Method for preparing fine-grain silicon carbide ceramic through reaction sintering

A silicon carbide ceramic and sintered silicon carbide technology, which is applied in the field of inorganic non-metallic materials, can solve the problems of restricting the practical scope, decreasing the mechanical strength of materials, and high content of free silicon, achieving scientific and reasonable raw material ratio, improving mechanical strength, microscopic The effect of uniform structure

Active Publication Date: 2016-09-21
浙江东新新材料科技有限公司
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Problems solved by technology

[0005] Although reaction-sintered silicon carbide ceramics have been mass-produced, the existing reaction-sintered silicon carbide ceramics have coarse grains, large free silicon content and large size, and poor microstructure uniformity.
Studies have shown that the melting point of silicon is low (1410°C), and its strength is very small (less than 100MPa), which is much lower than the mechanical properties of silicon carbide. Therefore, the size and content of free silicon particles affect the mechanical properties of reaction-sintered silicon carbide ceramics. performance
The larger the particle size of the free silicon particles, the greater the residual stress suffered by the silicon carbide particles, the mechanical strength of the material is significantly reduced and the corrosion resistance is poor, which restricts its application range

Method used

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  • Method for preparing fine-grain silicon carbide ceramic through reaction sintering

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] Embodiment 1, a kind of reaction sintering is prepared the production method of fine grain silicon carbide ceramics, carries out following steps successively:

[0054] 1), preparation of main ingredients:

[0055] The main material is composed of the following components by weight: 85% of green silicon carbide micropowder (SiC micropowder), 15% of activated carbon powder;

[0056] The green silicon carbide powder D 50 = 5 μm;

[0057] The particle size of the activated carbon micropowder is 20-100nm;

[0058] 2), ball mill mixing:

[0059] Use deionized water as the solvent and silicon carbide balls as the ball milling medium to carry out wet ball milling mixing; the details are as follows:

[0060] First add 1 part of dispersant and 50 parts of deionized water to 100 parts of the main material, and then add 15 parts of an aqueous solution of organic matter with high-temperature residual carbon in sequence (in this aqueous solution, the mass concentration of organic...

Embodiment 2

[0081] Embodiment 2, change "green silicon carbide micropowder (SiC micropowder) 85%, activated carbon powder 15%" in step 1) of embodiment 1 to "green silicon carbide micropowder (SiC micropowder) 90%, activated carbon powder 10%"; All the other are equal to embodiment 1; Its performance testing result is: the drainage method detects that bulk density is 3.03g / cm 3 , free silicon content 8.0%, flexural strength 370MPa, Rockwell hardness (HRA) 91.

Embodiment 3

[0082] Embodiment 3: Change "green silicon carbide micropowder (SiC micropowder) 85%, activated carbon powder 15%" in embodiment 1 step 1) to "green silicon carbide micropowder (SiC micropowder) 80%, activated carbon powder 20%" and the rest Identical to embodiment 1; Its performance testing result is: the drainage method detects that bulk density is 3.08g / cm 3 , the content of free silicon is 4.0%, the flexural strength is 390MPa, and the Rockwell hardness (HRA) is 92.0.

[0083] Comparative example 1-1, cancel the use of "15 parts of high-temperature organic carbon residue aqueous solution" in step 2) of embodiment 1, and the rest are equal to embodiment 1, but in step 6) during the car-making process, the green body is easy to crack , can not be turned normally, mainly because the high-temperature residual carbon organic matter of the present invention is cracked into network carbon during the wax removal process, which enhances the strength of the green body.

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Abstract

The invention discloses a method for preparing fine-grain silicon carbide ceramic through reaction sintering. The method sequentially comprises the following steps: preparing a main material comprising 75-90wt% of silicon carbide micro-powder and 10-15wt% of active carbon powder; adding a dispersant and deionized water to the main material, sequentially adding an aqueous solution of organic matters containing high temperature carbon residue and a water-soluble polymer binder solution, and stirring and mixing above materials in a ball mill to prepare a uniformly-dispersed water-based silicon carbide slip; and sequentially carrying out spray granulation, dry press molding, dewaxing, vehicle working, high temperature siliconising sintering and alkali treatment desilication to obtain the silicon carbide ceramic.

Description

technical field [0001] The invention belongs to the field of inorganic non-metallic materials, and relates to a method for preparing silicon carbide ceramics (fine grain silicon carbide ceramics) by reaction sintering. Background technique [0002] Since the birth of silicon carbide ceramic materials for more than a century, reaction sintered silicon carbide ceramic materials have the advantages of thermal shock resistance, high temperature resistance, wear resistance, thermal shock resistance, high thermal conductivity, high hardness, oxidation resistance and chemical corrosion resistance of silicon carbide ceramics. Compared with pressureless sintering and hot-pressing sintering, it has the advantages of simple equipment, short sintering time, low sintering temperature, low cost, small shrinkage (<1%) and net size sintering, which makes RBSiC realize large Large-scale industrial production, and has been widely used in various fields under severe conditions such as high ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/565C04B35/64
CPCC04B35/565C04B35/64C04B2235/422C04B2235/5436C04B2235/5454C04B2235/614C04B2235/6581
Inventor 郑浦任付生杨新领
Owner 浙江东新新材料科技有限公司
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