Preparation method for Mg2Si thermoelectricity material

Abstract

The present invention relates to a preparation method for an Mg2Si thermoelectricity material. The method comprises the following steps: (1) uniformly mixing Mg powder and Si powder under an Ar protection atmosphere to obtain a mixture; (2) placing the mixture in a glove box filled with Ar, and placing the glove box in a stainless steel vacuum ball milling tank to carry out intermittent ball milling to obtain uniformly-mixed powder; (3) carrying out tableting on the mixed powder to obtain a Mg-Si mixed powder tablet; (4) loading the Mg-Si mixed powder tablet into a graphite mold, and placing graphite mold in a tube furnace under an Ar atmosphere to carry out primary sintering and thermal insulation to obtain Mg2Si thermoelectricity material alloy powder; (5) carrying out tableting on the Mg2Si thermoelectricity material powder to obtain a Mg2Si alloy tablet; and (6) loading the Mg2Si alloy tablet into the graphite mold and placing the graphite mold in the tube furnace under an Ar atmosphere to carry out secondary sintering and thermal insulation to obtain the Mg2Si block thermoelectricity material. The preparation method has characteristics of simple process, easy operation and low cost. The obtained Mg2Si thermoelectricity material has characteristics of high product purity, small particle size and uniform distribution.

Description

technical field [0001] The invention relates to a preparation method of a thermoelectric material, in particular to a Mg 2 Preparation method of Si thermoelectric material. Background technique [0002] Thermoelectric materials are functional materials that utilize the movement of carriers inside solids to convert heat and electricity into each other. With the acceleration of global industrialization, energy depletion and environmental pollution have become problems that cannot be ignored by countries all over the world. Since the 1990s, thermoelectric materials have become a research hotspot in material science due to their unique properties. Its thermoelectric conversion efficiency is often characterized by thermoelectric figure of merit Z or dimensionless figure of merit ZT, Z=S 2 / ρκ, where S is the Seebeck coefficient, ρ is the resistivity, and κ is the thermal conductivity. According to existing research, the Mg centered on Mg 2 X (X=Si, Ge, Sn) series intermetalli...

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Problems solved by technology

[0003] At present, due to the volatile oxidation of Mg and the 2 Si compounds have a serious tendency of intergranular embrittlement, making Mg 2 The preparation and application of Si are greatly restricted. The preparation methods of bulk materials are mainly melting method and mechanical alloying method, but the melting method cannot solve the problem caused by the large melting point difference and density difference between Mg and Si. The high-temperature volatilization of Mg, the carbonization reaction of Si and the molten pool, and the two are not easy to mix and react, and the mechanical alloying method will also mix a small amount of impurities and partial oxidation

In order to solve these problems, some new synthesis methods have appeared recently, such as spark plasma sintering, microwave low-temperature solid-phase synthesis, etc. These new synthesis methods are gradually being valued by people because of their high product density, but due to their preparation costs High, out of touch with practical applications, such as to achieve high density requirements, expensive equipment is required, resulting in high preparation costs, and it is not suitable for practical applications

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