Experimental Investigation of Oxidation Rate of Thermal Barrier Coating for a Gas Turbine Combustion Chamber

Materials used in gas turbines must be capable of operating in hot gas environments. Only an appropriate coating system can supply protection for hot section components. The demands for increasing engine performance in higher operating temperatures, extended component life, and lower emissions continued to provide the driving force for the development of thermal barrier coating technology. The present research studies the oxidation behavior of the TBC system deposited on the combustion chamber of a gas turbine. This paper focuses on the TGO scale oxidation kinetic which its results are necessary for the life assessment model. TBC, including approximately 0.35 mm yttria partially stabilized zirconia top coat (YSZ) and about 0.2 mm NiCoCrAlY bond coat, is deposited by air plasma spraying (APS). Then TGO growth rate of the coatings is evaluated as a function of time and temperature under isothermal oxidation condition at 900°C and 1150°C up to 1000h. Thickness and phase analysis of the coating and TGO are investigated by optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).