Hafnium-niobium-based ternary solid solution boride conductive ceramic and preparation method and application thereof

A conductive ceramic and boride technology, applied in the field of ceramic materials, can solve the problems of reducing inherent mechanical strength and high temperature performance, difficult sintering and compacting of transition metal borides, reducing mechanical properties of ceramics, etc., and achieves short sintering time and small grain size. , the effect of small internal defects

Active Publication Date: 2021-05-25
GUANGDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to their strong covalent bonds and low diffusion coefficients, transition metal borides are difficult to sinter and dense
The preparation of dense phase-pure transition metal borides often requires higher temperature and pressure conditions, but high temperatures often lead to grain coarsening and reduce the mechanical properties of ceramics
Therefore, in order to promote the densification of transition metal borides, many scholars often increase the sintering driving force by adding sintering aids, such as Sciti et al. by adding 9vol% MoSi 2 , using SPS to successfully prepare 100% ZrB under the condition of 1700℃ / 100MPa 2 Ceramic, but glass phase MoSi 2 The presence of may reduce its inherent mechanical strength and high temperature performance

Method used

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  • Hafnium-niobium-based ternary solid solution boride conductive ceramic and preparation method and application thereof
  • Hafnium-niobium-based ternary solid solution boride conductive ceramic and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] 1. With HfO 2 (powder purity 99%, particle size 1μm), ZrO 2 (purity of powder 99.8%, particle size 1 μm), Nb (purity of powder 99%, particle size 10 μm), and B 4 C (powder purity 99.9%, particle size 0.5 μm), carbon powder (powder purity 99%, particle size 0.8 μm) as raw materials, ethanol as solvent, Si 4 N 3 As a ball milling medium, mix on a ball mill for 24 hours, and obtain a mixed powder after drying;

[0031] 2. Put the molded green body of the mixed powder into a graphite crucible, raise the temperature to 1600°C at a rate of 10°C / min and keep it warm for 1h, and obtain (Hf 1 / 3 Zr 1 / 3 Nb 1 / 3 )B 2 Hafnium and niobium based ternary solid solution boride conductive ceramic powder.

[0032] 3. Will (Hf 1 / 3 Zr 1 / 3 Nb 1 / 3 )B 2 The hafnium-niobium-based ternary solid solution boride conductive ceramic powder is placed in a graphite mold, and the temperature is raised to 1000°C at a rate of 150°C / min by spark plasma sintering and filled with an Ar protective ...

Embodiment 2

[0036] 1. With HfO 2 (powder purity 99%, particle size 2μm), TiO 2 (purity of powder 99.8%, particle size 2 μm), Nb (purity of powder 99%, particle size 10 μm), and B 4 C (powder purity 99.9%, particle size 0.5 μm), carbon powder (powder purity 99%, particle size 0.8 μm) as raw materials, ethanol as solvent, Si 4 N 3 As a ball milling medium, mix on a ball mill for 24 hours, and obtain a mixed powder after drying;

[0037] 2. Put the molded green body of the mixed powder into a graphite crucible, raise the temperature to 1600°C at a rate of 10°C / min and keep it warm for 1h, and obtain (Hf 1 / 3 Ti 1 / 3 Nb 1 / 3 )B 2 Hafnium and niobium based ternary solid solution boride conductive ceramic powder.

[0038] 3. Will (Hf 1 / 3 Ti 1 / 3 Nb 1 / 3 )B 2 The hafnium-niobium-based ternary solid solution boride conductive ceramic powder is placed in a graphite mold, and the temperature is raised to 1000°C at a rate of 150°C / min by spark plasma sintering and filled with an Ar protective ...

Embodiment 3

[0041] 1. With HfO 2 (powder purity 99%, particle size 1μm), TiO 2 (purity of powder 99.8%, particle size 1 μm), Nb (purity of powder 99%, particle size 10 μm), and B 4 C (powder purity 99.9%, particle size 0.5 μm), carbon powder (powder purity 99%, particle size 0.8 μm) as raw materials, ethanol as solvent, Si 4 N 3 As a ball milling medium, mix on a ball mill for 24 hours, and obtain a mixed powder after drying;

[0042] 2. Put the molded green body of the mixed powder into a graphite crucible, raise the temperature to 1600°C at a rate of 10°C / min and keep it warm for 1h, and obtain (Hf 1 / 4 Ti 1 / 4 Nb 1 / 2 )B 2 Hafnium and niobium based ternary solid solution boride conductive ceramic powder.

[0043] 3. Will (Hf 1 / 4 Ti 1 / 4 Nb 1 / 2 )B 2 The hafnium-niobium-based ternary solid solution boride conductive ceramic powder is placed in a graphite mold, and the temperature is raised to 1000°C at a rate of 150°C / min by spark plasma sintering and filled with an Ar protective ...

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Abstract

The invention belongs to the technical field of ceramic materials, and discloses hafnium-niobium-based ternary solid solution boride conductive ceramic and a preparation method and application thereof, the molecular formula of the conductive ceramic is (HfaNbbMic) B2, a is more than or equal to 0.1 and less than or equal to 0.9, bis more than 0 and less than 0.9,c is more than 0 and less than 0.9 and a+b+c=1, and Me is Zr, Ta or Ti. The conductive ceramic is prepared by the following steps of adding HfO2, Nb, Me oxide, B4C and carbon powder into a solvent, carrying out ball milling and mixing to obtain mixed powder, carrying out die pressing to obtain a green body, putting the green body into a graphite crucible, heating to 1400-1600 DEG C, carrying out heat preservation, and carrying out vacuum heat treatment to obtain (HfaNbbMec)B2 hafnium-niobium-based ternary solid solution boride powder, heating the boride powder to 1000-1400 DEG C by adopting spark plasma sintering, introducing a protective atmosphere, heating to 1900-2100 DEG C, and calcining at the pressure of 10-100 MPa.

Description

technical field [0001] The invention belongs to the technical field of ceramic materials, and more specifically relates to a conductive ceramic of hafnium-niobium-based ternary solid solution boride and its preparation method and application. Background technique [0002] As a kind of ultra-high temperature ceramics, transition metal borides have the advantages of high melting point, high hardness, excellent high temperature stability, corrosion resistance and high temperature creep resistance. Its application in harsh environments such as aerospace engines, supersonic vehicles, and furnace components has great potential. However, due to their strong covalent bonds and low diffusion coefficients, transition metal borides are difficult to sinter densely. The preparation of dense phase-pure transition metal borides often requires higher temperature and pressure conditions, but high temperature often leads to grain coarsening and reduces the mechanical properties of ceramics. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/58C04B35/622
CPCC04B35/58078C04B35/58064C04B35/622C04B2235/3244C04B2235/3251C04B2235/3821C04B2235/3873C04B2235/3232C04B2235/5436C04B2235/77C04B2235/96
Inventor 张泽熙郭伟明张岩许亮林华泰
Owner GUANGDONG UNIV OF TECH
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