Structural characterisation of thermal barrier coatings deposited using electrostatic spray assisted vapour deposition method

Gas turbine engines provide one of the harshest environments for engineerin g components today. Thermal barrier coatings (TBCs) such as 8wt.% Y2O3-ZrO2 (YSZ) are able to protect the blades and can lead to further increases in operating temperature by providing an effective thermal barrier on the blad es. YSZ coatings were deposited using a novel and cost-effective electrosta tic spray-assisted vapour deposition (ESAVD) technique. This method involve s spraying atomised precursor droplets across an electric field, where they undergo decomposition and/or chemical reactions in the vapour phase near t he vicinity of the heated substrate. A solution containing zirconium and yt trium alkoxide precursors was used for the deposition of YSZ films. The coa tings were characterised using a combination of scanning electron microscop y, X-ray diffraction (XRD) and Raman spectroscopy. Thick and uniform YSZ fi lms with columnar growth features were successfully deposited using the ESA VD method. The Raman investigations showed the presence of carbon in the as -deposited coatings. However, the carbon was removed when the YSZ coating w as heat-treated at 1000 degrees C for 2 h to improve the adhesion of the TB C coating to the bond coat. (C) 2000 Elsevier Science S.A. All rights reser ved.