Thermoelectric Properties of Pb_1-xSn_xTe Solid-Solution and Pb_0.75Sn0.25Te-Pb_0.50Sn_0.50Te Segment

摘要

The stoichiometric lead and tin tellurides and its solid solution were prepared using a rocking-freezing furnace with rocking cycle of 0.2 Hz. The carrier concentration and maximum power factor for pb_1-xSn_xTe increased and shifted to higher temperature with increasing x. The segmented thermoelectric materials with different x were joined by the liquid phase diffusion bonding under a pressure of 2.0 MPa at 700 K for 1800 s in an Ar-3 percent H_2 atmosphere using tin film as an intermediate material. The joints demonstrated that an electrical and the thermal resistance of the interface were found to be very low. It indicated that the effect of the junction on the electrical properties and the resistivity was negligible. The segmented material showed a higher effective maximum power P_max than that of each monolithic material of Pb_1-xSn_xTe at the examined temperature range. The P_max of the segmented material was evaluated to be 23 W/m at temperature difference of 300 K and this value agreed with the theoretical one expected from the properties of monolithic materials.