Production and characterization of Al2O3/CYSZ functionally graded thermal barrier coatings

Thermal barrier coatings (TBCs) are used for the purpose of protection metallic substrate, provide thermal insulation and increase the efficiency of combustor, turbine blades and vanes of aircraft and industrial engines. The ceramic coat in TBC systems supplies reduce in temperature influencing metal substrate surface. In addition, bond coat (MCrAlY) which is another component of TBC decreases coefficient of thermal elongation (CTE) mismatch between substrate and ceramic coat. In this study, one layered CYSZ, two-layered CYSZ / Al2O3 and 4, 8, 12 layered functionally graded (FG) thermal barrier coatings were produced as a ceramic topcoat material. The bond coat were applied by HVOF (High Velocity Oxygen Fuel) process on the substrate material. APS (Atmospheric Plasma Spraying) process was used to produce ceramic topcoat. Microstructure characterization, thermal conductivity measurement, thermal cycle failure test, adhesive strength test were fulfilled.