Evaluation of Titanium Nitride-Modified Bondcoat System Used in Thermal Barrier Coating in Corrosive Salts Environment at High Temperature

摘要

Thermal barrier coating (TBC) systems were produced by air plasma spraying system on nickel base superalloy. These coatings were composed of a Y2O3-stabilized ZrO2 topcoat and a CoNiCrAlY bondcoat and are known as standard TBC. In this paper, standard TBC samples were compared with TiN-modified bondcoat TBC samples. Titanium nitride was deposited by utilizing a physical vapor deposition technique. Both TBC systems were exposed to high temperature in the presence of corrosive salts, i.e. a mixture of V2O5 and Na2SO4 (50:50) for 50 h. It was observed that the TiN-modified samples showed better results in terms of oxidation resistance and delamination. The formation of Cr2Ti O-n-2(2n-1) phases at the interface of the topcoat-bondcoat, in TiN-modified samples were found to enhance the thermal and oxidation properties of the TBC.