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A method for preparing a thermoelectric material comprising a nano-superlattice and a micro-phase separation

A thermoelectric material and superlattice technology, applied in the field of materials, can solve the problems of limited reduction in thermal conductivity and electrical performance, and achieve the effect of simple process

Active Publication Date: 2017-06-23
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Taking SrTiO, which is currently researched more 3 For example, although its electrical properties are already comparable to alloy materials, its thermal conductivity at room temperature is as high as 11W / (m K), several times that of alloy compounds such as Bi 2 Te 3 2~3 W / (m K); the current main method to reduce thermal conductivity is to use solid solution or nanometerization method, but the reduction range of thermal conductivity is limited by the method of solid solution, and although the thermal conductivity is reduced by the method of nanometerization The effect is obvious, but the negative effect is that the electrical performance is also reduced due to the incoherence of the micro-nano particle interface and the existence of defects.

Method used

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  • A method for preparing a thermoelectric material comprising a nano-superlattice and a micro-phase separation
  • A method for preparing a thermoelectric material comprising a nano-superlattice and a micro-phase separation

Examples

Experimental program
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Effect test

Embodiment 1

[0025] Prepare Nd 2 O 3 , Li 2 O, TiO 2 And Nb 2 O 5 , The molar ratio of Nd, Li, Ti and Nb in all materials is 0.55:0.36:(1-x):x, where x=0.02; put all the materials in a ball mill tank and mix evenly to obtain a mixed material;

[0026] Calcining the mixed material at 1100°C for 12 hours to obtain a calcined material;

[0027] Grind the calcined material to a particle size of ≤100μm, then place it in a graphite crucible, and heat it to 1430±5℃ for 3 hours under the protection of argon to make the calcined material and graphite undergo a reduction reaction to obtain the heat-treated material;

[0028] Grind the heat-treated material to a particle size ≤100μm to obtain heat-treated powder;

[0029] Part of the heat-treated powder is formed by isostatic pressing, and the pressing pressure is 20MPa to obtain a block; the block is placed in a graphite crucible, and the block is covered with the remaining heat-treated powder, and then heated to 1250℃ for high-temperature sintering for 12 h...

Embodiment 2

[0032] The method is the same as in Example 1, the difference is:

[0033] (1) The molar ratio is 0.55:0.36:(1-x):x, where x=0.05;

[0034] (2) Calcining the mixed material at 1150℃ for 11h;

[0035] (3) Heat to 1430±5℃ for 4h;

[0036] (4) The pressing pressure of isostatic pressing is 22MPa; heating to 1270℃ for high temperature sintering for 11h; after the reaction is over, the temperature will be lowered to below 650℃ at a rate of 120℃ / h;

[0037] (5) The composition of thermoelectric materials containing nano-superlattice and micro-phase separation is (Nd 0.55 Li 0.36 ) (Ti 0.95 Nb 0.05 )O 3 ; In the temperature range of 30~450℃, the conductivity σ is 23~54S / cm, and the Seebeck coefficient is 61~188μV / K.

Embodiment 3

[0039] The method is the same as in Example 1, the difference is:

[0040] (1) The molar ratio is 0.55:0.36:(1-x):x, where x=0.10;

[0041] (2) Calcining the mixture at 1200℃ for 10h;

[0042] (3) Heat to 1430±5℃ for 5h;

[0043] (4) The pressing pressure of isostatic pressing is 25MPa; it is heated to 1300℃ for high temperature sintering for 12h; after the reaction is over, the temperature is lowered to below 650℃ at a rate of 150℃ / h;

[0044] (5) The composition of thermoelectric materials containing nano-superlattice and micro-phase separation is (Nd 0.55 Li 0.36 ) (Ti 0.9 Nb 0.1 )O 3 ; In the temperature range of 30~450℃, the conductivity σ is 25~53S / cm, and the Seebeck coefficient is 68~146μV / K.

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Abstract

A method for preparing thermoelectric materials containing nano-superlattice and micron phase separation, which belongs to the field of material technology and is carried out according to the following steps: (1) Place Nd2O3, Li2O, TiO2 and Nb2O5 in a ball mill tank and mix them evenly; (2) Calcined at 1100~1200℃; (3) After grinding, place it in a graphite crucible. Under argon protection, heat treatment causes the calcined material and graphite to undergo a reduction reaction; (4) Grinding; (5) Isostatic pressing to obtain a block material; place the block in a graphite crucible, cover the block with heat-treated powder, and sinter at high temperature to cause a reduction reaction between the block and graphite; cool down to normal temperature. The thermoelectric material synthesized by the invention has a microstructure of nanoscale superlattice and micron scale phase separation, and is a new type of oxide thermoelectric material with rich potential.

Description

Technical field [0001] The invention belongs to the technical field of materials, and particularly relates to a preparation method of a thermoelectric material containing nano superlattices and micron phase separation. Background technique [0002] Fossil energy is currently the main source of energy. The energy crisis caused by its non-renewability and the greenhouse effect caused by the emission of carbon dioxide during use have attracted more and more attention. According to statistics, about two-thirds of the energy of fossil energy is wasted in the form of waste heat; if this part of the waste heat can be recovered, it is obviously of great significance to alleviate the energy crisis and solve the greenhouse effect; In this context, thermoelectric materials, as functional materials that can realize the direct conversion of thermal energy and electrical energy, have received increasing attention in recent years. [0003] Thermoelectric materials are based on the Seebeck effect...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L35/14H10N10/851
Inventor 巴要帅巴德纯河本邦仁
Owner NORTHEASTERN UNIV LIAONING