Terahertz optical thickness and birefringence measurement for thermal barrier coating defect location.
Terahertz optical thickness and birefringence measurement for thermal barrier coating defect location.
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DOI：
10.1364/oe.398532
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发表时间：
2020-10
期刊：
影响因子：
3.8
通讯作者：
A. Waddie;Peter J. Schemmel;C. Chalk;L. Isern;J. Nicholls;A. Moore
中科院分区：
文献类型：
--
作者：
A. Waddie;Peter J. Schemmel;C. Chalk;L. Isern;J. Nicholls;A. Moore
提出了一种正入射太赫兹反射率技术来确定氧化钇稳定的氧化锆（YSZ）热障涂层（TBC）的光学厚度和双折射。该方法的初步验证是通过测量一组已知厚度的熔融石英校准样品来实现的，并且与文献显示出极好的一致性（<1%的折射率）。太赫兹测量的光学厚度和它的变化，通过YSZ涂层的深度剖面显示出良好的协议（<4%）与扫描电子显微镜横截面厚度测量。此外，光学厚度和双折射中不连续性的位置似乎与加速老化试验期间观察到的涂层失效点相关。
We present a normal incidence terahertz reflectivity technique to determine the optical thickness and birefringence of yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBCs). Initial verification of the method was achieved by measurement of a set of fused silica calibration samples with known thicknesses and showed excellent agreement (<1% of refractive index) with the literature. The THz-measured optical thickness and its variation through the depth profile of the YSZ coating are shown to be in good agreement (<4%) with scanning electron microscope cross-sectional thickness measurements. In addition, the position of discontinuities in both the optical thickness and birefringence appear to be correlated to coating failure points observed during accelerated aging trials.