A thermographic technique for the simultaneous estimation of in-plane and in-depth thermal diffusivities of TBCs
A thermographic technique for the simultaneous estimation of in-plane and in-depth thermal diffusivities of TBCs
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DOI：
10.1016/j.surfcoat.2010.11.013
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发表时间：
2011-02-15
影响因子：
5.4
通讯作者：
Capelli, S.
中科院分区：
文献类型：
--
作者：
Bison, P.;Cernuschi, F.;Capelli, S.
热障涂层的热物理和力学性能的绝对值和各向异性受显微组织的影响很大。因此，热性能随不同方向特定微观结构的变化是值得研究的。在本工作中，描述了一种能够在一次实验中估计TBC的面内和深度热扩散率的热成像技术，并将对三种不同独立式APS TBC样品的测量结果与三点弯曲试验测得的面内弹性模量值进行了比较。这取决于微观结构和热传播方向。TbC的热扩散率在3-7×10~(-7)m~(-7)m(2)S(~(-1))范围内。这项技术允许测量沿两个垂直方向的热扩散率，如果存在的话，突出任何各向异性的面内结构。一个分析模型已经被应用于半定量估计三个样品的深度和面内的热扩散率，从扫描电子显微镜获得的样品显微图像的定量图像分析表征开始。模型与实验数据的一致性令人满意。该模型解释了在某些样品中观察到的热扩散率的各向异性。(C)2010爱思唯尔B.V.保留所有权利。
Absolute values and anisotropy of thermo-physical and mechanical properties of TBC are significantly affected by the microstructure. The thermal properties as a function of the specific microstructure along the different directions are therefore worth studying.In the present work a thermographic technique able to estimate in a single experiment both in-plane and in-depth thermal diffusivities of TBC has been described and the results obtained on three different freestanding APS TBC samples will be compared with the in-plane elastic modulus as measured by the three-point bending test. Depending on the microstructure and on the heat propagation direction. TBC thermal diffusivity in the range of 3-7 x 10(-7) m(2) s(-1) has been found. The technique allows measuring the thermal diffusivity along two orthogonal directions highlighting, when present, any anisotropic in-plane structure.An analytical model has been applied to semi-quantitatively estimate both in-depth and in-plane thermal diffusivities of the three samples starting from quantitative image analysis characterization of sample micrographs obtained by scanning electron microscopy. The agreement between model and experimental data resulted quite satisfactory. The model accounts for the anisotropy of thermal diffusivity observed in some samples. (C) 2010 Elsevier B.V. All rights reserved.