Application of thermography in the evaluation of early signs of failure of thermal barrier coating systems
Application of thermography in the evaluation of early signs of failure of thermal barrier coating systems
复制标题
热成像技术在评估热障涂层系统早期失效迹象中的应用
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
J. Banks
中科院分区：
文献类型：
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作者：
J. Nunn;S. Saunders;J. Banks
多年来，压电谱(铬荧光)被用来监测热障涂层(TBC)系统中粘结层和热障涂层(TBC)之间形成的热生长氧化物(TGO)中的应力水平。这项工作的目的是观察故障的早期迹象，从而允许操作员在TBC系统发生故障之前安排服务间隔。本文报告了热成像技术作为评估TBC系统“健康状况”的另一种工具的使用。这项技术包括在样品受热时用高空间分辨率红外相机对TBC涂层样品的表面进行成像，并监测TBC外表面的温度。研究了通过衬底的传导加热和辐射加热入射到热障涂层上。早期的结果是令人鼓舞的，显示了使用传导和辐射加热形式获得的热图、使用压电谱获得的一些应力图和直接金相证据之间的明显相关性。对电子束物理气相沉积(EB PVD)和空气等离子喷涂(APS)TBC系统的实例进行了逐步老化的研究。与TGO和/或TBC有关的开裂和剥离已经在热成像显示不同加热的地方被观察到。
Abstract For a number of years piezospectroscopy (Cr fluorescence) has been used to monitor the stress levels in the thermally grown oxide (TGO) that forms between the bondcoat and the thermal barrier coating (TBC) in TBC systems. The purpose of that work has been to observe early signs of failure and thus allow operators to schedule service intervals before failure of the TBC system occurred. This paper reports the use of thermography as an additional tool that can be used to assess the “health” of TBC systems. The technique consists of imaging the surface of the TBC coated specimen with a high spatial resolution infra-red camera while the specimen is heated, and monitoring the temperature of the outer surface of the TBC. Conductive heating through the substrate and radiative heating incident on the TBC have been studied. Early results are encouraging, revealing a clear correlation between thermograms obtained using the conductive and radiative forms of heating, some of the stress maps obtained using piezospectroscopy and direct metallographic evidence. Examples of electron beam physical vapour deposited (EB PVD) and air plasma sprayed (APS) TBC systems have been studied as they were progressively aged. Cracking and disbonding associated with the TGO and/or TBC have been observed in places where thermography showed differential heating.