Papers by Author: Sheng Qiang Bai

Abstract: Sr-filled skutterudite compounds SryCo4Sb12 (y=0-0.20) were synthesized by melting method. XRD and EPMA results revealed that the obtained samples are single skutterudite phase with homogeneous chemical composition. The lattice parameters increase linearly with increasing Sr content in the range of y=0-0.20. The thermal conductivity, electrical conductivity and Seebeck coefficient were measured in the temperature range of 300-850K. The measurement of Hall effect was performed by Van de Pauw method at room temperature. The obtained Sr-filled skutterudite exhibits n-type conduction. The absolute value of the Seebeck coefficient of SryCo4Sb12 decreases with the increase of Sr content. The electrical conductivity increases with the increase of Sr content. The lattice thermal conductivity of SryCo4Sb12 is significantly depressed as compared with unfilled CoSb3. The maximum dimensionless thermoelectric figure of merit is 0.7 for Sr0.20Co4Sb12 at 850K. Further optimization of chemical composition would improve the thermoelectric performance.

Abstract: Ti5Si3-TiC-Ti3SiC2 composites containing different Ti3SiC2 volume fractions from 0 to 50% were in-situ fabricated by spark plasma sintering using Ti and SiC powders through adjusting the molar ratio of Ti to SiC. The morphologies of the fracture surfaces were analyzed by scanning electron microscopy (SEM). The room temperature mechanical properties of composites including hardness, bending strength and fracture toughness were tested.

Abstract: In-situ toughened TiC-Ti5Si3 composites were fabricated using reactive sintering of Ti and SiC via spark plasma sintering (SPS). The focus of this work on the content of TiC in final composites was different. The phase constituents and microstructures of the samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Fracture toughness at room temperature was also measured by indentation tests. The results showed that the corporation of TiC greatly enhances the fracture toughness of TiC-Ti5Si3 composites.

Abstract: The n-type Bi2(Te,Se)3 thermoelectric materials doped with different contents of TeI4 were fabricated through the spark plasma sintering (SPS) technique at 693K under a pressure of 60MPa. The sintered materials were rather dense and showed preferred grain orientation. Electrical conductivity (s), Seebeck coefficient (a), and thermal conductivity (k) were measured in the temperature range of 300-500K. The optimal figure of merit ZT (ZT=a2sT/k) of the sintered material in the direction perpendicular to the pressing direction showed a value of 0.75 for the sample containing 0.14wt% TeI4.