Simultaneous determination of the lattice thermal conductivity and grain/grain thermal resistance in polycrystalline diamond
Simultaneous determination of the lattice thermal conductivity and grain/grain thermal resistance in polycrystalline diamond
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DOI：
10.1016/j.actamat.2017.08.007
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发表时间：
2017-10-15
期刊：
影响因子：
9.4
通讯作者：
Kuball, M.
中科院分区：
文献类型：
--
作者：
Anaya, J.;Bai, T.;Kuball, M.
利用TiO2纳米粒子辅助拉曼热像仪和皮秒时域热反射（TDTR）测量了聚晶金刚石在成核区附近的面内和面间导热系数。该信息已与利用真实晶粒结构的有限元热模型相结合，包括通过透射电子显微镜（TEM）提取的薄膜的晶粒取向信息。该方法允许同时确定晶粒之间的热阻和样品的晶格热导率，而无需任何可调参数。结果表明：近成核金刚石的晶格导热系数比Ha单晶金刚石小5 ~ 8倍；晶粒之间的热阻比分子动力学模拟预测的值至少高一个数量级。最后，我们展示了在多晶金刚石中观察到的热导率的各向异性是如何自然地从其晶粒结构和晶界热阻中产生的。(C) 2017年作者。由Elsevier Ltd代表Acta Materialia Inc出版。
The in-plane and cross-plane thermal conductivity of polycrystalline diamond near its nucleation region have been measured by Raman thermography assisted by TiO2 nanoparticles and by picosecond time domain thermoreflectance (TDTR). This information has been combined with a finite element thermal model making use of the real grain structure, including information on the grain orientation, of the film extracted by transmission electron microscopy (TEM). This methodology allows to simultaneously determine the thermal resistance between grains and the lattice thermal conductivity of the sample without any adjustable parameter. The results show that the lattice thermal conductivity of the near nucleation diamond is 5-8 times smaller than the one observed in Ha single-crystalline diamond; the thermal resistance between grains is at least one order of magnitude higher than values predicted by molecular dynamic simulations. Finally, we show how the anisotropy in thermal conductivity observed in polycrystalline diamond naturally emerges from its grain structure and the thermal resistance at grain boundaries. (C) 2017 The Authors. Published by Elsevier Ltd on behalf of Acta Materialia Inc.