Investigation of Hot Section (Nozzle Guiding Vane) Distress due to Interaction of Thermal Barrier Coatings with CMAS

An investigation of distress of hot section nozzle guiding vane (NGV) was carried out. Thermal barrier coatings (TBCs) were applied to the components of gas turbine engines to operate at higher temperatures i.e. up to 1200°C. The cause of failure was hot corrosion of TBCs by chemical entities from atmosphere like oxides of Al, Ca, Si and Mg (CMAS). Source of CMAS was dust, which was ingested to airfoil engine components. Different techniques like scanning electron microscope, boroscopy, optical microscopy, X-ray Diffraction and optical emission spectroscopy were utilized to investigate the failure of nozzle guiding vanes.