| abstract |
The invention provides a thermoelectric material exhibiting a high dimensionless figure of merit and a method for producing the thermoelectric material effectively. The thermoelectric material is essentially formed of an Mg 2 Si-based compound represented by the chemical formula Mg 2-xyz Al x Zn y Mn z Si (x ≠ 0, y ≠ 0, z ≠ 0, 0.04 ≦ y / x ≦ 0.6 and 0.013 ≦ z / x ≦ 0.075), wherein the total amount of Al, Zn and Mn is 0.3 at% to 5 at%. The Mg 2-xyz Al x Zn y Mn z is provided in the form of a Mg alloy. In the manufacturing method, a Mg alloy is mixed with Si powder so that the atomic ratio of Mg alloy to Si is set to 2: 1, the Mg alloy is heated by the liquid / solid phase reaction process in an inert gas atmosphere at a temperature , which is equal to or higher than the melting point of the Mg alloy, allowed to react with Si while the Mg alloy coexists with Si in the solid state in the liquid state; the resulting product is cooled after completion of the reaction to thereby prepare a Mg 2 Si-based porous compound; the Mg 2 Si-based compound is crushed in an inert gas atmosphere; and the thus crushed product is pressure sintered under vacuum or in an inert atmosphere. |