SiHfOC ceramic material and preparation method thereof

A ceramic material and gel technology, applied in the field of SiHfOC ceramic materials and their preparation, can solve the problems of performance degradation, limit the high temperature resistance performance and high temperature application of SiOC ceramics, etc. The effect of high temperature resistance

Pending Publication Date: 2020-10-09
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the metastable ternary structure of SiOC ceramics, rearrangement, phase separation and carbothermal reduction reactions will occur at high temperatures, resulting in a decrease in performance, which limits the high temperature resistance and high temperature applications of SiOC ceramics.

Method used

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  • SiHfOC ceramic material and preparation method thereof
  • SiHfOC ceramic material and preparation method thereof
  • SiHfOC ceramic material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A preparation method of SiHfOC ceramic material, comprising the following steps:

[0025] 1) Preparation of hafnium sol:

[0026] At room temperature, take 6g HfOCl 2 ·8H 2 O was dissolved in 20g ethanol, after adding 6g acetylacetone therein, magnetically stirred for 20min to obtain hafnium sol;

[0027] Take 30g of MK silicone resin and dissolve it in 30g of ethanol to prepare a 50% MK silicone resin ethanol solution;

[0028] 2) Preparation of gel: Mix the prepared MK silicone resin ethanol solution and hafnium sol, dry at room temperature and let stand for 9 hours to form a gel;

[0029] 3) Preparing the precursor: heating the obtained gel to 150° C. in a drying oven, and drying for 20 hours to obtain a hafnium-modified polysiloxane precursor;

[0030] 4) Preparation of SiHfOC ceramic material by precursor conversion method: the obtained hafnium-modified polysiloxane precursor was placed in an inert gas atmosphere at 1000°C for cracking, and the cracking time wa...

Embodiment 2

[0034] A preparation method of SiHfOC ceramic material, comprising the following steps:

[0035] 1) Preparation of hafnium sol:

[0036] At room temperature, 4g HfOCl 2 ·8H 2 O was dissolved in 15g ethanol, after adding 1g acetylacetone therein, magnetically stirred for 10min to obtain hafnium sol;

[0037] Dissolve 20g of silicone resin in 30g of absolute ethanol to prepare a 40% MK silicone resin ethanol solution;

[0038] 2) Gel preparation: the prepared MK silicone resin ethanol solution and hafnium sol were mixed, dried at room temperature and allowed to stand for 17 hours to form a gel;

[0039] 3) Preparing the precursor: heating the obtained gel to 220° C. in the air, and drying for 4 hours to obtain a hafnium-modified polysiloxane precursor;

[0040] 4) Preparation of SiHfOC ceramic material by precursor conversion method: the obtained hafnium-modified polysiloxane precursor was placed in a high-temperature inert gas atmosphere at 1200°C for pyrolysis for 30 minut...

Embodiment 3

[0043] A preparation method of SiHfOC ceramic material, comprising the following steps:

[0044] 1) Preparation of hafnium sol:

[0045] At room temperature, 8g HfOCl 2 ·8H 2 O was dissolved in 20g ethanol, after adding 8g acetylacetone therein, magnetically stirred for 30min to obtain hafnium sol;

[0046] Dissolve 40g of silicone resin in 20g of absolute ethanol to prepare a 60% MK silicone resin ethanol solution;

[0047] 2) Preparation of gel: The prepared MK silicone resin ethanol solution and hafnium sol were mixed, dried at room temperature and left to stand for 12 hours to form a gel;

[0048] 3) Preparing the precursor: heating the obtained gel to 250° C. in air, and drying for 10 hours to obtain a hafnium-modified polysiloxane precursor;

[0049] 4) Preparation of SiHfOC ceramic material by precursor conversion method: the obtained hafnium-modified polysiloxane precursor was placed in a high-temperature inert gas atmosphere at 1100 ° C for 120 minutes to obtain t...

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Abstract

The invention discloses a SiHfOC ceramic material and a preparation method thereof. Silicon resin with small molecular weight is used as a raw material, an inorganic hafnium salt is introduced by a sol-gel method to form an Hf-containing PSO precursor, and the SiHfOC ceramic is obtained by precursor crosslinking and high-temperature cracking. In the process, adopted silicon resin is methyl siliconresin (MK) dissolved in ethanol, the inorganic hafnium salt is hafnium oxychloride (HfOCl2.8H2O) dissolved in ethanol, a chelating agent is added, sol is prepared through mixing, and gel is formed after standing. According to the preparation method of the SiHfOC ceramic, the high-temperature resistance of the SiOC ceramic is improved, and the preparation method has the advantages of low cost, good high-temperature resistance, simple process, low equipment requirement and the like.

Description

technical field [0001] The invention belongs to the technical field of high-temperature-resistant ceramic materials, and in particular relates to a SiHfOC ceramic material and a preparation method thereof. Background technique [0002] SiOC ceramic is a cost-effective lightweight high-temperature resistant structural material with low density (<2.2g / cm 3 ), good high temperature stability, chemical stability and other advantages. It has good application value in aerospace field. The mechanical properties, high temperature stability, and chemical stability of SiOC ceramic materials are significantly better than those of traditional SiO 2 materials; at the same time, SiOC ceramic materials can also have a variety of molecular structures or components, so that they have functional properties such as luminescence and dielectric properties, and can be used as lightweight high-temperature structural materials, optical materials, electronic packaging ceramic substrate material...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/56C04B35/624
CPCC04B35/5603C04B35/624C04B2235/444C04B2235/483C04B2235/3244C04B2235/3427C04B2235/6586
Inventor 郭蕾马青松
Owner NAT UNIV OF DEFENSE TECH
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