High-emissivity and high-entropy ceramic material and preparation method and application thereof

A high-emissivity, ceramic material technology, applied in the field of high-entropy ceramic materials, can solve the problems that limit the wide application of LaMgAl, and achieve the effects of favorable spectral emissivity, reduced band gap, and pure phase

Active Publication Date: 2021-08-10
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, LaMgAl prepared by pressureless sintering 11 o 19 The spectral emissivity in the 3μm-5μm band is only 0.70, which severely limits the performance of LaMgAl 11 o 19 wide application of

Method used

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  • High-emissivity and high-entropy ceramic material and preparation method and application thereof
  • High-emissivity and high-entropy ceramic material and preparation method and application thereof
  • High-emissivity and high-entropy ceramic material and preparation method and application thereof

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preparation example Construction

[0030] The present invention provides a method for preparing a high-emissivity high-entropy ceramic material described in the above technical solution, comprising the following steps:

[0031] Mix lanthanum source, neodymium source, gadolinium source, samarium source, rare earth oxide, magnesium source and aluminum source, and perform cold pressing to obtain a green body; the lanthanum source, neodymium source, gadolinium source, samarium source, rare earth oxide The molar ratio of lanthanum element, neodymium element, gadolinium element, samarium element, rare earth element, magnesium element and aluminum element in the magnesium source and aluminum source is (0.4-x):0.2:0.2:0.2:x:1:11; The rare earth oxides include Pr 6 o 11 , CeO 2 or Eu 2 o 3 ;

[0032] Insulating the green body in stages to obtain a high-emissivity high-entropy ceramic material;

[0033] The step-by-step heat preservation process includes: the first stage: the calcination temperature is 1300-1350°C,...

Embodiment 1

[0048] La 2 o 3 Powder (average particle size 50nm, purity ≥ 99.9%), Nd 2 o 3 Powder (average particle size 50nm, purity ≥ 99.9%), Gd 2 o 3 Powder (average particle size 50nm, purity ≥ 99.9%), Sm 2 o 3 Powder (average particle size 50nm, purity ≥ 99.9%), Pr 6 o 11 Powder (average particle size 50nm, purity ≥ 99.9%), Al 2 o 3 Powder (average particle size is 50nm, purity ≥ 99.9%) and MgO powder (average particle size is 50nm, purity ≥ 99.9%) according to (La 0.2 Nd 0.2 Gd 0.2 S m 0.2 PR 0.2 )MgAl 11 o 19 The stoichiometric ratio is batched, where La 2 o 3 Powder, Nd 2 o 3 Powder, Gd 2 o 3 Powder, Sm 2 o 3 Powder, Pr 6 o 11 powder, MgO powder and Al 2 o 3 The molar ratio of the powder is 0.2:0.2:0.2:0.2:0.067:2:11. Mix the obtained mixture with absolute ethanol and perform wet ball milling. The ball milling speed is 300rpm and the ball milling time is 6h to obtain light gray mixed powder body;

[0049] Put the light gray mixed powder into a stainless...

Embodiment 2

[0052] La 2 o 3 Powder (average particle size 50nm, purity ≥ 99.9%), Nd 2 o 3 Powder (average particle size 50nm, purity ≥ 99.9%), Gd 2 o 3 Powder (average particle size 50nm, purity ≥ 99.9%), Sm 2 o 3 Powder (average particle size 50nm, purity ≥ 99.9%), CeO 2 Powder (average particle size 50nm, purity ≥ 99.9%), Al 2 o 3 Powder (average particle size is 50nm, purity ≥ 99.9%) and MgO powder (average particle size is 50nm, purity ≥ 99.9%) according to (La 0.2 Nd 0.2 Gd 0.2 S m 0.2 Ce 0.2 )MgAl 11 o 19 The stoichiometric ratio is batched, where La 2 o 3 Powder, Nd 2 o 3 Powder, Gd 2 o 3 Powder, Sm 2 o 3 Powder, CeO 2 Powder, Al 2 o 3 The molar ratio of the powder and the MgO powder is 0.2:0.2:0.2:0.2:0.4:11:2, the resulting mixture is mixed with absolute ethanol, and wet ball milled, the ball milling speed is 325rpm, and the ball milling time is 5h, to obtain Light blue mixed powder;

[0053] Put the light blue mixed powder into a stainless steel mold, ho...

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Abstract

The invention provides a high-emissivity and high-entropy ceramic material and a preparation method and application thereof, and belongs to the technical field of high-entropy ceramic materials. Five rare earth elements with different doping proportions are simultaneously introduced into the crystal lattice position of La, the number of impurity energy levels between the valence band top and the conduction band bottom of LaMgAl11O19 is increased, the forbidden band width is reduced, electrons in the impurity energy levels can absorb energy of infrared light to jump to the conduction band, and then the spectral emissivity of the corresponding wave band is improved; according to the invention, Pr, Ce or Eu elements with variable valence are introduced into the LaMgAl11O19 ceramic material, and when the valence state of the Pr, Ce or Eu elements is changed, the concentration of free electrons in a system can be increased (for example, the valence of Pr < 3 + > is changed to Pr < 4 + >) so that the absorption of free carriers to infrared light is promoted, and the improvement of spectral emissivity is also facilitated. The spectral emissivity of the ceramic material in the infrared band of 3-5 [mu] m is greater than 0.85, and the ceramic material has a good application prospect.

Description

technical field [0001] The invention relates to the technical field of high-entropy ceramic materials, in particular to a high-emissivity high-entropy ceramic material and its preparation method and application. Background technique [0002] LaMgAl 11 o 19 Due to the characteristics of high melting point, low density, low thermal conductivity, large thermal expansion coefficient and high fracture toughness, ceramics have become promising thermal protection materials for aerospace vehicles and energy-saving materials for industrial furnace linings. According to current application requirements, if LaMgAl 11 o 19 Ceramics are used for thermal protection on the outside of aerospace vehicles or energy saving in industrial kilns. Pressureless sintering with high production efficiency is the most suitable method. At the same time, it is required to have a spectral emissivity of more than 0.85 in the 3μm-5μm infrared band to achieve satisfactory Effect. According to Kirchhoff'...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/10C04B35/622
CPCC04B35/10C04B35/622C04B2235/3206C04B2235/3227C04B2235/3224C04B2235/5454C04B2235/602C04B2235/656C04B2235/6562C04B2235/6567C04B2235/9646
Inventor 刘玲马壮柳彦博朱皓麟
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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