Remaining Fatigue Life Assessment of Plasma Sprayed Thermal Barrier Coatings

Abstract

International audienceCeramic functional coatings are frequently applied to structural materials, covering a wide range of thermomechanical and electrochemical applications. The main limiting feature is their reliability when subjected to cyclic transient thermal stresses. The study described in this article is a continuation of earlier research study focused on acoustic emission (AE) monitoring of the thermomechanical aging effects in ceramic coatings. Here, emphasis is placed on the usefulness of combining AE short-term monitoring with finite element modeling (FEM) to predict the performance of such coatings when subjected to cyclic thermal loads. The FEM study presented in this article is based on a three-dimensional, time-dependent approach, of the stress fields that developed within the coatings during the postdeposition cooling step and the thermal cycling. Experiments were conducted using yttrium-stabilized zirconia (YSZ) and Alumina (Al2O3) ceramic coatings combined with a NiCr-based intermetallic bond coat

Preparation of 8YSZ and Double-Ceramic-Layer La₂Zr₂O₇/8YSZ Thermal Barrier Coatings on GH4169 Superalloy Substrates and their Static High Temperature Oxidation Behaviour

“…The high degree of brittleness combined with low thermal expansion and thermal conductivity renders TBCs highly susceptible to the generation of thermal stresses with high magnitude. The life evolution and prediction are often based on the calculation of the distribution and evolution of the thermal stress in the TBCs [7][8][9][10]. Usually, there are two ways to fabricate the TBCs, i.e.…”