A kind of high emissivity high entropy ceramic material and its preparation method and application

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 effect of benefiting the spectral emissivity, increasing the spectral emissivity, and reducing the bandgap width

Active Publication Date: 2022-04-08
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Abstract
  • Description
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  • 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

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  • A kind of high emissivity high entropy ceramic material and its preparation method and application
  • A kind of high emissivity high entropy ceramic material and its preparation method and application
  • A kind of high emissivity high entropy ceramic material and its preparation method and application

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preparation example Construction

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

[0031] A lanthanum source, a neodymium source, a gadolinium source, a samarium source, a rare earth oxide, a magnesium source and an aluminum source are mixed, and cold-pressed to obtain a green body; the lanthanum source, the neodymium source, the gadolinium source, the samarium source, the rare earth oxide , the molar ratio of lanthanum, neodymium, gadolinium, samarium, rare earth, magnesium and aluminum in the magnesium source and the 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] The green body is thermally insulated in stages to obtain a high emissivity and high entropy ceramic material;

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

Embodiment 1

[0048] will La 2 O 3 Powder (average particle size is 50nm, purity ≥99.9%), Nd 2 O 3 Powder (average particle size is 50nm, purity ≥99.9%), Gd 2 O 3 Powder (average particle size is 50nm, purity ≥99.9%), Sm 2 O 3 Powder (average particle size is 50nm, purity ≥99.9%), Pr 6 O 11 Powder (average particle size is 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 ratios are 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, the obtained mixture is mixed with absolute ethanol, and wet ball milling is carried out, the ball milling speed is 300rpm, and the ball milling time is 6h to obtain light gray mixed powder body;

[0049] The light gray mixe...

Embodiment 2

[0052] will La 2 O 3 Powder (average particle size is 50nm, purity ≥99.9%), Nd 2 O 3 Powder (average particle size is 50nm, purity ≥99.9%), Gd 2 O 3 Powder (average particle size is 50nm, purity ≥99.9%), Sm 2 O 3 Powder (average particle size is 50nm, purity ≥99.9%), CeO 2 Powder (average particle size is 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 ratios are 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 to the MgO powder is 0.2:0.2:0.2:0.2:0.4:11:2, the obtained mixture is mixed with absolute ethanol, and wet ball milling is carried out, the ball milling speed is 325rpm, and the ball milling time is 5h, to obtain Light blue mixed powder;

[0053] The light blue mixed powder was lo...

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Abstract

The invention provides a high-emissivity high-entropy ceramic material and its preparation method and application, belonging to the technical field of high-entropy ceramic materials. The present invention simultaneously introduces five kinds of rare earth elements with different doping ratios at the lattice position of La, increasing the LaMgAl 11 o 19 The number of impurity energy levels between the top of the valence band and the bottom of the conduction band reduces the forbidden band width, which is conducive to the energy transition of electrons in the impurity energy levels absorbing infrared light to the conduction band, thereby increasing the spectral emissivity of the corresponding band; the present invention In LaMgAl 11 o 19 The introduction of variable valence Pr, Ce or Eu elements into ceramic materials can increase the concentration of free electrons in the system when their valence changes (such as Pr 3+ to Pr 4+ Variation), thereby promoting the absorption of infrared light by free carriers, and also conducive to the improvement of spectral emissivity. The spectral emissivity of the ceramic material provided by the invention is greater than 0.85 in the infrared band of 3 μm to 5 μm, and has good application prospects.

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 a preparation method and application thereof. Background technique [0002] LaMgAl 11 O 19 Because of its high melting point, low density, low thermal conductivity, large thermal expansion coefficient and high fracture toughness, ceramics have become a promising thermal protection material for aerospace vehicles and energy-saving materials for industrial furnace linings. According to the current application requirements, if the LaMgAl 11 O 19 Ceramics are used for thermal protection on the outer side of spacecraft or energy saving in industrial kilns. Pressureless sintering with high production efficiency is the most suitable method. At the same time, it is required that the spectral emissivity in the infrared band of 3 μm to 5 μm should reach 0.85 or more, in order to achieve satisfactory results. Eff...

Claims

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Application Information

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Patent Type & Authority Patents(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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