Nondestructive Thickness Measurement of Thermal Barrier Coatings for Turbine Blades by Terahertz Time Domain Spectroscopy

Liu, Longhai1,2; Yu, Haiyuan3; Zheng, Chenglong1; Ye, Dongdong4; He, Wei5; Wang, Silei1; Li, Jining1; Wu, Liang1; Zhang, Yating1; Xie, Jianhua2; Yao, Jianquan1,6

2023-02-01

10.3390/photonics10020105

PHOTONICS   Impact Factor & Quartile

2304-6732

Owing to its high penetrability with dielectric materials, terahertz time domain spectroscopy (THz-TDS) is a promising nondestructive measurement technology. The coating thickness deviation and defect of thermal barrier coatings (TBC) will affect its thermal insulation performance and lifetime. In this work, THz-TDS was applied to measure the coating thickness distribution of TBC. The refractive index was obtained by THz-TDS transmission mode. To avoid the normal incidence THz signal loss, the THz signal was reflected from the TBC with a 10 degrees incident angle, which also made the measurement result insensitive to the unevenness and tilt of the TBC sample. In the experiment, the yttria-stabilized zirconia (YSZ) TBC was measured by THz-TDS to estimate the thickness distribution. To validate the thickness measurements, metallography was introduced to correlate the TBC thickness result. The measurement deviation was within 12.1 mu m, i.e., 3.45% for the THz-TDS and metallography result. A piece of turbine blade was measured by THz-TDS and a eddy current test. The maximum deviation was 8.48 mu m, i.e., 2.36% of these two methods. Unlike the eddy current test, the THz-TDS thickness result was not affected by the cooling holes. The effectiveness of the nondestructive thickness measurement of TBC for turbine blades by THz-TDS was verified.

terahertz time domain spectroscopy nondestructive measurement thermal barrier coatings turbine blades yttria-stabilized zirconia

SCI

English

Corresponding

National Key Research and Development Program of China[2017YFA0700202] ; National Natural Science Foundation of China["61735010","52205547"] ; Basic Research Program of Shenzhen[JCYJ20170412154447469] ; Key Research and Development Projects in Anhui Province[2022a05020004]

Optics

Optics

WOS:000940121500001

MDPI

Web of Science

1.Tianjin Univ, Sch Precis Instruments & Opto Elect Engn, Key Lab Opto Elect Informat Technol, Minist Educ, Tianjin 300072, Peoples R China
2.Advantest China Co Ltd, Shanghai 201203, Peoples R China
3.Beijing Beiye Funct Mat Co Ltd, Mat Res Inst, Beijing 100192, Peoples R China
4.Anhui Polytech Univ, Sch Artificial Intelligence, Wuhu 241000, Peoples R China
5.Sci & Technol Electromagnet Scattering Lab, Beijing 100854, Peoples R China
6.Southern Univ Sci & Technol, Dept Elect & Elect Engn, Shenzhen 518055, Peoples R China

Liu, Longhai,Yu, Haiyuan,Zheng, Chenglong,et al. Nondestructive Thickness Measurement of Thermal Barrier Coatings for Turbine Blades by Terahertz Time Domain Spectroscopy[J]. PHOTONICS,2023,10(2).

Liu, Longhai.,Yu, Haiyuan.,Zheng, Chenglong.,Ye, Dongdong.,He, Wei.,...&Yao, Jianquan.(2023).Nondestructive Thickness Measurement of Thermal Barrier Coatings for Turbine Blades by Terahertz Time Domain Spectroscopy.PHOTONICS,10(2).

Liu, Longhai,et al."Nondestructive Thickness Measurement of Thermal Barrier Coatings for Turbine Blades by Terahertz Time Domain Spectroscopy".PHOTONICS 10.2(2023).