Method for preparing Bi-Sb-Te series thermoelectric material

Abstract

The invention provides a method for preparing thermoelectrical material in Bi-Sb-Te system, which comprises: preparing raw material powders in atom rate that Bi:Sb:Te=2x:2-2x:3, while 0.1<=x<=0.3; mixing and ball grinding it with high-energy to attain alloy powder, while the ball material mass percentage is 10:1-20:1, the rotational speed of ball grinding is 300-400r / min, the time of ball grinding is 8-12hours, and ball grinding uses inertia gas protection; activating said alloy powder with plasma to be sintered, while the temperature increase speed is 30-100Deg. C / min, the sintering temperature is 300-500Deg. C, the pressure when temperature increases is 15-25MPa, the pressure at constant temperature is 40-60MPa, and the time for constant temperature is 10-30mins; and the whole sintering process is process under the inertia gas protection or vacuum condition; the thermolelectrical valve at room temperature can reach 5.26*10-3 / K.

Description

technical field [0001] The invention belongs to the technical field of preparation of thermoelectric materials, and in particular relates to a preparation method of Bi-Sb-Te series thermoelectric materials. Background technique [0002] Bi-Sb-Te series thermoelectric materials are currently one of the most superior thermoelectric materials for semiconductor refrigeration, and have been used in various fields such as microelectronics, cooling and constant temperature of optoelectronic devices, biochips, medical equipment, and special refrigeration for national defense. . The preparation of Bi-Sb-Te thermoelectric materials usually adopts traditional single crystal preparation methods, such as zone melting method, Bridgman method and crystal pulling method. Although the uniform orientation of single crystal materials makes it perform better than polycrystalline materials in a certain direction, the preparation method of single crystal materials and the single crystal material...

AI Technical Summary

Problems solved by technology

Although the uniform orientation of single crystal materials makes it perform better than polycrystalline materials in a certain direction, the preparation method of single crystal materials and the single crystal materials themselves have the following disadvantages that are difficult to overcome: (1) The conditions for single crystal growth are harsh , long preparation cycle, high energy consumption and high cost

(2) The two ends of the ingot material prepared by the zone melting method will produce a high-concentration impurity segregation zone, which must be cut off and cannot be returned to the furnace for reuse, so the utilization rate of the material is low

(3) The Bi-Sb-Te series compound has a hexahedral layered structure, in which two adjacent Te atomic layers are bonded by van der Waals force, the bonding force is weak, and the crystal is easily cleaved and broken along this plane; single crystal During the preparation process of the method, the material grows directional and the grains are coarse, so its brittleness and poor machining performance bring difficulties to the subsequent modular processing and cause a lot of unnecessary waste

Defects such as high energy consumption, long cycle time, and low material utilization rate during the preparation of single crystal materials have not been improved (see ① Chen Lidong, Jiang Jun, Bai Shengqiang, Chinese patent, CN1488572A

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