Porous ceramics pore wall silicon carbide coating and its preparation method

A silicon carbide coating, porous ceramic technology, applied in ceramic products, other household appliances, household appliances, etc., can solve the problem that the slurry is difficult to penetrate into the porous ceramic body, the powder is difficult to coat, and the uniform silicon carbide coating cannot be formed. layer and other problems, to achieve the effect of high hardness, small thermal expansion coefficient, simple and effective preparation method

Inactive Publication Date: 2007-07-11
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

However, there are few reports on the silicon carbide coating treatment of porous ceramic bodies. The main reason is that the powder usually used in coating treatment is difficult to coat uniformly in the porous ceramic channels ...

Method used

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  • Porous ceramics pore wall silicon carbide coating and its preparation method
  • Porous ceramics pore wall silicon carbide coating and its preparation method
  • Porous ceramics pore wall silicon carbide coating and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The mullite-bonded silicon carbide porous ceramic is used as the coating substrate. The bonding phase of the porous ceramic is mullite, and the resistivity is 10 9 Ω.m is an insulator, the bending strength is 17.8MPa, the open porosity is 47.7%, and the bulk density is 1.57g / cm 3, The average pore size is 5μm. Use gasoline as a solvent to prepare a 30wt% polycarbosilane solution, put the porous ceramic body into a container, and then place it in a vacuum-high pressure impregnation tank, screw the impregnation tank tightly, and evacuate to 5Pa. Pour the polycarbosilane solution into the funnel on the top of the dipping tank, turn on the knob to make the solution flow into the beaker, the porous ceramic body is completely immersed in the polycarbosilane solution, close the knob, keep the vacuum state for 5 minutes, stop vacuuming, and slowly Pour high-pressure nitrogen into the immersion tank, keep the pressure in the tank at 5MPa, and then keep it for 10 minutes, stop the ni...

Embodiment 2

[0028] The porous ceramic obtained in Example 1 adopts the same impregnation and sintering process, and is subjected to a second impregnation and high temperature treatment to obtain a mullite-bonded silicon carbide porous ceramic having a second impregnation to form an impregnated-cracked silicon carbide coating. After the second coating, the electrical resistivity of the porous ceramic is 6.93Ω.m, the flexural strength is 38.8MPa, the open porosity is 38.3%, and the bulk density is 1.79g / cm 3 .

[0029] It can be seen that multiple immersion-cracking can increase the flexural strength and bulk density of the porous ceramics after coating, reduce the resistivity and open porosity, and enhance the mechanical and electrical properties of the material.

Embodiment 3

[0031] The alumina foam ceramic was used as the coating substrate, and gasoline was used as the solvent to prepare a polycarbosilane solution with a mass percentage of 70 wt%. The pore size of the foamed alumina was 5 mm. The preparation process of the silicon carbide coating was as in Example 1. After immersion, drying, pyrolysis and sintering, alumina foam ceramics with silicon carbide coating on the pore walls are obtained.

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Abstract

The invention discloses a pore wall carborundum coating and making method of porous ceramic in the surface modifying domain of porous ceramic, which is characterized by the following: placing modified porous ceramic bulk in the immersing tank; extracting the tank into vacuum; injecting polycarborundum solution in the immersing tank; aerating high-temperature gas; making polycarborundum solution into porous ceramic channel under high pressure completely; forming even coating on the pore wall; drying; proceeding high-temperature disposal for immersing bulk in the argon gas; carving polycarborundum into carborundum; obtaining the product with different thicknesses after multiple immersing-cracking disposals.

Description

Technical field [0001] The invention relates to a pore wall silicon carbide coating of porous ceramics and a preparation method thereof, and belongs to the field of surface modification of porous ceramics. Background technique [0002] Porous ceramics generally refer to bulk inorganic non-metallic materials with pore diameters above 50 nm and sintered. Porous ceramics have the advantages of high temperature resistance, chemical corrosion resistance, low density, etc., and are widely used in fields such as heat insulation, catalysis, and filtration. Especially when used as a carrier for molten metal filtration, high-temperature exhaust purification, and high-temperature catalysis, porous ceramics exhibit advantages that other porous metal materials cannot compare. With the development of modern industry, the application of porous ceramics is constantly expanding, and the requirements for its performance are constantly improving. In practice, most of the widely used porous ceramics...

Claims

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Application Information

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IPC IPC(8): C04B41/85C04B38/00
Inventor 丁书强曾宇平朱云洲江东亮
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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