Oxidation behavior of thermal barrier coatings with HVOF and detonation-sprayed NiCrAlY bondcoats

The high-velocity oxygen-fuel (HVOF) technology was employed to deposit the bondcoat of a thermal barrier coating (TBC) system. The isothermal oxidation rate at 1100 degrees C of the TBC system with the HVOF bondcoat is two times lower than that of the TBC system with the detonation-sprayed bondcoat. The better isothermal oxidation resistance of the TBCs with HVOF sprayed bondcoats demonstrates that unlike alumina dispersoids in the HVOF sprayed bondcoat, rough surface of the detonation-sprayed bondcoat is undesirable for the detonation-sprayed TBC system concerning oxidation due to a large specific surface area and unfavorable oxides on the bondcoat. (C) 2008 Elsevier Ltd. All rights reserved.