Microstructure of Thermal Barrier Coatings Deposited by Low Pressure Plasma Spraying and Chemical Vapour Deposition Methods on Rene 80 Nickel Superalloy

摘要

The paper presents microstructural characterization of a thermal barrier coating deposited in a double-step process. Bondcoat was obtained by overaluminizing of the MeCrAlY coating deposited by Low Pressure Plasma Spraying (LPPS). The outer ceramic layer of yttria stabilized Zirconia (Metco 6700) was deposited by Plasma Spray Physical Vapour Deposition (PS-PVD). For comparison purposes the LPPS-sprayed MeCrAlY bondcoats without aluminizing were analyzed as well. The Rene 80 nickel superalloy was used as a substrate. The research showed that overaluminizing by CVD enables formation of β-NiAl phase, which protects against oxidation. High chromium amount in this coating can increase hot corrosion resistance. The outer ceramic layer had columnar structure similar to the one deposited by EB-PVD method.