|
| Abstract No.: |
|
Scheduled at:
|
Friday, June 09, 2017, Hall 12 2:20 PM
Aviation & Power Generation Industry VI
|
|
| Title: |
The behavior of modified overlay Sol-Gel Al2O3 layer on TBC System
|
|
| Authors: |
Hesham Abdeldaim* / Ain Shams University, Egypt
Nahed Elmahallawy / Faculty of engineering, Ain shams university, Egypt
|
|
| Abstract: |
Surface engineering plays an essential role in enhancing the performance of high pressure turbines, which work under the most severe conditions of temperature and mechanical loading. Thermal Barrier Coating (TBC) systems are economically demanded for efficient and environmental friendly gas turbine engines. In recent study, an intermediate ±-Al2O3 layer was deposited by sol-gel on the raw surface of APS-CoNiCrAlY bond coat, which was deposited on superalloy substrate. The YSZ ceramic top coat was deposited on the top of Al2O3 layer by APS. The new TBC system was compared with the standard TBC system concerning the behavior under thermal cycling. The samples were investigated by optical microscopy, Scanning Electron Microscopy (SEM) equipped by Energy Dispersive X-ray analysis (EDS), X-ray Diffraction (XRD) and Raman spectroscopy. The effect of the intermediate layer on the residual stresses was studied. The crack length within the ceramic layer and the average thickness of Thermally Grown Oxide (TGO) layer were measured using image analysis software. The Experimental evidence was gathered showing that the presence of sol-gel overlay Al2O3 layer has the potential to reduce the crack length and TGO thickness by suppressing the formation of detrimental oxides. The Al2O3 layer acts as a barrier to diffusion of oxygen. This effect improves the oxidation resistance metallic CoNiCrAlY Bond and promotes the adhesion between bond and top coat, hence increases the TBC life.
|
|