Hot extrusion forming method of bismuth telluride thermoelectric material

A technology of thermoelectric materials and molding methods, which is applied in the direction of thermoelectric device node lead-out materials, thermoelectric device manufacturing/processing, etc., can solve the problems of weak mechanical properties and poor processability, and achieve high thermoelectric value, high strength, Solve the effect of low reliability

Pending Publication Date: 2022-03-22
CHINA ELECTRONIC TECH GRP CORP NO 18 RES INST
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to improve the weak mechanical properties and poor processability of bismuth telluride materials, it is very important to develop a new preparation process to obtain bulk bismuth telluride-based thermoelectric materials with good thermoelectric properties and excellent mechanical strength.

Method used

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  • Hot extrusion forming method of bismuth telluride thermoelectric material
  • Hot extrusion forming method of bismuth telluride thermoelectric material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] S1. Raw material crushing: Take out the raw materials tellurium ingot, bismuth ingot and selenium ingot from the vacuum cabinet respectively, put them into the powder tank and smash the materials into small pieces. Open the lid of the powder tank, and use tweezers to pick up small pieces with a diameter of no more than 30mm and place them on clean filter paper. Crushing the raw material into small pieces can make the raw material smelt better in step S2.

[0049] S2. High-frequency melting: Weigh the raw materials obtained in step S1 according to the stoichiometric ratio of Bi2Te2.8Se0.2, mix the raw materials and put them into a graphite crucible for melting in a vacuum high-frequency induction melting furnace with a heating rate of 20oC / min. The melting temperature is 800oC, and the melting time is 4h. Using high-frequency melting can overcome the defects of segregation or free of material components to the greatest extent, and prepare materials with uniform componen...

Embodiment 2

[0054] S1. Raw material crushing: Take out the raw materials tellurium ingot, bismuth ingot and antimony ingot from the vacuum cabinet respectively, put them into the powder tank and smash the materials into small pieces. Open the lid of the powder tank, and use tweezers to pick up small pieces with a diameter of no more than 30mm and place them on clean filter paper. Crushing the raw material into small pieces can make the raw material smelt better in step S2.

[0055] S2. High-frequency melting: Weigh the raw materials obtained in step S1 according to the stoichiometric ratio of Bi0.4Sb1.6Te3, mix the raw materials and put them into a graphite crucible for melting in a vacuum high-frequency induction melting furnace with a heating rate of 25oC / min. The melting temperature is 850oC, and the melting time is 3h. Using high-frequency melting can overcome the defects of segregation or free of material components to the greatest extent, and prepare materials with uniform componen...

Embodiment 3

[0060] S1. Raw material crushing: Take out the raw materials tellurium ingot, bismuth ingot and selenium ingot from the vacuum cabinet respectively, put them into the powder tank and smash the materials into small pieces. Open the lid of the powder tank, and use tweezers to pick up small pieces with a diameter of no more than 30mm and place them on clean filter paper. Crushing the raw material into small pieces can make the raw material smelt better in step S2.

[0061] S2. High-frequency melting: Weigh the raw materials obtained in step S1 according to the stoichiometric ratio of Bi2Te2.7Se0.3, mix the raw materials and put them into a graphite crucible for melting in a vacuum high-frequency induction melting furnace with a heating rate of 20oC / min. The melting temperature is 800oC, and the melting time is 4h. Using high-frequency melting can overcome the defects of segregation or free of material components to the greatest extent, and prepare materials with uniform componen...

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Abstract

The invention relates to a hot extrusion forming method of a bismuth telluride thermoelectric material. The method comprises the following steps: obtaining elementary substance raw materials of Bi, Te, Sb and Se; crushing the simple substance raw material into blocks with preset diameters; weighing the blocks according to a preset stoichiometric ratio; mixing the blocks, and smelting in a vacuum high-frequency induction smelting furnace in a first protective gas environment to obtain a cast ingot; the cast ingot is subjected to ball milling, and powder is obtained; screening the powder by using an ultrasonic inspection sieve; loading the screened powder into an extrusion die, and carrying out hot extrusion in a second protective gas environment to obtain a bismuth telluride bar; and placing the bismuth telluride bar in a tubular atmosphere furnace, and carrying out heat treatment in a third protective gas environment to obtain the bismuth telluride thermoelectric material. According to the method, powder metallurgy and a hot extrusion process are combined, so that precise forming and performance improvement of the high-brittleness bismuth telluride thermoelectric material are realized, and the problems of low reliability and performance degradation of a thermoelectric refrigerator are solved.

Description

technical field [0001] The invention belongs to the technical field of thermoelectric materials, and in particular relates to a hot extrusion molding method for bismuth telluride thermoelectric materials. Background technique [0002] As a functional material that can directly convert thermal energy and electrical energy, the essence of thermoelectric materials is to use the transport characteristics of material carriers to realize thermoelectric power generation and thermoelectric cooling through the Seebeck effect or Peltier effect. For nearly half a century, people have carried out in-depth research on thermoelectric materials, and found that bismuth telluride alloy and its solid solution are the best thermoelectric materials at room temperature. Bismuth telluride has a large Seebeck coefficient and low thermal conductivity, and the ZT value at room temperature is close to 1, so it is widely used in thermoelectric cooling devices. [0003] Bismuth telluride is an interme...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F3/20C22C1/04B22F3/24B22F9/04H01L35/34H01L35/16
CPCB22F3/20B22F3/24B22F9/04B22F2003/208B22F2003/248B22F2009/043C22C1/047H10N10/852H10N10/01
Inventor 孔繁宇吴跃齐雅青侯旭峰任保国
Owner CHINA ELECTRONIC TECH GRP CORP NO 18 RES INST
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