PVD thermal barrier coating applications and process development for aircraft engines

Abstract

Thermal barrier coatings (TBCs) have been developed for application to aircraft engine components to improve service life in an increasingly hostile thermal environment. The choice of TBC type is related to the component, intended use, and economics. Selection of electron beam physical vapor deposition processing for turbine blade is due in part to part size, surface finish requirements, thickness control needs, and hole closure issues. Process development ofPVD TBCs has been carried out at several different sites, including GE Aircraft Engines (GEAE). The influence of processing variables on microstructure is discussed, along with the GEAE development coater and initial experiences of pilot line operation.

Modelling the high temperature behaviour of TBCs using sequentially coupled microstructural–mechanical FE analyses

“…TBCs are composed of a ceramic top coat (TC) of ∼100-200 µm thickness of partially stabilized zirco-5 nia, i.e. ZrO 2 -7 wt% Y 2 O 3 (PSZ) applied using either the atmospheric plasma spraying (APS) technique [1,2] or the electron-beam physical vapour deposition (EB-PVD) [2,3] technique; the TC acts as the thermal insulator. A thermally grown oxide (TGO) of ∼1-10 µm composed mainly of alumina develops underneath the TC.…”

Development of Sintered MCrAlY Alloys for Aeronautical Applications

“…Thermal barrier coatings (TBCs) are widely used in turbines for propulsion and power generation (Bose & DeMasi-Marcin ,1995;Choi et al, 1998;Cruse et al 1988;DeMasi-Marcin & Gupta, 1994;DeMasi-Marcin et al, 1990;Eaton & Novak, 1987;Golightly et al, 1976;Hillery, 1996;Lee & Sisson, 1994;Mariochocchi et al, 1995;Meier et al ,1991Miller, 1984;Kingery et al, 1976;Rigney et al, 1995;Strangman, 1985;Stiger et al, 199;, & Evans, 1999. They comprise thermally insulating materials having sufficient thickness and durability that they can sustain an appreciable temperature difference between the load bearing alloy and the coating surface.…”

“…Two methods are used to deposit strain tolerant TBCs. Electron beam physical vapor deposition (EB-PVD) evaporates the oxide from an ingot and directs the vapor onto the preheated component (Hillery, 1996;Mariochocchi et al, 1995;Rigney et al 1995). The deposition conditions are designed to create a columnar grain structure with multiscale porosity (Fig.…”

Diffusion barrier behaviors of (Ru,Ni)Al/NiAl coatings on Ni-based superalloy substrate

“…Today, MCrAlY (M: Ni, Co) or the B2 intermetallic NiAl (simple or Pt-modified) coatings have been extensively used as high temperature protective coatings or as the bond coats of thermal barrier coatings (TBCs) in hot components of turbine engines [1,2]. Interdiffusion between the metallic coatings and superalloy substrate has become a serious problem.…”