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Thermal barrier coatings (TBCs) are used in high temperature applications to extend lifetime of metallic components. Especially, aircraft components such as turbine blades or vanes coated with TBCs [1]. In operating conditions, these components exposed to oxidation and corrosion. Thus, TBCs have limited lifetime in high temperature conditions. To determine the lifetime of TBCs, there are a few methods such as furnace thermal cyclic test, burner-rig test or jet engine thermal shock test [2]. Under high temperature conditions, oxygen diffuses from top coat to bond coat and, thermally grown oxide (TGO) layer form at the interface. This layer leads to high stress due to thermal expansion mismatch between bond and top coat. In figure 1, there is an example image taken at the end of furnace cyclic test for a tbc system. For this reason, TBCs are usually spalled from the TGO layer [3]. In this study, thermal cycling tests will be explained with experimental data.

International Symposium on Light Alloys and Composite Materials
UHAKS

Kadir Mert DOLEKER Yasin OZGURLUK Hayrettin Ahlatçı Abdullah Cahit KARAOGLANLI

Thermal barrier coatings (TBCs) are generally used as a protective coating in gas turbine engine components in aerospace and aircraft industry [1]. Especially, TBCs applications used critical region parts exposed to high temperatures such as oxidation, hot-corrosion, thermal shock failures and CMAS (calcia–magnesia–alumina–silica) attack [2]. Volcanic ash degradation of TBC is a serious problem for many high temperature applications in aggressive environment such as turbine blades and vanes in gas turbines [3]. Impurities arising from the desert and volcanic environment dusts such as calcia–magnesia–alumina–silica (CMAS) formations cause degradation during the service conditions [4]. In this study, the effect of volcanic ash based failures were investigated and discussed in TBC systems.

International Symposium on Light Alloys and Composite Materials
UHAKS

Yasin OZGURLUK Kadir Mert DOLEKER Hayrettin Ahlatçı Abdullah Cahit KARAOGLANLI