Abstract
Thermal barrier coatings have been widely used in gas turbine engines in order to protect the substrate metal alloy against high temperature and to enhance turbine efficiency. To monitor thermal barrier coating (TBC) integrity over its lifetime, the detection of top coat (TC) and thermally grown oxide (TGO) thicknesses was carried out using a microwave non-destructive technique. The results showed a good resolution of 1° change in phase for 15 μm TC thickness when a rectangular waveguide operating at relatively high frequency was applied. The phase of the reflection coefficient at the interface of TC and waveguide varies for different TGO and TC thicknesses. Therefore, measuring the phase of the reflection coefficient enables us to accurately calculate these thicknesses. Finally, a theoretical analysis was used to evaluate the reliability of the experimental results.
Original language | English |
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Pages (from-to) | 398-403 |
Number of pages | 6 |
Journal | NDT and E International |
Volume | 42 |
Issue number | 5 |
DOIs | |
Publication status | Published - 2009 Jul 1 |
Keywords
- Microwave NDE
- Thermal barrier coating
- Thermally grown oxide
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering