Method for preparing porous silicon-nitride ceramic material

A silicon nitride ceramic and silicon nitride technology, applied in ceramic products, other household appliances, household appliances, etc., can solve the problems of high open porosity and low density, and achieve the effect of low density and high open porosity

Active Publication Date: 2013-06-19
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, how to prepare silicon nitride ceramic materials with high open porosity, low density and good strength has not been reported so far.

Method used

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  • Method for preparing porous silicon-nitride ceramic material
  • Method for preparing porous silicon-nitride ceramic material
  • Method for preparing porous silicon-nitride ceramic material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] a) Stir 8 g of starch and 75 g of deionized water vigorously at 70° C. for 10 minutes to make it absorb water and swell to obtain pregelatinized starch;

[0032] b) Transfer the prepared pregelatinized starch to the ball mill tank, then add 50g silicon nitride, 2.5g sintering aid yttrium oxide, 2g binder polyvinyl alcohol and 1g defoamer n-octanol to the ball mill In the tank, the ball mill is used to make the mixture uniform, and the mixed slurry is obtained;

[0033] c) Cast the mixed slurry prepared in step b), and then put it into a vacuum drying oven at room temperature below 100Pa to vacuum degas for 15 minutes to eliminate the air bubbles in the slurry; then seal the sample and put it in an oven at 85°C Internal solidification for 30 minutes, after cooling to room temperature, place the sample in a low-temperature refrigerator at -30°C for 24 hours to completely freeze the sample; quickly transfer the frozen sample to a freeze dryer at 5°C and 10Pa Freeze drying...

Embodiment 2

[0040] a) Stir 8 g of starch and 70 g of deionized water vigorously at 90° C. for 5 minutes to make it absorb water and swell to obtain pregelatinized starch;

[0041] b) Transfer the prepared pregelatinized starch to the ball mill tank, then add 50g silicon nitride, 2g sintering aid yttrium oxide, 2g binder polyvinyl alcohol and 1.2g defoamer n-octanol to the ball mill In the tank, the ball mill is used to make the mixture uniform, and the mixed slurry is obtained;

[0042] c) Cast the mixed slurry prepared in step b), and then put it into a vacuum drying oven at room temperature below 100Pa for 20 minutes of vacuum degassing to eliminate the air bubbles in the slurry; then seal the sample and put it in an oven at 70°C Solidify within 60 minutes. After cooling to room temperature, place the sample in a low-temperature refrigerator at -30°C for 24 hours to completely freeze the sample; Freeze-drying for 24 hours to sublimate the ice crystals in the frozen body to form a porou...

Embodiment 3

[0047] a) Stir 5 g of starch and 60 g of deionized water vigorously at 70° C. for 10 minutes to make it absorb water and swell to obtain pregelatinized starch;

[0048] b) the prepared pregelatinized starch is transferred to the ball mill tank, then 50g silicon nitride, 2.5g sintering aid yttrium oxide, 0g binder polyvinyl alcohol and 0.8g defoamer n-octanol are added to the In the ball milling tank, the ball milling makes the mixing uniform and makes the mixed slurry;

[0049] c) Cast the mixed slurry prepared in step b), and then put it into a vacuum drying oven at room temperature below 100Pa for 20 minutes of vacuum degassing to eliminate the air bubbles in the slurry; then seal the sample and put it in an oven at 70°C Solidify within 60 minutes. After cooling to room temperature, place the sample in a low-temperature refrigerator at -30°C for 24 hours to completely freeze the sample; Freeze-drying for 24 hours to sublimate the ice crystals in the frozen body to form a po...

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Abstract

The invention discloses a method for preparing a porous silicon-nitride ceramic material, which comprises the following steps of: stirring starch and water at the temperature of 40-90 DEG C to prepare pre-gelatinized starch; adding silicon nitride, a sintering aid, a bonding agent and a defoaming agent to the pre-gelatinized starch, and uniformly mixing through ball milling to prepare a mixed slurry; molding the mixed slurry through casting, and carrying gout degassing, curing, complete sample-freezing and freeze-drying processing to prepare a porous silicon-nitride ceramic blank body; removing organic volatile substances in the porous silicon-nitride ceramic blank body through heating; and sintering, and cooling a sample along with a furnace after sintering. The silicon-nitride ceramic material prepared by utilizing the preparation method disclosed by the invention has high open porosity (which can reach 60-90 percent) and low density (0.32-1.28g / <cm>3), the bending strength can be regulated within the range of 5-140MPa, and the application-performance requirements of materials in the fields of high-temperature gas and liquid filtration, purification and separation, chemical catalytic carriers and the like can be met.

Description

technical field [0001] The present invention relates to a method for preparing a porous silicon nitride ceramic material, in particular to a method for preparing a silicon nitride ceramic material with high open porosity, low density and good strength by starch solidification combined with freeze-drying technology , belongs to the technical field of ceramic material preparation. Background technique [0002] Due to the characteristics of light weight, high temperature resistance, and corrosion resistance, porous silicon nitride ceramic materials have broad application prospects in the fields of high-temperature gas filtration, sensors, catalyst supports, and separation membranes. Therefore, the preparation method of porous silicon nitride ceramics has become One of the current research hotspots. For example: Chinese patent literature CN1473140A discloses a kind of metal Si powder as raw material, Sm 2 o 3 、Er 2 o 3 , Yb 2 o 3 etc. are sintering aids, a method for prep...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B38/00C04B35/584C04B35/622
Inventor 曾宇平姚冬旭
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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