Preparation method of CoSb3 pyroelectric material having nanometer/micron composite crystal structure

Abstract

The invention belongs to thermoelectric material manufacturing technology field. The current micron crystal grain CoSb3 material thermal conductivity is high. Although nanometer is low, its electric conductivity is greatly reduced to make ZT maximum only be 0.057 in 300-800K temperature range. The features of a nanometer / micron compound grain structure CoSb3 thermoelectric material manufacturing are using 80-100nm metallic cobalt and 20-40um antimony simple substance elemental powder as raw material; weighting and mixing by CoSb3 compound chemical formula under the protection of argon gas; grinding powder; doing SPS reaction in situ synthesis; and the pressure is 30-50MPa; heating rate is 120-150 centigrade degree per minute; temperature is 450-550 centigrade degree; holding time is 3-5min; atmosphere is vacuum. The thermoelectric material has nanometer / micron compound grain structure. The ZT value is 0.34 at 700K.

Description

Technical field [0001] The invention relates to a CoSb with a nano / micro composite crystal grain structure 3 Thermoelectric materials and preparation methods thereof belong to the technical field of manufacturing thermoelectric materials. Background technique [0002] Thermoelectric materials are new functional materials that use the Seebeck effect and the Peltier effect to convert heat and electric energy. It is a key material in the field of high-tech new energy and has broad applications in thermoelectric power generation and thermoelectric refrigeration. prospect. The performance of thermoelectric materials is usually characterized by the dimensionless figure of merit ZT: ZT=(α 2 σ / κ)T, where α is the Seebeck coefficient, σ is the electrical conductivity, κ is the thermal conductivity, and T is the temperature. A good thermoelectric material should have a high ZT value. [0003] In many thermoelectric material systems, CoSb 3 As a new type of thermoelectric material with pote...

AI Technical Summary

Problems solved by technology

In existing technologies, such as the Japanese patent [Open Gazette 1996 No. 186492A] and the patent [CN14229669A] disclosed by Yang Junyou, CoSb 3 The preparation of materials mostly adopts mechanical alloying (MA), solid state reaction method and melting method. These methods not only have a long reaction cycle and complicated procedures, but also the grain size is difficult to control.

In our previous work, CoSb with a single micro- and nano-grain structure has been successfully synthesized by SPS technique 3 Thermoelectric materials (ZL 02 1 56680.1), performance tests show that CoSb with micron grains 3 The material has high thermal conductivity, while the nanocrystalline CoSb 3 Although the material has a very low thermal conductivity, the electrical conductivity also drops significantly, so that the maximum value of ZT in the temperature range of 300-800K is only 0.057

In order to improve the CoSb 3 The ZT value of the material must make it have high Seebeck coefficient and electrical conductivity while ensuring low thermal conductivity. For this reason, the present invention proposes a CoSb with nano / micro composite grain structure 3 Thermoelectric materials and their preparation methods have not been reported yet

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