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Porous silicon nitride ceramic and preparation method thereof

A technology of silicon nitride ceramics and silicon nitride, which is applied in the field of ceramic materials, can solve the problems of low porosity and poor pore distribution uniformity, and achieve good pore uniformity, good pore distribution uniformity, and high porosity. Effect

Active Publication Date: 2018-09-28
江苏东浦精细陶瓷科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the porous ceramics prepared by adding pore-forming agents in the prior art usually have problems such as poor pore distribution uniformity and low porosity.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0019] The present invention provides a kind of preparation method of porous silicon nitride ceramics, it comprises:

[0020] S1. The raw materials are evenly mixed and pressed into a biscuit.

[0021] S2. Sintering the green body to obtain a green body.

[0022] S3, soaking the green body in hydrochloric acid for treatment.

[0023] In the S1 step, the raw materials of the porous silicon nitride ceramics include in parts by weight:

[0024] 90-100 parts by weight of α-silicon nitride, 4-8 parts by weight of β-silicon nitride, 1-2 parts by weight of metal oxides, 2-4 parts by weight of rare earth oxides, 8-12 parts by weight of Calcium carbonate and the calcium chloride of 15-20 parts by weight.

[0025] Optionally, the raw materials of the porous silicon nitride ceramics include by weight parts:

[0026] 90-95 parts by weight of α-silicon nitride, 6-8 parts by weight of β-silicon nitride, 1-2 parts by weight of metal oxides, 3-4 parts by weight of rare earth oxides, 10-12...

Embodiment 1

[0050] A preparation method of porous silicon nitride ceramics, comprising:

[0051] S1. Disperse 95 kg of α-silicon nitride, 6 kg of β-silicon nitride, 1 kg of alumina, and 3 kg of cerium oxide in 200 kg of absolute ethanol, and use silicon nitride balls in a ball mill to mill for 3 hours at a speed of 500 r / min , to get the first slurry. The first slurry was mixed with 10kg of calcium carbonate and 18g of calcium chloride, and stirred at a speed of 600r / min for 20min. Then dry it at 130°C to obtain a ceramic powder with an organic solvent content of 20 wt%. The ceramic powder is subjected to cold isostatic pressing with a pressure of 220 MPa. Get the biscuit.

[0052] S2. Carry out one-stage sintering of the green body under the conditions of nitrogen pressure of 2 MPa and temperature of 1350-1400° C. for 2.5 hours. Raise the nitrogen pressure to 5 MPa, raise the temperature to 1700-1850° C. to carry out two-stage sintering for 7 hours. Get the green body.

[0053] S3....

Embodiment 2

[0057] A preparation method of porous silicon nitride ceramics, comprising:

[0058] S1. Disperse 100kg of α-silicon nitride, 8kg of β-silicon nitride, 1kg of magnesium oxide, 1kg of titanium oxide, and 2kg of lanthanum oxide in 270kg of acetone, and use silicon nitride grinding balls in the ball mill at a speed of 400r / min Ball milled for 3.5 hours to obtain the first slurry. The first slurry was mixed with 12kg of calcium carbonate and 15g of calcium chloride, and stirred at a speed of 700r / min for 10min. Then it was dried at 150° C. to obtain a ceramic powder with an organic solvent content of 16 wt %. The ceramic powder is subjected to cold isostatic pressing with a pressure of 180 MPa. Get the biscuit.

[0059] S2. Carry out one-stage sintering of the green body under the conditions of nitrogen pressure of 1 MPa and temperature of 1350-1400° C. for 3 hours. Raise the nitrogen pressure to 8 MPa and raise the temperature to 1700-1850°C to carry out two-stage sintering f...

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PUM

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Abstract

The invention provides a porous silicon nitride ceramic and a preparation method thereof, and belongs to the field of ceramic materials. The method comprises the steps that by weight, 90-100 parts ofalpha-silicon nitride, 4-8 parts of beta-silicon nitride, 1-2 parts of metal oxide, 2-4 parts of rare earth oxide, 8-12 parts of calcium carbonate and 15-20 parts of calcium chloride are uniformly mixed to obtain ceramic powder, and the ceramic powder is pressed into a green body; the green body is sintered to obtain a body; the body is immersed in hydrochloric acid. The preparation method is simple, and the obtained porous silicon nitride ceramic has the advantages of good uniformity of pore distribution and high porosity.

Description

technical field [0001] The invention relates to the field of ceramic materials, and in particular to a porous silicon nitride ceramic and a preparation method thereof. Background technique [0002] Due to the advantages of high specific strength, high specific modulus, high temperature resistance, oxidation resistance and wear resistance, silicon nitride ceramics have special use value in the working environment of high temperature, high speed and strong corrosive medium. It has strong thermal shock ability, low dielectric constant and dielectric loss, and good high-frequency electromagnetic wave transmission performance, which makes it have a wide application prospect. [0003] In addition to the common characteristics of silicon nitride ceramics, silicon nitride porous ceramics also have small bulk density, large specific surface area and unique physical surface characteristics, have selective permeability to liquid and gas media, and have energy absorption and damping cha...

Claims

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Application Information

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IPC IPC(8): C04B38/00C04B35/584C04B35/622C04B35/64
CPCC04B35/584C04B35/622C04B35/64C04B38/0025C04B2235/3206C04B2235/3217C04B2235/3225C04B2235/3227C04B2235/3229C04B2235/3232C04B2235/3244
Inventor 颜井意蔡安澜杜建周高巍
Owner 江苏东浦精细陶瓷科技股份有限公司