A kind of preparation method of porous silicon carbide ceramic material

A technology of porous silicon carbide and ceramic materials, applied in the field of ceramic materials, can solve problems such as poor mechanical properties at high temperature, and achieve the effect of simple preparation method

Inactive Publication Date: 2011-11-30
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In order to solve the problems of poor high-temperature mechanical properties of porous silicon carbide ceramic materials prepared in the prior art, the present invention provides a preparation method of porous silicon carbide c

Method used

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  • A kind of preparation method of porous silicon carbide ceramic material
  • A kind of preparation method of porous silicon carbide ceramic material
  • A kind of preparation method of porous silicon carbide ceramic material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Weigh 15g of SiC (the average particle size of SiC powder is 0.5μm), 0.09g of B, 0.47g of C, 0.3g of polyethyleneimine and 11.42g of deionized water, add them to a 250mL polyethylene grinding bottle, and add 15 g of SiC balls were milled for 24 hours to obtain a uniformly dispersed ceramic water-based slurry with a solid content of 55 wt% (solid content%=SiC / (SiC+sintering aid+dispersant+water)). Add 7.5 g of 12 wt % polyvinyl alcohol (PVA) aqueous solution to the ceramic water-based slurry, and continue ball milling for 24 hours to obtain a uniformly dispersed slurry. Pour the dispersed slurry into the prepared mold, put it into the freezer of the refrigerator and freeze it at -18°C to -20°C for about 12 hours to obtain a frozen green body. Take the frozen green body out of the mold, put it into the drying box of the freeze dryer immediately, first keep it at 10°C and a vacuum of 9Pa for 4 hours, then raise the temperature to 60°C, and keep it warm for about 5 hours to...

Embodiment 2

[0037]The only difference between this embodiment and Example 1 is that 0g, 2.5g, and 12.5g of polyvinyl alcohol (PVA) aqueous solution with a concentration of 12wt% are added to the ceramic water-based slurry, and the remaining contents are the same as in Example 1. described in .

[0038] Figure 4 It is the scanning electron microscope image of the silicon carbide ceramic material prepared under the addition amount of different organic polymers, in the figure: a is the silicon carbide ceramic material prepared without adding polyvinyl alcohol, and b is the addition of 2.5g of polyvinyl alcohol with a concentration of 12wt%. The silicon carbide ceramic material prepared by polyvinyl alcohol (PVA) aqueous solution, c is the silicon carbide ceramic material prepared by adding 7.5g concentration of polyvinyl alcohol (PVA) aqueous solution; d is the addition of 12.5g concentration is 12wt% % of polyvinyl alcohol (PVA) aqueous solution made of silicon carbide ceramic material; b...

Embodiment 3

[0042] The only difference between this example and Example 1 is that 14.44g of SiC (average particle size of SiC powder is 0.5μm), 0.09g of B, 0.47g of C, and 0.3g of polyethyleneimine are added successively to 15g of SiC. Ionized water was used to prepare a ceramic water-based slurry with a solid content of 50 wt%, and all the other contents were the same as those described in Example 1.

[0043] Figure 7 It is the relationship diagram of different slurry solid content and the porosity of the prepared silicon carbide ceramic material, by Figure 7 It can be seen that the porosity gradually decreases with the increase of solid content.

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Abstract

The invention discloses a method for preparing a porous silicon carbide ceramic material, which comprises: a) adding SiC powder, a sintering aid and a dispersant to water to prepare a ceramic water-based slurry with a solid content of 10-60 wt %; b) pour the slurry into a mold, and freeze at -200-0°C to form a green body; c) dry the frozen green body at -60-80°C and 5-600Pa for 4-48 hours to obtain a porous element d) subjecting the obtained porous green body to high-temperature solid phase sintering. The present invention uses the combination of freeze-drying and high-temperature solid-phase sintering technology to prepare a porous silicon carbide ceramic material that can be used in a high-temperature environment higher than 1500 ° C, and by adjusting the solid content of the slurry, the slurry The content of the added organic polymer and the solid-state sintering temperature can obtain porous SiC ceramic materials with different porosity and strength, which can meet the application requirements of SiC ceramics in different fields.

Description

technical field [0001] The invention relates to a method for preparing a porous silicon carbide ceramic material, in particular to a method for preparing a porous silicon carbide ceramic material that can be used in an environment higher than 1500°C, and belongs to the technical field of ceramic materials. Background technique [0002] Some high-performance structural ceramic materials can be used in high-temperature environments due to their good high-temperature mechanical properties and corrosion resistance, for example, as filter elements, rocket nozzles and high-temperature gas blades. As a ceramic component used in a high temperature environment, it is usually used in an oxidizing or corrosive atmosphere, and it must also withstand frequent mechanical and thermal shocks. Therefore, components used in a high temperature environment need to have high stability and reliability. Porous silicon carbide ceramics have high chemical stability, acid and alkali resistance, high ...

Claims

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Application Information

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IPC IPC(8): C04B38/00C04B35/565C04B35/622
Inventor 左开慧曾宇平
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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