Method for preparing grain-refining preferred tropism Bi2Te3 thermoelectric materials

Abstract

The invention relates to the preparing method of a fine-grained thermoelectric material with a preferred orientation of Bi2Te3 and belongs to the field of energy material technology. The method consists of two parts of synthesizing and moulding forming of compound. Weighed and proportioned, the highly-purified Bi and simple substance Te are conducted a high-powered ball milling at a certain rotating speed and under the protection of inert gases. The dry-milled compound is wet-milled and then dried to obtain a finely pulverized powder of Bi2Te3. The mass material is obtained in the process of molding through spark plasma sintering, which includes two steps, i.e. firstly, the high-dense fine-grained mass of Bi2Te3 is obtained through spark plasma sintering; secondly, a hot-forging processing is conducted to obtain a textured structure through the technique of spark plasma sintering. As the spark plasma sintering has the advantages of short duration and relatively low sintering temperature, a well-distributed fine microstructure with a preferred orientation can be obtained by controlling the sintering technique. The method improves the thermoelectrical and mechanical properties of the material by controlling the crystal grain growth and the crystal grain orientation, has the advantages of simple technique and short synthesizing and molding period.

Description

technical field [0001] The invention belongs to the technical field of energy materials, and in particular provides a fine-grain preferred orientation Bi 2 Te 3 The preparation method of the thermoelectric material involves mechanical alloying (Mechanical Alloying, MA) and spark plasma sintering (Sparkplasma sintering, SPS) preparation processes. Background technique [0002] In 1823, German physicist Seebeck discovered the thermoelectric effect for the first time, thus beginning human research on thermoelectric materials. Bi 2 Te 3 Base alloy is currently the thermoelectric material with the best performance at room temperature, and it is also one of the earliest and most mature thermoelectric materials. It has a large Seebeck coefficient and low thermal conductivity. The dimensionless thermoelectric figure of merit ZT at room temperature is around 1. At present, most of the refrigeration and low temperature temperature difference conversion electric energy components a...

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Problems solved by technology

[0004] Judging from the current research, the preparation of Bi with fine grains and high ori

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