Influence of germanium on lattice heat conductivity of magnesium silicide- based solid solutions

Abstract
Detailed researches on thermoelectric Mg2Х-based solid solution materials have been carried out lately all over the world (Х = Si, Ge, Sn). These materials are good alternative for widely used dielectrics which are toxic and expensive. Pure compounds of Mg2Х have high heat conductivity which is an adverse factor for manufacturers. Mg2Si-Mg2Sn, Mg2Si-Mg2Ge, Mg2Ge-Mg2Sn solid solutions allows decreasing lattice heat conductivity significantly. Mg2Si-Mg2Sn solution has maximum decrease due to great difference between atomic masses of silicon and stannic. Mg2Si-Mg2Sn-Mg2Gе solid solutions are considered. Germanium belongs to the same group as silicon and stannic do, compounds making great variety of mutual solid solutions. The influence of 4-5% germanium introduction on lattice heat conductivity is analyzed. Experimental data are compared with theoretical ones and they match to a greater extent. Germanium is shown to have small effect on lattice heat conductivity. There is no need to use germanium that favors thermoelectric generators cost. Need for research on electrical properties of such substances is proved.