Thermal Diffusivity Measurements of the Layered Materials by the Laser Flash Method
Thermal Diffusivity Measurements of the Layered Materials by the Laser Flash Method
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激光闪光法测量层状材料的热扩散率
DOI：
10.4028/www.scientific.net/msf.631-632.103
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
F. Ono
中科院分区：
文献类型：
--
作者：
M. Akoshima;T. Baba;Mitsue Ogawa;Takashi Tanaka;Y. Harada;A. Kawasaki;F. Ono
采用陶瓷基热障涂料作为燃气轮机叶片的热防护和耐磨防护。涂层的导热系数、热扩散率和热容等热物理性能的评价是非常必要的。由于涂层附着在基材上，因此很难单独测量这些性能。为了评价涂层的热扩散率，我们尝试应用基于响应函数法的多层模型，建立了激光闪光法测量涂层热扩散率的程序。通过对博士刀片流延法制备的双层陶瓷样品从室温到约1000K的测量，验证了该方法的有效性。在SUS304衬底上热喷涂CoNiCrAlY涂层也被用于验证。附着在基材上的涂层的热扩散率与从基材上去除的单层涂层的热扩散率基本一致。在陶瓷样品的情况下，涂层的热扩散率包括界面热阻在约20%的不确定度内确定。比较了不同厚度热喷涂制备的样品的激光闪光测量信号，找出了不同厚度的样品之间的差异。结果表明，该方法具有足够的分辨率来检测厚度约为200m的变化引起的隔热效应。结果表明，该方法和分析方法对涂层在不剥离基板的情况下的热扩散率估算是有效的。
Ceramics-based thermal barrier coatings are used as heat and wear shields of blades of gas turbine. There are strong needs to evaluate thermophysical properties of coatings, such as thermal conductivity, thermal diffusivity and heat capacity of them. Since coatings are attached on substrates, it is not easy to measure these properties separately. In order to evaluate the thermal diffusivity of coating attached on substrate, we have tried to apply the multi-layer model based on the response function method and established a procedure for the measurement by the laser flash method. We verified the procedure by the measurements from room temperature to about 1000 K for two-layer ceramics sample prepared by the doctor blade tape casting method. The thermally sprayed CoNiCrAlY coating on the SUS304 substrate was also used for verification. The thermal diffusivity of coating attached on substrate approximately agreed with that of the single-layer coating removed from substrate. In the case of the ceramics sample, the thermal diffusivity of the coating including the interfacial thermal resistance determined within about 20 % uncertainty. We compared the laser flash measurement signals of the samples prepared by the thermal spraying with variant thickness and found the difference among them. It was found that the procedure has enough resolution to detect the heat shield effect caused by the change with about 200 m in thickness. The result shows that the procedure and analysis were practically effective for the thermal diffusivity estimation of coating attached on the substrate without remove from substrate.