbide and boron carbide powder, and ball mill to obtain a slurry with a solid content of 50vol%, and the viscosity of the slurry is about 300-600mPa.s. Add the initiator azobisimidazoline propane hydrochloride (AZIP·2HCl), the content of which is 1 / 10-1 / 15 of the monomer. Add while stirring vigorously and defoaming. Then pour into molds as needed. Cured at 45°C for 30-60min. Take it out and get the green body after demoulding. All the other are with embodiment 1.

Embodiment 3

[0023]Dissolve white dextrin in deionized water as required, and add appropriate amount of dimethyl sulfoxide. Monomer methacrylamide and cross-linking agent N,N'-methylenebisacrylamide (MBAM) were dissolved in deionized water at a ratio of 12:1, and then dispersant TMAH was added to prepare a premix. Add silicon carbide and boron carbide powder, and ball mill to obtain a slurry with a solid content of 50vol%, and the viscosity of the slurry is about 300-600mPa.s. Add the initiator ammonium persulfate, the content is 1 / 10-1 / 15 of the monomer. Add while stirring vigorously and defoaming. Then pour into molds as needed. Cured at 40°C for 30-60min. Take it out and get the green body after demoulding. All the other are with embodiment 1.

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Abstract

The invention relates to selecting a new 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 new 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 proposes an organic carbon source and molding process for silicon carbide water-based gel casting molding, which meets the requirements as a solid-phase sintering aid for silicon carbide, and at the same time meets the requirements of the water-based gel casting process, and is suitable for water-based gel casting Silicon carbide ceramics prepared by casting. The invention belongs to the preparation technology 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 heat engine material and can be used as engine parts, Combustion chambers of gas turbines, moving and stationary blades of turbines, nozzles of rocket engines, etc. In addition, it can also be us...

Claims

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Application Information

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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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