Starting with elementary powders, thermoelectric materials Ce_ x Co_4Sb_(12) were prepared by mechanical alloying and spark plasma sintering (MA-SPS). XRD analyses reveal that the expected major phase, named skutterud...Starting with elementary powders, thermoelectric materials Ce_ x Co_4Sb_(12) were prepared by mechanical alloying and spark plasma sintering (MA-SPS). XRD analyses reveal that the expected major phase, named skutterudite was formed in MA process and was kept after SPS. The thermoelectric properties of MA-SPS samples including resistivity, Seebeck coefficient, power factor, thermal conductivity and the dimensionless figure of merit ( ZT ) were studied by varying Ce content and temperature. Depending on Ce levels, both P and N types of thermoelectric semiconductors were obtained. MA-SPS sintered Ce_(1.0)Co_4Sb_(12) exhibits the highest ZT in the range of 100～500 ℃ and the maximum ZT is found at x =1.0 and 400 ℃.展开更多
In this study,a sequence of Ce_(2)[Zr_(1-x)(Co_(1/2)W_(1/2))_(x)]_(3)(MoO_(4))_(9)(CZ_(1-x)(CW)_(x)M)(x=0.02e0.10)ceramics with excellent microwave dielectric properties were obtained by the traditional solid-phase me...In this study,a sequence of Ce_(2)[Zr_(1-x)(Co_(1/2)W_(1/2))_(x)]_(3)(MoO_(4))_(9)(CZ_(1-x)(CW)_(x)M)(x=0.02e0.10)ceramics with excellent microwave dielectric properties were obtained by the traditional solid-phase method.The crystal structure,dielectric properties,and chemical bond characters of the ceramics were characterized and analyzed.X-ray diffraction and Rietveld refinement analysis show that CZ_(1-x)(CW)_(x)M could form a single-phase of the triangular crystal system in the entire doping range.The microstructure of the ceramic samples was obtained by scanning electron microscopy.The sintering temperature was reduced and the gain of the sample was refined as the increase of doping ion content.Furthermore,the intrinsic factors affecting the properties of CZ_(1-x)(CW)_(x)M were analyzed by employing P-V-L theory and through in-depth infrared analysis.When x was 0.04 and the sintering temperature was 750C,the best dielectric properties of the samples were achieved,includingεr=9.95,Q·f=80,803 GHz(at 9.99 GHz),and tf=-9.10 ppm/℃.展开更多
文摘Starting with elementary powders, thermoelectric materials Ce_ x Co_4Sb_(12) were prepared by mechanical alloying and spark plasma sintering (MA-SPS). XRD analyses reveal that the expected major phase, named skutterudite was formed in MA process and was kept after SPS. The thermoelectric properties of MA-SPS samples including resistivity, Seebeck coefficient, power factor, thermal conductivity and the dimensionless figure of merit ( ZT ) were studied by varying Ce content and temperature. Depending on Ce levels, both P and N types of thermoelectric semiconductors were obtained. MA-SPS sintered Ce_(1.0)Co_4Sb_(12) exhibits the highest ZT in the range of 100～500 ℃ and the maximum ZT is found at x =1.0 and 400 ℃.
基金This work was supported by the National Natural Science Foundation of China(No.51972143,51872119)This project is supported by State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(No.KFZD202101).
文摘In this study,a sequence of Ce_(2)[Zr_(1-x)(Co_(1/2)W_(1/2))_(x)]_(3)(MoO_(4))_(9)(CZ_(1-x)(CW)_(x)M)(x=0.02e0.10)ceramics with excellent microwave dielectric properties were obtained by the traditional solid-phase method.The crystal structure,dielectric properties,and chemical bond characters of the ceramics were characterized and analyzed.X-ray diffraction and Rietveld refinement analysis show that CZ_(1-x)(CW)_(x)M could form a single-phase of the triangular crystal system in the entire doping range.The microstructure of the ceramic samples was obtained by scanning electron microscopy.The sintering temperature was reduced and the gain of the sample was refined as the increase of doping ion content.Furthermore,the intrinsic factors affecting the properties of CZ_(1-x)(CW)_(x)M were analyzed by employing P-V-L theory and through in-depth infrared analysis.When x was 0.04 and the sintering temperature was 750C,the best dielectric properties of the samples were achieved,includingεr=9.95,Q·f=80,803 GHz(at 9.99 GHz),and tf=-9.10 ppm/℃.
