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Preparation method for low-porosity reaction-sintered silicon nitride bonded silicon carbide ceramic material

A silicon carbide ceramic, low-porosity technology, applied in the field of ceramics and refractories, can solve the problems of product performance impact, limited application scope, and high open porosity

Active Publication Date: 2017-05-17
XIAN XINGUI CERAMIC COMPOSITE MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] At present, large-scale and complex-structured products generally adopt the grouting molding method, and the product has a high opening porosity and a low volume density (usually the opening porosity is as high as 18%, and the volume density is 2.50g / cm 3 Below), the performance of the product is seriously affected and the scope of application is limited

Method used

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  • Preparation method for low-porosity reaction-sintered silicon nitride bonded silicon carbide ceramic material
  • Preparation method for low-porosity reaction-sintered silicon nitride bonded silicon carbide ceramic material
  • Preparation method for low-porosity reaction-sintered silicon nitride bonded silicon carbide ceramic material

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Experimental program
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Embodiment 1

[0032] Such as figure 1 As shown, a method for preparing a low porosity reaction sintered silicon nitride bonded silicon carbide ceramic material comprises the following steps:

[0033] Step 1: Soak metal Si powder in hydrochloric acid with a concentration of 0.1 mol / L for 24 hours, wash with deionized water until neutral, dry and set aside.

[0034] Step 2: Soak 1# SiC powder in deionized water for 24 hours, dry it and set aside.

[0035] Step 3: Weigh 2# and 3# SiC particles according to the mass ratio of 4:1, mix them evenly, add silica sol accounting for 20% of the total mass of the two, and stir them into wet sand.

[0036] Step 4: Weigh the treated 1# SiC powder and metal Si powder according to 7wt% and 16wt% of the wet sand material respectively, mix them evenly by dry ball milling, add them to the above wet sand material, stir evenly to form a slurry, and place it for 30 minutes. Add NH at 0.7% of the amount of silica sol 4 Cl, stir well.

[0037] Step 5: Rapidly p...

Embodiment 2

[0047] The difference between this embodiment and embodiment 1 is that the highest firing temperature is 1450°C.

[0048] The obtained reaction sintered silicon nitride bonded silicon carbide ceramics had an open porosity of 13.8% and a bulk density of 2.66 g / cm 3

Embodiment 3

[0050] The difference between this embodiment and embodiment 1 is: the concentration of the aluminum chloride solution used for soaking the biscuit is 10wt%.

[0051] The obtained reaction sintered silicon nitride bonded silicon carbide ceramics had an open porosity of 14.0% and a bulk density of 2.65 g / cm3

[0052] The microstructure of the sample was analyzed with a scanning electron microscope, such as image 3 As shown, the black ones are SiC particles, and it can be seen that the sample is composed of SiC particles of different particle sizes to form a skeleton, while the white ones are SiC particles. 3 N 4 The matrix is ​​filled between the SiC skeletons and wraps the SiC particles, forming a good combination.

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Abstract

The invention discloses a preparation method for a low-porosity reaction-sintered silicon nitride bonded silicon carbide ceramic material. A low-porosity silicon nitride bonded silicon carbide ceramic material is obtained through a reaction sintering method and a bonded densifying technology. The preparation method concretely comprises the following steps: (1) mixing SiC grains having two particle sizes, adding ludox and stirring the mixture uniformly; (2) adding metal Si powder and SiC powder which are subjected to pretreatment, stirring the slurry uniformly, standing the slurry, then adding a coagulant, and stirring again; (3) pouring the slurry into a mold quickly, carrying out vibration molding, and demolding after drying; (4) carrying out vacuum impregnation on prepared bisque for two times in an aluminum chloride solution; and (5) carrying out reaction sintering in a nitrogen atmosphere to obtain the reaction-sintered silicon nitride bonded silicon carbide ceramic material. Compared with the current slip casting technology, the reaction-sintered silicon nitride bonded silicon carbide ceramic prepared by the method disclosed by invention has the advantages that a plaster mold is not needed, the porosity of a material can be obviously reduced under the circumstance of not markedly increasing the cost of production, and the volume density is improved.

Description

technical field [0001] The invention belongs to the technical field of ceramics and refractory materials, in particular to a method for preparing a low porosity reaction sintered silicon nitride bonded silicon carbide ceramic material. Background technique [0002] Silicon carbide-based ceramic materials are a series of ceramic materials developed on the basis of silicon carbide ceramics, including a series of high-tech ceramic materials such as oxide-bonded silicon carbide, silicon nitride-bonded silicon carbide, and Sialon-bonded silicon carbide. This series of ceramic materials has a series of excellent properties such as high temperature resistance, high strength, corrosion resistance, thermal shock resistance, oxidation resistance, and wear resistance. Has a wide range of applications. Among them, the silicon nitride combined with silicon carbide ceramic material uses metal silicon powder to undergo nitriding reaction in nitrogen to form silicon nitride, and combines s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/565C04B35/591C04B35/622
CPCC04B35/565C04B35/591C04B35/622C04B2235/428C04B2235/77
Inventor 张军战张颖
Owner XIAN XINGUI CERAMIC COMPOSITE MATERIAL CO LTD