The porous p-type BiSbTebulks containing irregularly and randomly oriented pores were obtained by artificially controlling the relative density of sintered samples during resistance pressing sintering process. It is d...The porous p-type BiSbTebulks containing irregularly and randomly oriented pores were obtained by artificially controlling the relative density of sintered samples during resistance pressing sintering process. It is demonstrated that the thermoelectric performances are significantly affected by the porous structure, especially for the electrical and thermal conductivity due to the enhanced carrier scattering and phonon scattering. The increasing porosity resulted in the obvious decrease in electrical and thermal conductivity, and little change in Seebeck coefficients. It is encouraging that the reduction of thermal conductivity can compensate for the deterioration of electrical performance, leading to the enhancement in thermoelectric figure of merit(ZT). The maximum ZT value of 1.0 was obtained for the sample with a relative density of 90% at 333 K. Unfortunately, the increase in porosity also brought in obvious degradations in Vickers hardness from 51.71 to 27.74 HV. It is worth mentioning that although the Vickers hardness of the sample with a relative density of 90% decreased to 40.12 HV, it was still about twice as high as that of the zone melting sample(21.25 HV). To summarize, introducing pores structure into bulks properly not only enhances the ZT value of BiTebased alloys, but also reduces the use of raw materials and saves production cost.展开更多
基金supported financially by the National Natural Science Foundation of China(Nos.11074195 and 51674181)the Key Projects of Hubei Provincial Department of Education(No.D20151103)
文摘The porous p-type BiSbTebulks containing irregularly and randomly oriented pores were obtained by artificially controlling the relative density of sintered samples during resistance pressing sintering process. It is demonstrated that the thermoelectric performances are significantly affected by the porous structure, especially for the electrical and thermal conductivity due to the enhanced carrier scattering and phonon scattering. The increasing porosity resulted in the obvious decrease in electrical and thermal conductivity, and little change in Seebeck coefficients. It is encouraging that the reduction of thermal conductivity can compensate for the deterioration of electrical performance, leading to the enhancement in thermoelectric figure of merit(ZT). The maximum ZT value of 1.0 was obtained for the sample with a relative density of 90% at 333 K. Unfortunately, the increase in porosity also brought in obvious degradations in Vickers hardness from 51.71 to 27.74 HV. It is worth mentioning that although the Vickers hardness of the sample with a relative density of 90% decreased to 40.12 HV, it was still about twice as high as that of the zone melting sample(21.25 HV). To summarize, introducing pores structure into bulks properly not only enhances the ZT value of BiTebased alloys, but also reduces the use of raw materials and saves production cost.
