Graded thermal barrier coatings, deposited by EB-PVD

Variants of graded thermal barrier coating (TBC) are given, which consist of bond coats of NiAl or MCrAlY+NiAl and YSZ-based outer ceramic layer, produced in a one-step cycle by evaporation of a composite ingot. A design of the composite ceramic ingot is considered, as well as the ability to regulate in a broad range the composition and structure of the bond coats, outer ceramic layer, as well as the transition barrier zones of the substrate/bond coat and bond coat/outer ceramic layer. Distributions of chemical elements in the coating/substrate system and microstructure after deposition and after heat treatment are shown. Results are given of furnace thermal cycling tests of various types of graded TBC at 1150 °C. Design of a new generation of electron beam units for deposition of the above coatings and cost-effectiveness of the one-step deposition process are described.