Preparation method for Mg3Sb2-based thermoelectric material

Abstract

Provided is a preparation method for a Mg3Sb2-based thermoelectric material. A Mg3-xAxSb2-yBy block is prepared through the method combining induction smelting and the spark plasma sintering (SPS) technology; A is Ag, or Cu or the like, B is Si, or Ge, or Sn or the like, x is larger than or equal to 0 but smaller than or equal to 0.30, and y is larger than or equal to 0 but smaller than or equal to 0.20. The method includes the following steps that firstly, under the protection of high-purity argon gas which is deoxidized through an efficient deoxidizing agent, elementary raw materials are weighed according to stoichiometric ratios and placed into quasi-sealed smelting equipment to be smelted to ingots, and then the ingots are crushed; the crushed ingots are placed into a sintered carbide ball milling tank, and ball milling is carried out through mechanical ball milling equipment under the high-purity argon atmosphere; and then the ball-milled powder is loaded into a graphite die and then placed in an SPS cavity, and the high-compactness block is obtained after sintering under the vacuum atmosphere. According to the preparation method, cost is low, the ingredient application range is wide, operation is easy, reliability is high, and process parameters are easy to control; the problem that the Mg element is volatile and prone to oxidation can be solved, and the compactness and machinability of the material are improved.

Description

Technical field [0001] The invention belongs to the technical field of preparation of semiconductor thermoelectric materials and relates to Mg 3 Sb 2 Preparation method of base thermoelectric material. Background technique [0002] Thermoelectric material is a kind of functional material that realizes the mutual conversion of electric energy and heat energy through the movement of carriers (electrons or holes) inside a solid, and has broad application prospects in cooling or heating. The main properties of thermoelectric materials use dimensionless figure of merit ZT=Tα 2 σ / κ characterization. Here α is the Seebeck coefficient of the material, σ is the electrical conductivity, and κ is the thermal conductivity. Power generation devices and refrigeration devices made of thermoelectric materials or in the field of industrial waste heat and waste heat power generation, semiconductor refrigeration are widely used. The device made of thermoelectric materials has outstanding advantag...

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Problems solved by technology

In 2006, the Kauzlarich group at the University of California directly synthesized pure Mg using a solid-state reaction method at a relatively low temperature (around 800°C) using a material ratio of Mg / Sb of 3.5:2. 3 Sb 2 , and then pressed at 600°C, and measured its thermoelectric properties. It was measured that the thermoelectric figure of merit ZT at 600°C was only 0.21. low value

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