THERMAL CYCLES RESISTANCE BEHAVIOR OF ZIRCONIA APS COATINGS IN BURNER RIG AND FURNACE CYCLIC OXIDATION TESTS

摘要

Thermal barrier coatings, usually called TBC, is one of the technologies developed for components exposed to high temperatures. The degradation of these coatings are induced by thermal cycling and mechanical stresses. This type of failure is caused by mechanical stresses induced by thermal cycles and oxidation of the bond coat and the consequent growth of thermal growth oxide, TGO. The main objective of this paper is describe the development of the degradation of TBC submitted a burner rig and furnace cyclic oxidation tests. Porosity reduction was observed in APS coatings, especially on top surface, and a horizontal cracks formation with burner rig cycles. Otherwise, in samples tested in furnace cyclic oxidation, TGO thickness increase was more pronounced. Furnace cyclic oxidation promotes a better analysis of TGO formation, while burner rig tests promotes a better knowledge of cracks formation during cyclic tests