Non-destructive thickness measurement of thermal barrier coatings using terahertz radiation
Non-destructive thickness measurement of thermal barrier coatings using terahertz radiation
复制标题
热障涂层厚度的太赫兹辐射无损测量
DOI：
10.1007/s42247-021-00275-6
复制
发表时间：
2021-08-06
影响因子：
3.8
通讯作者：
Nicholls, John R.
中科院分区：
文献类型：
--
作者：
Isern, Luis;Waddie, Andrew J.;Nicholls, John R.
基于太赫兹（THz）反射率的非破坏性厚度测量技术被成功地部署以询问7 wt.%通过电子束物理气相沉积（EB-PVD）生产的氧化钇稳定的氧化锆热障涂层（TBC）。THz技术被证明可以在65 x 20 mm的表面上以1 x 1 mm的分辨率为不同样品产生准确的厚度图，并与直接检查关键横截面进行比较。不同样品的所有厚度测量值均使用单一折射率值计算。EB-PVD的小缺陷特性，如“胡萝卜生长”和柱倾斜的变化，进行了评估，并没有产生显着的变化，在TBC的折射率。此外，厚度图正确显示了EB-PVD蒸发的点源性质导致的厚度变化。总之，本文证明了该技术可以成功地部署在大表面上，并在相同沉积条件下生产的相同材料的不同涂层上。结果表明，一个单一的n值是需要映射的厚度分布的所有样品。这种品质的组合表明了该技术用于TBC制造的在线控制的潜力。
A non-destructive thickness measurement technique based on terahertz (THz) reflectivity was successfully deployed to interrogate 7 wt.% yttria-stabilised zirconia thermal barrier coatings (TBCs) produced by electron-beam physical vapour deposition (EB-PVD). The THz technique was shown to produce accurate thickness maps for different samples with a resolution of 1 x 1 mm over a surface of 65 x 20 mm that were compared with direct examination of key cross-sections. All thickness measurements on different samples were calculated using a single value of refractive index. Small defects characteristic of EB-PVD, such as "carrot growths" and variations on column inclination, were evaluated and did not produce significant variations in the refractive index of the TBC. Moreover, the thickness maps correctly display thickness variations that are a consequence of the point-source nature of EB-PVD evaporation. In summary, this paper demonstrates the technique can be successfully deployed on large surfaces, and across different coatings of the same material produced under the same deposition conditions. It is shown that a single n value is required to map the thickness distribution for all samples. This combination of qualities indicates the potential of the technique for in-line control of TBC manufacture.