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Thermoelectric material and preparation method thereof

A technology of thermoelectric materials and sintering method, which is applied in the field of material science, can solve the problems of high reaction temperature, long reaction time, and easy decomposition of materials, and achieve high-temperature thermoelectric performance, narrow size distribution, and overcome the effect of high reaction temperature

Inactive Publication Date: 2010-07-28
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of the solid phase reaction method is that the reaction temperature is high, the reaction time is long, the energy consumption is large, and the Ca 2 co 2 o 5 The material decomposes easily, causing the composition of the compound to deviate from the stoichiometric ratio

Method used

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  • Thermoelectric material and preparation method thereof
  • Thermoelectric material and preparation method thereof
  • Thermoelectric material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] This example is used to prepare Ca 1.98 Bi 0.02 co 2 o 5 thermoelectric material

[0037] According to Ca 1.98 Bi 0.02 co 2 o 5 The stoichiometric number, weigh 233.6g Ca(NO 3 ) 2 4H 2 Og, 353.0gCo(NO 3 ) 3 · 6H 2 O and 5.0g Bi(NO 3 ) 3 · 6H 2 0, the above-mentioned raw materials are mixed together, 600g deionized water is added therein, stirring and dissolving, then dripping concentration is that the NaOH solution of 50wt% is 13.0 to the pH of solution, makes precipitation completely, then stirs, carries out suction filtration, will obtain The precipitate was washed and dried. Then, send the dried precipitate into a calciner, and calcinate at 700°C for 1 hour to complete the phase formation stage of the material phase, put the calcined powder into a graphite mold, compact it, and use the discharge plasma sintering method Sintered into bulk material. The sintering conditions are heating rate of 100°C / min, temperature of 700°C, pressure of 40MPa, and ...

Embodiment 2

[0039] This example is used to prepare Ca 1.92 Bi 0.08 co 2 o 5 thermoelectric material

[0040] According to Ca 1.92 Bi 0.08 co 2 o 5 The stoichiometric number, weigh 226.5g Ca(NO 3 ) 2 · 4H 2 Og, 353.0gCo(NO 3 ) 3 · 6H 2 O and 20.0g Bi(NO 3 ) 3 · 6H 2 0, the above-mentioned raw materials are mixed together, 800g deionized water is added therein, stirring and dissolving, then dripping concentration is that the NaOH solution of 50wt% is 13.0 to the pH of solution, makes precipitation completely, then stirs, carries out suction filtration, will obtain The precipitate was washed and dried to obtain a dry precipitate. Then, send the dried precipitate into a calciner and calcinate at 750°C for 6 hours to complete the phase formation stage of the material phase, put the calcined powder into a graphite mold, compact it, and use the discharge plasma sintering method Sintered into bulk material. The sintering conditions are heating rate of 200°C / min, temperature o...

Embodiment 3

[0042] This example is used to prepare Ca 1.9 Bi 0.1 co 2 o 5 thermoelectric material

[0043] According to Ca 1.9 Bi 0.1 co 2 o 5 The stoichiometric number, weigh 224.2g Ca(NO 3 ) 2 · 4H 2 Og, 353.0gCo(NO 3 ) 3 ·6H 2 O and 25.0g Bi(NO 3 ) 3 · 6H 2 O, the above raw materials are mixed together, 800g of deionized water is added thereto, stirred and dissolved, and then 900g of Na is added dropwise with a concentration of 35%wt 2 CO 3 Solution, make the precipitation complete, then stir, carry out suction filtration, wash the precipitate obtained, and dry to obtain the dry precipitate. Then put the dried precipitate into the calcination furnace and calcine at 800°C for 4 hours to complete the phase formation stage of the material phase, put the powder obtained after calcination into a graphite mold, compact it, and sinter it with the discharge plasma sintering method into bulk material. The sintering conditions are heating rate of 250°C / min, temperature of 80...

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Abstract

The invention discloses a thermoelectric material and a preparation method thereof. The thermoelectric material consists of flaky crystal grains of which the length is between 2 and 5 micrometers and the thickness is between 100 and 400 micrometers, and the chemical composition of the thermoelectric material is Ca2-xBixCo2O5, wherein x is more than 0 and less than or equal to 0.20. The method comprises the following steps of: preparing solution containing Ca<2+>, Bi<+3> and Co<+3> in the stoichiometric ratio of a general formula Ca2-xBixCo2O5, wherein x is more than 0 and less than or equal to 0.20; precipitating Ca<2+>, Bi<+3> and Co<+3> in the solution for filtration to obtain precipitates by filtration; calcining the precipitates at the temperature of between 700 and 850 DEG C to prepare calcined materials; and sintering the calcined materials by using a discharge plasma sintering method at the temperature of 700 and 850 DEG C to obtain the thermoelectric material. The thermoelectric material is excellent in high-temperature pyroelectricity. By the preparation method, the Ca2Co2O5-based thermoelectric material with good chemical homogeneity and excellent thermoelectric performance can be synthesized at low temperature in a short time.

Description

technical field [0001] The invention belongs to the field of material science, and relates to a thermoelectric material and a preparation method thereof, more specifically, to a Bi-doped Ca 2 co 2 o 5 Based thermoelectric materials and their preparation methods. Background technique [0002] A thermoelectric material is a material that can convert heat to electricity in a solid state with few moving parts. In recent years, due to the need of environmental protection, the research of new thermoelectric materials has attracted more and more attention. Thermoelectric materials can be used as carriers for reversible conversion of heat energy and electric energy. Thermoelectric devices with thermoelectric materials as the core module have the advantages of light structure, small size, long service life, no pollution to the environment, and can be used under very harsh environmental conditions. , and the reversibility of the thermoelectric effect also determines that the therm...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/01C04B35/622
Inventor 林元华李国晶兰金叻南策文
Owner TSINGHUA UNIV