Thickness evaluation of thermally sprayed coatings after exposure to boiler tube environments by eddy current testing

Subtitle:

Article type: Research Article

Authors: Uchimoto, Tetsuya^{a; *} | Takagi, Toshiyuki^a | Takahashi, Yohei^a | Naganuma, Hiroshi^b | Sugawara, Kazufumi^b | Sasaki, Yoriaki^b | Douillard, Thierry^c | Masenelli-Varlot, Karine^c | Courbon, Jöel^c

Affiliations: [a] Institute of Fluid Science, Tohoku University, Katahira, Aoba, Sendai, Miyagi, Japan | [b] Technical Research and Development Section, Engineering Department, Tohoku Electric Power Engineering and Construction Co Inc, Miyagi, Japan | [c] Université de Lyon, INSA-Lyon, MATEIS, CNRS UMR, Villeurbanne, France

Correspondence: [*] Corresponding author: Tetsuya Uchimoto, Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi 980-8577, Japan. Tel./Fax: +81 022-217-5262; E-mail:uchimoto@ifs.tohoku.ac.jp

Abstract: This paper discusses the feasibility of determining the thickness of Ni-based alloy sprayed coatings that have been heated in plant environments using swept frequency eddy current testing based on the measurement of the impedance spectrum of the measurement coil. Through a comparison of the experimental and computed signals, an electromagnetic model simulating the test geometry including the coating and the substrate is presented, with particular focus on the effects of heat treatment. Using these models, the coating thickness is estimated using the measured impedance spectra, and the estimation error was found to be around 30 μ m.

Keywords: Thermally sprayed coating, coating thickness, swept frequency eddy current testing, boiler tube environment

DOI: 10.3233/JAE-140050

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 4, pp. 993-1001, 2015