Microstructures of Y 2 O 3 ‐Stabilized ZrO 2 Electron Beam‐Physical Vapor Deposition Coatings on Ni‐Base Superalloys

The microstructures of ZrO 2 –20 wt% Y 2 O 3 thermal barrier coatings formed by electron beam‐physical vapor deposition on a Nibase superalloy have been studied by transmission electron microscopy. The coating systems consist of several layers, including a superalloy substrate, a bond coat, an Al 2 O 3 scale, and the PVD coating. The overall ceramic thermal barrier coatings were characterized, with special emphasis being given to the α‐Al 2 O 3 scale which forms between the bond coat and the ZrO 2− Y 2 O 3 coating. The oxide scale exhibited various morphologies in different coating systems; the majority of the porosity formed in this region for all coatings.