Implementation method of large-range continuous adjustment of porosity of amorphous precursor ceramic

A realization method and precursor technology, applied in the field of large-scale continuous adjustment of the porosity of amorphous precursor ceramics, can solve the problems of destroying the integrity of bulk ceramics, ceramic cracks, etc., and achieve continuous adjustment, low price, and easy-to-achieve effects

Inactive Publication Date: 2017-12-19
HARBIN INST OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This will lead to the generation of cracks in the ceramic, thereby destroying the integrity of the bulk ceramic

Method used

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  • Implementation method of large-range continuous adjustment of porosity of amorphous precursor ceramic
  • Implementation method of large-range continuous adjustment of porosity of amorphous precursor ceramic
  • Implementation method of large-range continuous adjustment of porosity of amorphous precursor ceramic

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specific Embodiment approach 1

[0032] Specific implementation mode 1: This implementation mode records a method for realizing large-scale continuous adjustment of the porosity of amorphous precursor ceramics. The specific steps of the method are as follows:

[0033] Step 1: Preparation of partially cross-linked precursor: put the polysilazane precursor PSN into a tube furnace, raise the temperature to 150-200°C at a rate of 1.5-5°C / min under the protection of argon, and keep it warm for 30 ~60min to obtain partially cross-linked PC-PSN;

[0034] Step 2: Preparation of fully cross-linked precursor: put the polysilazane precursor PSN into a tube furnace, raise the temperature to 350°C at a rate of 1.5~5°C / min under the protection of argon, and keep it warm for 3 hours. Obtain fully cross-linked CC-PSN;

[0035] Step 3: Flour making: Ball mill the PC-PSN cross-linked and cured in Step 1 and the CC-PSN cross-linked and cured in Step 2 respectively, and pass through a 200-mesh standard sieve for 3 to 5 times; ...

Embodiment 1

[0041] In this example, the proportion of CC-PSN in the precursor embryo body was 0 wt%, and the obtained precursor embryo body was completely dense. The pyrolyzed SiCN ceramics are also fully dense. Such as image 3 Shown is a photo of the microstructure of the SiCN ceramics prepared in this example.

[0042] The preparation method of fully dense SiCN ceramics is carried out as follows:

[0043] 1. Preparation of partially cross-linked precursors. Put the polysilazane precursor PSN into a tube furnace, raise it to 150-200°C at a rate of 1.5-5°C / min under the protection of argon, and keep it warm for 30-60 minutes to obtain a partially cross-linked PC- PSN;

[0044] Second, milling. Ball mill the cross-linked and solidified PC-PSN, and pass through a 200-mesh standard sieve for 3 to 5 times;

[0045] 3. Preparation of precursor bulk embryo bodies. The PC-PSN powder is hot-pressed. The whole hot-pressing process is carried out in a high vacuum environment (< 0.1Pa). The ...

Embodiment 2

[0048] In this example, the proportion of CC-PSN in the precursor embryo body was 25 wt%, and the precursor embryo body containing pores was obtained. The porosity of SiCN ceramics after pyrolysis is 4.82%. Such as Figure 4Shown is a photo of the microstructure of the SiCN ceramics prepared in this example.

[0049] The preparation method of 4.82% porosity SiCN ceramics is carried out as follows:

[0050] 1. Preparation of partially cross-linked precursors. Put the polysilazane precursor PSN into a tube furnace, raise it to 150-200°C at a rate of 1.5-5°C / min under the protection of argon, and keep it warm for 30-60 minutes to obtain a partially cross-linked PC- PSN;

[0051] 2. Preparation of fully cross-linked precursors. Put the polysilazane precursor PSN into a tube furnace, raise it to 350°C at a rate of 1.5~5°C / min under the protection of argon, and keep it warm for 3 hours to obtain a fully crosslinked CC-PSN;

[0052] Three, milling. Ball mill the cross-linked a...

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Abstract

The invention discloses an implementation method of large-range continuous adjustment of the porosity of amorphous precursor ceramic, and belongs to the technical field of ceramic material preparation processes. The method comprises the following steps: 1, preparation of part of a crosslinked precursor; 2, preparation of a complete crosslinked precursor; 3, powder preparation; 4, mixing of powder; 5, preparation of a precursor block-shaped green body; 6, preparation of SiCN block-shaped ceramic. The implementation method has the advantages that the implementation method is simple in theory, easy to implement and low in cost. The invention provides a method for continuously adjusting the porosity of the amorphous precursor ceramic within a relatively wide range; the porosity of the SiCN ceramic can be continuously adjusted from complete densification, and the maximum porosity can be up to 21.32 percent, so that the gas discharge and intensity requirements of the SiCN ceramic in various sizes can be met; solidified precursors are in a powder form, and are mixed more conveniently and uniformly. The method can be used for preparing completely densified precursor conversion ceramic, and also can realize the continuous adjustment of the porosity within the relatively large range.

Description

technical field [0001] The invention belongs to the technical field of ceramic material preparation technology, and in particular relates to a method for realizing large-scale continuous adjustment of the porosity of amorphous precursor ceramics. Background technique [0002] Precursor-converted ceramics (PDCs) have unique nanostructures such as covalent bonds and amorphous structures, which enable PDCs to exhibit a series of excellent high-temperature properties, including high specific strength and creep resistance, and excellent oxidation resistance. and high crystallization / decomposition stability. Therefore, precursor-converted ceramics have broad prospects for structural applications in extreme environments. [0003] It is very difficult to prepare bulk ceramics using precursor conversion methods. Because in the process of transforming the precursor into ceramics, a large amount of gas will be released. This will lead to the generation of cracks in the ceramic, ther...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/565C04B35/584C04B35/626C04B35/64
CPCC04B35/571C04B35/589C04B35/62615C04B35/64C04B2235/483C04B2235/6586C04B2235/96
Inventor 孟松鹤牛家宏张高铭李金平易法军许承海
Owner HARBIN INST OF TECH
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