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A kind of high entropy rare earth niobium/tantalum/molybdate ceramic and its preparation method

A molybdate and rare earth technology, applied in the field of high-entropy ceramic materials, can solve the problems of low thermal conductivity, unfavorable material structure and performance of high-entropy ceramics, and achieve low equipment requirements, low energy consumption, and strong controllability Effect

Active Publication Date: 2021-10-26
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the high-entropy rare earth niobate ceramics and high-entropy rare earth tantalate ceramics prepared in the prior art are limited to the formation of high-entropy solid solutions at the RE site, which is not conducive to further regulating the structure and properties of materials.
In addition, the inventors found that the thermal conductivity of high-entropy ceramics prepared in the prior art that can be used as thermal barrier coating materials is still not low enough to meet the needs of some practical applications

Method used

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  • A kind of high entropy rare earth niobium/tantalum/molybdate ceramic and its preparation method
  • A kind of high entropy rare earth niobium/tantalum/molybdate ceramic and its preparation method

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preparation example Construction

[0021] In one or some embodiments of the present invention, a method for preparing the above-mentioned high-entropy rare earth niobium / tantalum / molybdate ceramics is provided, comprising the following steps:

[0022] (1) Weigh the rare earth oxide (RE) according to the stoichiometric ratio 2 o 3 ), niobium pentoxide (Nb 2 o 5 ), tantalum pentoxide (Ta 2 o 5 ), molybdenum trioxide (MoO 3 ) and molybdenum dioxide (MoO 2 );

[0023] (2) adding solvent and ball milling medium, using wet ball milling to mix raw materials, vacuum drying and sieving to obtain uniformly mixed powder;

[0024] (3) placing the uniformly mixed powder in a stainless steel mold for hydraulic compaction, and then obtaining a densified green body through cold isostatic pressing;

[0025] (4) Put the green body into an alumina crucible, place it in a high-temperature sintering furnace, and sinter it in an air atmosphere to obtain a high-entropy rare earth niobium / tantalum / molybdate ceramic.

[0026] ...

Embodiment 1

[0038] (1) put Y 2 o 3 、Er 2 o 3 , Yb 2 o 3 , Nb 2 o 5 、 Ta 2 o 5 、MoO 3 and MoO 2 Dosing according to molar ratio 3:3:3:1:1:1:1;

[0039] (2) Mix the proportioned powder in absolute ethanol, place it in a planetary ball mill for ball milling (the speed of the ball mill is 300r / min, and the ball milling time is 24h), and the powder after ball milling is vacuum-dried at 80°C for 24h Pass through a 200-mesh sieve to obtain a uniformly mixed powder;

[0040] (3) Put the uniformly mixed powder in a stainless steel mold, press it with hydraulic pressure (holding pressure is 15MPa, holding time is 10min), and then further form it by cold isostatic pressing (holding pressure is 220MPa, holding time is 10min). Time is 15min), obtain green body;

[0041] (4) Put the green body in an alumina crucible, then place the crucible in a high-temperature sintering furnace, raise the temperature to 1600°C at 10°C / min in an air atmosphere, keep it warm for 10h, and let it cool naturall...

Embodiment 2

[0044] (1) put Y 2 o 3 、Eu 2 o 3 、Gd 2 o 3 、Dy 2 o 3 、Er 2 o 3 , Nb 2 o 5 、 Ta 2 o 5 、MoO 3 and MoO 2 Dosing according to molar ratio 9:9:9:9:9:5:5:5:5;

[0045] (2) Mix the proportioned powder in absolute ethanol, place it in a planetary ball mill for ball milling (the speed of the ball mill is 350r / min, and the ball milling time is 20h), and the powder after ball milling is vacuum-dried at 90°C for 20h Pass through a 200-mesh sieve to obtain a uniformly mixed powder;

[0046] (3) Put the uniformly mixed powder in a stainless steel mold, press it with hydraulic pressure (holding pressure is 12MPa, holding time is 10min), and then further form it by cold isostatic pressing (holding pressure is 220MPa, holding time is 10min). Time is 20min), obtain green body;

[0047] (4) Put the body in an alumina crucible, then place the crucible in a high-temperature sintering furnace, raise the temperature to 1650°C at 10°C / min in an air atmosphere, keep it warm for 12h, a...

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Abstract

The invention relates to the technical field of high-entropy ceramic materials, and specifically provides a high-entropy rare earth niobium / tantalum / molybdate ceramic and a preparation method thereof. The chemical formula of the high-entropy rare earth niobium / tantalum / molybdate ceramic is RE 3 (Nb 1 / 3 Ta 1 / 3 Mo 1 / 3 )O 7 , where RE is Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb and Lu any three to seven different elements. The preparation method comprises the following steps: (1) weighing rare earth oxide, niobium pentoxide, tantalum pentoxide, molybdenum trioxide and molybdenum dioxide according to the stoichiometric ratio; (2) adding solvent and ball milling medium, adopting wet method Ball mill the mixed raw materials, vacuum dry and sieve to obtain a uniformly mixed powder; (3) put the uniformly mixed powder in a stainless steel mold for hydraulic compaction, and then undergo cold isostatic pressing to obtain a densified green body; (4) ) Put the green body into an alumina crucible, place it in a high-temperature sintering furnace, and sinter it in an air atmosphere. The high-entropy ceramics prepared by the invention have low thermal conductivity, and the preparation method adopted has the advantages of simple and fast process, low equipment requirements, low energy consumption, strong controllability, etc., and is easy to realize large-scale production.

Description

technical field [0001] The invention relates to the technical field of high-entropy ceramic materials, and specifically provides a high-entropy rare earth niobium / tantalum / molybdate ceramic and a preparation method thereof. Background technique [0002] The statements herein merely provide background information related to the present invention and may not necessarily constitute prior art. [0003] Rare earth niobate ceramics and rare earth tantalate ceramics have high melting point, good high temperature stability and excellent thermophysical properties, and have become new thermal barrier coating materials. [0004] High-entropy ceramics are single-phase solid solutions formed by dissolving various components in an equimolar ratio or approximately equimolar ratio. The huge lattice distortion caused by high-entropy solid solution will significantly reduce the thermal conductivity of ceramic materials. Therefore, applying high-entropy methods to rare earth niobate and rare ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/50C04B35/495
CPCC04B35/495C04B35/50C04B2235/3225C04B2235/6562C04B2235/6567
Inventor 孙国勋王伟礼孙晓宁张爱敏
Owner SHANDONG UNIV
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