Sputtered ceramic coatings and sealing layers. [Hybrid CoCrAlY/ZrO/sub 2/-20Y/sub 2/O/sub 3/]

Progress on the development of hybrid ceramic/metal sputter deposited coatings which are designed to be adherent to metal substrates in gas turbine hot sections is reported. The ceramic materials investigated are ZrO/sub 2/ + 20% Y/sub 2/O/sub 3/ and pure Al/sub 2/O/sub 3/. The metal is CoCrAlY. In general, a CoCrAlY layer is sputter deposited first. The composition is then graded so that the ceramic content increases towards the coating surface. This transition zone has a segmented (columnar) structure, and varies in thickness. In some cases, the coating surface still contained some CoCrAlY. Heat treatments have been conducted on these deposits in an effort to provide a continuous metal (minority phase) matrix along the ceramic grain boundaries. For other deposits, the grading is continued until no metal is present, and a thick layer of pure ceramic has been deposited over the graded material. Preliminary thermal cycle results, microstructural characterization, and composition profile data are presented.