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Preparation method of silicon carbide ceramic foam

A silicon carbide ceramic and a technology for preparation steps, applied in ceramic products, applications, household appliances, etc., can solve the problems of uncontrollable porosity, uneven density distribution of sample components, low mechanical properties, etc., and achieve controllable morphology and pore size. Good size and overall effect

Active Publication Date: 2017-04-19
CENTRAL SOUTH UNIVERSITY OF FORESTRY AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the traditional silicon carbide foam manufacturing process - the organic foam impregnation method, due to the gravitational settlement of the slurry during the preparation process, causes uneven density distribution of the sample components, uncontrollable porosity, and low mechanical properties.

Method used

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  • Preparation method of silicon carbide ceramic foam
  • Preparation method of silicon carbide ceramic foam
  • Preparation method of silicon carbide ceramic foam

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Put the mixture of mesophase pitch powder and polyacrylonitrile-based nano-carbon fiber ground into 100 meshes into the FDK-autoclave. Raise the temperature to 330°C at a heating rate of 2°C / min, and hold for 2 hours; heat to 430°C at a heating rate of 2°C / min, hold for 2 hours, and naturally cool to room temperature to obtain asphalt foam. The whole process starts circulation cooling water. At this point, the pressure inside the autoclave is the final foaming pressure; then the asphalt foam is heated to 850° C. in a carbonization furnace under a nitrogen protection environment and kept for 1 hour to obtain a carbon foam template; according to the carbon foam template and The amount of silicon powder is 1:1, weigh the silicon powder and sprinkle it on the outer surface of the top of the prepared carbon foam template, raise the temperature in the graphitization furnace at 4°C / min to 1900°C, and keep it for 2 hours to obtain silicon carbide ceramic foam . Electron micro...

Embodiment 2

[0038] Put the mixture of mesophase pitch powder and polyacrylonitrile-based nano-carbon fiber ground into 100 meshes into the autoclave, first fill the autoclave with nitrogen or inert gas to replace the air in the autoclave, open the release valve, and discharge the autoclave Air; then close the vent valve, fill the autoclave with nitrogen or inert gas until the pressure in the autoclave is not lower than 4MPa, and let it stand for 30 minutes until the autoclave does not leak, and the leak test is qualified;

[0039] Then adjust the FDK-autoclave controller, first raise the temperature to 330°C at a heating rate of 2°C / min, and keep it warm for 2 hours; then heat it to 430°C at a heating rate of 2°C / min, keep it warm for 2 hours, and cool to room temperature naturally , to get asphalt foam, and the whole process starts to circulate cooling water. Now, the pressure in the autoclave is the final foaming pressure;

[0040] Then, the asphalt foam is heated to 850° C. in a carbo...

Embodiment 3

[0043]The mesophase pitch powder ground into 100 meshes and polyacrylonitrile-based nano-carbon fibers are mixed according to the weight ratio of 20:1 and then loaded into the FDK-autoclave. First, nitrogen or inert gas is filled into the autoclave to replace the air in the autoclave. Open the air release valve to discharge the air in the kettle; then close the air release valve, fill the autoclave with nitrogen or inert gas until the pressure in the autoclave is not lower than 4MPa, and leave it for 30 minutes until there is no air leakage in the autoclave. Gas leak test is qualified;

[0044] Then adjust the FDK-autoclave controller, first raise the temperature to 330°C at a heating rate of 2°C / min, and keep it warm for 2 hours; then heat it to 430°C at a heating rate of 2°C / min, keep it warm for 2 hours, and cool to room temperature naturally , to get asphalt foam, and the whole process starts to circulate cooling water. Now, the pressure in the autoclave is the final foam...

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Abstract

The invention relates to a preparation method of a composite material with good adsorption performance and high-temperature filtering performance, in particular to a preparation method for in-situ preparation of silicon carbide ceramic foam by a template method. The method comprises the main preparation steps of charging a mixture raw material of intermediate phase asphalt powder and polyacrylonitrile-based nanometer carbon fibers into an autoclave; ensuring the qualification of air leakage detection of the autoclave after the air in the autoclave is thoroughly exhausted at first; preparing asphalt foam; preparing a carbon foam template; and preparing the silicon carbide ceramic foam, and the like. The method has the beneficial effects that the preparation process is simple; the process parameters can be easily controlled; the intensity of the composite material is high; the integrality is high; the pores are uniform; and the problem that the pore size and the aperture ratio of the silicon carbide ceramic foam cannot be controlled is solved.

Description

technical field [0001] The invention relates to a method for preparing an adsorption and high-temperature filter composite material, in particular to a method for preparing silicon carbide ceramic foam in situ by a template method. Background technique [0002] Silicon carbide ceramic foam has many excellent properties, such as high porosity, good thermal shock resistance, good oxidation resistance at high temperature, and high specific strength, making it widely used in the fields of fine chemical industry, energy saving and environmental protection . Silicon carbide ceramic foam can be used in high temperature gas purifiers, solid particle filters emitted by diesel engines, molten metal filters and other devices that require high temperature resistance and chemical corrosion resistance. However, the traditional silicon carbide foam manufacturing process - organic foam impregnation method, due to the gravitational sedimentation of the slurry during the preparation process,...

Claims

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Application Information

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IPC IPC(8): C04B38/10C04B35/565
CPCC04B35/573C04B38/10C04B2235/428C04B2235/48C04B2235/5248C04B35/571
Inventor 李万千张红波陈贺
Owner CENTRAL SOUTH UNIVERSITY OF FORESTRY AND TECHNOLOGY