Method of quickly preparing Mg-Si-Sn-based thermoelectric material in controllable manner

Abstract

The invention relates to a method of quickly preparing Mg-Si-Sn-based thermoelectric material in a controllable manner. The method comprises the following steps: 1) dosing and tabletting, namely in the presence of inert gases, weighing Mg powder, Mg2Si powder, Sn powder and Sb powder which are used as raw materials according to a stoichiometric ratio of each element in a chemical formula Mg2(1+z)Si1-xSnxSby (z is not smaller than 0 and not greater than 0.12, x is not smaller than 0 and not greater than 1.0, and y is not smaller than 0 and not greater than 0.025), and mixing and uniformly pressing the raw materials into blocks; 2) sealing the blocks in vacuum, then, heating the blocks to 823-833K, carrying out heat preservation for 5-10 minutes, and cooling the blocks along with a furnace; 3), grinding products obtained in the step 2) into powder in the presence of inert gases, and carrying out discharge plasma activated sintering to obtain the high-performance Mg-Si-Sn-based thermoelectric material. The method has the characteristics of simple process, low energy consumption, short preparation period, good repeatability, excellent thermoelectric properties of obtained block materials, and the like.

Description

technical field [0001] The invention belongs to the field of new energy materials, and in particular relates to a method for rapid and controllable preparation of Mg-Si-Sn-based thermoelectric materials. Background technique [0002] The energy issue is an important issue related to the development of human society. In recent years, with the decreasing reserves of fossil fuels such as coal, oil, and natural gas, and the resulting environmental problems such as the greenhouse effect, dust pollution, and acid rain becoming more and more serious, the development of environmentally friendly new energy has become a priority for researchers in various countries. a consensus. People's requirements for new energy technologies mainly include the following points: (1) extensive and renewable energy sources; (2) environmentally friendly; (3) simple equipment and easy to use; (4) low cost. Representatives of these new energy sources include solar energy, water energy, wind energy, tid...

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Problems solved by technology

However, since the melting point of Si is as high as 1687K, the melting method has extremely high requirements on equipment, and this preparation process cannot solve the high-temperature volatilization and dissipation of Mg caused by the high melting point difference between Mg and Si, and the easy oxidation of Mg at high temperature or contact with the container. Reaction and other problems; while the mechanical alloying method has the disadvantages of being easily mixed with impurities and oxidation, and Mg is very easy to adhere to the surface of the ball and the inner wall of the ball mill, causing the actual composition to deviate from the nominal stoichiometric ratio, so it is difficult to produce purer Mg 2 Si 1－x sn x compound; vacuum induction melting has extremely high requirements on equipment, and it is difficult to solve the problem of component segregation; adopt B 2 o 3 Although the flux method can use the liquid seal to reduce the contact between the sample and the air, but due to the Mg and B 2 o 3 It can be reacted (magnesia thermal reduction method to prepare boron powder: 3Mg+B 2 o 3 →3MgO+2B), resulting in the mixing of MgO into the Mg-Si-Sn sample; the tantalum tube packaging has problems such as high cost and complicated process; the two-step solid-state reaction has the disadvantages of long preparation period and poor repeatability

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