High-entropy carbide ultrahigh-temperature ceramic with ultrahigh porosity and preparation method

A technology of ultra-high temperature ceramics and carbides, applied in ceramic products, applications, household appliances, etc., can solve the problems of high thermal conductivity and achieve the effects of uniform composition, convenient operation, and high porosity

Active Publication Date: 2021-06-29
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the intrinsic thermal conductivity of carbide is generally relatively high, and it is necessary to take effective measures to reduce its thermal conductivity to meet the requirements of aerospace thermal insulation materials.

Method used

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  • High-entropy carbide ultrahigh-temperature ceramic with ultrahigh porosity and preparation method
  • High-entropy carbide ultrahigh-temperature ceramic with ultrahigh porosity and preparation method
  • High-entropy carbide ultrahigh-temperature ceramic with ultrahigh porosity and preparation method

Examples

Experimental program
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Effect test

Embodiment 1

[0028] In this embodiment, the high-entropy carbide ultra-high temperature ceramic with ultra-high porosity and its preparation method are as follows:

[0029] Weigh 7.93g ZrC, 14.62g HfC, 8.05g NbC, 14.81g TaC and 4.60g TiC powder, pour into Si 3 N 4 In the ball mill tank, add 30ml of absolute ethanol and then carry out ball milling, in which the mass ratio of balls to materials is 4:1, use a planetary ball mill to mill at a speed of 350rpm for 12 hours, and dry the evenly mixed suspension in an oven at 90°C, and the dried powder Pass through a 200 mesh sieve to obtain a uniform mixture powder.

[0030] Add the mixture powder after ball milling, 30g deionized water, 0.5g dispersant ammonium citrate, and 1g sintering aid graphite into the beaker and stir continuously, and form a slurry after stirring for 2 hours; add 0.3g foaming Sodium dodecyl sulfonate, stirred rapidly for 15 minutes to foam, then added 1.8g of gelatin gelatin, stirred for 10 minutes, injected into the mol...

Embodiment 2

[0034] In this embodiment, the high-entropy carbide ultra-high temperature ceramic with ultra-high porosity and its preparation method are as follows:

[0035] Weigh 13.7g ZrC, 12.6g HfC, 20.9g NbC, 38.5g TaC and 4.2g VC powder, pour Si 3 N 4 In the ball milling tank, add 35ml of absolute ethanol and then carry out ball milling, in which the mass ratio of balls to materials is 3:1, use a planetary ball mill to mill at a speed of 260rpm for 28 hours, and dry the uniformly mixed suspension in an oven at 60°C, and the dried powder Pass through a 200 mesh sieve to obtain a uniform mixture powder.

[0036] Put the mixture powder after ball milling, 45g deionized water, 5.4g dispersant polyethyleneimine, 0.5g aluminum nitride into the beaker and keep stirring, and form a slurry after stirring for 1h; add 4.5g foam to the obtained slurry Foaming agent sodium lauryl sulfate, stirring rapidly for 25 minutes to foam, then adding 4.5g of gelatin gelatin, stirring for 20 minutes, inject...

Embodiment 3

[0040] In this embodiment, the high-entropy carbide ultra-high temperature ceramic with ultra-high porosity and its preparation method are as follows:

[0041] Weigh 4.1g ZrC, 15.1g HfC, 4.2g NbC, 23.0g TaC and 23.4g WC powder, pour into Si 3 N 4 In the ball milling tank, add 40ml of absolute ethanol and carry out ball milling, wherein the mass ratio of balls to materials is 6:1, use a planetary ball mill to mill at a speed of 310rpm for 20h, and dry the evenly mixed suspension in an oven at 75°C, and the dried powder Pass through a 200 mesh sieve to obtain a uniform mixture powder.

[0042] Add the mixture powder after ball milling, 30g of deionized water, 2.5g of dispersant polyethyleneimine, and 0.7g of silicon molybdenum to the beaker and stir continuously, and form a slurry after stirring for 4 hours; add 2.5g of foaming agent to the obtained slurry Sodium dodecyl sulfonate, stirred rapidly for 30 minutes to foam, then added 0.6g of gelatin gelatin, stirred for 15 minut...

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Abstract

The invention relates to the field of porous high-entropy ultrahigh-temperature ceramic thermal insulation materials, in particular to ultrahigh-porosity high-entropy carbide ultrahigh-temperature ceramic and a preparation method thereof, wherein the framework matrix material of the porous (ZraHfbNbcTadXe) C ceramic is a single-phase high-entropy ultrahigh-temperature ceramic with a face-centered cubic structure, calculated as atomic percent, the value range of a, b, c, d and e is 10-35%, a + b + c + d + e is equal to 1, and X is Ti, W, V, Cr or Mo. The preparation method comprises: taking mixture powder of five carbides as a raw material, preparing slurry of the mixture powder, adding a foaming agent, foaming, adding a gel, carrying out injection molding, and freezing and drying; and presintering at a temperature of 1300-1550 DEG C, and carrying out high-temperature non-pressure in-situ reaction sintering at a temperature of 1750-2000 DEG C to prepare the porous high-entropy ultrahigh-temperature ceramic thermal insulation material. The ultrahigh-temperature thermal insulation material synthesized by the invention has the advantages of ultrahigh porosity (83-96%), low density (0.25-1.90 g / cm<3>), high strength (0.21-16.92 MPa), low thermal conductivity (0.10-0.35 W / (m.K)) and ultrahigh temperature (more than 2000 DEG C)resistance, and has a wide application prospect in the field of aerospace thermal protection.

Description

technical field [0001] The invention relates to the field of porous high-entropy ultra-high-temperature ceramic heat-insulating materials, in particular to an ultra-high-porosity high-entropy carbide ultra-high-temperature ceramic and a preparation method thereof. Background technique [0002] Due to the rapid development of the aerospace industry, the flying speed of hypersonic vehicles is getting faster and faster, which brings more serious aerodynamic heating effects, causing the surface temperature of the vehicle to reach above 2000 °C. Conventional oxide system insulation materials have a relatively low melting point, and cannot maintain thermal stability under ultra-high temperature conditions greater than 2000 ° C. Traditional insulation materials encounter temperature resistance bottlenecks. Therefore, there is an urgent need to develop new ultra-high temperature resistant insulation materials to meet the needs of national strategic development. Carbide ultra-high t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/10C04B35/66C04B35/622C04B35/56
CPCC04B38/10C04B35/66C04B35/5607C04B35/5626C04B35/622C04B2235/3839C04B2235/3843C04B2235/425C04B2235/606C04B2235/656C04B2235/6562C04B2235/6567C04B2235/658C04B2235/95C04B2235/96C04B2235/9607
Inventor 王京阳邵卓杰吴贞孙鲁超
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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