A kind of preparation method of silicon carbide nanowire toughened silicon carbide ceramics in situ

A silicon carbide nanowire and nanowire toughening technology, which is applied in the field of preparation of silicon carbide ceramics, can solve the problems of complex process, high cost, and difficulty in controlling the dispersion of nanowires, and achieve simple and controllable preparation process, low cost, Effect of reducing cracking tendency

Active Publication Date: 2021-04-09
BEIHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In order to solve the problem of strengthening and toughening SiC ceramics, in order to overcome the disadvantages of difficult control of nanowire dispersion, high cost, and complicated process in the process of preparing SiC nanowire toughened ceramics by existing methods, at the same time realize the in-situ growth of SiC nanowires and the synthesis of dense SiC ceramics, the present invention proposes a preparation method for in-situ reaction growth of SiC nanowires to toughen SiC ceramics, the specific technical scheme is as follows:

Method used

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  • A kind of preparation method of silicon carbide nanowire toughened silicon carbide ceramics in situ
  • A kind of preparation method of silicon carbide nanowire toughened silicon carbide ceramics in situ
  • A kind of preparation method of silicon carbide nanowire toughened silicon carbide ceramics in situ

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Embodiment 1

[0042] (1) Take 50 g of PCS raw material, place it in an agate mortar and grind it into a powder with a particle size of 200 mesh, then place it in a box furnace, and oxidize it in an air environment at 300 ° C for 3 hours;

[0043] (2) Weigh 0.2g of ferrocene, 19.8g of pre-oxidized PCS powder and 20g of xylene to form a mixed solution, stir it magnetically for 1 hour, dry it, and grind it into a precursor powder with a particle size of 200 mesh for later use;

[0044] (3) Take by weighing 20g of pre-oxidized PCS powder and 80g of xylene respectively to form a mixed solution, stir magnetically for 2h, and mix well for subsequent use;

[0045] (4) Take 0.3g of the precursor powder prepared in step (2) and pour it into a stainless steel cold press mold and spread it evenly, use a pressure of 15MPa for 30s, and press it into a precursor green body at room temperature;

[0046] (5) Wrap the precursor green body obtained in step (4) with graphite paper, embed it in activated carbon p...

Embodiment 2

[0052] (1) Take 50 g of PCS raw material, place it in an agate mortar and grind it into a powder with a particle size of 200 mesh, then place it in a box furnace, and oxidize it in an air environment at 300 ° C for 3 hours;

[0053] (2) Weigh 0.6g of ferrocene, 19.4g of pre-oxidized PCS powder and 20g of xylene to form a mixed solution, stir it with magnetic force for 1 hour, dry it, and grind it into a precursor powder with a particle size of 200 mesh for later use;

[0054] (3) Take by weighing 30g of pre-oxidized PCS powder and 70g of xylene respectively to form a mixed solution, magnetically stir for 2h, and mix uniformly for subsequent use;

[0055] (4) Take 0.5g of the precursor powder prepared in step (2) and pour it into a stainless steel cold press mold and spread it evenly, use a pressure of 15MPa for 30s, and press it into a precursor green body at room temperature;

[0056] (5) The activated carbon powder is loaded into the corundum crucible to half of its depth, t...

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Abstract

The invention discloses a preparation method of in-situ silicon carbide nanowire toughened silicon carbide ceramics, which utilizes the pyrolysis reaction of polycarbosilane to in-situ grow silicon carbide inside and on the surface while synthesizing silicon carbide bulk ceramics Nanowires, through further precursor impregnation and pyrolysis (PIP) densification process, prepare high-density silicon carbide nanowire toughened silicon carbide ceramics, with the help of the toughening effect of nanowires, reduce the cracking tendency of silicon carbide ceramics and improve its Thermal shock resistance.

Description

technical field [0001] The invention belongs to the technical field of preparing silicon carbide (SiC) ceramics, and in particular relates to a method for preparing SiC nanowire toughened SiC ceramics by in-situ reaction growth. Background technique [0002] SiC ceramics exhibit excellent high-temperature mechanical properties, and have great application potential as aerospace thermal structural components. However, due to the inherent brittleness of SiC ceramics, it is very easy to crack and fail in practical applications. At present, the inherent brittleness has become a bottleneck restricting the wide application of SiC ceramics. In response to this problem, researchers at home and abroad have proposed many solutions. Introducing a diffusely distributed nanoscale toughening phase during the preparation of SiC ceramics is an effective means to improve its toughness. Compared with bulk SiC, SiC nanowires have more excellent mechanical properties, and its unique high stren...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/80C04B35/565C04B35/84C04B35/622C04B35/66
CPCC04B35/571C04B35/622C04B35/66C04B2235/9607
Inventor 李露孙冰马朝利李志坚徐昊
Owner BEIHANG UNIV
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