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In-depth and in-plane diffusivity measurement of Thermal Barrier Coating by IR camera: evaluation of ageing.

pubblicazioni - Articolo

In-depth and in-plane diffusivity measurement of Thermal Barrier Coating by IR camera: evaluation of ageing.

Recently updated on Maggio 11th, 2021 at 08:33 am

Barrier Coatings by IR Camera: Evaluation of Ageing Rivista: Int J Thermophys DOI 10.1007/s10765-008-0421-1- Springer 9 Aprile 2008 Federico Cernuschi*, Paolo Giulio Bison**, Ermanno Grinzato** * CESI RICERCA ** CNR ITC PADOVA Ceramic thermal barrier coatings (TBCs) are widely used for protect-ing hot path components from combustion gases in gas turbines for both aero-and land-based applications. TBCs undergo degradation and eventually detach from the substrate. Forecasting of the detachment of TBCs for timely maintenance is an open problem in gas turbine technology. It is known that sintering happens in the TBCs when exposed to high temperature. Sintering affects the mechanical properties of TBCs and mainly their strain compliance for which degradation causes the detach-ment. As sintering strongly affects the termal diffusivity of TBCs also, the idea is to measure the latter parameter to account for the former. Pulsed thermography is the technique selected to monitor the thermal diffusivity variation due to TBC ageing. In perspective, it should be applied to monitor the gas turbine during the normal stop for maintenance. This article reports preliminary laboratory tests carried out on a set of metal samples coated with TBCs. The samples were aged during cyclic oxidation tests at various percentages of the irestimated life, the end of life being the time of the TBC detachment from the substrate. The identification of the thermal diffusivity in the coating layer is carried out for the general case of anisotropic conductivity. Keywords Thermal diffusivity measurement·Thermal barrier coating·Thermography

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