One of the major problems facing the users of aircraft engines and stationary gas turbines in dusty and dirty environments is erosion, causing engine performance deterioration. Thermal barrier coatings (TBCs) are often applied on metal engine components as combustor heat shields or tiles as well as turbine blades allowing enhanced operating temperatures and resulting in increased thermal efficiency of the turbine and also reduced fuel consumption and gaseous emission. Erosive attack by airborne dust or fly ash, coarse particles causes coating degradation resulting in lifing issues of engine components. In the present study an erosion test facility was used to simulate the mechanisms of coating degradation expected in gas turbines in a more realistic way closer to real engine conditions. A loading situation combining thermal gradient cycling and erosive media was used. The experiments has been performed with an arc heated plasma wind tunnel (total enthalpy up to 20 MJ/kg), which is available at the Institute for Thermodynamics at the University of the Federal Armed Forces in Munich, Germany. The experimental setup and the integration of the air jet erosion test rig into the existing plasma wind tunnel will be elucidated. Different plasma sprayed thermal barrier coating materials, including the standard TBC material yttria-stabilised zirconia, were investigated regarding their erosion resistance. For validation and verification, samples of nickel-based Mar-M 247 and INCO 718 alloys have been used.
Potential use of quasicrystalline materials as thermal barrier coatings for diesel engine components
