A kind of synthesis method of ultra-high temperature resistant zrc/sic composite ceramic precursor

A technology of multiphase ceramics and synthesis method, which is applied in the field of synthesis of ultra-high temperature resistant ZrC/SiC multiphase ceramic precursors, can solve the problems of low zirconium content in products, poor ceramic performance, low utilization rate of zirconium sources, etc., to achieve purity High, low oxygen content, high zirconium utilization effect

Active Publication Date: 2017-09-26
NAT UNIV OF DEFENSE TECH
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  • Abstract
  • Description
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Problems solved by technology

[0008] In summary, most of the currently existing methods require harsh reaction conditions of high temperature or (and) high pressure or electrification, the process is complicated, and the controllability is poor.
What's more unfavorable is that in the existing technology of synthesizing the precursor of ZrC / SiC composite phase ceramics, all adopt polymerized polycarbosilane as raw material, which has a certain degree of polymerization, and is made into ZrC / SiC composite phase ceramics. The homogeneity and chain length of the precursor are limited by the raw material polycarbosilane, and the zirconium-containing reagent only plays a role in modifying the polycarbosilane, and the utilization rate of the zirconium source is low, resulting in a product with low zirconium content and poor uniformity. Poor performance of ceramics

Method used

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  • A kind of synthesis method of ultra-high temperature resistant zrc/sic composite ceramic precursor
  • A kind of synthesis method of ultra-high temperature resistant zrc/sic composite ceramic precursor
  • A kind of synthesis method of ultra-high temperature resistant zrc/sic composite ceramic precursor

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Experimental program
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Effect test

Embodiment 1

[0041] This embodiment includes the following steps:

[0042] (1) Put 5 g (17.1 mmol) of zirconocene dichloride in the flask; evacuate the reaction system, then replace the gas in the reaction system with nitrogen to normal pressure, repeat 3 times; stir, add 60 mL of anhydrous Oxygen in n-hexane was dissolved, 3.8 mL (25.6 mmol) of TMEDA was added, and 79.2 mmol of n-butyllithium (33 mL of commercially available 2.4 mol / L n-butyllithium in n-hexane solution) was added dropwise, and the reaction was carried out for 12 hours. Wash and vacuum dry to obtain 8.1 g of active dibutyl zirconocene dilithium salt (component a);

[0043] (2) Under the protection of nitrogen atmosphere, dissolve 5 g (11.8 mmol) of component a obtained in step (1) in 50 mL of anhydrous and oxygen-free tetrahydrofuran to obtain solution I; add 2.5 ml (13.1 mmol) of methyltrichlorosilane to Dissolve in 30 mL of anhydrous and oxygen-free tetrahydrofuran to obtain solution II; drop solution II into solution ...

Embodiment 2

[0051] This embodiment includes the following steps:

[0052] (1) Put 10 g (34.2 mmol) of zirconocene dichloride in the flask; evacuate the reaction system, and then replace the gas in the reaction system with argon to normal pressure, repeat 3 times; stir, add 80 mL of anhydrous Dissolve in anaerobic tetrahydrofuran, add 7.6 mL (51.3 mmol) of TMEDA, and dropwise add 158.4 mmol of n-butyllithium (66 mL of commercially available 2.4 mol / L n-butyllithium in n-hexane solution), react for 7 hours, and filter under reduced pressure , washed, and dried under vacuum to obtain 18.6 g of active dibutyl zirconocene dilithium salt (component a);

[0053] (2) Under the protection of nitrogen atmosphere, dissolve 5 g (11.8 mmol) of the component a obtained in step (1) in 50 mL of anhydrous and oxygen-free tetrahydrofuran to obtain a solution I; Chlorosilane was dissolved in 30 mL of anhydrous and oxygen-free tetrahydrofuran to obtain solution II of halosilane monomer dimethyldichlorosilan...

Embodiment 3

[0057] This embodiment includes the following steps:

[0058] (1) Place 10 g (34.2 mmol) of zirconocene dichloride in a flask; evacuate the reaction system, then replace the gas in the reaction system with nitrogen to normal pressure, repeat 3 times; stir, add 80 mL of anhydrous Oxytetrahydrofuran was dissolved, 7.6 mL (51.3 mmol) of TMEDA was added, and 144 mmol of methyllithium (90 mL of a commercially available 1.6 mol / L methyllithium solution in ether) was added dropwise, and the reaction was carried out for 10 hours, filtered under reduced pressure, washed, and dried in vacuo , to obtain active dimethyl zirconocene dilithium salt (component a);

[0059] (2) Under the protection of nitrogen atmosphere, dissolve 5 g (15.8 mmol) of the component a obtained in step (1) in 50 mL of anhydrous and oxygen-free tetrahydrofuran to obtain a solution I; 2.3 ml (16.7 mmol) of dimethyl dimethyl After the chlorosilane was dissolved in 30 mL of anhydrous and oxygen-free tetrahydrofuran,...

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Abstract

A method for synthesizing an ultra-high temperature resistant ZrC / SiC composite ceramic precursor, comprising the following steps: (1) under the protection of an inert gas atmosphere, dissolving zirconocene dichloride in an organic solvent, stirring and adding an organolithium compound, a compound (2) Under the protection of an inert gas atmosphere, add the halosilane monomer to the active component a obtained in the stirring step (1), and a polymerization reaction occurs to obtain component b, drop The reaction is terminated by adding a terminator, concentrated by filtration, purified by precipitation, and dried in vacuum to obtain the precursor of ultra-high temperature resistant ZrC / SiC multiphase ceramics. The present invention starts from the monomer and polymerizes step by step, the product chain length is controllable and uniform, and ZrC / SiC multi-phase ceramics with high purity and good uniformity can be further prepared; the two-step process is simple and can be reacted at normal temperature and pressure , the conditions are easy to control, the raw materials are easy to obtain, and are suitable for large-scale production.

Description

technical field [0001] The invention relates to a method for synthesizing a precursor of ultra-high temperature resistant ZrC / SiC multiphase ceramics, in particular to a method for synthesizing a precursor of ZrC / SiC multiphase ceramics with organolithium reagent, zirconocene dichloride and halosilane. method. Background technique [0002] With the rapid development of science and technology, high-precision weapons and equipment such as aerospace vehicles, missiles, and high-temperature ramjets characterized by hypersonic speed have become a new high ground for scientific and technological competition among countries. There is an urgent need for ultra-high temperature resistant materials. ZrC / SiC multiphase ceramics have attracted great attention due to their excellent high temperature resistance and thermal shock resistance. [0003] The organic precursor conversion method is an important method for the preparation of ultra-high temperature resistant ZrC / SiC composite cer...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G77/60C04B35/56
Inventor 苟燕子张千策王军王浩简科谢征芳邵长伟
Owner NAT UNIV OF DEFENSE TECH
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