Microstructure and high-temperature thermoelectric properties of polycrystalline CuAl1−xMgxO2 ceramics

We investigated the effect of Mg-substitution on the microstructure and high-temperature thermoelectric properties of CuA1 1-x Mg x O 2 (0 ≤ x ≤ 0. 2) fabricated by the tape casting method. The sintered CuA1 1-x Mg x O 2 bodies crystallized in CuA1 1-x Mg x O 2 solid solutions along with MgAl 2 O 4 and Cu 2 MgO 3 phases. Mg substitution up to x= 0.12 in the CuA1 1-x Mg x O 2 yielded a higher electrical conductivity and lower Seebeck coefficient mainly because of an enhanced carrier density. The highest value of the power factor (3.47 x 10 -5 W m -1 K -2 ) was attained for CuA1 0.88 Mg 0.12 O 2 at 800 °C. It is demonstrated that Mg substitution is highly effective for improving high-temperature thermoelectric properties.