fig3

Figure 3. (A) Comparison of measured contact resistance before and after aging for ~2100 h at 573 K for the single TE leg composed of NiFe and n-type Mg_3+δBi_1.5Sb_0.5. Aging-time dependence of (B) the resistivity of the TE material extracted from the slopes of the measured contact resistance curves [as shown, for example, in (A)] of different samples as specified and (C) the contact resistivity of single M/TE legs composed of n-type Mg_3+δBi_1.5Sb_0.5 and different contact materials as specified. (D) contact resistivity of single TE legs composed of n-type Mg_3+δBi_1.5Sb_0.5 and different contact materials as specified after temperature cycling and quenching. (E) temperature-dependent CTE values of NiFe, NiCrFe, and Mg_3+δBi_1.5Sb_0.5 in comparison with those of Ni and Fe.