Method for preparing n-type CaMnO3-group thermoelectric ceramic

A thermoelectric and ceramic technology, applied in chemical instruments and methods, thermoelectric device junction lead-out materials, manganate/permanganate, etc. Excellent thermoelectric performance and low resistivity

Inactive Publication Date: 2017-08-11
GUIZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At room temperature, undoped CaMnO 3 The power factor is about 0.99μW / cmK 2 , and Ankam Bhaskar et al. used Bi doping to increase it to 2.99μW / cmK 2 , the corresponding Seebeck coefficient is -159μV / K; the Dy / Bi double element doped CaMnO prepared by Zhu Yuanhu et al. 3 The power factor is about 4.2μW / cmK at 850K 2 , corresponding to the absolute value of the Seebeck coefficient is only 80μV / K, and the metal doping leads to a sharp decrease in the thermoelectromotive force in the high temperature section
So far, no n-type oxide material can match the performance of p-type oxide thermoelectric materials, and it is still an urgent work to find n-type oxide thermoelectric materials with good thermoelectric properties

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Weigh CaCO according to stoichiometric ratio 3 , MnO 2 The raw material powder is ball milled and calcined at 950°C for 12h to obtain CaMnO 3 Precursor powder, weigh graphite powder and CaMnO according to graphite ratio 0.1%wt 3 Precursor powder, then first add 1 / 2 graphite powder to CaMnO 3 The precursor powder is pre-sintered at 1100°C to obtain a sintered material. After the sintered material is crushed, the rest of the graphite powder is added, then ground, and passed through a 200-mesh sieve. The sieved material is formed and placed at 1190 ℃ heat preservation and sintering for 24h to obtain CaMnO containing graphite 3 thermoelectric ceramics. The whole preparation process was carried out in air atmosphere.

[0033] The sample in this embodiment is an n-type semiconductor thermoelectric material, which has good electrical conductivity at high temperatures. At 450K, the Seebeck coefficient is -327.46μV / K, and the resistivity is 1.06Ω cm; the power factor of th...

Embodiment 2

[0035] The preparation steps are similar to Example 1, except that the graphite powder and CaMnO are weighed according to the graphite ratio of 0.5%wt 3Precursor powder. The sample in this embodiment exhibits semiconductor transport properties, and the material has good electrical conductivity at high temperatures. At 450K, the Seebeck coefficient is -429.97μV / K, and the resistivity is 3.64Ω cm; at 800K, the power factor of the sample reaches 4.038μW / cmK 2 , the resistivity 0.02Ω·cm corresponds to the Seebeck coefficient -290.25μV / K.

Embodiment 3

[0037] The preparation steps are similar to Example 1, except that: 1. The amount of graphite powder added during the first sintering is 1 / 3, and the temperature for the first sintering is 1100°C; 2. The proportion of graphite is 1%wt Weigh graphite powder and CaMnO 3 Precursor powder. The sample in this embodiment exhibits semiconductor transport properties, and the material has good electrical conductivity at high temperatures. At 450K, the Seebeck coefficient is -344.01μV / K, and the resistivity is 0.225Ω·cm; at 800K, the power factor of the sample reaches 3.48μW / cmK 2 , the resistivity 0.016Ω·cm corresponds to the Seebeck coefficient -239.38μV / K.

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Abstract

The invention discloses a method for preparing n-type CaMnO3-group thermoelectric ceramic. The raw materials of the thermoelectric ceramic comprise graphite and CaMnO3, and the preparation method includes the steps of (1) mixing partial graphite with CaMnO3, and carrying out presintering to obtain sintering materials; (2) breaking the sintered material obtained by the step (1) to add with residual graphite, mixing uniformly, grinding and sieving to obtain micro powder; (3) molding and sintering the micro powder obtained by the step (2) to obtain the prepared n-type CaMnO3-group thermoelectric ceramic. The thermoelectric ceramic has good thermoelectric properties, and the preparation method has the advantages of simple technological operation, low requirements of equipment conditions, environmental-friendly processes and low cost; moreover, the obtained materials have the characteristics of big thermo electromotive force, low resistivity at high temperature and a big power factor.

Description

technical field [0001] The invention relates to a method for preparing thermoelectric ceramics, in particular to a method for preparing n-type CaMnO 3 method based on thermoelectric ceramics. Background technique [0002] Thermoelectric materials are functional materials that can realize direct mutual conversion of heat energy and electric energy. Refrigerators made of them can be used for fluorine-free and local refrigeration, and thermoelectric generators made of them can be used for waste heat recovery and power generation. Compared with traditional heat engines, components made of thermoelectric materials have outstanding advantages such as small size, light weight, no noise, no moving parts, long service life, environmental protection and no pollution. They are used in superconductors, high-power high-speed computers, aerospace, microelectronics Technology, civil waste heat recovery and other fields have great application prospects. [0003] The energy conversion effi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/01C04B35/622C01G45/12H01L35/22
CPCC01G45/125C04B35/016C04B35/622C04B2235/9607C04B2235/96C04B2235/425H10N10/855
Inventor 陈前林高洪李翠芹
Owner GUIZHOU UNIV
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