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Hydrothermal synthesis and thermoelectric properties of PbS

Zhang H., Wang H., Zhu H., Li H., Su T., Li S., Hu M., Fan H.

Materials Science Poland

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2016

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Vol. 34, No. 4

754--759

EN

In this paper, hydrothermal approach combined with high pressure sintering method was employed to synthesize PbS. The X-ray diffraction results show that single phase PbS can be obtained by a simple hydrothermal method. The scanning electron microscope results show that the PbS sample has nearly cubic shape and preserves well crystallized and coarse grains after high pressure sintering. The thermoelectric performance of PbS obtained in this study is comparable to that of a PbS sample prepared by conventional method. The carrier type and concentration of PbS can be tuned effectively by doping with Bi. The maximum figure of merit for PbS doped with 1 mol% Bi reaches 0.44 at 550 K, which is about 30 % higher than that of undoped PbS. These results indicate that hydrothermal method provides a viable and controllable way of tuning the electrical transport and thermoelectric properties for PbS.

2

Variation of Wave Velocity and Porosity of Sandstone after High Temperature Heating

Sun Q., Zhang W., Su T., Zhu S.

Acta Geophysica

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2016

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Vol. 64, no. 3

633--648

EN

This paper reports the variations of mass, porosity, and wave velocity of sandstone after high temperature heating. The range of temperature to which the sandstone specimens have been exposed is 25-850°C, in a heating furnace. It has been shown that below 300°C, porosity and wave velocity change very little. Above 300°C, there is a rapid increase in porosity, but the wave velocity decreases significantly. The results of thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC) and mercury intrusion porosimetry (MIP) suggest that a series of changes occurred between 400 and 600°C in sandstone could be responsible for the different patterns of variation in porosity and wave velocity

3

High temperature thermoelectric properties of PbTe prepared by high pressure method

Fan H., Su T., Li H., Zeng Y., Li S., Hu M., Ma H., Jia X.

Materials Science Poland

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2015

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Vol. 33, No. 1

152--156

EN

Thermoelectric materials PbTe were synthesized by high pressure method. The microstructure and temperature dependence of thermoelectric properties were studied. Some second phases with nano-structure were found in the high pressure synthesized samples. Compared with that of PbTe prepared at an atmospheric pressure, the samples prepared by high pressure method had smaller grain sizes, lower resistivity and lower phonon thermal conductivity. The maximum figure of merit, Z reached 8.86 × 104 K1 for the sample prepared at 4 GPa. This value was about twice times higher than that of the sample prepared at ambient pressure and it matched to that of highly doped PbTe.

4

Fast preparation and thermoelectric properties of Zn4Sb3 by HPHT

Su T., Zhu H., Ma H., Li S., Hu M.

Materials Science Poland

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2012

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Vol. 30, No. 4

355--358

EN

In this paper, crack-free bulk thermoelectric material Zn4Sb3 was prepared rapidly by high pressure and high temperature (HPHT) method. Near a single-phase Zn4Sb3 specimen was obtained using nominal stoichiometric powder mixtures, which were indexed by powder X-ray diffraction. The temperature-dependent thermoelectric properties including the Seebeck coefficient and electrical resistivity were studied. The maximum power factor of Zn4Sb3 specimen prepared by HPHT reaches 10.8 žW/(cmK 2)at 637 K, which is comparable to the published data. The results show that the HPHT offers potential processing route to produce the thermoelectric material Zn4Sb3 quickly and effectively.