Heat capacities and thermal conductivities of palladium and titanium melts and correlation between thermal diffusivity and density of states for transition metals in a liquid state
Heat capacities and thermal conductivities of palladium and titanium melts and correlation between thermal diffusivity and density of states for transition metals in a liquid state
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DOI：
10.1016/j.molliq.2020.115138
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发表时间：
2021-02
影响因子：
6
通讯作者：
Manabu Watanabe;M. Adachi;H. Fukuyama
中科院分区：
文献类型：
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作者：
Manabu Watanabe;M. Adachi;H. Fukuyama
用电磁悬浮技术测量了Pd和Ti熔体在静磁场中的807和940 nm的法向光谱发射率、恒压热容和热导率。静磁场抑制了电磁悬浮样品上的表面振荡、平移运动和对流。悬浮的Pd和Ti熔体中的对流得到了充分的抑制，可以用静磁场测量导热系数。在实验温度范围内，Pd和Ti熔体的发射率和热容与温度无关。在实验温度范围内，Pd熔体的导热系数不变，而Ti熔体的导热系数随温度升高而增大。将测量的发射率和导热系数与自由电子模型如Drude模型和Wiedemann-Franz定律的计算值进行了比较。在此基础上，讨论了过渡金属费米能态密度与热扩散系数之间的关系。
The normal spectral emissivities at 807 and 940 nm, heat capacities at constant pressure and thermal conductivities of Pd and Ti melts were measured using an electromagnetic levitation technique in a static magnetic field. The static magnetic field suppresses the surface oscillation, translational motion, and convection flow on electromagnetically levitated samples. The convections in the levitated Pd and Ti melts were suppressed sufficiently for thermal conductivity measurement by the static magnetic field. The emissivities and heat capacities of Pd and Ti melts showed no temperature dependence within the experimental temperature region. The thermal conductivity of Pd melt was constant within experimental temperature region, on the other hand, the thermal conductivity of Ti melt increased with increasing temperature. The measured emissivity and thermal conductivity were compared with values evaluated by a free electron model such as Drude model and Wiedemann-Franz law. Based on the results, the correlation between density of states (DOS) at Fermi energy and thermal diffusivities for transition metals was discussed.