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Method for preparing silicon nitride foam ceramic

A technology of foam ceramics and silicon nitride, which is applied in the field of foam ceramics, can solve the problems of pore distribution uniformity and pore size, low strength, large pore size of silicon nitride foam ceramics, etc., and achieve reduced surface tension and high bending strength , The effect of uniform distribution of foam pores

Active Publication Date: 2013-07-31
AEROSPACE INST OF ADVANCED MATERIALS & PROCESSING TECH
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  • Abstract
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  • Application Information

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Problems solved by technology

Geng Haoran of Shandong University, Pu Xipeng of Liaocheng University, and Zhang Wu of Ningbo Ordnance Science Research Institute prepared silicon nitride foam ceramics by organic foam impregnation process. In the process of slurry configuration, silica sol was used as binder, carboxymethyl fiber CMC is used as a slurry rheology modifier to improve the performance of foam slurry. The prepared silicon nitride foam ceramics have large pore size (≥200μm), low strength, and difficult to control the uniformity of pore distribution and pore size.

Method used

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  • Method for preparing silicon nitride foam ceramic
  • Method for preparing silicon nitride foam ceramic
  • Method for preparing silicon nitride foam ceramic

Examples

Experimental program
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Embodiment 1

[0031] Take by weighing 40g silicon nitride powder, add 2.4g sintering aid (0.8g aluminum oxide and 1.6g yttrium oxide), the dispersant of 0.4g, 6g carboxymethylcellulose (CMC) solution (carboxymethylcellulose (CMC ) aqueous solution concentration is 4%) and 0.8g foaming agent, add 60g deionized water to form a mixture, utilize concentrated ammonia water to adjust the pH value of the mixture to be 10, and make a slurry after ball milling for 12h; the slurry after ball milling continues at a high speed Stir for 20 minutes to foam, add an appropriate amount of initiator and catalyst, stir for 5 minutes, injection mold, solidify and form, then dry the green body (in the air) and debinding (burn out organic matter); the green body after debinding is in a nitrogen atmosphere ( Atmospheric pressure) sintering, the sintering process is carried out in stages: the heating rate below 800°C is 15°C / min, the atmosphere is vacuum; the heating rate above 800°C is 10°C / min to the sintering te...

Embodiment 2

[0038] Weigh 40g silicon nitride powder, add 2.4g sintering aid (0.8g aluminum oxide and 1.6g yttrium oxide), 0.4g dispersant, add 4g carboxymethylcellulose (CMC) solution (carboxymethylcellulose ( CMC) solution concentration is 3%) and the foaming agent of 0.8g, add 60g deionized water to form mixed material, utilize concentrated ammonia water to adjust mixed material pH value to be 10, make slurry after ball milling 12h; The slurry after ball milling continues Stir at high speed for 20 minutes to foam, add an appropriate amount of initiator and catalyst, stir for 5 minutes, injection mold, solidify and form, then dry the green body (in the air) and debinding (burn out organic matter); the green body after debinding is in a nitrogen atmosphere (Atmospheric pressure) sintering, the sintering process is carried out in stages: the heating rate below 800 ° C is 15 ° C / min, the atmosphere is vacuum; the heating rate above 800 ° C is 10 ° C / min to the sintering temperature, the ...

Embodiment 3

[0044] Weigh 40g silicon nitride powder, add 2.4g sintering aid (0.8g aluminum oxide and 1.6g yttrium oxide), 0.4g dispersant, add 8g carboxymethylcellulose (CMC) solution (carboxymethylcellulose ( CMC) solution concentration is 3%) and the foaming agent of 0.8g, add 60g deionized water to form mixed material, utilize concentrated ammonia water to adjust mixed material pH value to be 10, make slurry after ball milling 12h; The slurry after ball milling continues Stir at high speed for 20 minutes to foam, add an appropriate amount of initiator and catalyst, stir for 5 minutes, injection mold, solidify and form, then dry the green body (in the air) and debinding (burn out organic matter); the green body after debinding is in a nitrogen atmosphere (Atmospheric pressure) sintering, the sintering process is carried out in stages: the heating rate below 800 ° C is 15 ° C / min, the atmosphere is vacuum; the heating rate above 800 ° C is 10 ° C / min to the sintering temperature, the ...

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Abstract

The invention provides a method for preparing silicon nitride foam ceramic. The method comprises raw material proportioning, raw material blending, pH adjustment, foaming molding curing and sintering. Through utilization of a carboxymethyl cellulose aqueous solution as a binder, foam system surface tension is reduced; slurry viscoelasticity is improved; foam slurry fluidity and stability are improved; a shrinking percentage in foam drying is low; a yield is high; foam stability is good; foam pore sizes are small; sintered body mechanical properties are excellent; and foam pore distribution is uniform. Through a direct mechanical stirring foaming technology, the silicon nitride foam ceramic having good foam stability and excellent mechanical properties is prepared, wherein under the premise of equal porosity, compared with silicon nitride foam ceramic prepared by the prior art, the silicon nitride foam ceramic provided by the invention has bending strength improved by 10 to 30%, and the silicon nitride foam ceramic has porosity more than 60%.

Description

technical field [0001] The invention relates to a method for preparing silicon nitride foam ceramics, which belongs to the technical field of foam ceramics. Background technique [0002] Foam ceramics is the third generation of porous ceramics developed after porous ceramics and honeycomb ceramics. It is a porous ceramic product with a three-dimensional network skeleton and interconnected or closed pore structure. In addition to excellent properties such as high temperature resistance and corrosion resistance, foam ceramics also have low density (0.25-0.65g / cm 3 ), high porosity (60% ~ 90%), large specific surface area (10m 2 / g) and strong self-disturbance to fluids, it can be used as a high-performance green environmental protection material, and has been widely used in purification and separation, chemical catalyst carriers, advanced insulation materials and sensor materials, and has attracted great attention from material scientists. [0003] The preparation methods of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/02C04B35/584C04B35/622
Inventor 余娟丽杨金龙吕毅张天翔赵英民曾庆川王涛浑丙利余悠然
Owner AEROSPACE INST OF ADVANCED MATERIALS & PROCESSING TECH
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