Method for synthesizing high-density SiC ceramic at low temperature

A ceramic and dense technology, applied in the field of high-temperature ceramics, can solve problems such as the difficulty in effectively preparing high-density SiC ceramics, and achieve the effects of tight combination, short production cycle, and improved exhaust efficiency

Active Publication Date: 2022-04-15
ZHENGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to solve the problem that traditional PDC technology is difficult to effectively prepare high-density SiC ceramics, and to provide a method for synthesizing high-density SiC ceramics at low temperature, which can effectively suppress the pores and microcracks generated during the preparation process, and can be prepared under low temperature conditions. High Density SiC Ceramics

Method used

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  • Method for synthesizing high-density SiC ceramic at low temperature
  • Method for synthesizing high-density SiC ceramic at low temperature
  • Method for synthesizing high-density SiC ceramic at low temperature

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] In this embodiment, liquid polycarbosilane VHPCS purchased from the Institute of Chemistry, Chinese Academy of Sciences was used as the SiC polymer precursor.

[0034] The steps of low-temperature synthesis of high-density SiC ceramics provided in this example are as follows:

[0035] (1) Add DCP cross-linking agent to the SiC polymer precursor (the amount of DCP cross-linking agent added is 1.5wt.% of the weight of the SiC polymer precursor), cross-link at 70°C for 3 hours and put it into a vacuum drying oven (vacuum degree <0.09MPa) and cured at 150°C for 4h; after curing, the sample C / Si=1.184.

[0036] (2) The solidified product in step (1) is heated up to 1000° C. at a heating rate of 2° C. / min under an argon atmosphere, and kept at this temperature for 3 hours for pyrolysis treatment.

[0037] (3) Add sintering aids (which include 2.85wt.% Y 2 o 3 and 2.15wt.% Al 2 o 3 ), then according to the ball-to-material ratio of 5:1, the rotation speed of 250rpm, the p...

Embodiment 2

[0041] In this embodiment, liquid polycarbosilane VHPCS and divinylbenzene DVB purchased from the Institute of Chemistry, Chinese Academy of Sciences were used as SiC polymer precursors, and the mass ratio of VHPCS to DVB was 9:1.

[0042] The steps of low-temperature synthesis of high-density SiC ceramics provided in this example are as follows:

[0043] (1) Add DCP cross-linking agent to the SiC polymer precursor (the amount of DCP cross-linking agent added is 1.5wt.% of the weight of the SiC polymer precursor), cross-link at 70°C for 3 hours and put it into a vacuum drying oven (vacuum degree <0.09MPa) and cured at 150°C for 4h; the sample C / Si=1.552 after curing.

[0044] (2) The product cured in step (1) was heated up to 1400° C. at a heating rate of 2° C. / min under an argon atmosphere, and kept at this temperature for 3 hours for pyrolysis treatment.

[0045] (3) Add sintering aids (which include 2.85wt.% Y 2 o 3 and 2.15wt.% Al 2 o 3 ), then according to the ball-t...

Embodiment 3

[0049] In this embodiment, liquid polycarbosilane VHPCS and divinylbenzene DVB purchased from the Institute of Chemistry, Chinese Academy of Sciences were used as SiC polymer precursors, and the mass ratio of VHPCS to DVB was 8:2.

[0050] The steps of low-temperature synthesis of high-density SiC ceramics provided in this example are as follows:

[0051] (1) Add DCP cross-linking agent to the SiC polymer precursor (the amount of DCP cross-linking agent added is 1.5wt.% of the weight of the SiC polymer precursor), cross-link at 70°C for 3 hours and put it into a vacuum drying oven (vacuum degree <0.09MPa) and cured at 150°C for 4h; the sample C / Si=2.068 after curing.

[0052] (2) The product cured in step (1) was heated up to 1400° C. at a heating rate of 2° C. / min under an argon atmosphere, and kept at this temperature for 3 hours for pyrolysis treatment.

[0053] (3) Add sintering aids (which include 2.85wt.% Y 2 o 3 and 2.15wt.% Al 2 o 3 ), then according to the ball-t...

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Abstract

The invention discloses a method for synthesizing high-density SiC ceramic at low temperature, which mainly utilizes polycarbosilane as a precursor, and realizes close packing among silicon carbide grains by adopting a high-vacuum hot pressed sintering technology through cross-linking curing, high-temperature cracking and granulation to obtain high-density polycrystalline bulk ceramic. The volume density of the silicon carbide ceramic prepared by the method is close to theoretical density, and the porosity is close to zero.

Description

technical field [0001] The invention belongs to the technical field of high-temperature ceramics, and relates to SiC and high-power MESFETs SiC microwave devices used in anti-irradiation structural ceramics, in particular to a technology for synthesizing high-density SiC ceramics at low temperature. Background technique [0002] Silicon carbide ceramics have excellent properties such as good high-temperature mechanical properties, high hardness, wear resistance, oxidation resistance, corrosion resistance, small thermal expansion coefficient, and high thermal conductivity. Ideal material for extreme use environment parts. [0003] Due to its extremely high strength and thermal stability, silicon carbide ceramics have problems such as difficult sintering and difficult finishing. Polymer Derived Ceramics (PDCs) is a technology that converts silicon-based polymer precursors (precursors are a form of existence before obtaining the target product) into ceramics through cross-link...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/571C04B35/622C04B35/645
CPCY02E30/30
Inventor 刘雯林兆昀李丽杰王海龙张锐王一光
Owner ZHENGZHOU UNIV
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