Mechanical and transport properties of pseudo-binary alloys (PbTe)1-x-(SnTe)x by pressureless sintering

The pseudo-binary alloys (PbTe)(1-x)-(SnTe)(x) in the whole composition range were prepared by pressureless sintering. It was found that the electrical conductivities increased with mole fraction x (xless than or equal to0.6), and then decreased. A transition from extrinsic to intrinsic state for the carriers occurred while temperature was elevated to 573 K. The temperature, corresponding to the maximum Seebeck coefficients for the alloys which decreased with mole fraction x, shifted to higher temperature region when xless than or equal to0.6, and then remained constant. In addition, thermal conductivities were observed to be very low, especially for the alloys with smaller x values, mainly attributed to the low densities and phonon-grain boundary scattering for the compacts. Higher Z values were observed in the higher temperature region, especially for the alloy with x=0.4. Higher compression strengths (310-330 MPa) and hardness (HV95) were obtained for the alloys with mole fraction x ranging from 0.2 to 0.6, which is closely related to the higher densities of the alloys. (C) 2003 Elsevier B.V. All rights reserved.